Smart Note Taker

Definition

The Smart NoteTaker is such a helpful product that satisfies the needs of the people in today's technologic and fast life. This product can be used in many ways. The Smart NoteTaker provides taking fast and easy notes to people who are busy one's self with something. With the help of Smart NoteTaker, people will be able to write notes on the air, while being busy with their work. The written note will be stored on the memory chip of the pen, and will be able to read in digital medium after the job has done. This will save time and facilitate life.

The Smart NoteTaker is good and helpful for blinds that think and write freely. Another place, where our product can play an important role, is where two people talks on the phone. The subscribers are apart from each other while their talk, and they may want to use figures or texts to understand themselves better. It's also useful especially for instructors in presentations. The instructors may not want to present the lecture in front of the board. The drawn figure can be processed and directly sent to the server computer in the room. The server computer then can broadcast the drawn shape through network to all of the computers which are present in the room. By this way, the lectures are aimed to be more efficient and fun. This product will be simple but powerful. The product will be able to sense 3D shapes and motions that user tries to draw. The sensed information will be processed and transferred to the memory chip and then will be monitored on the display device. The drawn shape then can be broadcasted to the network or sent to a mobile device.

There will be an additional feature of the product which will monitor the notes, which were taken before, on the application program used in the computer. This application program can be a word document or an image file. Then, the sensed figures that were drawn onto the air will be recognized and by the help of the software program we will write, the desired character will be printed in the word document. If the application program is a paint related program, then the most similar shape will be chosen by the program and then will be printed on the screen.

Since, JAVA Applet is suitable for both the drawings and strings, all these applications can be put together by developing a single JAVA program. The JAVA code that we will develop will also be installed on the pen so that the processor inside the pen will type and draw the desired shape or text on the display panel.

Synthetic Aperture Radar System


Introduction


When a disaster occurs it is very important to grasp the situation as soon as possible. But it is very difficult to get the information from the ground because there are a lot of things which prevent us from getting such important data such as clouds and volcanic eruptions. While using an optical sensor, large amount of data is shut out by such barriers. In such cases, Synthetic Aperture Radar or SAR is a very useful means to collect data even if the observation area is covered with obstacles or an observation is made at night at night time because SAR uses microwaves and these are radiated by the sensor itself. The SAR sensor can be installed in some satellite and the surface of the earth can be observed.

To support the scientific applications utilizing space-borne imaging radar systems, a set of radar technologies have been developed which can dramatically lower the weight, volume, power and data rates of the radar systems. These smaller and lighter SAR systems can be readily accommodated in small spacecraft and launch vehicles enabling significantly reduced total mission cost.

Specific areas of radar technology development include the antenna, RF electronics, digital electronics and data processing. A radar technology development plan is recommended to develop and demonstrate these technologies and integrate them into the radar missions in a timely manner. It is envisioned that these technology advances can revolutionize the approach to SAR missions leading to higher performance systems at significantly reduced mission costs.

The SAR systems are placed on satellites for the imaging process. Microwave satellites register images in the microwave region of the electromagnetic spectrum. Two mode of microwave sensors exit- the active and the passive modes. SAR is an active sensor which carry on -board an instrument that sends a microwave pulse to the surface of the earth and register the reflections from the surface of the earth.

One way of collecting images from the space under darkness or closed cover is to install the SAR on a satellite . As the satellite moves along its orbit, the SAR looks out sideways from the direction of travel, acquiring and storing the radar echoes which return from a strip of earth's surface that was under observation.

The raw data collected by SAR are severely unfocussed and considerable processing is required to generate a focused image. The processing has traditionally been done on ground and a downlink with a high data rate is required. This is a time consuming process as well. The high data rate of the downlink can be reduced by using a SAR instrument with on-board processing.

X-Band SAR Instrument Demonstrator

The X-band SAR instrument demonstrator forms the standardized part or basis for a future Synthetic Aperture Radar (SAR) instrument with active front- end. SAR is an active sensor. Active sensors carry on-board an instrument that sends a microwave pulse to the surface of the earth and register the reflections from the surface of the earth. Different sensor use different bands in the microwave regions of the electromagnetic spectrum for collecting data. In the X-band SAR instrument, the X-band is used for collecting data.

Touch Screens

Introduction


A type of display screen that has a touch-sensitive transparent panel covering the screen. Instead of using a pointing device such as a mouse or light pen, you can use your finger to point directly to objects on the screen.
Although touch screens provide a natural interface for computer novices, they are unsatisfactory for most applications because the finger is such a relatively large object. It is impossible to point accurately to small areas of the screen. In addition, most users find touch screens tiring to the arms after long use.


Touch-screens are typically found on larger displays, in phones with integrated PDA features. Most are designed to work with either your finger or a special stylus. Tapping a specific point on the display will activate the virtual button or feature displayed at that location on the display.Some phones with this feature can also recognize handwriting written on the screen using a stylus, as a way to quickly input lengthy or complex information


A touchscreen is an input device that allows users to operate a PC by simply touching the display screen. Touch input is suitable for a wide variety of computing applications. A touchscreen can be used with most PC systems as easily as other input devices such as track balls or touch pads. Browse the links below to learn more about touch input technology and how it can work for you.

History Of Touch Screen Technology
A touch screen is a special type of visual display unit with a screen which is sensitive to pressure or touching. The screen can detect the position of the point of touch. The design of touch screens is best for inputting simple choices and the choices are programmable. The device is very user-friendly since it 'talks' with the user when the user is picking up choices on the screen.


Touch technology turns a CRT, flat panel display or flat surface into a dynamic data entry device that replaces both the keyboard and mouse. In addition to eliminating these separate data entry devices, touch offers an "intuitive" interface. In public kiosks, for example, users receive no more instruction than 'touch your selection.
Specific areas of the screen are defined as "buttons" that the operator selects simply by touching them. One significant advantage to touch screen applications is that each screen can be customized to reflect only the valid options for each phase of an operation, greatly reducing the frustration of hunting for the right key or function.

Pen-based systems, such as the Palm Pilot® and signature capture systems, also use touch technology but are not included in this article. The essential difference is that the pressure levels are set higher for pen-based systems than for touch.Touch screens come in a wide range of options, from full color VGA and SVGA monitors designed for highly graphic Windows® or Macintosh® applications to small monochrome displays designed for keypad replacement and enhancement.

Specific figures on the growth of touch screen technology are hard to come by, but a 1995 study last year by Venture Development Corporation predicted overall growth of 17%, with at least 10% in the industrial sector.Other vendors agree that touch screen technology is becoming more popular because of its ease-of-use, proven reliability, expanded functionality, and decreasing cost.

A touch screen sensor is a clear glass panel with a touch responsive surface. The touch sensor/panel is placed over a display screen so that the responsive area of the panel covers the viewable area of the video screen. There are several different touch sensor technologies on the market today, each using a different method to detect touch input. The sensor generally has an electrical current or signal going through it and touching the screen causes a voltage or signal change. This voltage change is used to determine the location of the touch to the screen.

Tempest and Echelon


Introduction


The notion of spying is a very sensitive topic after the September 11 attack of Terrorists in New York. In the novel 1984, George Orwell foretold a future where individuals had no expectation of privacy because the state monopolized the technology of spying. Now the National security Agency Of USA developed a secret project to spy on people for keep tracing their messages to make technology enabled interception to find out the terrorist activities across the globe, named as Echelon. Leaving the technology ahead of the any traditional method of interception .

The secret project Developed by NSA (National Security Agency of USA) and its allies is tracing every single transmission even a single of keyboard. The allies of USA in this project are UK, Australia, New Zealand and Canada. Echelon is developed with the highest computing power of computers connected through the satellites all over the world. In this project the NSA left the wonderful method of Tempest and Carnivores behind.

Echelon is the technology for sniffing through the messages sent over a network or any transmission media, even it is wireless messages. Tempest is the technology for intercepting the electromagnetic waves over the air. It simply sniffs through the electromagnetic waves propagated from any devices, even it is from the monitor of a computer screen. Tempest can capture the signals through the walls of computer screens and keystrokes of key board even the computer is not connected to a network. Thus the traditional way of hacking has a little advantage in spying.
For the common people it is so hard to believe that their monitor can be reproduced from anywhere in one kilometer range without any transmission media in between the equipment and their computer. So we have to believe the technology enabled us to reproduce anything from a monitor of computer to the Hard Disks including the Memory (RAM) of a distant computer without any physical or visual contact. It is done with the Electromagnetic waves propagated from that device.

The main theory behind the Tempest(Transient Electromagnetic Pulse Emanation Standard.) is that any electronic or electrical devices emit Electromagnetic radiations of specific key when it is operated. For example the picture tube of computer monitor emits radiations when it is scanned up on vertical of horizontal range beyond the screen. It will not cause any harm to a human and it is very small. But it has a specific frequency range. You can reproduce that electromagnetic waves by tracing with the powerful equipments and the powerful filtering methods to correct the errors while transmission from the equipment. Actually this electromagnetic waves are not necessary for a human being because it not coming from a transmitter, but we have a receiver to trace the waves.

For the project named as Echelon the NSA is using supercomputers for sniffing through the packets and any messages send as the electromagnetic waves. They are using the advantage of Distributed computing for this. Firstly they will intercept the messages by the technology named as the Tempest and also with the Carnivore. Every packet is sniffed for spying for the USA's NSA for security reasons.

Computer Aided Process Planning

Introduction


Technological advances are reshaping the face of manufacturing, creating paperless manufacturing environments in which computer automated process planning (CAPP) will play a preeminent role. The two reasons for this effect are: Costs are declining, which encourages partnerships between CAD and CAPP developers and access to manufacturing data is becoming easier to accomplish in multivendor environments. This is primarily due to increasing use of LANs; IGES and the like are facilitating transfer of data from one point to another on the network; and relational databases (RDBs) and associated structured query language (SQL) allow distributed data processing and data access.
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With the introduction of computers in design and manufacturing, the process planning part needed to be automated. The shop trained people who were familiar with the details of machining and other processes were gradually retiring and these people would be unavailable in the future to do process planning. An alternative way of accomplishing this function was needed and Computer Aided Process Planning (CAPP) was the alternative. Computer aided process planning was usually considered to be a part of computer aided manufacturing. However computer aided manufacturing was a stand alone system. Infact a synergy results when CAM is combined with CAD to create a CAD/CAM. In such a system CAPP becomes the direct connection between design and manufacturing.

Moreover, the reliable knowledge based computer-aided process planning application MetCAPP software looks for the least costly plan capable of producing the design and continuously generates and evaluates the plans until it is evident that non of the remaining plans will be any better than the best one seen so far. The goal is to find a useful reliable solution to a real manufacturing problem in a safer environment. If alternate plans exist, rating including safer conditions is used to select the best plans

COMPUTER AIDED DESIGN (CAD)

A product must be defined before it can be manufactured. Computer Aided Design involves any type of design activity that makes use of the computer to develop, analyze or modify an engineering design. There are a number of fundamental reasons for implementing a computer aided design system.
a. Increase the productivity of the designer: This is accomplished by helping the designer to visualize the product and its component subassemblies and parts; and by reducing the time required in synthesizing, analyzing, and documenting the design. This productivity improvement translates not only into lower design cost but also into shorter project completion times.
b. To improve the quality of the design: A CAD system permits a more thorough engineering analysis and a larger number of design alternatives can be investigated. Design errors are also reduced through the greater accuracy provided by the system. These factors lead to a better design.
c. To improve communications: Use of a CAD system provides better engineering drawings, more standardization in the drawings, better documentation of the design, fewer drawing error, and greater legibility.
d. To create a database for manufacturing: In the process of creating a the documentation for the product design (geometries and dimensions of the product and its components, material specification for components, bill of materials etc), much of the required data base to manufacture the product is also created.

Design usually involves both creative and repetitive tasks. The repetitive tasks within design are very appropriate for computerization.

Fractal Image Compression


Introduction


The subject of this work is image compression with fractals. Today JPEG has become an industrial standard in image compression. Further researches are held in two areas, wavelet based compression and fractal image compression. The fractal scheme was introduced by Michael F Barnsley in the year 1945.His idea was that images could be compactly stored as iterated functions which led to the development of the IFS scheme which forms the basis of fractal image compression. Further work in this area was conducted by A.Jacquin, a student of Barnsley who published several papers on this subject. He was the first to publish an efficient algorithm based on local fractal system.


Fractal image compression has the following features:

" Compression has high complexity.
" Fast image decoding
" High compression ratios can be achieved.
These features enable applications such as computer encyclopedias, like the Microsoft Atlas that came with this technology. The technology is relatively new.


Overview Of Image Compression

Images are stored as pixels or picture forming elements. Each pixel requires a certain amount of computer memory to be stored on. Suppose we had to store a family album with say a hundred photos. To store this on a computer memory would require say a few thousands of dollars.

This problem can be solved by image compression. The number of pixels involved in the picture can be drastically reduced by employing image compression techniques. The human eye is insensitive to a wide variety of information loss. The redundancies in images cannot be easily detected and certain minute details in pictures can also be eliminated while storing so as to reduce the number of pixels. These can be further incorporated while reconstructing the image for minimum error. This is the basic idea behind image compression. Most of the image compression techniques are said to be lossy as they reduce the information being stored.

The present method being employed consists of storing the image by eliminating the high frequency Fourier co-efficients and storing only the low frequency coefficients. This is the principle behind the DCT transformation which forms the basis of the JPEG scheme of image compression.

Barnsley suggested that storing of images as iterated functions of parts of itself leads to efficient image compression.In the middle of the 80's this concept of IFS became popular. Barnsley and his colleagues in the Georgia University first observed the use of IFS in computerized graphics applications. They found that IFS was able to cress colour images upto 10000 times. The compression contained two phases. First the image was partitioned to segments that were self-similar as possible. Then each part was described as IFS with probabilities



Data Compression Techniques

Introduction


Data compression is the process of converting an input data stream or the source stream or the original raw data into another data stream that has a smaller size. data compression is popular because of two reasons

1) People like to accumulate data and hate to throw anything away. No matter however large a storage device may be, sooner or later it is going to overflow. Data compression seems useful because it delays this inevitability
2) People hate to wait a long time for data transfer. There are many known methods of data compression. They are based on the different ideas and are suitable for different types of data.

They produce different results, but they are all based on the same basic principle that they compress data by removing the redundancy from the original data in the source file. The idea of compression by reducing redundancy suggests the general law of data compression, which is to "assign short codes to common events and long codes to rare events". Data compression is done by changing its representation from inefficient to efficient form.


The main aim of the field of data compression is of course to develop methods for better and better compression. Experience shows that fine tuning an algorithm to squeeze out the last remaining bits of redundancy from the data gives diminishing returns. Data compression has become so important that some researches have proposed the "simplicity and power theory". Specifically it says, data compression may be interpreted as a process of removing unnecessary complexity in information and thus maximizing the simplicity while preserving as much as possible of its non redundant descriptive power.

Basic Types Of Data Compression


There are two basic types of data compression.
1. Lossy compression
2. Lossless compression

Lossy Compression
In lossy compression some information is lost during the processing, where the image data is stored into important and unimportant data. The system then discards the unimportant data
It provides much higher compression rates but there will be some loss of information compared to the original source file. The main advantage is that the loss cannot be visible to eye or it is visually lossless. Visually lossless compression is based on knowledge about colour images and human perception.

Lossless Compression
In this type of compression no information is lost during the compression and the decompression process. Here the reconstructed image is mathematically and visually identical to the original one. It achieves only about a 2:1 compression ratio. This type of compression technique looks for patterns in strings of bits and then expresses them more concisely.


VoCable


Introduction


Voice (and fax) service over cable networks is known as cable-based Internet Protocol (IP) telephony. Cable based IP telephony holds the promise of simplified and consolidated communication services provided by a single carrier at a lower cost than consumers currently to pay to separate Internet, television and telephony service providers. Cable operators have already worked through the technical challenges of providing Internet service and optimizing the existing bandwidth in their cable plants to deliver high speed Internet access. Now, cable operators have turned their efforts to the delivery of integrated Internet and voice service using that same cable spectrum.

Cable based IP telephony falls under the broad umbrella of voice over IP (VoIP), meaning that many of the challenges that telecom carriers facing cable operators are the same challenges that telecom carriers face as they work to deliver voice over ATM (VoATM) and frame-relay networks. However, ATM and frame-relay services are targeted primarily at the enterprise, a decision driven by economics and the need for service providers to recoup their initial investments in a reasonable amount of time. Cable, on the other hand, is targeted primarily at home. Unlike most businesses, the overwhelming majority of homes in the United States is passed by cable, reducing the required up-front infrastructure investment significantly.

Cable is not without competition in the consumer market, for digital subscriber line (xDSL) has emerged as the leading alternative to broadband cable. However, cable operators are well positioned to capitalize on the convergence trend if they are able to overcome the remaining technical hurdles and deliver telephony service that is comparable to the public switched telephone system.


In the case of cable TV, each television signal is given a 6-megahertz (MHz, millions of cycles per second) channel on the cable. The coaxial cable used to carry cable television can carry hundreds of megahertz of signals -- all the channels we could want to watch and more.


In a cable TV system, signals from the various channels are each given a 6-MHz slice of the cable's available bandwidth and then sent down the cable to your house. In some systems, coaxial cable is the only medium used for distributing signals. In other systems, fibre-optic cable goes from the cable company to different neighborhoods or areas. Then the fiber is terminated and the signals move onto coaxial cable for distribution to individual houses.
When a cable company offers Internet access over the cable, Internet information can use the same cables because the cable modem system puts downstream data -- data sent from the Internet to an individual computer -- into a 6-MHz channel. On the cable, the data looks just like a TV channel. So Internet downstream data takes up the same amount of cable space as any single channel of programming. Upstream data -- information sent from an individual back to the Internet -- requires even less of the cable's bandwidth, just 2 MHz, since the assumption is that most people download far more information than they upload.


Putting both upstream and downstream data on the cable television system requires two types of equipment: a cable modem on the customer end and a cable modem termination system (CMTS) at the cable provider's end. Between these two types of equipment, all the computer networking, security and management of Internet access over cable television is put into place.

Space Shuttles and its Advancements

Definition


The successful explortion of space requires a system that will reliably transport payloads into space and return back to earth; without subjecting them an uncomfortable or hazardous environment. In other words, the space crafts and its pay loads have to be recovered safely into the earth. The space shuttle used at older times were not re-usable. So NASA invented re-usable space shuttle that could launch like a rocket but deliver and land like an aeroplane. Now NASA is planning to launch a series of air-breathing planes that would replace the space shuttle.

A Brief History Of The Space Shuttle

Near the end of the Apollo space program, NASA officials were looking at the future of the American space program. At that time, the rockets used to place astronauts and equipment in outer space was one-shot disposable rockets. What they needed was a reliable, but less expensive, rocket, perhaps one that was reusable. The idea of a reusable "space shuttle" that could launch like a rocket but deliver and land like an airplane was appealing and would be a great technical achievement.

NASA began design, cost and engineering studies on a space shuttle. Many aerospace companies also explored the concepts. In 1972 NASA announced that it would develop a reusable space shuttle or space transportation programme (STS).NASA decided that the shuttle would consist of an orbiter attached to solid rocket boosters and an external fuel tank because this design was considered safer and more cost effective.

At that time, spacecraft used ablative heat shields that would burn away as the spacecraft re-entered the Earth's atmosphere. However, to be reusable, a different strategy would have to be used. The designers of the space shuttle came up with an idea to cover the space shuttle with many insulating ceramic tiles that could absorb the heat of re-entry without harming the astronauts.

Finally, after many years of construction and testing (i.e. orbiter, main engines, external fuel tank, solid rocket boosters), the shuttle was ready to fly. Four shuttles were made (Columbia, Discovery, Atlantis, Challenger). The first flight was in 1981 with the space shuttle Columbia, piloted by astronauts John Young and Robert Crippen. Columbia performed well and the other shuttles soon made several successful flights.

The space shuttle consists of the following major components:
" Two solid rocket boosters (SRB) - critical for the launch
" External fuel tank (ET) - carries fuel for the launch
" Orbiter - carries astronauts and payload

The Space Shuttle Mission

A typical shuttle mission lasts seven to eight days, but can extend to as much as 14 days depending upon the objectives of the mission.
A typical shuttle mission is as follows:
1. Getting into orbit
1.1 Launch - the shuttle lifts off the launching pad.
1.2 Ascent.
1.3 Orbital maneuvering burn.
2. Orbit-life in space.
3. Re-entry.
4. Landing.



Welding Robots


Definition


Welding technology has obtained access virtually to every branch of manufacturing; to name a few bridges, ships, rail road equipments, building constructions, boilers, pressure vessels, pipe lines, automobiles, aircrafts, launch vehicles, and nuclear power plants. Especially in India, welding technology needs constant upgrading, particularly in field of industrial and power generation boilers, high voltage generation equipment and transformers and in nuclear aero-space industry.

Computers have already entered the field of welding and the situation today is that the welding engineer who has little or no computer skills will soon be hard-pressed to meet the welding challenges of our technological times. In order for the computer solution to be implemented, educational institutions cannot escape their share of responsibilities.

Automation and robotics are two closely related technologies. In an industrial context, we can define automation as a technology that is concerned with the use of mechanical, electronics and computer-based systems in the operation and control of production. Examples of this technology include transfer lines, mechanized assembly machines, feed back control systems, numerically controlled machine tools, and robots. Accordingly, robotics is a form of industrial automation.

There are three broad classes of industrial automation: fixed automaton, programmable automation, and flexible automation. Fixed automation is used when the volume of production is very high and it is therefore appropriate to design specialized equipment to process the product very efficiently and at high production rates. A good example of fixed automation can be found in the automobile industry, where highly integrated transfer lines consisting of several dozen work stations are used to perform machining operations on engine and transmission components. The economics of fixed automation are such that the cost of the special equipment can be divided over a large number of units, and resulting unit cost are low relative to alternative methods of production. The risk encountered with fixed automation is this; since the initial investment cost is high, if the volume of production turns out to be lower than anticipated, then the unit costs become greater than anticipated. Another problem in fixed automation is that the equipment is specially designed to produce the one product, and after that products life cycle is finished, the equipment is likely to become obsolete. For products with short life cycle, the use of fixed automation represents a big gamble.

Programmable automation is used when the volume of production is relatively low and there are a variety of products to be made. In this case, the production equipment is designed to be adaptable to variations in product configuration. This adaptability feature is accomplished by operating the equipment under the control of "program" of instructions which has been prepared especially for the given product. The program is read into the production equipment, and the equipment performs the particular sequence of processing operations to make that product. In terms of economics, the cost of programmable equipment can be spread over a large number of products even though the products are different. Because of the programming feature, and the resulting adaptability of the equipment, many different and unique products can be made economically in small batches.

Power System Contingencies

Introduction


Power system voltage control has a hierarchy structure with three levels: the primary, secondary, and the tertiary voltage control. Over the past 20 yrs, one of the most successful measures proposed to improve power system voltage regulation has been the application of secondary voltage control, initiated by the French electricity company, EDF, and followed by some other electricity utilities in European countries.

The secondary voltage control closes the control loop of the references value setting of controllers at the primary level. The primary objective of secondary voltage control is to achieve better voltage regulation in power systems. In addition, it brings in the extra benefit of improvement of power system voltage stability, for this application, several methods to design secondary voltage controllers have been proposed.

The useful concept of secondary voltage control is explored for a new application-the elimination of the voltage violations in power system contingencies. For this particular application, the coordination of various secondary voltage controllers is proposed to be based on a multi agent request -and- answer type of protocol to between any two agents. The resulted secondary voltage control can only cover the location where voltage controllers are installed. This paper presents results of significant progresses in investigating this new application to eliminate voltage violations in power system contingencies via secondary voltage control.

A collaboration protocol, expressed graphically as finite state machine, is proposed for the coordination among multiple FACTS voltage controllers. The coordinated secondary voltage control is suggested to cover multiple locations to eliminate voltage violations in the adjacent locations to a voltage controller. A novel scheme of a learning fuzzy logic control is proposed for the design of the secondary voltage controller. A key parameter of the learning fuzzy logic controller is proposed to be trained through off-line simulation with the injection of artificial loads in the controller's adjacent locations.


FACTS (Flexible AC Transmission Systems)

Sudden changes in the power demands or changes in the system conditions in the power system are often followed by prolonged electromechanical oscillations leading to power system instability. AC transmission lines are dominantly reactive networks characterized by their per mile series inductance and shunt capacitances. Suitably changing the line impedance and thus the real and reactive power flow through the transmission line is an effective measure for controlling the power system oscillations and thereby improving the system stability.

Advances in high power semiconductors and sophisticated electronic control technologies have led to the development of FACTS. Through FACTS the effective line impedance can be controlled within a few milliseconds time. Damping of the power system oscillation is possible through effective changes in the line impedance by employing FACTS members (SVC, STATCOM, UPFC etc).

Sensotronic Brake Control


Definition


Sensotronic Brake Control (SBC™) works electronically, and thus faster and more precisely, than a conventional hydraulic braking system. As soon as you press the brake pedal and the sensors identify the driving situation in hand, the computer makes an exact calculation of the brake force necessary and distributes it between the wheels as required. This allows SBC™ to critically reduce stopping distances. SBC™ also helps to optimise safety functions such as ESP®, ASR, ABS and BAS.

With Sensotronic Brake Control, electric impulses are used to pass the driver's braking commands onto a microcomputer which processes various sensor signals simultaneously and, depending on the particular driving situation, calculates the optimum brake pressure for each wheel. As a result, SBC offers even greater active safety than conventional brake systems when braking in a corner or on a slippery surface.

A high-pressure reservoir and electronically controllable valves ensure that maximum brake pressure is available much sooner. Moreover, the system offers innovative additional functions to reduce the driver's workload. These include Traffic Jam Assist, which brakes the vehicle automatically in stop-and-go traffic once the driver takes his or her foot off the accelerator. The Soft-Stop function - another first - allows particularly soft and smooth stopping in town traffic

When drivers hit the brake pedal today, their foot moves a piston rod which is linked to the brake booster and the master brake cylinder. Depending on the pedal force, the master brake cylinder builds up the appropriate amount of pressure in the brake lines which - in a tried and tested interaction of mechanics and hydraulics - then presses the brake pads against the brake discs via the wheel cylinders.


By contrast, in the Mercedes-Benz Sensotronic Brake Control, a large number of mechanical components are simply replaced by electronics. The brake booster will not be needed in future either. Instead sensors gauge the pressure inside the master brake cylinder as well as the speed with which the brake pedal is operated, and pass these data to the SBC computer in the form of electric impulses. To provide the driver with the familiar brake feel, engineers have developed a special simulator which is linked to the tandem master cylinder and which moves the pedal using spring force and hydraulics.

In other words: during braking, the actuation unit is completely disconnected from the rest of the system and serves the sole purpose of recording any given brake command. Only in the event of a major fault or power failure does SBC automatically use the services of the tandem master cylinder and instantly establishes a direct hydraulic link between the brake pedal and the front wheel brakes in order to decelerate the car safely.


The central control unit under the bonnet is the centrepiece of the electrohydraulic brake. This is where the interdisciplinary interaction of mechanics and electronics provides its greatest benefits - the microcomputer, software, sensors, valves and electric pump work together and allow totally novel, highly dynamic brake management:
In addition to the data relating to the brake pedal actuation, the SBC computer also receives the sensor signals from the other electronic assistance systems.

For example, the anti-lock braking system (ABS) provides information about wheel speed, while Electronic Stability Program (ESP®) makes available the data from its steering angle, turning rate and transverse acceleration sensors. The transmission control unit finally uses the data highway to communicate the current driving range. The result of these highly complex calculations is rapid brake commands which ensure optimum deceleration and driving stability as appropriate to the particular driving scenario. What makes the system even more sophisticated is the fact that SBC calculates the brake force separately for each wheel.



Mobile IP


Introduction


While Internet technologies largely succeed in overcoming the barriers of time and distance, existing Internet technologies have yet to fully accommodate the increasing mobile computer usage. A promising technology used to eliminate this current barrier is Mobile IP. The emerging 3G mobile networks are set to make a huge difference to the international business community. 3G networks will provide sufficient bandwidth to run most of the business computer applications while still providing a reasonable user experience.

However, 3G networks are not based on only one standard, but a set of radio technology standards such as cdma2000, EDGE and WCDMA. It is easy to foresee that the mobile user from time to time also would like to connect to fixed broadband networks, wireless LANs and, mixtures of new technologies such as Bluetooth associated to e.g. cable TV and DSL access points.

In this light, a common macro mobility management framework is required in order to allow mobile users to roam between different access networks with little or no manual intervention. (Micro mobility issues such as radio specific mobility enhancements are supposed to be handled within the specific radio technology.) IETF has created the Mobile IP standard for this purpose.

Mobile IP is different compared to other efforts for doing mobility management in the sense that it is not tied to one specific access technology. In earlier mobile cellular standards, such as GSM, the radio resource and mobility management was integrated vertically into one system. The same is also true for mobile packet data standards such as CDPD, Cellular Digital Packet Data and the internal packet data mobility protocol (GTP/MAP) of GPRS/UMTS networks. This vertical mobility management property is also inherent for the increasingly popular 802.11 Wireless LAN standard.

Mobile IP can be seen as the least common mobility denominator - providing seamless macro mobility solutions among the diversity of accesses. Mobile IP is defining a Home Agent as an anchor point with which the mobile client always has a relationship, and a Foreign Agent, which acts as the local tunnel-endpoint at the access network where the mobile client is visiting. Depending on which network the mobile client is currently visiting; its point of attachment Foreign Agent) may change. At each point of attachment, Mobile IP either requires the availability of a standalone Foreign Agent or the usage of a Co-located care-of address in the mobile client itself.

The concept of "Mobility" or "packet data mobility", means different things depending on what context the word is used within. In a wireless or fixed environment, there are many different ways of implementing partial or full mobility and roaming services. The most common ways of implementing mobility (discrete mobility or IP roaming service) support in today's IP networking environments includes simple "PPP dial-up" as well as company internal mobility solutions implemented by means of renewal of IP address at each new point of attachment. The most commonly deployed way of supporting remote access users in today's Internet is to utilize the public telephone network (fixed or mobile) and to use the PPP dial-up functionality.

Continuously variable transmission (CVT)


Definition


After more than a century of research and development, the internal combustion (IC) engine is nearing both perfection and obsolescence: engineers continue to explore the outer limits of IC efficiency and performance, but advancements in fuel economy and emissions have effectively stalled. While many IC vehicles meet Low Emissions Vehicle standards, these will give way to new, stricter government regulations in the very near future. With limited room for improvement, automobile manufacturers have begun full-scale development of alternative power vehicles. Still, manufacturers are loath to scrap a century of development and billions or possibly even trillions of dollars in IC infrastructure, especially for technologies with no history of commercial success. Thus, the ideal interim solution is to further optimize the overall efficiency of IC vehicles.

One potential solution to this fuel economy dilemma is the continuously variable transmission (CVT), an old idea that has only recently become a bastion of hope to automakers. CVTs could potentially allow IC vehicles to meet the first wave of new fuel regulations while development of hybrid electric and fuel cell vehicles continues. Rather than selecting one of four or five gears, a CVT constantly changes its gear ratio to optimize engine efficiency with a perfectly smooth torque-speed curve. This improves both gas mileage and acceleration compared to traditional transmissions.

The fundamental theory behind CVTs has undeniable potential, but lax fuel regulations and booming sales in recent years have given manufacturers a sense of complacency: if consumers are buying millions of cars with conventional transmissions, why spend billions to develop and manufacture CVTs?

Although CVTs have been used in automobiles for decades, limited torque capabilities and questionable reliability have inhibited their growth. Today, however, ongoing CVT research has led to ever-more robust transmissions, and thus ever-more-diverse automotive applications. As CVT development continues, manufacturing costs will be further reduced and performance will continue to increase, which will in turn increase the demand for further development. This cycle of improvement will ultimately give CVTs a solid foundation in the world's automotive infrastructure.

CVT Theory & Design

Today's automobiles almost exclusively use either a conventional manual or automatic transmission with "multiple planetary gear sets that use integral clutches and bands to achieve discrete gear ratios" . A typical automatic uses four or five such gears, while a manual normally employs five or six. The continuously variable transmission replaces discrete gear ratios with infinitely adjustable gearing through one of several basic CVT designs.


High-availability power systems: Redundancy options


Introduction


In major applications like major computer installations, process control in chemical plants, safety monitors, IC units of hospitals etc., even a temporary power failure may lead to large economic losses. For such critical loads, it is of paramount importance to use UPS systems.

But all UPS equipments should be completely de-energized for preventive maintenance at least once per year. This limits the availability of the power system. Now there are new UPS systems in the market to permit concurrent maintenance.

High-Availability Power Systems

The computing industry talks in terms of "Nines" of availability. This refers to the percentage of time in a year that a system is functional and available to do productive work. A system with four "Nines" is 99.99 percent available, meaning that downtime is less than 53 minutes in a standard 365-day year. Five "Nines" (99.999 percent available) equates to less than 5.3 minutes of downtime per year. Six "Nines" (99.9999 percent available) equates to just 32 seconds of downtime per year. These same numbers apply when we speak of availability of conditioned power. The goal is to maximize the availability of conditioned power and minimize exposure to unconditioned utility power. The concept of continuous availability of conditioned power, takes this concept one step further. After all, 100 percent is greater than 99.99999 percent.

The Road To Continuous Availability

We determine availability by studying four key elements:

o Reliability
The individual UPS modules, static transfer switches and other power distribution equipment must be incredibly reliable, as measured by field-documented MTBF (Mean Time Between Failures). In addition, the system elements must be designed and assembled in a way that minimizes the complexity and single points of failure.

o Functionality
The UPS must be able to protect the critical load from the full range of power disturbances, and only a true double-conversion UPS can do this. Some vendors offer single- conversion (line-interactive) three-phase UPS products as a lower cost alternative. However, these alternative UPS's do not protect against all disturbances, including power system short circuits, frequency variations, harmonics and common mode noise. If your critical facility is truly critical, only a true double conversion UPS is suitable.


o Maintainability
The system design must permit concurrent maintenance of all power system components, supporting the load with part of the UPS system while other parts are being serviced. As we shall see, single bus solutions do not completely support concurrent maintenance.

o Fault Tolerance
The system must have fault resiliency to cope with a failure of any power system component without affecting the operation of the critical load equipment. Furthermore, the power distribution system must have fault resiliency to survive the inevitable load faults and human error.

The two factors of field-proven critical bus MTBF in excess of one million hours and double-conversion technology ensure reliability and functionality. With reliability and functionality assured, let us look at how different UPS system configurations compare for maintainability and fault tolerance.


IGCT


Introduction


Thyristor technology is inherently superior to transistor for blocking voltage values above 2.5kV, plasma distributions equal to those of diodes offering the best trade-off between the on-state and blocking voltages. Until the introduction of newer power switches, the only serious contenders for high-power transportation systems and other applications were the GTO (thyristor), with its cumbersome snubbers, and the IGBT (transistor), with its inherently high losses. Until now, adding the gate turn-off feature has resulted in GTO being constrained by a variety of unsatisfactory compromises. The widely used standard GTO drive technology results in inhomogenous turn-on and turn-off that call for costly dv/dt and di/dt snubber circuits combined with bulky gate drive units.

Rooting from the GTO is one of the newest power switches, the Gate-Commutated Thyristor (GCT). It successfully combines the best of the thyristor and transistor characteristics, while fulfilling the additional requirements of manufacturability and high reliability. The GCT is a semiconductor based on the GTO structure, whose cathode emitter can be shut off "instantaneously", thereby converting the device from a low conduction-drop thyristor to a low switching loss, high dv/dt bipolar transistor at turn- off.

The IGCT (Integrated GCT) is the combination of the GCT device and a low inductance gate unit. This technology extends transistor switching performance to well above the MW range, with 4.5kV devices capable of turning off 4kA, and 6kV devices capable of turning off 3kA without snubbers. The IGCT represents the optimum combination of low loss thyristor technology and snubberles gate effective turn off for demanding medium and high voltage power electronics applications.

The thick line shows the variation of the anode voltage during turn-off. The lighter shows the variation of the anode current during turn-off process of IGCT.

GTO and thyristor are four layer (npnp) devices. As such, they have only two stable points their characteristics-'on' and 'off'. Every state in between is unstable and results in current filamentation. The inherent instability is worsened by processing imperfections. This has led to the widely accepted myth that a GTO cannot be operated without a snubber. Essentially, the GTO has to be reduced to a stable pnp device i.e. a transistor, for the few critical microseconds during turn-off.

To stop the cathode (n) from taking part in the process, the bias of the cathode n-p junction has to be reversed before voltage starts to build up at the main junction. This calls for commutation of the full load current from the cathode (n) to the gate (p) within one microsecond. Thanks to a new housing design, 4000A/us can be achieved with a low cost 20V gate unit. Current filamentation is totally suppressed and the turn-off waveforms and safe operating area are identical to those of a transistor.

IGCT technology brings together the power handling device (GCT) and the device control circuitry (freewheeling diode and gate drive) in an integrated package. By offering four levels of component packaging and integration, it permits simultaneous improvement in four interrelated areas; low switching and conduction losses at medium voltage, simplified circuitry for operating the power semiconductor, reduced power system cost, and enhanced reliability and availability. Also, by providing pre- engineered switch modules, IGCT enables medium-voltage equipment designers to develop their products faster.


Iris Scanning

Introduction


In today's information age it is not difficult to collect data about an individual and use that information to exercise control over the individual. Individuals generally do not want others to have personal information about them unless they decide to reveal it. With the rapid development of technology, it is more difficult to maintain the levels of privacy citizens knew in the past. In this context, data security has become an inevitable feature. Conventional methods of identification based on possession of ID cards or exclusive knowledge like social security number or a password are not altogether reliable. ID cards can be almost lost, forged or misplaced: passwords can be forgotten.

Such that an unauthorized user may be able to break into an account with little effort. So it is need to ensure denial of access to classified data by unauthorized persons. Biometric technology has now become a viable alternative to traditional identification systems because of its tremendous accuracy and speed. Biometric system automatically verifies or recognizes the identity of a living person based on physiological or behavioral characteristics.

Since the persons to be identified should be physically present at the point of identification, biometric techniques gives high security for the sensitive information stored in mainframes or to avoid fraudulent use of ATMs. This paper explores the concept of Iris recognition which is one of the most popular biometric techniques. This technology finds applications in diverse fields.

Biometrics - Future Of Identity
Biometric dates back to ancient Egyptians who measured people to identify them. Biometric devices have three primary components.
1. Automated mechanism that scans and captures a digital or analog image of a living personal characteristic
2. Compression, processing, storage and comparison of image with a stored data.
3. Interfaces with application systems.


A biometric system can be divided into two stages: the enrolment module and the identification module. The enrolment module is responsible for training the system to identity a given person. During an enrolment stage, a biometric sensor scans the person's physiognomy to create a digital representation. A feature extractor processes the representation to generate a more compact and expressive representation called a template. For an iris image these include the various visible characteristics of the iris such as contraction, Furrows, pits, rings etc. The template for each user is stored in a biometric system database.

The identification module is responsible for recognizing the person. During the identification stage, the biometric sensor captures the characteristics of the person to be identified and converts it into the same digital format as the template. The resulting template is fed to the feature matcher, which compares it against the stored template to determine whether the two templates match.

The identification can be in the form of verification, authenticating a claimed identity or recognition, determining the identity of a person from a database of known persons. In a verification system, when the captured characteristic and the stored template of the claimed identity are the same, the system concludes that the claimed identity is correct. In a recognition system, when the captured characteristic and one of the stored templates are the same, the system identifies the person with matching template.


Loop magnetic couplers


Introduction


Couplers, also known as "isolators" because they electrically isolate as well as transmit data, are widely used in industrial and factory networks, instruments, and telecommunications. Every one knows the problems with optocouplers. They take up a lot of space, are slow, optocouplers age and their temperature range is quite limited. For years, optical couplers were the only option. Over the years, most of the components used to build instrumentation circuits have become ever smaller. Optocoupler technology, however, hasn't kept up. Existing coupler technologies look like dinosaurs on modern circuit boards.


Magnetic couplers are analogous to optocouplers in a number of ways. Design engineers, especially in instrumentation technology, will welcome a galvanically-isolated data coupler with integrated signal conversion in a single IC. My report will give a detailed study about 'ISOLOOP MAGNETIC COUPLERS'. GROUND LOOPS
When equipment using different power supplies is tied together (with a common ground connection) there is a potential for ground loop currents to exist. This is an induced current in the common ground line as a result of a difference in ground potentials at each piece of equipment.

Normally all grounds are not in the same potential. Widespread electrical and communications networks often have nodes with different ground domains. The potential difference between these grounds can be AC or DC, and can contain various noise components. Grounds connected by cable shielding or logic line ground can create a ground loop-unwanted current flow in the cable. Ground-loop currents can degrade data signals, produce excessive EMI, damage components, and, if the current is large enough, present a shock hazard.


Galvanic isolation between circuits or nodes in different ground domains eliminates these problems, seamlessly passing signal information while isolating ground potential differences and common-mode transients. Adding isolation components to a circuit or network is considered good design practice and is often mandated by industry standards. Isolation is frequently used in modems, LAN and industrial network interfaces (e.g., network hubs, routers, and switches), telephones, printers, fax machines, and switched-mode power supplies.


Giant Magnetoresistive (GMR):
Large magnetic field dependent changes in resistance are possible in thin film ferromagnet/nonmagnetic metallic multilayers. The phenomenon was first observed in France in 1988, when changes in resistance with magnetic field of up to 70% were seen. Compared to the small percent change in resistance observed in anisotropic magnetoresistance, this phenomenon was truly 'giant' magnetoresistance.


The spin of electrons in a magnet is aligned to produce a magnetic moment. Magnetic layers with opposing spins (magnetic moments) impede the progress of the electrons (higher scattering) through a sandwiched conductive layer. This arrangement causes the conductor to have a higher resistance to current flow.


An external magnetic field can realign all of the layers into a single magnetic moment. When this happens, electron flow will be less effected (lower scattering) by the uniform spins of the adjacent ferromagnetic layers. This causes the conduction layer to have a lower resistance to current flow. Note that these phenomenon takes places only when the conduction layer is thin enough (less than 5 nm) for the ferromagnetic layer's electron spins to affect the conductive layer's electron's path.

LWIP


Introduction


Over the last few years, the interest for connecting computers and computer supported devices to wireless networks has steadily increased. Computers are becoming more and more seamlessly integrated with everyday equipment and prices are dropping. At the same time wireless networking technologies, such as Bluetooth and IEEE 802.11b WLAN , are emerging. This gives rise to many new fascinating scenarios in areas such as health care, safety and security, transportation, and processing industry. Small devices such as sensors can be connected to an existing network infrastructure such as the global Internet, and monitored from anywhere.

The Internet technology has proven itself flexible enough to incorporate the changing network environments of the past few decades. While originally developed for low speed networks such as the ARPANET, the Internet technology today runs over a large spectrum of link technologies with vastly different characteristics in terms of bandwidth and bit error rate. It is highly advantageous to use the existing Internet technology in the wireless networks of tomorrow since a large amount of applications using the Internet technology have been developed. Also, the large connectivity of the global Internet is a strong incentive.

Since small devices such as sensors are often required to be physically small and inexpensive, an implementation of the Internet protocols will have to deal with having limited computing resources and memory. This report describes the design and implementation of a small TCP/IP stack called lwIP that is small enough to be used in minimal systems.

Overview

As in many other TCP/IP implementations, the layered protocol design has served as a guide for the design of the implementation of lwIP. Each protocol is implemented as its own module, with a few functions acting as entry points into each protocol. Even though the protocols are implemented separately, some layer violations are made, as discussed above, in order to improve performance both in terms of processing speed and memory usage. For example, when verifying the checksum of an incoming TCP segment and when demultiplexing a segment, the source and destination IP addresses of the segment has to be known by the TCP module. Instead of passing these addresses to TCP by the means of a function call, the TCP module is aware of the structure of the IP header, and can therefore extract this information by itself.

Image Authentication Techniques


Introduction


This paper explores the various techniques used to authenticate the visual data recorded by the automatic video surveillance system. Automatic video surveillance systems are used for continuous and effective monitoring and reliable control of remote and dangerous sites. Some practical issues must be taken in to account, in order to take full advantage of the potentiality of VS system. The validity of visual data acquired, processed and possibly stored by the VS system, as a proof in front of a court of law is one of such issues. But visual data can be modified using sophisticated processing tools without leaving any visible trace of the modification.

So digital or image data have no value as legal proof, since doubt would always exist that they had been intentionally tampered with to incriminate or exculpate the defendant. Besides, the video data can be created artificially by computerized techniques such as morphing. Therefore the true origin of the data must be indicated to use them as legal proof. By data authentication we mean here a procedure capable of ensuring that data have not been tampered with and of indicating their true origin.

Automatic Visual Surveillance System

Automatic Visual Surveillance system is a self monitoring system which consists of a video camera unit, central unit and transmission networks A pool of digital cameras is in charge of frame the scene of interest and sent corresponding video sequence to central unit. The central unit is in charge of analyzing the sequence and generating an alarm whenever a suspicious situation is detected.

Central unit also transmits the video sequences to an intervention centre such as security service provider, the police department or a security guard unit. Somewhere in the system the video sequence or some part of it may be stored and when needed the stored sequence can be used as a proof in front of court of law. If the stored digital video sequences have to be legally credible, some means must be envisaged to detect content tampering and reliably trace back to the data origin

Authentication Techniques

Authentication techniques are performed on visual data to indicate that the data is not a forgery; they should not damage visual quality of the video data. At the same time, these techniques must indicate the malicious modifications include removal or insertion of certain frames, change of faces of individual, time and background etc. Only a properly authenticated video data has got the value as legal proof. There are two major techniques for authenticating video data.


They are as follows


1. Cryptographic Data Authentication

It is a straight forward way to provide video authentication, namely through the joint use of asymmetric key encryption and the digital Hash function.

Cameras calculate a digital summary (digest) of the video by means of hash function. Then they encrypt the digest with their private key, thus obtaining a signed digest which is transmitted to the central unit together with acquired sequences. This digest is used to prove data integrity or to trace back to their origin. Signed digest can only read by using public key of the camera.

2. Watermarking- based authentication

Watermarking data authentication is the modern approach to authenticate visual data by imperceptibly embedding a digital watermark signal on the data.

Digital watermarking is the art and science of embedding copyright information in the original files. The information embedded is called 'watermarks '. Digital watermarks are difficult to remove without noticeably degrading the content and are a covert means in situation where copyright fails to provide robustness.

Seasonal Influence on Safety of Substation Grounding


Introduction


With the development of modern power system to the direction of extra-high voltage, large capacity, far distance transmission and application of advanced technologies the demand on the safety, stability and economic operation of power system became higher. A good grounding system is the fundamental insurance to keep the safe operation of the power system. The good grounding system should ensure the following:


" To provide safety to personnel during normal and fault conditions by limiting step and touch potential.
" To assure correct operation of electrical devices.
" To prevent damage to electrical apparatus.
" To dissipate lightning strokes.
" To stabilize voltage during transient conditions and therefore to minimize the probability of flashover during the transients


As it is stated in the ANSI/IEEE Standard 80-1986 "IEEE Guide for Safety in AC substation grounding," a safe grounding design has two objectives:


" To provide means to carry electric currents into the earth under normal and fault condition without exceeding any operational and equipment limit or adversely affecting continuity of service.
" To assure that a person in the vicinity of grounded facilities is not exposed to the danger of critical electrical shock.


A practical approach to safe grounding considers the interaction of two grounding systems: The intentional ground, consisting of ground electrodes buried at some depth below the earth surface, and the accidental ground, temporarily established by a person exposed to a potential gradient at a grounded facility.


An ideal ground should provide a near zero resistance to remote earth. In practice, the ground potential rise at the facility site increases proportionally to the fault current; the higher the current, the lower the value of total system resistance which must be obtained. For most large substations the ground resistance should be less than 1 Ohm. For smaller distribution substations the usually acceptable range is 1-5 Ohms, depending on the local conditions.
When a grounding system is designed, the fundamental method is to ensure the safety of human beings and power apparatus is to control the step and touch voltages in their respective safe region. step and touch voltage can be defined as follows.

Step Voltage
It is defined as the voltage between the feet of the person standing in near an energized object. It is equal to the difference in voltage given by the voltage distribution curve between two points at different distance from the electrode.


Touch Voltage
It is defined as the voltage between the energized object and the feet of the person in contact with the object. It is equal to the difference in voltage between the object and a point some distance away from it.
In different season, the resistivity of the surface soil layer would be changed. This would affect the safety of grounding systems. The value of step and touch voltage will move towards safe region or to the hazard side is the main concerned question



Wavelet transforms


Introduction


Wavelet transforms have been one of the important signal processing developments in the last decade, especially for the applications such as time-frequency analysis, data compression, segmentation and vision. During the past decade, several efficient implementations of wavelet transforms have been derived. The theory of wavelets has roots in quantum mechanics and the theory of functions though a unifying framework is a recent occurrence. Wavelet analysis is performed using a prototype function called a wavelet.

Wavelets are functions defined over a finite interval and having an average value of zero. The basic idea of the wavelet transform is to represent any arbitrary function f (t) as a superposition of a set of such wavelets or basis functions. These basis functions or baby wavelets are obtained from a single prototype wavelet called the mother wavelet, by dilations or contractions (scaling) and translations (shifts). Efficient implementation of the wavelet transforms has been derived based on the Fast Fourier transform and short-length 'fast-running FIR algorithms' in order to reduce the computational complexity per computed coefficient.

First of all, why do we need a transform, or what is a transform anyway?

Mathematical transformations are applied to signals to obtain further information from that signal that is not readily available in the raw signal. Now, a time-domain signal is assumed as a raw signal, and a signal that has been transformed by any available transformations as a processed signal.

There are a number of transformations that can be applied such as the Hilbert transform, short-time Fourier transform, Wigner transform, the Radon transform, among which the Fourier transform is probably the most popular transform. These mentioned transforms constitute only a small portion of a huge list of transforms that are available at engineers and mathematicians disposal. Each transformation technique has its own area of application, with advantages and disadvantages.

Importance Of The Frequency Information

Often times, the information that cannot be readily seen in the time-domain can be seen in the frequency domain. Most of the signals in practice are time-domain signals in their raw format. That is, whatever that signal is measuring, is a function of time. In other words, when we plot the signal one of the axis is time (independent variable) and the other (dependent variable) is usually the amplitude.

When we plot time-domain signals, we obtain a time-amplitude representation of the signal. This representation is not always the best representation of the signal for most signal processing related applications. In many cases, the most distinguished information is hidden in the frequency content of the signal. The frequency spectrum of a signal is basically the frequency components (spectral components) of that signal. The frequency spectrum of a signal shows what frequencies exist in the signal.

Cyberterrorism

Definition

Cyberterrorism is a new terrorist tactic that makes use of information systems or digital technology, especially the Internet, as either an instrument or a target. As the Internet becomes more a way of life with us,it is becoming easier for its users to become targets of the cyberterrorists. The number of areas in which cyberterrorists could strike is frightening, to say the least.

The difference between the conventional approaches of terrorism and new methods is primarily that it is possible to affect a large multitude of people with minimum resources on the terrorist's side, with no danger to him at all. We also glimpse into the reasons that caused terrorists to look towards the Web, and why the Internet is such an attractive alternative to them.

The growth of Information Technology has led to the development of this dangerous web of terror, for cyberterrorists could wreak maximum havoc within a small time span. Various situations that can be viewed as acts of cyberterrorism have also been covered. Banks are the most likely places to receive threats, but it cannot be said that any establishment is beyond attack. Tips by which we can protect ourselves from cyberterrorism have also been covered which can reduce problems created by the cyberterrorist.


We, as the Information Technology people of tomorrow need to study and understand the weaknesses of existing systems, and figure out ways of ensuring the world's safety from cyberterrorists. A number of issues here are ethical, in the sense that computing technology is now available to the whole world, but if this gift is used wrongly, the
consequences could be disastrous. It is important that we understand and mitigate cyberterrorism for the benefit of society, try to curtail its growth, so that we can heal the present, and live the future…


Ipv6 - The Next Generation Protocol



Definition

The Internet is one of the greatest revolutionary innovations of the twentieth century.It made the 'global village utopia ' a reality in a rather short span of time. It is changing the way we interact with each other, the way we do business, the way we educate ourselves and even the way we entertain ourselves. Perhaps even the architects of Internet would not have foreseen the tremendous growth rate of the network being witnessed today.With the advent of the Web and multimedia services, the technology underlying t he Internet has been under stress.

It cannot adequately support many services being envisaged, such as real time video conferencing, interconnection of gigabit networks with lower bandwidths, high security applications such as electronic commerce, and interactive virtual reality applications. A more serious problem with today's Internet is that it can interconnect a maximum of four billion systems only, which is a small number as compared to the projected systems on the Internet in the twenty-first century.

Each machine on the net is given a 32-bit address. With 32 bits, a maximum of about four billion addresses is possible. Though this is a large a number, soon the Internet will have TV sets, and even pizza machines connected to it, and since each of them must have an IP address, this number becomes too small. The revision of IPv4 was taken up mainly to resolve the address problem, but in the course of refinements, several other features were also added to make it suitable for the next generation Internet.

This version was initially named IPng (IP next generation) and is now officially known as IPv6. IPv6 supports 128-bit addresses, the source address and the destination address, each being, 128 bits long. IPv5 a minor variation of IPv4 is presently running on some routers. Presently, most routers run software that support only IPv4. To switch over to IPv6 overnight is an impossible task and the transition is likely to take a very long time.

However to speed up the transition, an IPv4 compatible IPv6 addressing scheme has been worked out. Major vendors are now writing softwares for various computing environments to support IPv6 functionality. Incidentally, software development for different operating systems and router platforms will offer major jobs opportunities in coming years.


Driving Optical Network Evolution

Definition

Over the years, advancement in technologies has improved transmission limitations, the number of wavelengths we can send down a piece of fiber, performance, amplification techniques, and protection and redundancy of the network. When people have described and spoken at length about optical networks, they have typically limited the discussion of optical network technology to providing physical-layer connectivity.

When actual network services are discussed, optical transport is augmented through the addition of several protocol layers, each with its own sets of unique requirements, to make up a service-enabling network. Until recently, transport was provided through specific companies that concentrated on the core of the network and provided only point-to- point transport services.

A strong shift in revenue opportunities from a service provider and vendor perspective, changing traffic patterns from the enterprise customer, and capabilities to drive optical fiber into metropolitan (metro) areas has opened up the next emerging frontier of networking. Providers are now considering emerging lucrative opportunities in the metro space. Whereas traditional or incumbent vendors have been installing optical equipment in the space for some time, little attention has been paid to the opportunity available through the introduction of new technology advancements and the economic implications these technologies will have.

Specifically, the new technologies in the metro space provide better and more profitable economics, scale, and new services and business models. The current metro infrastructure comprises this equipment, which emphasizes voice traffic; is limited in scalability; and was not designed to take advantage of new technologies, topologies, and changing traffic conditions.

Next-generation equipment such as next-generation Synchronous Optical Network (SONET), metro core dense wavelength division multiplexing (DWDM), metro-edge DWDM, and advancements in the optical core have taken advantage of these limitations, and they are scalable and data optimized; they include integrated DWDM functionality and new amplification techniques; and they have made improvements in the operational and provisioning cycles.This tutorial provides technical information that can help engineers address numerous Cisco innovations and technologies for Cisco Complete Optical Multiservice Edge and Transport (Cisco COMET). They can be broken down into five key areas: photonics, protection, protocols, packets, and provisioning.

Radio Network Controller


Definition

A Radio Network Controller (RNC) provides the interface between the wireless devices communicating through Node B transceivers and the network edge. This includes controlling and managing the radio transceivers in the Node B equipment, as well as management tasks like soft handoff.

The RNC performs tasks in a 3G wireless network analogous to those of the Base Station Controller (BSC) in a 2G or 2.5G network. It interfaces with GPRS Service Nodes (SGSNs) and Gateways (GGSNs) to mediate with the network service providers.

A radio network controller manages hundreds of Node B transceiver stations while switching and provisioning services off the Mobile Switching Center and 3G data network interfaces. The connection from the RNC to a Node B is called the User Plane Interface Layer and it uses T1/E1 transport to the RNC.

Due to the large number of Node B transceivers, a T1/E1 aggregator is used to deliver the Node B data over channelized OC-3 optical transport to the RNC. The OC-3 pipe can be a direct connection to the RNC or through traditional SONET/SDH transmission networks.

A typical Radio Network Controller may be built on a PICMG or Advanced TCA chassis. It contains several different kinds of cards specialized for performing the functions and interacting with the various interfaces of the RNC.

Wireless Networked Digital Devices


Definition

The proliferation of mobile computing devices including laptops, personal digital assistants (PDAs),and wearable computers has created a demand for wireless personal area networks (PANs).PANs allow proximal devices to share
information and resources.The mobile nature of these devices places unique requirements on PANs,such as low power consumption, frequent make-and-break connections, resource discovery and utilization, and international regulations.

This paper examines wireless technologies appropriate for PANs and reviews promising research in resource discovery and service utilization. We recognize the need for PDAs to be as manageable as mobile phones and also the restrictive screen area and input area in mobile phone. Thus the need for a new breed of computing devices to fit the bill for a PAN. The above devices become especially relevant for mobile users such as surgeons and jet plane mechanics who need both hands free and thus would need to have "wearable" computers.

This paper first examines the technology used for wireless communication.Putting a radio in a digital device provides physical connectivity;however,to make the device useful in a larger context a networking infrastructure is required. The
infrastructure allows devices o share data,applications,and resources such as printers, mass storage, and computation power. Defining a radio standard is a tractable problem as demonstrated by the solutions presented in this paper.
Designing a network infrastructure is much more complex.

The second half of the paper describes several research projects that try to address components of the networking infrastructure. Finally there are the questions that go beyond the scope of this paper, yet will have he greatest effect on the direction,capabilities,and future of this paradigm. Will these networking strategies be incompatible, like he various cellular phone systems in the United States, or will there be a standard upon which manufacturers and developers agree, like the GSM (global system for mobile communication)cellular phones in Europe?

Communication demands compatibility, which is challenging in a heterogeneous marketplace. Yet by establishing and implementing compatible systems, manufacturers can offer more powerful and useful devices to their customers. Since these are, after all, digital devices living in a programmed digital
world, compatibility and interoperation are possible.

Technologies explored:
1. Electric field- use human body as a current conduit.
2.Magnetic field-use base station technology for picocells of space.
3.Infra Red- Basic issues including opaque body obstruction.
4.Wireless Radio Frequency- The best technology option however has to deal with the finite resource of the electro magnetic spectrum.

Also must meet international standards by a compatible protocol.
a. UHF Radio.
b. Super regenerative receiver
c. SAW/ASH Receiver.


3D IC's


Introduction
There is a saying in real estate; when land get expensive, multi-storied buildings are the alternative solution. We have a similar situation in the chip industry. For the past thirty years, chip designers have considered whether building integrated circuits multiple layers might create cheaper, more powerful chips.

Performance of deep-sub micrometer very large scale integrated (VLSI) circuits is being increasingly dominated by the interconnects due to increasing wire pitch and increasing die size. Additionally, heterogeneous integration of different technologies on one single chip is becoming increasingly desirable, for which planar (2-D) ICs may not be suitable.

The three dimensional (3-D) chip design strategy exploits the vertical dimension to alleviate the interconnect related problems and to facilitate heterogeneous integration of technologies to realize system on a chip (SoC) design. By simply dividing a planar chip into separate blocks, each occupying a separate physical level interconnected by short and vertical interlayer interconnects (VILICs), significant improvement in performance and reduction in wire-limited chip area can be achieved.In the 3-Ddesign architecture, an entire chip is divided into a number of blocks, and each block is placed on a separate layer of Si that are stacked on top of each other.

Motivation For 3-D ICs

The unprecedented growth of the computer and the information technology industry is demanding Very Large Scale Integrated ( VLSI ) circuits with increasing functionality and performance at minimum cost and power dissipation. Continuous scaling of VLSI circuits is reducing gate delays but rapidly increasing interconnect delays. A significant fraction of the total power consumption can be due to the wiring network used for clock distribution, which is usually realized using long global wires.

Furthermore, increasing drive for the integration of disparate signals (digital, analog, RF) and technologies (SOI, SiGe, GaAs, and so on) is introducing various SoC design concepts, for which existing planner (2-D) IC design may not be suitable.

3D Architecture

Three-dimensional integration to create multilayer Si ICs is a concept that can significantly improve interconnect performance ,increase transistor packing density, and reduce chip area and power dissipation. Additionally 3D ICs can be very effective large scale on chip integration of different systems.

In 3D design architecture, and entire(2D) chips is divided into a number of blocks is placed on separate layer of Si that are stacked on top of each other. Each Si layer in the 3D structure can have multiple layer of interconnects(VILICs) and common global interconnects.



Sensors on 3D Digitization


Introduction


Digital 3D imaging can benefit from advances in VLSI technology in order to accelerate its deployment in many fields like visual communication and industrial automation. High-resolution 3D images can be acquired using laser-based vision systems. With this approach, the 3D information becomes relatively insensitive to background illumination and surface texture. Complete images of visible surfaces that are rather featureless to the human eye or a video camera can be generated. Intelligent digitizers will be capable of measuring accurately and simultaneously colour and 3D.

Colour 3D Imaging Technology

Machine vision involves the analysis of the properties of the luminous flux reflected or radiated by objects. To recover the geometrical structures of these objects, either to recognize or to measure their dimension, two basic vision strategies are available [1].

Passive vision, attempts to analyze the structure of the scene under ambient light. [1] Stereoscopic vision is a passive optical technique. The basic idea is that two or more digital images are taken from known locations. The images are then processed to find the correlations between them. As soon as matching points are identified, the geometry can be computed.

Active vision attempts to reduce the ambiguity of scene analysis by structuring the way in which images are formed. Sensors that capitalize on active vision can resolve most of the ambiguities found with two-dimensional imaging systems. Lidar based or triangulation based laser range cameras are examples of active vision technique. One digital 3D imaging system based on optical triangulation were developed and demonstrated.

Sensors For 3D Imaging

The sensors used in the autosynchronized scanner include

1. Synchronization Circuit Based Upon Dual Photocells

This sensor ensures the stability and the repeatability of range measurements in environment with varying temperature. Discrete implementations of the so-called synchronization circuits have posed many problems in the past. A monolithic version of an improved circuit has been built to alleviate those problems. [1]

2. Laser Spot Position Measurement Sensors

High-resolution 3D images can be acquired using laser-based vision systems. With this approach, the 3D information becomes relatively insensitive to background illumination and surface texture. Complete images of visible surfaces that are rather featureless to the human eye or a video camera can be generated.[1]




Fuzzy Logic


Introduction


In this context, FL is a problem-solving control system methodology that lends itself to implementation in systems ranging from simple, small, embedded micro-controllers to large, networked, multi-channel PC or workstation-based data acquisition and control systems. It can be implemented in hardware, software, or a combination of both. FL provides a simple way to arrive at a definite conclusion based upon vague, ambiguous, imprecise, noisy, or missing input information.

FL's approach to control problems mimics how a person would make decisions, only much faster.
As the complexity of a system increases, it becomes more difficult and eventually impossible to make a precise statement about its behavior, eventually arriving at a point of complexity where the fuzzy logic method born in humans is the only way to get at the problem.


History


The concept of Fuzzy Logic (FL) was conceived by Lotfi Zadeh, a professor at the University of California at Berkley, and presented not as a control methodology, but as a way of processing data by allowing partial set membership rather than crisp set membership or non-membership. This approach to set theory was not applied to control systems until the 70's due to insufficient small-computer capability prior to that time. Professor Zadeh reasoned that people do not require precise, numerical information input, and yet they are capable of highly adaptive control. If feedback controllers could be programmed to accept noisy, imprecise input, they would be much more effective and perhaps easier to implement. Unfortunately, U.S. manufacturers have not been so quick to embrace this technology while the Europeans and Japanese have been aggressively building real products around it.



Simputer


Introduction


Simputer is a multilingual mass access low cost hand held device currently being developed. The information mark up language is the primary format of the content accessed by the Simputer. The information mark up language (IML) has been created to provide a uniform experience to users and to allow rapid development of solution on any platform.
The Simputer proves that illiteracy is no longer a barrier in handling a computer. The Simputer through its smart card feature allows for personal information management at the individual level for a unlimited number of users. Applications in diverse sectors can be made possible at an affordable price.

A rapid growth of knowledge can only happen in an environment which admits free exchange of thought of information. Indeed, nothing else can explain the astounding progress of science in the last three hundred years. Technology has unfortunately not seen this freedom two often. Several rounds of intends discussions among the trustees convinced them that the only way to break out the current absurdities is to foster a spirit of co-operation in inventing new technologies. The common mistake of treating to-operation as a synonym of charity poses its own challenges. The Simputer Licensing Framework is the Trust's responds to these challenges.

What is Simputer?
A Simputer is a multilingual, mass access, low cost, portable alternative to PC's by which the benefits of IT can reach the common man. It has a special role in the third world because it is ensures that illiteracy is no longer barrier in handling a computer. The key to bridging the digital divide is to have shared devices that permit truly simple and natural users interfaces based on sight, touch and studio. The Simputer meets these demands through a browser for the Information Markup Language (IML). IML has been created to provide a uniform experience to users to allow rapid development of solutions on any platform.

Features
Simputer is a hand held device with the following features:
- It is portable
- A (320 X 240) LCD Panel which is touch enabled
- A speaker, microphone and a few keys
- A soft keyboard
- A stylus is a pointing device
- Smart card reader in Simputer
- The use of extensive audio in the form of text to speech and audio snippets
The display resolution is much smaller than the usual desktop monitor but much higher than usual wireless devices (cell phones, pagers etc). The operating system for Simputer is Linux. It is designed so that Linux is to be started up in frequently, but the Simputer is in a low power mode during the times it is not in use. When the Simputer is 'powered on', the user is presented with a screed having several icons.

What Makes Simputer Different From Regular PCs?
Simputer is not a personal computer. It could however be a pocket computer. It is much more powerful than a Palm, with screen size 320 x 240 and memory capability (32MB RAM). The Wintel (Windows + Intel) architecture of the de facto standard PC is quite unsuitable for deployment on the low cost mass market. The entry barrier due to software licensing is just too high. While the Wintel PC provides a de facto level f standardization, it is not an open architecture. The Simputer mean while is centered around Linux which is freely available, open and modular.

Wavelet Video Processing Technology


Introduction


Uncompressed multimedia data requires considerable storage capacity and transmission bandwidth. Despite rapid progress in mass storage density processor speeds and digital communication system performance, demand for data storage capacity and data transmission bandwidth continues to outstrip the capabilities of available technologies. The recent growth of data intensive multimedia-based web applications have not only sustained the need for more efficient ways to encode signals and images but have made compression of such signals central to storage and communication technology.

For still image compression, the joint photographic experts group (JPEG) standard has been established. The performance of these codes generally degrades at low bit rates mainly because of the underlying block-based Discrete cosine Transform (DCT) scheme. More recently, the wavelet transform has emerged as a cutting edge technology, within the field of image compression. Wavelet based coding provides substantial improvements in picture quality at higher compression ratios. Over the past few years, a variety of powerful and sophisticated wavelet based schemes for image compression have been developed and implemented. Because of the many advantages, the top contenders in JPEG-2000 standard are all wavelet based compression algorithms.

Image Compression

Image compression is a technique for processing images. It is the compressor of graphics for storage or transmission. Compressing an image is significantly different than compressing saw binary data. Some general purpose compression programs can be used to compress images, but the result is less than optimal. This is because images have certain statistical properties which can be exploited by encoders specifically designed for them. Also some finer details in the image can be sacrificed for saving storage space.

Compression is basically of two types.
1. Lossy Compression
2. Lossless Compression.

Lossy compression of data concedes a certain loss of accuracy in exchange for greatly increased compression. An image reconstructed following lossy compression contains degradation relative to the original. Often this is because the compression scheme completely discards redundant information. Under normal viewing conditions no visible is loss is perceived. It proves effective when applied to graphics images and digitized voice.
Lossless compression consists of those techniques guaranteed to generate an exact duplicate of the input data stream after a compress or expand cycle. Here the reconstructed image after compression is numerically identical to the original image. Lossless compression can only achieve a modest amount of compression. This is the type of compression used when storing data base records, spread sheets or word processing files.

IP Telephony


Introduction


If you've never heard of Internet Telephony, get ready to change the way you think about long-distance phone calls. Internet Telephony, or Voice over Internet Protocol, is a method for taking analog audio signals, like the kind you hear when you talk on the phone, and turning them into digital data that can be transmitted over the Internet.
How is this useful? Internet Telephony can turn a standard Internet connection into a way to place free phone calls. The practical upshot of this is that by using some of the free Internet Telephony software that is available to make Internet phone calls, you are bypassing the phone company (and its charges) entirely.


Internet Telephony is a revolutionary technology that has the potential to completely rework the world's phone systems. Internet Telephony providers like Vonage have already been around for a little while and are growing steadily. Major carriers like AT&T are already setting up Internet Telephony calling plans in several markets around the United States, and the FCC is looking seriously at the potential ramifications of Internet Telephony service.
Above all else, Internet Telephony is basically a clever "reinvention of the wheel." In this article, we'll explore the principles behind Internet Telephony, its applications and the potential of this emerging technology, which will more than likely one day replace the traditional phone system entirely.


The interesting thing about Internet Telephony is that there is not just one way to place a call.

There are three different "flavors" of Internet Telephony service in common use today:
ATA - The simplest and most common way is through the use of a device called an ATA (analog telephone adaptor). The ATA allows you to connect a standard phone to your computer or your Internet connection for use with Internet Telephony.

The ATA is an analog-to-digital converter. It takes the analog signal from your traditional phone and converts it into digital data for transmission over the Internet. Providers like Vonage and AT&T CallVantage are bundling ATAs free with their service. You simply crack the ATA out of the box, plug the cable from your phone that would normally go in the wall socket into the ATA, and you're ready to make Internet Telephony calls. Some ATAs may ship with additional software that is loaded onto the host computer to configure it; but in any case, it is a very straightforward setup.


IP Phones - These specialized phones look just like normal phones with a handset, cradle and buttons. But instead of having the standard RJ-11 phone connectors, IP phones have an RJ-45 Ethernet connector. IP phones connect directly to your router and have all the hardware and software necessary right onboard to handle the IP call. Wi-Fi phones allow subscribing callers to make Internet Telephony calls from any Wi-Fi hot spot.


Computer-to-computer - This is certainly the easiest way to use Internet Telephony. You don't even have to pay for long-distance calls. There are several companies offering free or very low-cost software that you can use for this type of Internet Telephony. All you need is the software, a microphone, speakers, a sound card and an Internet connection, preferably a fast one like you would get through a cable or DSL modem. Except for your normal monthly ISP fee, there is usually no charge for computer-to-computer calls, no matter the distance.


If you're interested in trying Internet Telephony, then you should check out some of the free Internet Telephony software available on the Internet. You should be able to download and set it up in about three to five minutes. Get a friend to download the software, too, and you can start tinkering with Internet Telephony to get a feel for how it works.


RPR


Introduction


The nature of the public network has changed. Demand for Internet Protocol (IP) data is growing at a compound annual rate of between 100% and 800%1, while voice demand remains stable. What was once a predominantly circuit switched network handling mainly circuit switched voice traffic has become a circuit-switched network handling mainly IP data. Because the nature of the traffic is not well matched to the underlying technology, this network is proving very costly to scale. User spending has not increased proportionally to the rate of bandwidth increase, and carrier revenue growth is stuck at the lower end of 10% to 20% per year. The result is that carriers are building themselves out of business.

Over the last 10 years, as data traffic has grown both in importance and volume, technologies such as frame relay, ATM, and Point-to-Point Protocol (PPP) have been developed to force fit data onto the circuit network. While these protocols provided virtual connections-a useful approach for many services-they have proven too inefficient, costly and complex to scale to the levels necessary to satisfy the insatiable demand for data services. More recently, Gigabit Ethernet (GigE) has been adopted by many network service providers as a way to network user data without the burden of SONET/SDH and ATM. GigE has shortcomings when applied in carrier networks were recognized and for these problems, a technology called Resilient Packet Ring Technology were developed.

RPR retains the best attributes of SONET/SDH, ATM, and Gigabit Ethernet. RPR is optimized for differentiated IP and other packet data services, while providing uncompromised quality for circuit voice and private line services. It works in point-to-point, linear, ring, or mesh networks, providing ring survivability in less than 50 milliseconds. RPR dynamically and statistically multiplexes all services into the entire available bandwidth in both directions on the ring while preserving bandwidth and service quality guarantees on a per-customer, per-service basis. And it does all this at a fraction of the cost of legacy SONET/SDH and ATM solutions.

Data, rather than voice circuits, dominates today's bandwidth requirements. New services such as IP VPN, voice over IP (VoIP), and digital video are no longer confined within the corporate local-area network (LAN). These applications are placing new requirements on metropolitan-area network (MAN) and wide-area network (WAN) transport. RPR is uniquely positioned to fulfill these bandwidth and feature requirements as networks transition from circuit-dominated to packet-optimized infrastructures.

RPR technology uses a dual counter rotating fiber ring topology. Both rings (inner and outer) are used to transport working traffic between nodes. By utilizing both fibers, instead of keeping a spare fiber for protection, RPR utilizes the total available ring bandwidth. These fibers or ringlets are also used to carry control (topology updates, protection, and bandwidth control) messages. Control messages flow in the opposite direction of the traffic that they represent. For instance, outer-ring traffic-control information is carried on the inner ring to upstream nodes.




PH Control Technique using Fuzzy Logic


Introduction
Fuzzy control is a practical alternative for a variety of challenging control applications since it provides a convenient method for constructing non-linear controllers via the use of heuristic information. Since heuristic information may come from an operator who has acted as "a human in the loop" controller for a process. In the fuzzy control design methodology, a set of rules on how to control the process is written down and then it is incorporated into a fuzzy controller that emulates the decision making process of the human.

In other cases, the heuristic information may come from a control engineer who has performed extensive mathematical modelling, analysis and development of control algorithms for a particular process. The rest of the process is the same as the earlier case. The ultimate objective of using fuzzy control is to provide a user-friendly formalism for representing and implementing the ideas we have about how to achieve high performance control. Apart from being a heavily used technology these days, fuzzy logic control is simple, effective and efficient. In this paper, the structure, working and design of a fuzzy controller is discussed in detail through an in-depth analysis of the development and functioning of a fuzzy logic pH controller.

PH Control

To illustrate the application of fuzzy logic, the remaining section of the paper is directed towards the design and working of a pH control system using fuzzy logic.

PH is an important variable in the field of production especially in chemical plants, sugar industries, etc. PH of a solution is defined as the negative of the logarithm of the hydrogen ion concentration, to the base 10. I.e., PH= -log 10 [H+]
Let us consider the stages of operation of a sugar industry, where PH control is required. The main area of concern is the clarification of raw juice of sugarcane. The raw juice will be having a PH of 5.1 to 5.5. The clarified juice should ideally be neutral. I.e., the set point should be a PH of 7. The process involves addition of lime and SO2 gas for clarifying the raw juice. The addition of these two are called liming and sulphitation respectively. Since the process involves continuous addition of lime and SO2 ; lime has a property of increasing the PH of the clarified juice. This is the principle used for PH control in sugar industries. The PH of the raw juice is measured and this value is compared to the set point and this is further used for changing the diameter of the lime flow pipe as per the requirement.

The whole process can be summarised as follows. The PH sensor measures the PH. This reading is amplified and recorded. The output of the amplifier is also fed to the PH indicator and interface. The output of this block is fed to the fuzzy controller. The output of fuzzy controller is given to the stepper motor drive. This inturn adjusts the diameter of lime flow pipe as per the requirement. Thus, the input to the fuzzy controller is the PH reading of the raw juice.

The output of the fuzzy controller is the diameter of the lime flow pipe valve or a quantity that controls the diameter of the lime flow pipe valve like a DC current, voltage, etc. The output obtained from the fuzzy controller is used to drive a stepper motor which inturn controls the diameter of the value opening of the lime flow pipe. This output tends to maintain the pH value of sugar juice to a target value. A detailed description of the design and functioning of the fuzzy controller is given in the following section.


Multisensor Fusion and Integration


Introduction
Sensor is a device that detects or senses the value or changes of value of the variable being measured. The term sensor some times is used instead of the term detector, primary element or transducer.

The fusion of information from sensors with different physical characteristics, such as light, sound, etc enhances the understanding of our surroundings and provide the basis for planning, decision making, and control of autonomous and intelligent machines.


Sensors Evolution

A sensor is a device that responds to some external stimuli and then provides some useful output. With the concept of input and output, one can begin to understand how sensors play a critical role in both closed and open loops.

One problem is that sensors have not been specified. In other words they tend to respond variety of stimuli applied on it without being able to differentiate one from another. Neverthless, sensors and sensor technology are necessary ingredients in any control type application. Without the feedback from the environment that sensors provide, the system has no data or reference points, and thus no way of understanding what is right or wrong g with its various elements.

Sensors are so important in automated manufacturing particularly in robotics. Automated manufacturing is essentially the procedure of remo0ving human element as possible from the manufacturing process. Sensors in the condition measurement category sense various types of inputs, condition, or properties to help monitor and predict the performance of a machine or system.

Multisensor Fusion And Integration

Multisensor integration is the synergistic use of the information provided by multiple sensory devices to assist in the accomplishment of a task by a system.

Multisensor fusion refers to any stage in the integration process where there is an actual combination of different sources of sensory information into one representational format.


Multisensor Integration

The diagram represents multisensor integration as being a composite of basic functions. A group of n sensors provide input to the integration process. In order for the data from each sensor to be used for integration, it must first be effectively modelled. A sensor model represents the uncertainty and error in the data from each sensor and provides a measure of its quality that can be 7used by the subsequent integration functions.

Integrated Power Electronics Module


Introduction


In power electronics, solid-state electronics is used for the control and conversion of electric power .The goal of power electronics is to realize power conversion from electrical source to an electrical load in a highly efficient, highly reliable and cost effective way. Power electronics modules are key units in a power electronics system. These modules contain integration of power switches and associated electronic circuitry for drive control and protection and other passive components.

During the past decades, power devices underwent generation-by-generation improvements and can now handle significant power density. On the other hand power electronics packaging has not kept pace with the development of semiconductor devices. This is due to the limitations of power electronics circuits. The integration of power electronics circuit is quite different from that of other electronics circuits. The objective of power electronics circuits is electronics energy processing and hence require high power handling capability and proper thermal management.

Most of the currently used power electronic modules are made by using wire-bonding technology [1,2]. In these packages power semi conductor dies are mounted on a common substrate and interconnected with wire bonds. Other associated electronic circuitries are mounted on a multi layer PCB and connected to the power devices by vertical pins. These wire bonds are prone to resistance, parasitic and fatigue failure. Due to its two dimensional structure the package has large size. Another disadvantage is the ringing produced by parasitic associated with the wire bonds.

To improve the performance and reliability of power electronics packages, wire bonds must be replaced. The researches in power electronic packaging have resulted in the development of an advanced packaging technique that can replace wire bonds. This new generation package is termed as 'Integrated Power Electronics Module' (IPEM) [1]. In this, planar metalization is used instead of conventional wire bonds. It uses a three-dimensional integration technique that can provide low profile high-density systems. It offers high frequency operation and improved performance. It also reduces the size, weight and cost of the power modules.

Features Of IPEMS

The basic structure of an IPEM contains power semi conductor devices, control/drive/protection electronics and passive components. Power devices and their drive and protection circuit is called the active IPEM and the remaining part is called passive IPEM. The drive and protection circuits are realized in the form of hybrid integrated circuit and packaged together with power devices. Passive components include inductors, capacitors, transformers etc.

The commonly used power switching devices are MOSFETs and IGBTs [3]. This is mainly due to their high frequency operation and low on time losses. Another advantage is their inherent vertical structure in which the metalization electrode pads are on two sides. Usually the gate source pads are on the top surface with non-solderable thin film metal Al contact. The drain metalization using Ag or Au is deposited on the bottom of chip and is solderable. This vertical structure of power chips offers advantage to build sand witch type 3-D integration constructions.

H.323


Introduction


In a constantly changing industry, HDMI is the next major attempt at an all-in-one, standardized, universal connector for audio/video applications. Featuring a modern design and backed by the biggest names in the electronic industry, HDMI is set to finally unify all digital media components with a single cable, remote, and interface.


HDMI is built with a 5 Gbps bandwidth limit, over twice that of HDTV (which runs at 2.2 Gbps), and is built forwards-compatible by offering unallocated pipeline for future technologies. The connectors are sliding contact (like FireWire and USB) instead of screw-on (like DVI), and are not nearly as bulky as most current video interfaces.
HDMI 1.3 further increases the bandwith limit to 10.2 Gbps, to allow for the video and audio improvements of the upgraded standard.


The screaming bandwidth of HDMI is structured around delivering the highest-quality digital video and audio throughout your entertainment center. Capable of all international frequencies and resolutions, the HDMI cable will replace all analog signals (i.e. S-Video, Component, Composite, and Coaxial), as well as HDTV digital signals (i.e. DVI, P&D, DFP), with absolutely no compromise in quality.


Additionally, HDMI is capable of carrying up to 8 channels of digital-audio, replacing the old analog connections (RCA, 3.5mm) as well as optical formats (SPDIF, Toslink).


The HDMI Founders include leading consumer electronics manufacturers Hitachi, Matsushita Electric Industrial (Panasonic), Philips, Sony, Thomson (RCA), Toshiba, and Silicon Image. Digital Content Protection, LLC (a subsidiary of Intel) is providing High-bandwidth Digital Content Protection (HDCP) for HDMI. In addition, HDMI has the support of major motion picture producers Fox and Universal, and system operators DirecTV, EchoStar (Dish Network) as well as CableLabs.

HDMI and HDCP are two distinctly separate standards, owned by separate governing entities. The HDMI Working Group is comprised of seven founding companies: Hitachi, Matsushita (best known for the Panasonic brand), Philips, Silicon Image, Sony, Thomson (known for RCA branded products) and Toshiba. These companies worked together to develop the HDMI specification, which is currently at version 1.1. The HDMI Licensing LLC administers HDMI licenses and the mandatory compliance testing associated for HDMI.

GMPLS


Introduction


The emergence of optical transport systems has dramatically increased the raw capacity of optical networks and has enabled new sophisticated applications. For example, network-based storage, bandwidth leasing, data mirroring, add/drop multiplexing [ADM], dense wavelength division multiplexing [DWDM], optical cross-connect [OXC], photonic cross-connect [PXC], and multiservice switching platforms are some of the devices that may make up an optical network and are expected to be the main carriers for the growth in data traffic.

Multiple Types of Switching and Forwarding Hierarchies

Generalized MPLS (GMPLS) differs from traditional MPLS in that it supports multiple types of switching, i.e. the addition of support for TDM, lambda, and fiber (port) switching. The support for the additional types of switching has driven GMPLS to extend certain base functions of traditional MPLS and, in some cases, to add functionality. These changes and additions impact basic LSP properties, how labels are requested and communicated, the unidirectional nature of LSPs, how errors are propagated, and information provided for synchronizing the ingress and egress LSRs.

1. Packet Switch Capable (PSC) interfaces:
Interfaces that recognize packet boundaries and can forward data based on the content of the packet header. Examples include interfaces on routers that forward data based on the content of the IP header and interfaces on routers that forward data based on the content of the MPLS "shim" header.

2 . Time-Division Multiplex Capable (TDM) interfaces:
Interfaces that forward data based on the data's time slot in a repeating cycle. An example of such an interface is that of a SDH/SONET Cross-Connect (XC), Terminal Multiplexer (TM), or Add-Drop Multiplexer (ADM).

3 . Lambda Switch Capable (LSC) interfaces:
Interfaces that forward data based on the wavelength on which the data is received. An example of such an interface is that of a Photonic Cross-Connect (PXC) or Optical Cross-Connect (OXC) that can operate at the level of an individual wavelength. Additional examples include PXC interfaces that can operate at the level of a group of wavelengths, i.e. a waveband.

4. Fiber-Switch Capable (FSC) interfaces:
Interfaces that forward data based on a position of the data in the real world physical spaces. An example of such an interface is that of a PXC or OXC that can operate at the level of a single or multiple fibers.

The diversity and complexity in managing these devices have been the main driving factors in the evolution and enhancement of the MPLS suite of protocols to provide control for not only packet-based domains, but also time, wavelength, and space domains. GMPLS further extends the suite of IP-based protocols that manage and control the establishment and release of label switched paths (LSP) that traverse any combination of packet, TDM, and optical networks. GMPLS adopts all technology in MPLS.


Fluorescent Multi-layer Disc


Introduction


Requirements for removable media storage devices (RMSDs) used with personal computers have changed significantly since the introduction of the floppy disk in 1971. At one time, desktop computers depended on floppy disks for all of their storage requirements. Even with the advent of multigigabyte hard drives, floppy disks and other RMSDs are still an integral part of most computer systems, providing.

¢ Transport between computers for data files and software
¢ Backup to preserve data from the hard dive
¢ A way to load the operating system software in the event of a hard failure.

Data storage devices currently come in a variety of different capacities, access time, data transfer rate and cost per Gigabyte. The best overall performance figures are currently achieved using hard disk drives (HDD), which can be integrated into RAID systems (reliable arrays of inexpensive drives) at costs of $10 per GByte (1999). Optical disc drives (ODD) and tapes can be configured in the form of jukeboxes and tape libraries, with cost of a few dollars per GByte for the removable media. However, the complex mechanical library mechanism serves to limit data access time to several seconds and affects the reliability adversely.

Most information is still stored in non-electronic form, with very slow access and excessive costs (e.g., text on paper, at a cost of $10 000 per GByte).Some RMSD options available today are approaching the performance, capacity, and cost of hard-disk drives. Considerations for selecting an RMSD include capacity, speed, convenience, durability, data availability, and backward-compatibility. Technology options used to read and write data include.

¢ Magnetic formats that use magnetic particles and magnetic fields.
¢ Optical formats that use laser light and optical sensors.
¢ Magneto-optical and magneto-optical hybrids that use a combination of magnetic and optical properties to increase storage capacity.


The introduction of the Fluorescent Multi-layer Disc (FMD) smashes the barriers of existing data storage formats. Depending on the application and the market requirements, the first generation of 120mm (CD Sized) FMD ROM discs will hold 20 - 100 GigaBytes of pre -recorded data on 12 - 30 data layers with a total thickness of under 2mm.In comparison, a standard DVD disc holds just 4.7 gigabytes. With C3D's (Constellation 3D) proprietary parallel reading and writing technology, data transfer speeds can exceed 1 gigabit per second, again depending on the application and market need.


WHY FMD?

Increased Disc Capacity
DVD data density (4.7 GB) on each layer of data carriers up to 100 layers. Initially, the FMD disc will hold anywhere from 25 - 140 GB of data depending on market need. Eventually a terabyte of data on a single disc will be achievable.

Quick Parallel Access and Retrieval of Information
Reading from several layers at a ime and multiple tracks at a time nearly impossible using the reflective technology of a CD/DVD - is easily achieved in FMD. This will allow for retrieval speeds of up to 1 gigabyte per second.

Media Tolerances
By using incoherent light to read data the FMD/FMC media will have far fewer restrictions in temperature range, vibration and air- cleanness during manufacturing. And will provide a considerably more robust data carrier than existing CD and DVDs.


Digital Visual Interface


Introduction


In a constantly changing industry, DVI is the next major attempt at an all-in-one, standardized, universal connector for audio/video applications. Featuring a modern design and backed by the biggest names in the electronic industry, DVI is set to finally unify all digital media components with a single cable, remote, and interface.
DVI is built with a 5 Gbps bandwidth limit, over twice that of HDTV (which runs at 2.2 Gbps), and is built forwards-compatible by offering unallocated pipeline for future technologies. The connectors are sliding contact (like FireWire and USB) instead of screw-on (like DVI), and are not nearly as bulky as most current video interfaces.


The screaming bandwidth of HDMI is structured around delivering the highest-quality digital video and audio throughout your entertainment center. Capable of all international frequencies and resolutions, the HDMI cable will replace all analog signals (i.e. S-Video, Component, Composite, and Coaxial), as well as HDTV digital signals (i.e. DVI, P&D, DFP), with absolutely no compromise in quality.
Additionally, HDMI is capable of carrying up to 8 channels of digital-audio, replacing the old analog connections (RCA, 3.5mm) as well as optical formats (SPDIF, Toslink).


VIDEO INTERFACES

Video Graphics Array (VGA) is an analog computer display standard first marketed in 1987 by IBM. While it has been obsolete for some time, it was the last graphical standard that the majority of manufacturers decided to follow, making it the lowest common denominator that all PC graphics hardware supports prior to a device-specific driver being loaded. For example, the Microsoft Windows splash screen appears while the machine is still operating in VGA mode, which is the reason that this screen always appears in reduced resolution and color depth.


The term VGA is often used to refer to a resolution of 640×480, regardless of the hardware that produces the picture. It may also refer to the 15-pin D-subminiature VGA connector which is still widely used to carry analog video signals of all resolutions.


VGA was officially superseded by IBM's XGA standard, but in reality it was superseded by numerous extensions to VGA made by clone manufacturers that came to be known as "Super VGA".


A Male DVI-I Plug
The DVI interface uses a digital protocol in which the desired brightness of pixels is transmitted as binary data. When the display is driven at its native resolution, all it has to do is read each number and apply that brightness to the appropriate pixel. In this way, each pixel in the output buffer of the source device corresponds directly to one pixel in the display device, whereas with an analog signal the appearance of each pixel may be affected by its adjacent pixels as well as by electrical noise and other forms of analog distortion.
Previous standards such as the analog VGA were designed for CRT-based devices and thus did not use discrete time. As the analog source transmits each horizontal line of the image, it varies its output voltage to represent the desired brightness. In a CRT device, this is used to vary the intensity of the scanning beam as it moves across the screen.


Compact peripheral component interconnect (CPCI)


Introduction


Compact peripheral component interconnect (CPCI) is an adaptation of the peripheral component interconnect (PCI) specification for industrial computer applications requiring a smaller, more robust mechanical form factor than the one defined for the desktop. CompactPCI is an open standard supported by the PCI Industrial Computer Manufacturer's Group (PICMG). CompactPCI is best suited for small, high-speed industrial computing applications where transfers occur between a number of high-speed cards.

It is a high-performance industrial bus that uses the Eurocard form factor and is fully compatible with the Enterprise Computer Telephony Forum(ECTF) computer telephony (CT) Bus™ H.110 standard specification. CompactPCI products make it possible for original equipment manufacturers (OEM), integrators, and resellers to build powerful and cost-effective solutions for telco networks, while using fewer development resources. CompactPCI products let developers scale their applications to the size, performance, maintenance, and reliability demands of telco environments by supporting the CT Bus, hot swap, administrative tools such as simple network management protocol (SNMP), and extensive system diagnostics. The move toward open, standards-based systems has revolutionized the computer telephony (CT) industry. There are a number of reasons for these changes. Open systems have benefited from improvements in personal computer (PC) hardware and software, as well as from advances in digital signal processing (DSP) technology. As a result, flexible, high performance systems are scalable to thousands of ports while remaining cost effective for use in telco networks. In addition, fault-tolerant chassis, distributed software architecture, and N+1 redundancy have succeeded in meeting the demanding reliability requirements of network operators.

One of the remaining hurdles facing open CT systems is serviceability. CT systems used in public networks must be extremely reliable and easy to repair without system downtime. In addition, network operation requires first-rate administrative and diagnostic capabilities to keep services up and running.


The Compact PCI Standard

The Peripheral Component Interconnect Industrial Computer Manufacturer's Group (PICMG) developed the compact peripheral component interconnect (CompactPCI) specification in 1994. CompactPCI is a high-performance industrial bus based on the peripheral component interconnect (PCI) electrical standard. It uses the Eurocard form factor first popularized by VersaModule-Eurocard (VME). Compared to the standard PCI desktop computer, CompactPCI supports twice as many PCI slots (eight) on a single system bus. In addition, CompactPCI boards are inserted from the front of the chassis and can route input/output (I/O) through the backplane to the back of the chassis. These design considerations make CompactPCI ideal for telco environments.

CompactPCI offers a substantial number of benefits for developers interested in building telco-grade applications. CompactPCI systems offer the durability and maintainability required for network applications. At the same time, they can be built using standard, off-the-shelf components and can run almost any operating system and thousands of existing software applications without modification. Other advantages of CompactPCI are related to its Eurocard form factor, durable and rugged design, hot swap capability, and compatibility with the CT Bus.


Datalogger


Introduction
A data logger (or datalogger) is an electronic instrument that records data over time or in relation to location. Increasingly, but not necessarily, they are based on a digital processor (or computer). They may be small, battery powered and portable and vary between general purpose types for a range of measurement applications to very specific devices for measuring in one environment only.It is common for general purpose types to beprogrammable.
Standardisation of protocols and data formats is growing in the industry and XML is increasingly being adopted for data exchange. The development of the Semantic Web is likely to accelerate this trend. A smart protocol, SDI-12, exists that allows some instrumentation to be connected to a variety of data loggers. The use of this standard has not gained much acceptance outside the environmental industry. SDI-12 also supports multi drop instruments.

Some datalogging companies are also now supporting the MODBUS standard, this has been used traditionally in the industrial control area there are many industrial instruments which support this communication standard. Some data loggers utilize a flexible scripting environment to adapt themselves to various non-standard protocols.
Another multi drop protocol which is now stating to become more widely used is based upon CANBUS (ISO 11898) this bus system was originally developed by Robert Bosch for the automotive industry. This protocol is ideally suited to higher speed logging, the data is divided into small individually addressed 64 bit packets of information with a very strict priority. This standard from the automotive/machine area is now seeping into more traditional data logging areas, a number of newer players and some of the more traditional players have loggers supporting sensors with this communications bus.


DATA LOGGING VERSUS DATA ACQUISITION


The terms data logging and data acquisition are often used interchangeably. However, in a historical context they are quite different. A data logger is a data acquisition system, but a data acquisition system is not necessarily a data logger.
" Data loggers typically have slower sample rates. A maximum sample rate of 1 Hz may be considered to be very fast for a data logger, yet very slow for a typical data acquisition system.


" Data loggers are implicitly stand-alone devices, while typical data acquisition system must remain tethered to a computer to acquire data. This stand-alone aspect of data loggers implies on-board memory that is used to store acquired data. Sometimes this memory is very large to accommodate many days, or even months, of unattended recording. This memory may be battery-backed static random access memory, flash memory or EEPROM. Earlier data loggers used magnetic tape, punched paper tape, or directly viewable records such as "strip chart recorders".


" Given the extended recording times of data loggers, they typically feature a time- and date-stamping mechanism to ensure that each recorded data value is associated with a date and time of acquisition. As such, data loggers typically employ built-in real-time clocks whose published drift can be an important consideration when choosing between data loggers.


" Data loggers range from simple single-channel input to complex multi-channel instruments. Typically, the simpler the device the less programming flexibility. Some more sophisticated instruments allow for cross-channel computations and alarms based on predetermined conditions. The newest of data loggers can serve web pages, allowing numerous people to monitor a system remotely.


Voice morphing


Definition

Voice morphing means the transition of one speech signal into another. Like image morphing, speech morphing aims to preserve the shared characteristics of the starting and final signals, while generating a smooth transition between them. Speech morphing is analogous to image morphing. In image morphing the in-between images all show one face smoothly changing its shape and texture until it turns into the target face. It is this feature that a speech morph should possess. One speech signal should smoothly change into another, keeping the shared characteristics of the starting and ending signals but smoothly changing the other properties.

The major properties of concern as far as a speech signal is concerned are its pitch and envelope information. These two reside in a convolved form in a speech signal. Hence some efficient method for extracting each of these is necessary. We have adopted an uncomplicated approach namely cepstral analysis to do the same. Pitch and formant information in each signal is extracted using the cepstral approach. Necessary processing to obtain the morphed speech signal include methods like Cross fading of envelope information, Dynamic Time Warping to match the major signal features (pitch) and Signal Re-estimation to convert the morphed speech signal back into the acoustic waveform.

INTROSPECTION OF THE MORPHING PROCESS

Speech morphing can be achieved by transforming the signal's representation from the acoustic waveform obtained by sampling of the analog signal, with which many people are familiar with, to another representation. To prepare the signal for the transformation, it is split into a number of 'frames' - sections of the waveform. The transformation is then applied to each frame of the signal. This provides another way of viewing the signal information. The new representation (said to be in the frequency domain) describes the average energy present at each frequency band.

Further analysis enables two pieces of information to be obtained: pitch information and the overall envelope of the sound. A key element in the morphing is the manipulation of the pitch information. If two signals with different pitches were simply cross-faded it is highly likely that two separate sounds will be heard. This occurs because the signal will have two distinct pitches causing the auditory system to perceive two different objects. A successful morph must exhibit a smoothly changing pitch throughout.

The pitch information of each sound is compared to provide the best match between the two signals' pitches. To do this match, the signals are stretched and compressed so that important sections of each signal match in time. The interpolation of the two sounds can then be performed which creates the intermediate sounds in the morph. The final stage is then to convert the frames back into a normal waveform.

VISNAV


Definition

The VISNAV system uses a Position Sensitive Diode (PSD) sensor for 6 DOF estimation. Output current from the PSD sensor determines the azimuth and elevation of the light source with respect to the sensor. By having four or more light source called beacons in the target frame at known positions the six degree of freedom data associated with the sensor is calculated.

The beacon channel separation and demodulation are done on a fixed point digital signal processor (DSP) Texas Instruments TMS320C55x [2] using digital down conversion, synchronous detection and multirate signal processing techniques. The demodulated sensor currents due to each beacon are communicated to a floating point DSP Texas Instruments TMS320VC33 [2] for subsequent navigation solution by the use of colinearity equations.

Among other competitive systems [3] a differential global positioning system (GPS) is limited to midrange accuracies, lower bandwidth, and requires complex infrastructures. The sensor systems based on differential GPS are also limited by geometric dilution of precision, multipath errors, receiver errors, etc.These limitations can be overcome by using the DSP embedded VISNAV system


FACTORS AFECTING MEASUREMENT

There is likely to be a large amount of ambient light at short wavelength and low carrier frequencies due to perhaps the sun, its reflections, incandescent or discharge tube lights, LCD and cathode ray tube displays etc. In many cases this ambient energy would swap a relatively small beacon signal and the PSD centroid data would mostly correspond to this unwanted background light.

In order to avoid this problem by modulating the beacon controller current by a sinusoidal carrier of high frequency. The resulting PSD signal currents then vary sinsuoidally at approximately the same frequency and have to be demodulated to recover the actual current proportional to the beacon light centroid. This modulation or demodulation scheme leads high degree of insensitivity to variations in ambient light and it is a key to make the PSD sensing approach practical.

Speed Detection of moving vehicle using speed cameras


Definition

Although there is good road safety performance the number of people killed and injured on our roads remain unacceptably high. So the roads safety strategy was published or introduced to support the new casualty reduction targets. The road safety strategy includes all forms of invention based on the engineering and education and enforcement and recognizes that there are many different factors that lead to traffic collisions and casualties. The main reason is speed of vehicle. We use traffic lights and other traffic manager to reduce the speed. One among them is speed cameras.

Speed cameras on the side of urban and rural roads, usually placed to catch transgressors of the stipulated speed limit for that road. The speed cameras, the solely to identify and prosecute those drivers that pass by the them when exceed the stipulated speed limit.

At first glance this seemed to be reasonable that the road users do not exceed the speed limit must be a good thing because it increases road safety, reduces accidents and protect other road users and pedestrians.
So speed limits are good idea. To enforce these speed limit; laws are passed making speed an offence and signs are erected were of to indicate the maximum permissible speeds. The police can't be every where to enforce the speed limit and so enforcement cameras art director to do this work; on one who's got an ounce of Commons sense, the deliberately drive through speed camera in order fined and penalized .

So nearly everyone slowdown for the speed Camera. We finally have a solution to the speeding problem. Now if we are to assume that speed cameras are the only way to make driver's slowdown, and they work efficiently, then we would expect there to be a great number of these every were and that day would be highly visible and identifiable to make a drivers slow down.


Optical Switching


Definition

Explosive information demand in the internet world is creating enormous needs for capacity expansion in next generation telecommunication networks. It is expected that the data- oriented network traffic will double every year.

Optical networks are widely regarded as the ultimate solution to the bandwidth needs of future communication systems. Optical fiber links deployed between nodes are capable to carry terabits of information but the electronic switching at the nodes limit the bandwidth of a network. Optical switches at the nodes will overcome this limitation. With their improved efficiency and lower costs, Optical switches provide the key to both manage the new capacity Dense Wavelength Division Multiplexing (DWDM) links as well as gain a competitive advantage for provision of new band width hungry services. However, in an optically switched network the challenge lies in overcoming signal impairment and network related parameters. Let us discuss the present status, advantages and challenges and future trends in optical switches.


A fiber consists of a glass core and a surrounding layer called the cladding. The core and cladding have carefully chosen indices of refraction to ensure that the photos propagating in the core are always reflected at the interface of the cladding. The only way the light can enter and escape is through the ends of the fiber. A transmitter either alight emitting diode or a laser sends electronic data that have been converted to photons over the fiber at a wavelength of between 1,200 and 1,600 nanometers.

Today fibers are pure enough that a light signal can travel for about 80 kilometers without the need for amplification. But at some point the signal still needs to be boosted. Electronics for amplitude signal were replaced by stretches of fiber infused with ions of the rare-earth erbium. When these erbium-doped fibers were zapped by a pump laser, the excited ions could revive a fading signal. They restore a signal without any optical to electronic conversion and can do so for very high speed signals sending tens of gigabits a second. Most importantly they can boost the power of many wavelengths simultaneously.

Now to increase information rate, as many wavelengths as possible are jammed down a fiber, with a wavelength carrying as much data as possible. The technology that does this has a name-dense wavelength division multiplexing (DWDM ) - that is a paragon of technospeak.Switches are needed to route the digital flow to its ultimate destination. The enormous bit conduits will flounder if the light streams are routed using conventional electronic switches, which require a multi-terabit signal to be converted into hundreds of lower-speed electronic signals. Finally, switched signals would have to be reconverted to photons and reaggregated into light channels that are then sent out through a designated output fiber.





Optical Satellite Communication


Definition

The European Space Agency (ESA) has programmes underway to place Satellites carrying optical terminals in GEO orbit within the next decade. The first is the ARTEMIS technology demonstration satellite which carries both microwave and SILEX (Semiconductor Laser Intro satellite Link Experiment) optical interorbit communications terminal. SILEX employs direct detection and GaAIAs diode laser technology; the optical antenna is a 25cm diameter reflecting telescope.

The SILEX GEO terminal is capable of receiving data modulated on to an incoming laser beam at a bit rate of 50 Mbps and is equipped with a high power beacon for initial link acquisition together with a low divergence (and unmodulated) beam which is tracked by the communicating partner. ARTEMIS will be followed by the operational European data relay system (EDRS) which is planned to have data relay Satellites (DRS). These will also carry SILEX optical data relay terminals.

Once these elements of Europe's space Infrastructure are in place, these will be a need for optical communications terminals on LEO satellites which are capable of transmitting data to the GEO terminals. A wide range of LEO space craft is expected to fly within the next decade including earth observation and science, manned and military reconnaissance system.

The LEO terminal is referred to as a user terminal since it enables real time transfer of LEO instrument data back to the ground to a user access to the DRS s LEO instruments generate data over a range of bit rates extending of Mbps depending upon the function of the instrument. A significant proportion have data rates falling in the region around and below 2 Mbps. and the data would normally be transmitted via an S-brand microwave IOL

ESA initiated a development programme in 1992 for LEO optical IOL terminal targeted at the segment of the user community. This is known as SMALL OPTICAL USER TERMINALS (SOUT) with features of low mass, small size and compatibility with SILEX. The programme is in two phases. Phase I was to produce a terminal flight configuration and perform detailed subsystem design and modelling. Phase 2 which started in september 1993 is to build an elegant bread board of the complete terminal.



Optical Packet Switching Network


Definition

With in today's Internet data is transported using wavelength division multiplexed (WDM) optical fiber transmission system that carry 32-80 wavelengths modulated at 2.5gb/s and 10gb/s per wavelength. Today's largest routers and electronic switching systems need to handle close to 1tb/s to redirect incoming data from deployed WDM links. Mean while next generation commercial systems will be capable of single fiber transmission supporting hundreds of wavelength at 10Gb/s and world experiments have demonstrated 10Tb/shutdown transmission.

The ability to direct packets through the network when single fiber transmission capacities approach this magnitude may require electronics to run at rates that outstrip Moor's law. The bandwidth mismatch between fiber transmission systems and electronics router will becomes more complex when we consider that future routers and switches will potentially terminate hundreds of wavelength, and increase in bit rate per wavelength will head out of beyond 40gb/s to 160gb/s. even with significance advances in electronic processor speed, electronics memory access time only improve at the rate of approximately 5% per year, an important data point since memory plays a key role in how packets are buffered and directed through a router.

Additionally opto-electronic interfaces dominate the power dissipations, footprint and cost of these systems, and do not scale well as the port count and bit rate increase. Hence it is not difficult to see that the process of moving a massive number of packets through the multiple layers of electronics in a router can lead to congestion and exceed the performance of electronics and the ability to efficiently handle the dissipated power.


In this article we review the state of art in optical packet switching and more specifically the role optical signal processing plays in performing key functions. It describe how all-optical wavelength converters can be implemented as optical signal processors for packet switching, in terms of their processing functions, wavelength agile steering capabilities, and signal regeneration capabilities. Examples of how wavelength converters based processors can be used to implement asynchronous packet switching functions are reviewed. Two classes of wavelength converters will be touched on: monolithically integrated semiconductor optical amplifiers (SOA) based and nonlinear fiber based.


SATRACK


Definition

According to the dictionary guidance is the 'process of guiding the path of an object towards a given point, which in general may be moving'. The process of guidance is based on the position and velocity if the target relative to the guided object. The present day ballistic missiles are all guided using the global positioning system or GPS.GPS uses satellites as instruments for sending signals to the missile during flight and to guide it to the target.

SATRACK is a system that was developed to provide an evaluation methodology for the guidance system of the ballistic missiles. This was developed as a comprehensive test and evaluation program to validate the integrated weapons system design for nuclear powered submarines launched ballistic missiles.this is based on the tracking signals received at the missile from the GPS satellites. SATRACK has the ability to receive record, rebroadcast and track the satellite signals.

SATRACK facility also has the great advantage that the whole data obtained from the test flights can be used to obtain a guidance error model. The recorded data along with the simulation data from the models can produce a comprehensive guidance error model. This will result in the solution that is the best flight path for the missile.

The signals for the GPS satellite navigation are two L-band frequency signals. They can be called L1 and L2.L1 is at 1575.42 MHz and L2 at 1227.60 MHz.The modulations used for these GPS signals are

1. Narrow band clear/acquisition code with 2MHz bandwidth.
2. Wide band encrypted P code with 20MHz bandwidth.

L1 is modulated using the narrow band C/A code only. This signal will give an accuracy of close to a 100m only. L2 is modulated using the P code. This code gives a higher accuracy close to 10m that is why they are encrypted. The parameters that a GPS signal carries are latitude, longitude, altitude and time. The modulations applied to each frequency provide the basis for epoch measurements used to determine the distances to each satellite. Tracking of the dual frequency GPS signals provides a way to correct measurements from the effect of refraction through the ionosphere. An alternate frequency L3 at 1381.05MHz was also used to compensate for the ionospheric effects.


Crusoe Processor


Definition

Mobile computing has been the buzzword for quite a long time. Mobile computing devices like laptops, webslates & notebook PCs are becoming common nowadays. The heart of every PC whether a desktop or mobile PC is the microprocessor. Several microprocessors are available in the market for desktop PCs from companies like Intel, AMD, Cyrix etc.The mobile computing market has never had a microprocessor specifically designed for it. The microprocessors used in mobile PCs are optimized versions of the desktop PC microprocessor.

Mobile computing makes very different demands on processors than desktop computing, yet up until now, mobile x86 platforms have simply made do with the same old processors originally designed for desktops. Those processors consume lots of power, and they get very hot. When you're on the go, a power-hungry processor means you have to pay a price: run out of power before you've finished, run more slowly and lose application performance, or run through the airport with pounds of extra batteries. A hot processor also needs fans to cool it; making the resulting mobile computer bigger, clunkier and noisier.

A newly designed microprocessor with low power consumption will still be rejected by the market if the performance is poor. So any attempt in this regard must have a proper 'performance-power' balance to ensure commercial success. A newly designed microprocessor must be fully x86 compatible that is they should run x86 applications just like conventional x86 microprocessors since most of the presently available software's have been designed to work on x86 platform.


Crusoe is the new microprocessor which has been designed specially for the mobile computing market. It has been designed after considering the above mentioned constraints. This microprocessor was developed by a small Silicon Valley startup company called Transmeta Corp. after five years of secret toil at an expenditure of $100 million. The concept of Crusoe is well understood from the simple sketch of the processor architecture, called 'amoeba'. In this concept, the x86-architecture is an ill-defined amoeba containing features like segmentation, ASCII arithmetic, variable-length instructions etc. The amoeba explained how a traditional microprocessor was, in their design, to be divided up into hardware and software.

Thus Crusoe was conceptualized as a hybrid microprocessor that is it has a software part and a hardware part with the software layer surrounding the hardware unit. The role of software is to act as an emulator to translate x86 binaries into native code at run time. Crusoe is a 128-bit microprocessor fabricated using the CMOS process. The chip's design is based on a technique called VLIW to ensure design simplicity and high performance. Besides this it also uses Transmeta's two patented technologies, namely, Code Morphing Software and Longrun Power Management. It is a highly integrated processor available in different versions for different market segments.



Wearable Bio-Sensors


Definition

Wearable sensors and systems have evolved to the point that they can be considered ready for clinical application. The use of wearable monitoring devices that allow continuous or intermittent monitoring of physiological signals is critical for the advancement of both the diagnosis as well as treatment of diseases. Wearable systems are totally non-obtrusive devices that allow physicians to overcome the limitations of ambulatory technology and provide a response to the need for monitoring individuals over weeks or months.

They typically rely on wireless miniature sensors enclosed in patches or bandages or in items that can be worn, such as ring or shirt. The data sets recorded using these systems are then processed to detect events predictive of possible worsening of the patient's clinical situations or they are explored to access the impact of clinical interventions.


It is a pulse oximetry sensor that allows one to continuously monitor heart rate and oxygen saturation in a totally unobtrusive way. The device is shaped like a ring and thus it can be worn for long periods of time without any discomfort to the subject. The ring sensor is equipped with a low power transceiver that accomplishes bi-directional communication with a base station, and to upload date at any point in time.

Each time the heart muscle contracts,blood is ejected from the ventricles and a pulse of pressure is transmitted through the circulatory system.This pressure pulse when traveling through the vessels,causes vessel wall displacement which is measurable at various points.inorder to detect pulsatile blood volume changes by photoelectric method,photo conductors are used.normally photo resistors are used, for amplification purpose photo transistors are used.

Light is emitted by LED and transmitted through the artery and the resistance of photo resistor is determined by the amount of light reaching it.with each contraction of heart,blood is forced to the extremities and the amount of blood in the finger increases.it alters the optical density with the result that the light transmission through the finger reduces and the resistance of the photo resistor increases accordingly.The photoresistor is connected as a part of voltage divider circuit and produces a voltage that varies with the amount of blood in the finger.This voltage that closely follows the pressure pulse.

Radio Frequency Light Sources


Definition

RF light sources follow the same principles of converting electrical power into visible radiation as conventional gas discharge lamps. The fundamental difference between RF lamps and conventional lamps is that RF lamps operate without electrodes .the presence of electrodes in conventional florescent and High Intensity Discharge lamps has put many restrictions on lamp design and performance and is a major factor limiting lamp life.

Recent progress in semiconductor power switching electronics, which is revolutionizing many factors of the electrical industry, and a better understanding of RF plasma characteristics, making it possible to drive lamps at high frequencies.The very first proposal for RF lighting, as well as the first patent on RF lamps, appeared about 100years ago, a half century before the basic principles lighting technology based on gas discharge had been developed.

Discharge tubes
Discharge Tube is the device in which a gas conducting an electric current emits visible light. It is usually a glass tube from which virtually all the air has been removed (producing a near vacuum), with electrodes at each end. When a high-voltage current is passed between the electrodes, the few remaining gas atoms (or some deliberately introduced ones) ionize and emit coloured light as they conduct the current along the tube. T

he light originates as electrons change energy levels in the ionized atoms. By coating the inside of the tube with a phosphor, invisible emitted radiation (such as ultraviolet light) can produce visible light; this is the principle of the fluorescent lamp. We will consider different kinds of RF discharges and their advantages and restrictions for lighting applications.


QoS in Cellular Networks Based on MPT


Definition

In recent years, there has been a rapid increase in wireless network deployment and mobile device market penetration. With vigorous research that promises higher data rates, future wireless networks will likely become an integral part of the global communication infrastructure. Ultimately, wireless users will demand the same reliable service as today's wire-line telecommunications and data networks. However, there are some unique problems in cellular networks that challenge their service reliability.

In addition to problems introduced by fading, user mobility places stringent requirements on network resources. Whenever an active mobile terminal (MT) moves from one cell to another, the call needs to be handed off to the new base station (US), and network resources must be reallocated. Resource demands could fluctuate abruptly due to the movement of high data rate users. Quality of service (QoS) degradation or even forced termination may occur when there are insufficient resources to accommodate these handoffs.

If the system has prior knowledge of the exact trajectory of every MT, it could take appropriate steps to reserve resources so that QoS may be guaranteed during the MT's connection lifetime. However, such an ideal scenario is very unlikely to occur in real life. Instead, much of the work on resource reservation has adopted a predictive approach.

One approach uses pattern matching techniques and a self-adaptive extended Kalman filter for next-cell prediction based on cell sequence observations, signal strength measurements, and cell geometry assumptions. Another approach proposes the concept of a shadow cluster: a set of BSs to which an MT is likely to attach in the near future. The scheme estimates the probability of each MT being in any cell within the shadow cluster for future time intervals, based on knowledge about individual MTs' dynamics and call holding patterns.


Project Oxygen


Definition

Oxygen enables pervasive, human-centered computing through a combination of specific user and system technologies.

Oxygen's user technologies directly address human needs. Speech and vision technologies enable us to communicate with Oxygen as if we're interacting with another person, saving much time and effort. Automation, individualized knowledge access, and collaboration technologies help us perform a wide variety of tasks that we want to do in the ways we like to do them.

Oxygen's system technologies dramatically extend our range by delivering user technologies to us at home, at work, or on the go. Computational devices, called Enviro21s (E21s), embedded in our homes, offices, and cars sense and affect our immediate environment. Hand-held devices, called Handy21s (H21s), empower us to communicate and compute no matter where we are. Dynamic networks (N21s) help our machines locate each other as well as the people, services, and resources we want to reach.


Oxygen's user technologies include:
The Oxygen technologies work together and pay attention to several important themes:


" Distribution and mobility - for people, resources, and services.
" Semantic content - what we mean, not just what we say.
" Adaptation and change - essential features of an increasingly dynamic world.
" Information personalities - the privacy, security, and form of our individual interactions with Oxygen.

Oxygen is an integrated software system that will reside in the public domain. Its development is sponsored by DARPA and the Oxygen Alliance industrial partners, who share its goal of pervasive, human-centered computing. Realizing that goal will require a great deal of creativity and innovation, which will come from researchers, students, and others who use Oxygen technologies for their daily work during the course of the project. The lessons they derive from this experience will enable Oxygen to better serve human needs.


Polymer Memory


Definition

Polymers are organic materials consisting of long chains of single molecules. Polymers are highly adaptable materials, suitable for myriad applications. Until the 1970s and the work of Nobel laureates Alan J. Heeger, Alan G. MacDiarmid and Hideki Shirakawa, polymers were only considered to be insulators. Heeger et al showed that polymers could be conductive. Electrons were removed, or introduced, into a polymer consisting of alternately single and double bonds between the carbon atoms. As these holes or extra electrons are able to move along the molecule, the structure becomes electrically conductive.

Thin Film Electronics has developed a specific group of polymers that are bistable and thus can be used as the active material in a non-volatile memory. In other words, the Thin Film polymers can be switched from one state to the other and maintain that state even when the electrical field is turned off. This polymer is "smart", to the extent that functionality is built into the material itself, like switchability, addressability and charge store.

This is different from silicon and other electronic materials, where such functions typically are only achieved by complex circuitry. "Smart" materials can be produced from scratch, molecule by molecule, allowing them to be built according to design. This opens up tremendous opportunities in the electronics world, where "tailor-made" memory materials represent unknown territory

Polymers are essentially electronic materials that can be processed as liquids. With Thin Film's memory technology, polymer solutions can be deposited on flexible substrates with industry standard processes like spin coating in ultra thin layers. Digital memory is an essential component of many electronic devices, and memory that takes up little space and electricity is in high demand as electronic devices continue to shrink Researchers from the Indian Association for the Cultivation of Science and the Italian National used positive and negative electric charges, or space charges, contained within plastic to store binary numbers Research Council. A polymer retains space charges near a metal interface when there is a bias, or electrical current, running across the surface.

These charges come either from electrons, which are negatively charged, or the positively-charged holes vacated by electrons. We can store space charges in a polymer layer, and conveniently check the presence of the space charges to know the state of the polymer layer. Space charges are essentially differences in electrical charge in a given region. They can be read using an electrical pulse because they change the way the devices conduct electricity.


Navbelt and Guiecane


Definition

Recent revolutionary achievements in robotics and bioengineering have given scientists and engineers great opportunities and challenges to serve humanity. This seminar is about "NAVBELT AND GUIDECANE", which are two computerised devices based on advanced mobile robotic navigation for obstacle avoidance useful for visually impaired people. This is "Bioengineering for people with disabilities".

NavBelt is worn by the user like a belt and is equipped with an array of ultrasonic sensors. It provides acoustic signals via a set of stereo earphones that guide the user around obstacles or displace a virtual acoustic panoramic image of the traveller's surroundings. One limitation of the NavBelt is that it is exceedingly difficult for the user to comprehend the guidance signals in time, to allow fast work.

A newer device, called GuideCane, effectively overcomes this problem. The GuideCane uses the same mobile robotics technology as the NavBelt but is a wheeled device pushed ahead of the user via an attached cane. When the Guide Cane detects an obstacle, it steers around it. The user immediately feels this steering action and can follow the Guide Cane's new path easily without any conscious effort. The mechanical, electrical and software components, user-machine interface and the prototypes of the two devices are described.



Multisensor Fusion and Integration


Introduction
Sensor is a device that detects or senses the value or changes of value of the variable being measured. The term sensor some times is used instead of the term detector, primary element or transducer.

The fusion of information from sensors with different physical characteristics, such as light, sound, etc enhances the understanding of our surroundings and provide the basis for planning, decision making, and control of autonomous and intelligent machines.


Sensors Evolution

A sensor is a device that responds to some external stimuli and then provides some useful output. With the concept of input and output, one can begin to understand how sensors play a critical role in both closed and open loops.

One problem is that sensors have not been specified. In other words they tend to respond variety of stimuli applied on it without being able to differentiate one from another. Neverthless, sensors and sensor technology are necessary ingredients in any control type application. Without the feedback from the environment that sensors provide, the system has no data or reference points, and thus no way of understanding what is right or wrong g with its various elements.

Sensors are so important in automated manufacturing particularly in robotics. Automated manufacturing is essentially the procedure of remo0ving human element as possible from the manufacturing process. Sensors in the condition measurement category sense various types of inputs, condition, or properties to help monitor and predict the performance of a machine or system.

Multisensor Fusion And Integration

Multisensor integration is the synergistic use of the information provided by multiple sensory devices to assist in the accomplishment of a task by a system.

Multisensor fusion refers to any stage in the integration process where there is an actual combination of different sources of sensory information into one representational format.


Multisensor Integration

The diagram represents multisensor integration as being a composite of basic functions. A group of n sensors provide input to the integration process. In order for the data from each sensor to be used for integration, it must first be effectively modelled. A sensor model represents the uncertainty and error in the data from each sensor and provides a measure of its quality that can be 7used by the subsequent integration functions.


Magneto-optical current transformer technology (MOCT)


Definition

An accurate electric current transducer is a key component of any power system instrumentation. To measure currents power stations and substations conventionally employ inductive type current transformers with core and windings. For high voltage applications, porcelain insulators and oil-impregnated materials have to be used to produce insulation between the primary bus and the secondary windings. The insulation structure has to be designed carefully to avoid electric field stresses, which could eventually cause insulation breakdown.

The electric current path of the primary bus has to be designed properly to minimize the mechanical forces on the primary conductors for through faults. The reliability of conventional high-voltage current transformers have been questioned because of their violent destructive failures which caused fires and impact damage to adjacent apparatus in the switchyards, electric damage to relays, and power service disruptions.

With short circuit capabilities of power systems getting larger, and the voltage levels going higher the conventional current transformers becomes more and more bulky and costly also the saturation of the iron core under fault current and the low frequency response make it difficult to obtain accurate current signals under power system transient conditions.

In addition to the concerns, with the computer control techniques and digital protection devices being introduced into power systems, the conventional current transformers have caused further difficulties, as they are likely to introduce electro-magnetic interference through the ground loop into the digital systems. This has required the use of an auxiliary current transformer or optical isolator to avoid such problems.

It appears that the newly emerged Magneto-optical current transformer technology provides a solution for many of the above mentioned problems. The MOCT measures the electric current by means of Faraday Effect, which was first observed by Michael Faraday 150 years ago. The Faraday Effect is the phenomenon that the orientation of polarized light rotates under the influence of the magnetic fields and the rotation angle is proportional to the strength of the magnetic field component in the direction of optical path.

Mobile Virtual Reality Service (VRS)


Definition

A mobile virtual reality service (VRS) will make the presence and presentation of the sounds and sights of an actual physical environment virtually available everywhere in real time through the use of mobile telecommunication devices and networks. Furthermore, the VRS is the conversion of a physical system into its digital representation in a three-dimension (3D) multimedia format. This paper addresses one aspect of the notion of bringing an actual multimedia environment to its virtual presence everywhere in real time .

An international telecommunication union (ITC) recommendation document, containing ITU's visions on mostly forward-looking and innovative services and network capabilities, addresses the capability needed in a telecommunication system to allow mobile access to real-time sights and sounds of an actual physical environment in the contest and forms of a VRS episode .

Presently, the availability of a VRS is limited to fixed-access phenomena in non-real time , for example , entertainment machines and various simulations equipment. There are also some limited fixed-access and real-time services that require low data transmission rates, such as net meetings. In the latter case, a user can experience a limited real-life environment as opposed to the former case of a non-real-life computer-generated environment. These existing virtual reality services do not allow user control in viewing 3D environments, and they are generally limited to viewing images on a monitor in two dimensions.

The VRS-capable systems, however, will allow rather 3D representations of remote real-life environments. For instance, a passenger in a train or in a car could become a participant in a conference call in a 3D environment or become virtually present among the audience in a concert hall or sports stadium viewing a live concert or event.



Smart Pixel Arrays (SPAs)


Definition

High speed smart pixel arrays (SPAs) hold great promise as an enabling technology for board-to-board interconnections in digital systems. SPAs may be considered an extension of a class of optoelectronic components that have existed for over a decade, that of optoelectronic integrated circuits (OEICs). The vast majority of development in OEICs has involved the integration of electronic receivers with optical detectors and electronic drivers with optical sources or modulators.

In addition, very little of this development has involved more than a single optical channel. But OEICs have underpinned much of the advancement in serial fiber links. SPAs encompass an extension of these optoelectronic components into arrays in which each element of the array has a signal processing capability. Thus, a SPA may be described as an array of optoelectronic circuits for which each circuit possesses the property of signal processing and, at a minimum, optical input or optical output (most SPAs will have both optical input and output).

The name smart pixel is combination of two ideas, "pixel" is an image processing term denoting a small part, or quantized fragment of an image, the word "smart" is coined from standard electronics and reflects the presence of logic circuits. Together they describe a myriad of devices. These smart pixels can be almost entirely optical in nature, perhaps using the non-linear optical properties of a material to manipulate optical data, or they can be mainly electronic, for instance a photoreceiver coupled with some electronic switching.

Smart pixel arrays for board-to-board optical interconnects may be used for either backplane communications or for distributed board-to-board communications, the latter known as 3-D packaging. The former is seen as the more near-term of the two, employing free-space optical beams connecting SPAs located on the ends of printed circuit boards in place of the current state-of-the-art, multi-level electrical interconnected boards. 3-D systems, on the other hand, are distributed board-to-board optical interconnects, exploiting the third dimension and possibly employing holographic interconnect elements to achieve global connectivity (very difficult with electrical interconnects).

Adaptive Blind Noise Suppression in some Speech Processing Applications


In many applications of speech processing the noise reveals some specific features. Although the noise could be quite broadband, there are a limited number of dominant frequencies, which carry the most of its energy. This fact implies the usage of narrow-band notch filters that must be adaptive in order to track the changes in noise characteristics. In present contribution, a method and a system for noise suppression are developed. The method uses adaptive notch filters based on second-order Gray-Markel lattice structure. The main advantages of the proposed system are that it has very low computational complexity, is stable in the process of adaptation, and has a short time of adaptation. Under comparable SNR improvement, the proposed method adjusts only 3 coefficients against 250-450 for the conventional adaptive noise cancellation systems. A framework for a speech recognition system that uses the proposed method is suggested.

INTRODUCTION

The noise existence is inevitable in real applications of speech processing. It is well known that the additive noise affects negatively the performance of the speech codecs designed to work with noise-free speech especially codecs based on linear prediction coefficients (LPC). Another application strongly influenced by noise is related to the hands free phones where the background noise reduces the signal to noise ratio (S/N) and the speech intelligibility.

Last but not least, is the problem of speech recognition in a noisy environment. A system that works well in noise-free conditions, usually shows considerable degradation in performance when background noise is present It is clear that a strong demand for reliable noise cancellation methods exists that efficiently separate the noise from speech signal. The endeavors in designing of such systems can be followed some 20 years ago The core of the problem is that in most situations the characteristics of the noise are not known a priori and moreover they may change in time. This implies the use of adaptive systems capable of identifying and tracking the noise characteristics. This is why the application of adaptive filtering for noise cancellation is widely used.

The classical systems for noise suppression rely on the usage of adaptive linear filtering and the application of digital filters with finite impulse response (FIR). The strong points of this approach are the simple analysis of the linear systems in the process of adaptation and the guaranteed stability of FIR structures. It is worth mentioning the existence of relatively simple and well investigated adaptive algorithms for such kind of systems as least mean squares (LMS) and recursive least squares (RLS) algorithms. The investigations in the area of noise cancellation reveal that in some applications the nonlinear filters outperform their linear counterparts. That fact is a good motivation for a shift towards the usage of nonlinear systems in noise reduction .Another approach is based on a microphone array instead of the two microphones, reference and primary, that are used in the classical noise cancellation scheme .

A brief analysis of all mentioned approaches leads to the conclusion that they try to model the noise path either by a linear or by a nonlinear system. Each of these methods has its strengths and weaknesses. For example, for the classical noise cancellation with two microphones this is the need of reference signal; for the neural filters - the fact that as a rule they are slower than classic adaptive filters and they are efficient only for noise suppression on relatively short data sequences which is not true for speech processing and finally for microphone arrays - the need of precise space alignment In present contribution the approach is slightly different.

The basic idea is that in many applications, for instance, hands-free cellular phones in car environment howling control in hands-free phones, noise reduction in an office environment, the noise reveals specific features that can be exploited. In most instances although the noise might be quite wide-band, there are always, as a rule, no more than two or three regions of its frequency spectrum that carry most of the noise energy and the removal of these dominant frequencies results in a considerable improvement of S/N ratio. This brings the idea to use notch adaptive filters capable of tracking the noise characteristics. In this paper a modification of all-pass structures is used They are recursive, and at the same time, are stable during the adaptive process. The approach is called "blind" because there is no need of a reference signal.

An Efficient Algorithm for iris pattern Recognition using 2D Gabor Wavelet Transformation in Matlab


Wavelet analysis have received significant attention because their multi-resolution decomposition allows efficient image analysis. It is widely used for varied applications such as noise reduction, and data compression, etc. In this paper we have introduced and applied the concept of 2 dimensional Gabor wavelet transform to Biometric Iris recognition system. The application of this transform in encoding the iris image for pattern recognition proves to achieve increased accuracy and processing speed compared to other methods. With a strong scientific approach and mathematical background we have developed an algorithm to facilitate the implementation of this method under the platforms of MATLAB


IMAGES - An introduction:
A dictionary defines image as a "reproduction or representation of the form of a person or thing". The inherent association of a human with the visual senses, predisposes one to conceive an image as a stimulus on the retina of the eye, in which case the mechanism of optics govern the image formation resulting in continuos range, multi-tone images.

A digital image can be defined to be a numerical representation of an object or more strictly to be sampled, quantized function of two dimensions which has been generated by optical means, sampled in an equally spaced rectangular grid pattern, and quantized in equal intervals of graylevel.

The word is crying out for the simpler access controls to personal authentication systems and it looks like biometrics may be the answer. Instead of carrying bunch of keys, all those access cards or passwords you carry around with you, your body can be used to uniquely identify you. Furthermore, when biometrics measures are applied in combination with other controls, such as access cards or passwords, the reliability of authentication controls takes a giant step forward.

BIOMETRICS-AN OVERVIEW:
Biometrics is best defined as measurable physiological and/or behavioral characteristics that can be utilized to verify the identity of an indivisual. They include the following:
" Iris scanning
" Facial recognition
" Fingerprint verification
" Hand geometry
" Retinal scanning
" Signature verification
" Voice verification

ADVANTAGES OF THE IRIS IDENTIFICATION:
" Highly protected internal organ of the eye.
" Iris patterns possess a high degree of randomness.
" Variability: 244 degrees of freedom.
" Entropy: 3.2 bits per square millimetre.
" Uniqueness: set by combinatorial complexity.
" Patterns apparently stable throughout life.


IRIS - An introduction:
The iris is a colored ring that surrounds the pupil and contains easily visible yet complex and distinct combinations of corona, pits, filaments, crypts, striations, radial furrows and more.
The iris is called the "Living password" because of its unique, random features. It's always with you and can't be stolen or faked. As such it makes an excellent biometrics identifier.



Artificial Intelligence Substation Control


Controlling a substation by a fuzzy controller speeds up response time diminishes up the possibility of risks normally related to human operations. The automation of electric substation is an area under constant development Our research has focused on, the Selection of the magnitude to be controlled, Definition and implementation of the soft techniques, Elaboration of a programming tool to execute the control operations. it is possible to control the desired status while supervising some important magnitudes as the voltage, power factor, and harmonic distortion, as well as the present status. The status of the circuit breakers can be control by using a knowledge base that relates some of the operation magnitudes, mixing status variables with time variables and fuzzy sets .The number of necessary magnitudes to a supervise and to control a substation can be very high in the present research work, many magnitudes were not included .To avoid the extensive number of required rules nevertheless , controlling a substation by a fuzzy controller has the advantage that it can speed up the response time and diminish the possibility of risks normally related to human operations.


Introduction

Electric substations are facilities in charge of the voltage transformation to provide safe and effective energy to the consumers. This energy supply has to be carried out with sufficient quality and should guarantee the equipment security. The associated cost to ensure quality and security during the supply in substations is high. Automatic mechanisms are generally used in greater or lesser scale, although they mostly operate according to an individual control and protection logic related with the equipment itself and not with the topology of the whole substation in a given moment.


The automation of electric substation is an area under constant development. Nevertheless, the control of a substation is a very complex task due to the great number of related problems and, therefore, the decision variables that can influence the substation performance. Under such circumstances, the use of learning control systems can be very useful.


Many papers on applications of artificial intelligence (AI) techniques to power system have been published in the last year. The difficulties associated with the application of this technique include:


" Selection of the magnitude to be controlled
" Definition and implementation of the soft techniques
" Elaboration of a programming tool to execute the control operations
" Selection, acquisition and installation of the measurement and control equipment
" Interface with this equipment and


Applications of the controlling technique in existent substations.
Even when all the magnitudes to be controlled cannot be included in the analysis (mostly due to the great number of measurements and status variables of the substation and, therefore, to the rules that would be required by the controller), it is possible to control the desired status while supervising some important magnitudes as the voltage, power factor, and harmonic distortion, as well as the present status.


Speech Compression - a novel method


This paper illustrates a novel method of speech compression and transmission. This method saves the transmission bandwidth required for the speech signal by a considerable amount. This scheme exploits the property of low pass nature of the speech signal. Also this method applies equally well for any signal, which is low pass in nature, speech being the more widely used in Real Time Communication, is highlighted here.

As per this method, the low pass signal (speech) at the transmitter is divided into set of packets, each containing, say N number of samples. Of the N samples per packet, only certain lesser number of samples, say N alone are transmitted. Here is less than unity, so compression is achieved. The N samples per packet are subjected to a N-Point DFT. Since low pass signals alone are considered here, the number of significant values in the set of DFT samples is very limited. Transmitting these significant samples alone would suffice for reliable transmission. The number of samples, which are transmitted, is determined by the parameter .

The parameter is almost independent of the source of the speech signal. In other methods of speech compression, the specific characteristics of the source such as pitch are important for the algorithm to work. An exact reverse process at the receiver reconstructs the samples. At the receiver, the N-point IDFT of the received signal is performed after necessary zero padding. Zero padding is necessary because at the transmitter of the N samples only N samples are transmitted, but at the receiver N samples are again needed to honestly reconstruct the signal.

Hence this method is efficient as only a portion of the total number of samples is transmitted thereby saving the bandwidth. Since the frequency samples are transmitted the phase information has also to be transmitted. Here again by exploiting the property of signals and their spectra that the PHASE INFORMATION CAN BE EMBEDDED WITHIN THE MAGNITUDE SPECTRUM by using simple mathematics without any heavy computations or by increasing the bandwidth.

Also the simulation result of this method shows that smaller the size of the packet the more faithful is the reproduction of received signal that is again an advantage as the computation time is reduced. The reduction in the computation time is due to the fact that the transmitter has to wait until N samples are obtained before starting the transmission. If N is small, the transmitter has to wait for a less duration of time and a smaller value of N achieves a better reconstruction at the receiver.


Thus this scheme provides a more efficient method of speech compression and this scheme is also very easy to implement with the help of available high-speed processors.Transmitting the spectrum of the signal instead of transmitting the original signal is far more efficient. This is because the energy of the speech signal above 4 kHz is negligible; we can very well compute the spectrum of the signal and transmit only the samples that correspond to 4 KHz of the spectrum irrespective of the sampling frequency. By this type of transmission we can save the bandwidth required for transmission considerably. Also it is not necessary that we have to transmit all the samples corresponding to the 4 kHz frequency as it is sufficient to transmit a fraction of the samples without any degradation in the quality.


Since the spectrum is considered in the above method both the magnitude and phase information must be transmitted to reproduce the signal without any error. But this requires twice the actual bandwidth. Exploiting the property of real and even signals can solve this problem. The spectrum of the samples is real and evenliness is artificially introduced such that their spectra are also real and even. Thus by simple mathematics the complete phase information is embedded within the magnitude spectrum and it is needed only to send 'aN' samples instead of '2N'samples of the spectra (Magnitude and phase).


Adopting all these procedures and embedding the phase information in the magnitude spectrum have performed a MATLAB simulation performed to determine the optimum value of 'a' and 'N'. The result of the simulation is also provided.

Class-D Amplifiers


Class D amplifiers present us with a revolutionary solution, which would help us eliminate loss and distortions caused due to conversion of digital signals to analog while amplifying signals before transmitting it to speakers. This inchoate piece of knowledge could prove to detrimental in improving and redefining essence of sound and take it to a different realm.

This type of amplifiers do not require the use of D-A conversion and hence reduce the costs incurred for developing state of art output technology. The digital output from sources such as CD's, DVD's and computers now can directly be sent for amplification without the need for any conversion.

Another important feature of these unique and novel kind of amplifiers are that they give us a typical efficiency of 90% compared to that of the normal ones which give us a efficiency of 65-70%. This obviously means less amount of dissipation that indirectly means lower rated heat sinks and low waste of energy. This makes the use of D type amplifiers in miniature and portable devices all the more apt.

All these years D type amplifiers have been used for purposes where efficiency was the key whereas now developments in this technology have made its entry possible into other domain that are less hi-fi. Thus showing up in MP3 players, portable CD players, laptop computers, cell phones, even personal digital assistants.

Digital Audio's Final Frontier-Class D Amplifier

Introduction
Digital technology continues its march from media like CDs and DVDs toward your audio speakers. Today, amplifiers based on digital principles are already having a profound effect on equipment efficiency and size. They are also beginning to set the standard for sound quality.


An old idea, the Class D amplifier has taken on new life as equipment manufacturers and consumers redefine the musical experience to be as likely to occur in a car, on a personal stereo, or on an airplane as in a living room. For most consumers today, portability and style outweigh other factors in the choice of new audio gear. Class D amplifiers are ideally suited to capitalize on the trend. They are already starting to displace conventional high-fidelity amplifiers, particularly in mobile and portable applications, where their high efficiency and small size put them in a class by themselves. For example, they are fast becoming the dominant technology for entertainment systems in cars, where passengers are now apt to watch a DVD-and expect from the vehicle's compact, ill-ventilated electronics the same rousing surround-sound experience they get at home.


The new amplifiers can provide it. They are typically around 90 percent efficient at rated power, versus 65-70 percent for conventional audio amps. Such high efficiency means, for one thing, that the amplifiers can get by with much smaller heat sinks to carry away the energy they waste. Also, portable devices like MP3 players can go much longer on a battery charge or can be powered by tinier, lighter batteries.

Class D amplifiers have been used for decades in industrial and medical applications when high efficiency is key. They have been applied with great success in devices as small as hearing aids and as large as controllers for hefty motors and electromagnets. They blossomed as a significant force in high-fidelity audio a few years ago, when Class D power amplifier chips were released by companies like Tripath Technology, Texas Instruments, and Cirrus Logic in the United States; Philips and STMicroelectronics(partnering with ApogeeDDX) in Europe; and Sanyo (partnering with Bang & Olufsen) in Japan.


More recently, Class D amps have expanded beyond the hi-fi niche, showing up in MP3 players, portable CD players, laptop computers, cellphones, even personal digital assistants (PDAs). At the same time, they have been making forays into the world of home audio in the form of products based on those new chips. Notable entries include amplifiers from Bel Canto Design Ltd. (Minneapolis, Minn.) and PS Audio (Boulder, Colo.).


Digital Audio's Final Frontier-Class D Amplifier


Digital technology continues its march from media like CDs and DVDs toward your audio speakers. Today, amplifiers based on digital principles are already having a profound effect on equipment efficiency and size. They are also beginning to set the standard for sound quality.


An old idea, the Class D amplifier has taken on new life as equipment manufacturers and consumers redefine the musical experience to be as likely to occur in a car, on a personal stereo, or on an airplane as in a living room. For most consumers today, portability and style outweigh other factors in the choice of new audio gear.


Class D amplifiers are ideally suited to capitalize on the trend. They are already starting to displace conventional high-fidelity amplifiers, particularly in mobile and portable applications, where their high efficiency and small size put them in a class by themselves. For example, they are fast becoming the dominant technology for entertainment systems in cars, where passengers are now apt to watch a DVD-and expect from the vehicle's compact, ill-ventilated electronics the same rousing surround-sound experience they get at home.


The new amplifiers can provide it. They are typically around 90 percent efficient at rated power, versus 65-70 percent for conventional audio amps. Such high efficiency means, for one thing, that the amplifiers can get by with much smaller heat sinks to carry away the energy they waste. Also, portable devices like MP3 players can go much longer on a battery charge or can be powered by tinier, lighter batteries.


Class D amplifiers have been used for decades in industrial and medical applications when high efficiency is key. They have been applied with great success in devices as small as hearing aids and as large as controllers for hefty motors and electromagnets. They blossomed as a significant force in high-fidelity audio a few years ago, when Class D power amplifier chips were released by companies like Tripath Technology, Texas Instruments, and Cirrus Logic in the United States; Philips and STMicroelectronics


Optical Networking and Dense Wavelength Division Multiplexing


This paper deals with the twin concepts of optical networking and dense wavelength division multiplexing. The paper talks about the various optical network architectures and the various components of an all-optical network like Optical Amplifiers, Optical Add/Drop Multiplexers, Optical Splitters etc. Important optical networking concepts like wavelength routing and wavelength conversion are explained in detail. Finally this paper deals with industry related issues like the gap between research and the industry, current and projected market for optical networking & DWDM equipment and future direction of research in this field.

INTRODUCTION
One of the major issues in the networking industry today is tremendous demand for more and more bandwidth. Before the introduction of optical networks, the reduced availability of fibers became a big problem for the network providers. However, with the development of optical networks and the use of Dense Wavelength Division Multiplexing (DWDM) technology, a new and probably, a very crucial milestone is being reached in network evolution. The existing SONET/SDH network architecture is best suited for voice traffic rather than today's high-speed data traffic. To upgrade the system to handle this kind of traffic is very expensive and hence the need for the development of an intelligent all-optical network. Such a network will bring intelligence and scalability to the optical domain by combining the intelligence and functional capability of SONET/SDH, the tremendous bandwidth of DWDM and innovative networking software to spawn a variety of optical transport, switching and management related products.

Optical Networking
Optical networks are high-capacity telecommunications networks based on optical technologies and component that provide routing, grooming, and restoration at the wavelength level as well as wavelength-based services. The origin of optical networks is linked to Wavelength Division Multiplexing (WDM) which arose to provide additional capacity on existing fibers. The optical layer, whose standards are being developed, will ideally be transparent to the SONET layer, providing restoration, performance monitoring, and provisioning of individual wavelengths instead of electrical SONET signals. So in essence a lot of network elements will be eliminated and there will be a reduction of electrical equipment.

It is possible to classify networks into three generations depending on the physical-level technology employed. First generation networks use copper-based or microwave technologies e.g Ethernet, satellites etc. In second generation networks, these copper links or microwave links with optical fibers. However, these networks still perform the switching of data in the electronic domain though the transmission of data is done in the optical domain. Finally we have the third generation networks that employ Wavelength Division Multiplexing technology. They do both the transmission and the switching of data in the optical domain. This has resulted in the onset of tremendous amount of bandwidth availability. Further the use of non-overlapping channels allows each channel to operate at peak speeds.
1.2 Dense Wavelength Division Multiplexing (DWDM)


Dense Wavelength Division Multiplexing (DWDM) is a fiber-optic transmission technique. It involves the process of multiplexing many different wavelength signals onto a single fiber. So each fiber has a set of parallel optical channels each using slightly different light wavelengths. It employs light wavelengths to transmit data parallel-by-bit or serial-by-character. DWDM is a very crucial component of optical networks that will allow the transmission of data: voice, video-IP, ATM and SONET/SDH respectively, over the optical layer.

Hence with the development of WDM technology, optical layer provides the only means for carriers to integrate the diverse technologies of their existing networks into one physical infrastructure. For example, though a carrier might be operating both ATM and SONET networks, with the use of DWDM it is not necessary for the ATM signal to be multiplexed up to the SONET rate to be carried on the DWDM network. Hence carriers can quickly introduce ATM or IP without having to deploy an overlay network for multiplexing.

Optical Burst Switching


Optical burst switching is a promising solution for all optical WDM networks It combines the benefits of optical packet switching and wavelength routing while taking into account the limitations of current all optical technology In OBS the user data is collected at the edge of the network, sorted based on destination address,and grouped into variable sized bursts Prior to transmitting a burst, a control packet is created and immediately send toward the destination in order to setup a buffer less optical path for its corresponding burst After an offset delay time, the data burst itself is transmitted without waiting for positive acknowledgement from the destination node the OBS framework has been widely studied in the past few years because it achieves high traffic throughput and high resource utilization .

Introduction:

Optical communication has been used for a long time and it very much popular with the invention of wavelength-division multiplexing(WDM) Current WDM works over point-to-point links,where optical-to-electrical-to-optical(OEO) conversion is required over each step The elimination of OEO conversion in all optical networks(AON) allows for unprecedented transmission rates AON's can further be categorized as wavelength-routed networks(WRNs).,optical burst switched networks(OBSNs),or optical packet switched networks(OPSNs).Now we discuss here about optical burst switching(OBS)


In optical burst switching(OBS) data is transported in variable sized units called bursts Due to the great variability in the duration of bursts the OBS network can be viewed as lying between OPSNs and WRNS That is, when all burst durations are very short,equal to the duration of an optical packet,OBSN can be seen as resembling an OPSN On the other hand,when all the burst durations are extremely long the OBSN may seem resembling a WRN In OBS there is strong separation between the data and control planes,which allows for greater network manageability and flexibility In addition its dynamic nature leads to high network adaptability and scalability,which makes it quite suitable for transmission of bursty traffic .


In general,the OBS network consists of interconnected core nodes that transport data from various edge users The users consist of an electronic router and an OBS interface, while the core OBS nodes require an optical switching matrix,a switch control; unit and routing and signaling processors OBS has received considerable attention in the past few years and various solutions have been proposed and analyzed in an attempt to improve it's performance Here we describe the various OBS architectures by grouping the material logically per OBS design parameter

Burst aggregation:

OBS collects upper layer traffic and sort it based on destination addresses and aggregate it into variable size bursts The exact algorithm for creating the bursts can greatly impact the overall network operation because it allows the network designers to control the burst characteristics and therefore shape the burst arrival traffic The burst assembly algorithm has to consider a preset timer and maximum and minimum burst lengths The burst aggregation algorithm may use bit-padding ,the differentiation of class traffic , create classes of service by varying the preset timers and maximum/minimum burst sizes

One of the most interesting benefit of burst aggregation is it shapes the traffic by reducing the degree of self-similarity,making it less bursty in comparison to the flow of the original higher-layer packets Traffic is considered bursty if busy periods with a large of arrivals are followed by long idle periods The term self-similar traffic refers to an arrival process that exhibits burstiness when viewed at varying time scales:milliseconds,seconds,minutes,hours even days and weeks Self-similar traffic is characterized by longer queuing delays therefore degrades network performance Therefore reducing self-similarity is a desirable feature of the burst assembly process and concluded that traffic is less self-similar after the assembly.

Bluetooth Based Smart Sensor Networks


Definition
The communications capability of devices and continuous transparent information routes are indispensable components of future oriented automation concepts. Communication is increasing rapidly in industrial environment even at field level.In any industry the process can be realized through sensors and can be controlled through actuators. The process is monitored on the central control room by getting signals through a pair of wires from each field device in Distributed Control Systems (DCS). With advent in networking concept, the cost of wiring is saved by networking the field devices. But the latest trend is elimination of wires i.e., wireless networks.


Wireless sensor networks - networks of small devices equipped with sensors, microprocessor and wireless communication interfaces.In 1994, Ericsson Mobile communications, the global telecommunication company based in Sweden, initiated a study to investigate, the feasibility of a low power, low cost ratio interface, and to find a way to eliminate cables between devices. Finally, the engineers at the Ericsson named the new wireless technology as "Blue tooth" to honour the 10th century king if Denmark, Harald Blue tooth (940 to 985 A.D).
The goals of blue tooth are unification and harmony as well, specifically enabling different devices to communicate through a commonly accepted standard for wire less connectivity.


BLUE TOOTH
Blue tooth operates in the unlicensed ISM band at 2.4 GHZ frequency band and use frequency hopping spread spectrum technique. A typical Blue tooth device has a range of about 10 meters and can be extended to 100meters. Communication channels supports total bandwidth of 1 Mb / sec. A single connection supports a maximum asymmetric data transfer rate of 721 KBPS maximum of three channels.


BLUE TOOTH - NETWORKS
In bluetooth, a Piconet is a collection of up to 8 devices that frequency hop together. Each Piconet has one master usually a device that initiated establishment of the Piconet, and up to 7 slave devices. Master's Blue tooth address is used for definition of the frequency hopping sequence. Slave devices use the master's clock to synchronize their clocks to be able to hop simultaneously.


A Piconet
When a device wants to establish a Piconet it has to perform inquiry to discover other Blue tooth devices in the range. Inquiry procedure is defined in such a way to ensure that two devices will after some time, visit the same frequency same time when that happens, required information is exchanged and devices can use paging procedure to establish connection.When more than 7 devices needs to communicate, there are two options. The first one is to put one or more devices into the park state. Blue tooth defines three low power modes sniff, hold and park. When a device is in the park mode then it disassociates from and Piconet, but still maintains timing synchronization with it. The master of the Piconet periodically broadcasts beacons (Warning) to invite the slave to rejoin the Piconet or to allow the slave to request to rejoin. The slave can rejoin the Piconet only if there are less than seven slaves already in the Piconet. If not so, the master has to 'park' one of the active slaves first.

All these actions cause delay and for some applications it can be unacceptable for eg: process control applications, that requires immediate response from the command centre (central control room).Scatternet consists of several Piconets connected by devices participating in multiple Piconet. These devices can be slaves in all Piconets or master in one Piconet and slave in other Piconets. Using scatternets higher throughput is available and multi-hop connections between devices in different Piconets are possible. i.e., The unit can communicate in one Piconet at time so they jump from pioneer to another depending

Laser Communications


Definition
Laser communications offer a viable alternative to RF communications for inter satellite links and other applications where high-performance links are a necessity. High data rate, small antenna size, narrow beam divergence, and a narrow field of view are characteristics of laser communications that offer a number of potential advantages for system design.

Lasers have been considered for space communications since their realization in 1960. Specific advancements were needed in component performance and system engineering particularly for space qualified hardware. Advances in system architecture, data formatting and component technology over the past three decades have made laser communications in space not only viable but also an attractive approach into inter satellite link applications.

Information transfer is driving the requirements to higher data rates, laser cross -link technology explosions, global development activity, increased hardware, and design maturity. Most important in space laser communications has been the development of a reliable, high power, single mode laser diode as a directly modulable laser source. This technology advance offers the space laser communication system designer the flexibility to design very lightweight, high bandwidth, low-cost communication payloads for satellites whose launch costs are a very strong function of launch weigh. This feature substantially reduces blockage of fields of view of most desirable areas on satellites. The smaller antennas with diameter typically less than 30 centimeters create less momentum disturbance to any sensitive satellite sensors. Fewer on board consumables are required over the long lifetime because there are fewer disturbances to the satellite compared with heavier and larger RF systems. The narrow beam divergence affords interference free and secure operation.


Laser communication systems offer many advantages over radio frequency (RF) systems. Most of the differences between laser communication and RF arise from the very large difference in the wavelengths. RF wavelengths are thousands of times longer than those at optical frequencies are. This high ratio of wavelengths leads to some interesting differences in the two systems. First, the beam-width attainable with the laser communication system is narrower than that of the RF system by the same ratio at the same antenna diameters (the telescope of the laser communication system is frequently referred as an antenna). For a given transmitter power level, the laser beam is brighter at the receiver by the square of this ratio due to the very narrow beam that exits the transmit telescope. Taking advantage of this brighter beam or higher gain, permits the laser communication designer to come up with a system that has a much smaller antenna than the RF system and further, need transmit much less power than the RF system for the same receiver power. However since it is much harder to point, acquisition of the other satellite terminal is more difficult. Some advantages of laser communications over RF are smaller antenna size, lower weight, lower power and minimal integration impact on the satellite. Laser communication is capable of much higher data rates than RF.

The laser beam width can be made as narrow as the diffraction limit of the optic allows. This is given by beam width = 1.22 times the wavelength of light divided by the radius of the output beam aperture. The antennae gain is proportional to the reciprocal of the beam width squared. To achieve the potential diffraction limited beam width a single mode high beam quality laser source is required; together with very high quality optical components throughout the transmitting sub system. The possible antennae gain is restricted not only by the laser source but also by the any of the optical elements. In order to communicate, adequate power must be received by the detector, to distinguish the signal from the noise. Laser power, transmitter, optical system losses, pointing system imperfections, transmitter and receiver antennae gains, receiver losses, receiver tracking losses are factors in establishing receiver power. The required optical power is determined by data rate, detector sensitivity, modulation format ,noise and detection methods


CorDECT


Definition
This report describes a new wireless local loop system for rapid expansion of telecom services developed under a joint project involving Indian scientists form Indian Institute Of Technology, Chennai, Midas technology and Analog Devices Inc., USA. The new system, called corDECT, is based on microcellular architecture and uses a modest bandwidth of 20MHz to provide voice, fax, and data communication in low as well as very high subscriber density environments. The high capacity at a modest bandwidth is made possible without prior frequency planning through a completely decentralized channel allocation procedure called dynamic channel selection. This technology provides cost-effective simultaneous high quality voice and data connectivity, a voice communication using 32Kbps ADPCM and Internet connectivity at 35\70 Kbps. This report discusses the relevance of corDECT in the context of current trends towards wireless systems, contrasts the microcellular architecture of corDECT with existing wireless systems based on macrocellular architectures, and outlines its market potential.

INTRODUCTION/OVERVIEW
A new wireless local loop system to eliminate the physical connections between telephone exchanges and subscribers has just hit the market after a two-year long joint research effort by Indian and US engineers. The new system, called corDECT, is said to offer significant cost-savings, rapid installation, and improved reliability over traditional connections based on copper cables. It is based on a microcellular architecture that is said to offer cost and operational advantages over wireless/mobile telephone systems based on macrocellular architectures. The corDECT system is based on the European Digital Enhanced Cordless Telecommunications standard that uses a modest bandwidth of 20MHz in the 1880-1900 MHz range and does not require prior frequency planning necessary in conventional mobile cellular systems.

The corDECT technology uses relatively low-cost, easy-to-install subsystems and can serve relatively high subscriber density environments -several thousands of subscribers per square kilometer. Four Indian companies have bought the technology for domestic manufacture. Its developers believe there is a large market potential in the Asia-Pacific region and in other developing countries. This report will describe the CorDECT wireless local loop system and its subsystems and compare the microcellular architecture of corDECT with macrocellular architectures employed in many wireless telephone systems.

Need for wireless local loop system:
The telephone and the Internet have changed the way we deliver and receive information and the way we use it for business, entertainment, planning and living. Unfortunately, only 15 percent of the world's population is believed to have access to the Internet. And more than 80 percent of people in the world are believed to have never even heard a dial tone. This Digital divide -between the information 'haves' and 'have nots' -is widening. In India, the problem is acute. Among 1000 million people. There are fewer than 35 million people; there are fewer than 35 million phones connections and around two million Internet connections. There is an urgent need to bridges the gap.
The biggest reason for is high cost. The existing per line cost of a telephone network is Rs.30, 000, which most people in India cannot afford; this has to be reduced by a factor of three to four. In order to reduce the cost, we must consider the factors responsible for overall system cost. The telecom network consists of two components.


1.A backbone network consisting of routers, switches and interconnection of exchanges and routers, including intercity and international connections.
2.An access network that includes the connection of the exchange to the office and home.


Fortunately, the cost of the backbone network is reducing rapidly each successive year with improvements in technology. In order to reduce overall costs. There is a need to focus on the cost of the access networks- that is, the cost of the local loop. By reducing this cost, it is possible to reduce overall per line cost by Rs12, 000 to Rs.16, 000.

For nearly a century, these connections have relied on pairs of copper cables. But laying out wired local loops has been an expensive, time-consuming process that also requires detailed planning and intensive labor costs. According to a projection by the International Telecommunications Union, developing countries alone will require 35-million pair kilometers of copper cable by the turn of the century just to maintain existing waiting lists. The increasing cost of copper, the operational problems associated with wired lines, and the demands for mobility are factors fueling the move towards wireless local loops.


Importance of CorDECT in present scenario:
Internet connections today, for the most part, use a modem to connect a computer to a telephone line. In this case, Internet traffic passes through the telecom network, which overloads the telecom network. It is necessary to develop an access network technology, which separates Internet data form the voice and prevent it from interfering with the telephone network. This would also make it possible to use the telephone and the Internet on the same line simultaneously.


E-Intelligence


Definition
As corporations move rapidly toward deploying e-business systems, the lack of business intelligence facilities in these systems prevents decision-makers from exploiting the full potential of the Internet as a sales, marketing, and support channel. To solve this problem, vendors are rapidly enhancing their business intelligence offerings to capture the data flowing through e-business systems and integrate it with the information that traditional decision-making systems manage and analyze. These enhanced business intelligence-or e-intelligence-systems may provide significant business benefits to traditional brick-and-mortar companies as well as new dot-com ones as they build e-business environments.

Organizations have been successfully using decision-processing products, including data warehouse and business intelligence tools, for the past several years to optimize day-to-day business operations and to leverage enterprise-wide corporate data for a competitive advantage. The advent of the Internet and corporate extranets has propelled many of these organizations toward the use of e-business applications to further improve business efficiency, decrease costs and increase revenues - and to compete with new dot.com companies appearing in the marketplace.
The explosive growth in the use of e-business has led to the need for decision-processing systems to be enhanced to capture and integrate business information flowing through e-business systems. These systems also need to be able to apply business intelligence techniques to this captured-business information. These enhanced decision processing systems, or E-Intelligence, have the potential to provide significant business benefits to both traditional bricks-and-mortar companies and new dot.com companies as they begin to exploit the power of e-business processing.


E-INTELLIGENCE FOR BUSINESS
E-intelligence systems provide internal business users, trading partners, and corporate clients rapid and easy access to the e-business information, applications, and services they need in order to compete effectively and satisfy customer needs. They offer many business benefits to organizations in exploiting the power of the Internet. For example, e-intelligence systems give the organization the ability to:


1.Integrate e-business operations into the traditional business environment, giving business users a complete view of all corporate business operations and information.
2.Help business users make informed decisions based on accurate and consistent e-business information that is collected and integrated from e-business applications.
This business information helps business users optimize Web-based offerings (products offered, pricing and promotions, service and support, and so on) to match marketplace requirements and analyze business performance with respect to competitors and the organization's business-performance objectives.
3.Assist e-business applications in profiling and segmenting e-business customers. Based on this information, businesses can personalize their Web pages and the products and services they offer.
4.Extend the business intelligence environment outside the corporate firewall, helping the organization share internal business information with trading partners. Sharing this information will let it optimize the product supply chain to match the demand for products sold through the Internet and minimizes the costs of maintaining inventory.
5.Extend the business intelligence environment outside the corporate firewall to key corporate clients, giving them access to business information about their accounts.
With this information, clients can analyze and tune their business relationships with other organization, improving client service and satisfaction.
6.Link e-business applications with business intelligence and collaborative processing applications, allowing internal and external users to seamlessly move among different systems.


INTELLIGENT E-SERVICES
The building blocks of new, sophisticated, intelligent data warehousing applications are now intelligent e-services. An e-service is any asset made available via the Internet to drive new revenue streams or create new efficiencies. What makes e-services valuable is not only the immediacy of the service, but also the intelligence behind the service. While traditional data warehousing meant simple business rules, simple queries and pro-active work to take advantage of the Web, E-Intelligence is much more sophisticated and enables the Web to work on our behalf. Combining intelligence with e-services promises exciting business opportunities.



White LED


Until recently, though, the price of an LED lighting system was too high for most residential use. With sales rising and prices steadily decreasing, it's been said that whoever makes the best white LED will open a goldmine.
White LED lighting has been used for years by the RV and boating crowd, running off direct current (DC) battery systems. It then got popular in off-the-grid houses, powered by photovoltaic cells. It used to be that white LED was possible only by "rainbow" groups of three LEDs -- red, green, and blue -- and controlling the current to each to yield an overall white light. Now a blue indium gallium chip with a phosphor coating is used to create the wave shift necessary to emit white light from a single diode. This process is much less expensive for the amount of light generated.


Each diode is about 1/4 inch and consumes about ten milliamps (a tenth of a watt). Lamps come in various arrangements of diodes on a circuit board. Standard arrays are three, six, 12, or 18 diodes, or custom sizes -- factories can incorporate these into custom-built down lights, sconces and surface-mounted fixtures. With an inexpensive transformer, they run on standard 120-volt alternating current (AC), albeit with a slight (about 15% to 20%) power loss. They are also available as screw-in lamps to replace incandescent. A 1.2 watt white LED light cluster is as bright as a 20-watt incandescent lamp.


Carbon Nanotube Flow Sensors


Introduction
Direct generation of measurable voltages and currents is possible when a fluids flows over a variety of solids even at the modest speed of a few meters per second. In case of gases underlying mechanism is an interesting interplay of Bernoulli's principle and the See beck effect: Pressure differences along streamlines give rise to temperature differences across the sample; these in turn produce the measured voltage. The electrical signal is quadratically dependent on the Mach number M and proportional to the Seebeck coefficient of the solids.

This discovery was made by professor Ajay sood and his student Shankar Gosh of IISC Bangalore, they had previously discovered that the flow of liquids, even at low speeds ranging from 10 -1 meter/second to 10 -7 m/s (that is, over six orders of magnitude), through bundles of atomic-scale straw-like tubes of carbon known as nanotubes, generated tens of micro volts across the tubes in the direction of the flow of the liquid. Results of experiment done by Professor Sood and Ghosh show that gas flaw sensors and energy conversion devices can be constructed based on direct generation of electrical signals. The experiment was done on single wall carbon nanotubes (SWNT).These effect is not confined to nanotubes alone these are also observed in doped semiconductors and metals.


The observed effect immediately suggests the following technology application, namely gas flow sensors to measure gas velocities from the electrical signal generated. Unlike the existing gas flow sensors, which are based on heat transfer mechanisms from an electrically heated sensor to the fluid, a device based on this newly discovered effect would be an active gas flow sensor that gives a direct electrical response to the gas flow. One of the possible applications can be in the field of aerodynamics; several local sensors could be mounted on the aircraft body or aerofoil to measure streamline velocities and the effect of drag forces. Energy conversion devices can be constructed based on direct generation of electrical signals i.e. if one is able to cascade millions these tubes electric energy can be produced.

As the state of art moves towards the atomic scales, sensing presents a major hurdle. The discovery of carbon nanotubes by Sujio Iijima at NEC, Japan in 1991 has provided new channels towards this end. A carbon nanotube (CNT) is a sheet of graphene which has been rolled up and capped with fullerenes at the end. The nanotubes are exceptionally strong, have excellent thermal conductivity, are chemically inert and have interesting electronic properties which depend on its chirality. The main reason for the popularity of the CNTs is their unique properties. Nanotubes are very strong, mechanically robust, and have a high Young's modulus and aspect ratio. These properties have been studied experimentally as well as using numerical tools. Bandgap of CNTs is in the range of 0~100 meV, and hence they can behave as both metals and semiconductors.

A lot of factors like the presence of a chemical species, mechanical deformation and magnetic field can cause significant changes in the band gap, which consequently affect the conductance of the CNTs. Its unique electronic properties coupled with its strong mechanical strength are exploited as various sensors. And now with the discovery of a new property of flow induced voltage exhibited by nanotubes discovered by two Indian scientists recently, has added another dimension to micro sensing devices.


CNT Electronic Properties
Electrically CNTs are both semiconductor and metallic in nature which is determined by the type of nanotube, its chiral angle, diameter, relation between the tube indices etc. The electronic properties structure and properties is based on the two dimensional structure of Graphene. For instance if the tube indices, n and m, satisfies the condition n-m=3q where q is and integer it behaves as a metal. Metal, in the sense that it has zero band gap energy. But in case of armchair (where n=m) the Fermi level crosses i.e. the band gap energy merges. Otherwise it is expected the properties of tube will be that of semiconductor. The table below (Table 1) is the observations of experiments done on nanotubes by Scanning tunneling microscope (STM) and Scanning tunneling spectroscopes (STS).


Fluid Flow Through Carbon


Nanotube
Recently there has been extensive study on the effect of fluid flow through nanotubes, which is a part of an ongoing effort worldwide to have a representative in the microscopic nano-world of all the sensing elements in our present macroscopic world. Indian Institute of Science has a major contribution in this regard. It was theoretically predicted that flow of liquid medium would lead to generation of flow-induced voltage. This was experimentally established by two Indian scientist at IISc. Only effect of liquid was theoretically investigated and established experimentally, but effect of gas flow over nanotubes were not investigated, until A.K Sood and Shankar Ghosh of IISc investigated it experimentally and provided theoretical explanation for it. The same effect as in case of liquid was observed, but for entirely different reason. These results have interesting application in biotechnology and can be used in sensing application. Micro devices can be powered by exploiting these properties.

Cellular Positioning


Introduction
Location related products are the next major class of value added services that mobile network operators can offer their customers. Not only will operators be able to offer entirely new services to customers, but they will also be able to offer improvements on current services such as location-based prepaid or information services. The deployment of location based services is being spurred by several factors:


Competition
The need to find new revenue enhancing and differentiating value added services has been increasing and will continue to increase over time. Regulation The Federal Communications Commission (FCC) of the USA adopted a ruling in June 1996 (Docket no. 94-102) that requires all mobile network operators to provide location information on all calls to "911", the emergency services. The FCC mandated that by 1 st October 2001, all wireless 911 calls must be pinpointed within125 meters, 67% of the time. On December 24 1998, the FCC amended its ruling to allow terminal based solutions as well as network based ones (CC Docket No. 94-102, Waivers for Handset-Based Approaches). There are a number of regulations that location based services must comply with, not least of all to protect the privacy of the user. Mobile Streams believes that it is essential to comply with all such regulations fully. However, such regulations are only the starting point for such services- there are possibilities for a high degree of innovation in this new market that should not be overlooked.


Technology
There have been continuous improvements in handset, network and positioning technologies. For example, in 1999, Benefon, a Finnish GSM and NMT terminal vendor launched the ESC! GSM/ GPS mapping phone.


Needs Of Cellular Positioning
There are a number of reasons why it is useful to be able to pinpoint the position of a mobile telephone, some of which are described below. Location-Sensitive billing Different tariff can be provided depending upon the position of the cell phone. This allows the operator without a copper cable based PSTN to offer competitive rates for calls from home or office. Increased subscriber safety. A significant number of emergency calls like US.911 are coming from cell phones, and in most of the cases the caller can not provide the accurate information about their position. As a real life example let us take the following incident. In February 1997 a person became stranded along a highway during a winter blizzard (Associated press 1997).She used her cellular phone to call for help but could not provide her location due to white-out conditions. To identify the callers approximate position authorities asked her to tell them when she could hear the search plane flying above. From the time of her first call forty hours elapsed before a ground rescue team reached her. An automatic positioning system would have allowed rescuers to reach her far sooner.


Positioning Techniques
There are a variety of ways in which position can be derived from the measurement of signals and these can be applied to any cellular system including GSM. The important measurements are the Time of Arrival (TOA), the Time Difference of Arrival (TDOA), the Angle of Arrival (AOA) and Carrier phase. All these measurement put the object to be positioned on a particular locus. Multiple measurements give multiple loci and the point of their intersection gives the position. If the density of the base stations is such that more measurements can be done than required then a least square approach can be used. If the measurements are too few in number the loci will intersect at more than one point result in ambiguous position estimate. In the following discussion we assume that the mobile station and base station are lying in the same plane. This is approximately true for most networks unless the geography include hilly topology or high rise buildings.


Time of Arrival (TOA)
In a remote positioning system this involves the measurement of the propagation time of a signal from the mobile phone to a base station. Each measurement fixes the position of the mobile on a circle. With two stations there will be two circle and they can intersect in a maximum of two points. This gives rise to an ambiguity and it is resolved by including a priory information of the trajectory of the mobile phone or making a propagation time measurement to a third base station. The TOA measurement requires exact time synchronization between the base stations and the receiver should have an accurate clock, so that the receiver knows the exact time of transmission and an exact TOA measurement have made by the receiver.


Iontophoresis


Iontophoresis is an effective and painless method of delivering medication to a localized tissue area by applying electrical current to a solution of the medication. The delivered dose depends on the current flowing and its duration.
Iontophoresis is a recognized therapeutic method for delivering ionic compounds, i.e. drugs, into and through the skin by applying electrical current. It has proven to be a beneficial treatment for many localized skin disorders such as; nail diseases, Herpies lesions, psoriasis, eczematous, and cutaneous T-cell lymphoma. The method has also been reported useful for topical anesthesia to the skin prior to cut-down for artificial kidney dialysis, insertion of tracheotomy tubes and infiltration of lidocaine into the skin prior to venipuncture.


Treatment of various musculoskeletal disorders with anti-inflammatory agents has been reported in the literature. Iontophoresis enhances the transdermal delivery of ionized drugs through the skin's outermost layer (stratum corneum) which is the main barrier to drug transport. The absorption rate of the drug is increased, however, once the drug passes through the skin barrier natural diffusion and circulation are required to shuttle the drug to its proper location. The mechanism by which iontophoresis works is based upon the knowledge that like electrical charges repel. Application of a positive current from an electrode to a solution applied to a skin surface will drive the positively charged drug ions away from the electrode and into the skin. Obviously, negatively charged ions will behave in the same manner.


Dual Energy X-ray Absorptiometry


Definition
The basic principles of Dual Energy X-ray Absorptiometry have been discussed in this presentation. DEXA is a instrumental technique used to measure bone mineral density (BMD), which is the widely accepted indicator of bone strength. DEXA scanner is the most widely used modern electronic machine to diagnose the disease osteoporosis, the thinning of bones. Human body being a heterogeneous system, use of a dual energy, rather than single energy, X-ray source is necessary for scanning. The interaction of the sample with the X-ray beams results in a reduction or attenuation of the energy of the X-ray beam. The extent to which the photon energy is attenuated is a function of the initial energy of the X-ray photon, the mass per unit area (M) of the absorber material and the mass attenuation coefficient (U) of the absorber. For a given absorber material, U (which is a measure of the degree of attenuation) is a constant at any given photon energy.


U increases with the density of the absorber material and decreases with the energy of the X-ray beam. U can be used to calculate the Mass per unit area (M) of a homogenous absorber irradiated at a specific incident X-ray energy. The mass of bone and soft tissue 'below' this square would represent the mass per unit area of the absorber, viz., leg. For instance, if there are 100 grams of bone and soft tissue below this square, the mass per unit area (M) would be 100 g/cm 2 . Knowledge of M of the human body components, especially of bone, is important in determining the possibility of osteoporosis. The calculations of M of the various components of the body are discussed in detail. From knowledge of mass attenuation coefficient (U) of the absorber and the energy of the incident X-ray beam (E0) and of the emerging beam (E), we can calculate M of a homogeneous absorber from the following relationship connecting these properties.


Dual Energy X-ray Absorptiometry (DEXA) is an instrumental technique used to measure bone mineral density (BMD) that includes the hip and spine, compared to SXA (Single Energy X-ray Absorptiometry) that measures only the wrist or heel bone. BMD is the widely accepted indicator of bone strength. DEXA (the whole body scanner) uses low dose x-rays to give us information on bone content and density. It is currently the most widely used machine in the clinical setting to diagnose the disease osteoporosis, the thinning of bones.


DEXA is the most commonly used modern technique to determine the bone density and hence the bone strength. The DEXA results help to predict the patient's risk factors for osteoporosis. It is a fast, accurate, and less expensive technique. It exposes the patient to fewer amounts of radiations. So the risk is reduced to a great extend. Studies using DEXA scanning have shown that women with osteoporosis have substantially lower bone density measurements than normal, age-matched women. Bone mineral density is widely accepted as a good indicator of bone strength. Thus low values can be compared against standard bone density measurements and help predict a patient's risk for fracture based upon the DEXA scan measurements.


Pervasive Computing


Definition
Pervasive computing refers to embedding computers and communication in our environment. Pervasive computing provides an attractive vision for the future of computing. The idea behind the pervasive computing is to make the computing power disappear in the environment, but will always be there whenever needed or in other words it means availability and invisibility. These invisible computers won't have keyboards or screens, but will watch us, listen to us and interact with us. Pervasive computing makes the computer operate in the messy and unstructured world of real people and real objects. Distributed devices in this environment must have the ability to dynamically discover and integrate other devices.

The prime goal of this technology is to make human life more simple, safe and efficient by using the ambient intelligence of computers. Pervasive computing environments involve the interaction, coordination, and cooperation of numerous, casually accessible, and often invisible computing devices. These devices will connect via wired and wireless links to one another as well as to the global networking infrastructure to provide more relevant information and integrated services. Existing approaches to building distributed applications, including client/server computing, are ill suited to meet this challenge. They are targeted at smaller and less dynamic computing environments and lack sufficient facilities to manage changes in the network configurations.

Networked computing devices will proliferate in the user's landscape, being embedded in objects ranging from home appliances to clothing. Applications will have greater awareness of context, and thus will be able to provide more intelligent services that reduce the burden on users to direct and interact with applications. Many applications will resemble agents that carry out tasks on behalf of users by exploiting the rich sets of services available within computing environments.


Mobile computing and communication is one of the major parts of the pervasive computing system. Here data and computing resources are shared among the various devices. The coordination between these devices is maintained through communication, which may be wired or wireless. With the advent of Bluetooth and Ad hoc networking technologies the wireless communication has overtaken the wired counter part.The reduction in size and cost of processor chips made it possible to implement it in every field of life. Nowadays about 99% of processors made are for embedded devices compared to the PC applications. Voice and Gesture recognition along with steerable interface will make the interactions and use of these devices more user friendly. Efficient security and privacy policies along with power management can enhance the performance of such systems.


Current Embedded Technology
Embedded technology is the process of introducing computing power to various appliances. These devices are intended to perform certain specific jobs and processors giving the computing power are designed in an application oriented way.
Computers are hidden in numerous information appliances which we use in our day-to- day life. These devices find there application in every segment of life such as consumer electronics, avionics, biomedical engineering, manufacturing, process control, industrial, communication, defence etc…

Embedded systems, based on there functionality and performance requirement are basically categorized as:
i. Stand alone systems
ii. Real time systems
iii. Networked systems
iv. Mobile devices

Passive Millimeter-Wave


Definition
Passive millimeter-wave (PMMW) imaging is a method of forming images through the passive detection of naturally occurring millimeter-wave radiation from a scene. Although such imaging has been performed for decades (or more, if one includes microwave radiometric imaging), new sensor technology in the millimeter-wave regime has enabled the generation of PMMW imaging at video rates and has renewed interest in this area. This interest is, in part, driven by the ability to form images during the day or night; in clear weather or in low-visibility conditions, such as haze, fog, clouds, smoke, or sandstorms; and even through clothing. This ability to see under conditions of low visibility that would ordinarily blind visible or infrared (IR) sensors has the potential to transform the way low-visibility conditions are dealt with. For the military, low visibility can become an asset rather than a liability.

In the commercial realm, fog-bound airports could be eliminated as a cause for flight delays or diversions. For security concerns, imaging of concealed weapons could be accomplished in a nonintrusive manner with PMMW imaging. Like IR and visible sensors, a camera based on PMMW sensors generates easily interpretable imagery in a fully covert manner; no discernible radiation is emitted, unlike radar and lidar. However, like radar PMMW sensors provide penetrability through a variety of low-visibility conditions (moderate/heavy rainfall is an exception). In addition, the underlying phenomenology that governs the formation of PMMW images leads to two important features. First, the signature of metallic objects is very different from natural and other backgrounds.

Second, the clutter variability is much less in PMMW images than in other sensor images. Both of these characteristics lead to much easier automated target detection with fewer false alarms. The wide range of military imaging missions that would benefit from an imaging capability through low-visibility conditions, coupled with its inherent covertness, includes surveillance, precision targeting, navigation, aircraft landing, refueling in clouds, search and rescue, metal detection in a cluttered environment, and harbor navigation/surveillance in fog. Similarly, a number of civilian missions would benefit, such as commercial aircraft landing aid in fog, airport operations in fog, harbor surveillance, highway traffic monitoring in fog, and concealed weapons detection in airports and other locations. This article introduces the concept of PMMW imaging, describes the phenomenology that defines its performance, explains the technology advances that have made these systems a reality, and presents some of the missions in which these sensors can be used.

Overview of millimeter wave radiometry:
The regime of the electromagnetic spectrum where it is possible for humans to see is that part where the sun's radiance peaks (at about 6,000 K): the visible regime. In that regime, the human eye responds to different wavelengths of scattered light by seeing different colors. In the absence of sunlight, however, the natural emissions from Earth objects (at about 300 K) are concentrated in the IR regime. Advances in IR-sensor technology in the last 30 years have produced detectors sensitive in that frequency regime, making night vision possible. The exploitation of the millimeter-wave regime (defined to lie between 30 and 300 GHz, with corresponding wavelengths between 10 and 1 mm) follows as a natural progression in the quest to expand our vision. The great advantage of millimeter-wave radiation is that it can be used not only in day and night conditions, but also in fog and other poor visibility conditions that normally limit the "seeing" ability of both visual and IR sensors.

RAID


Definition
Information has become a commodity in today's world, and protecting that information has become mission critical. The Internet has helped push this information age forward. Popular websites process so much information, that any type of slowdown or downtime can mean the loss of millions of dollars. Clearly, just a bunch of hard disks won't be able to cut it anymore. So Redundant Array of Independent (or Inexpensive) Disks (RAID) was developed to increase the performance and reliability of data storage by spreading data across multiple drives. RAID technology has grown and evolved throughout the years to meet these ever-growing demands for speed and data security.


A technique was developed to provide speed, reliability, and increased storage capacity using multiple disks, rather than single disk solutions. RAID takes multiple hard drives and allows them to be used as one large hard drive with benefits depending on the scheme or level of RAID being used. The better the RAID implementation, the more expensive it is. There is no one best RAID implementation. Some implementations are better than others depending upon the actual application. It used to be that RAID was only available in expensive server systems. However, with the advent of inexpensive RAID controllers, it seems it has pretty much reached the mainstream market.


The Array And Raid Controller Concept:
A drive array is a collection of hard disk drives that are grouped together. When we talk about RAID, there is often a distinction between physical drives and arrays and logical drives and arrays. Physical arrays can be divided or grouped together to form one or more logical arrays. These logical arrays can be divided into logical drives that the operating system sees. The logical drives are treated as single hard drives and can be partitioned and formatted accordingly.


The RAID controller is what manages how the data is stored and accessed across the physical and logical arrays. It ensures that the operating system sees the logical drives only and need not worry about managing the underlying schema. As far as the system is concerned, it is dealing with regular hard drives. A RAID controller's functions can be implemented in hardware or software. Hardware implementations are better for RAID levels that require large amounts of calculations. With today's incredibly fast processors, software RAID implementations are more feasible, but the CPU still gets bogged-down with large amounts of I/O.


The basic concepts made use of in RAID are:
.Mirroring
.Parity
.ECC
.Exclusive OR
.Striping


Mirroring:
Mirroring involves having two copies of the same data on separate hard drives or drive arrays. So the data is effectively mirrored on another drive. The system writes data simultaneously to both hard drives. This is one of the two data redundancy methods used in RAID to protect from data loss. The benefit is that when one hard drive or array fails, the system can still continue to operate since there are two copies of data. Downtime is minimal and data recovery is relatively simple. All you need to do is rebuild the data from good copy.
A raid controller writes the same data blocks to each mirrored drive. This means that each drive or array has the same information in it. We can add another level of complexity by introducing yet another technique called striping. If we have one striped array we can mirror the array at the same time on the second striped array. To set up mirroring the number of drives will have to be in the power of two.

Holographic Data Storage


Mass memory systems serve computer needs in both archival and backup needs. There exist numerous applications in both the commercial and military sectors that require data storage with huge capacity, high data rates and fast access. To address such needs 3-D optical memories have been proposed. Since the data are stored in volume, they are capable of much higher storage densities than existing 2-D memory systems. In addition this memory system has the potential for parallel access. Instead of writing or reading a sequence of bits at each time, entire 2-D data pages can be accessed at one go. With advances in the growth and preparation of various photorefractive materials, along with the advances in device technologies such as spatial light modulators(SLM), and detector arrays, the realizations of this optical system is becoming feasible.

A hologram is a recording of the optical interference pattern that forms at the intersection of two coherent optical beams. Typically, light from a single laser is split into two paths, the signal path and the reference path.. The beam that propagates along the signal path carries information, whereas the reference is designed to be simple to reproduce. A common reference beam is a plane wave: a light beam that propagates without converging or diverging. The two paths are overlapped on the holographic medium and the interference pattern between the two beams is recorded. A key property of this interferometric recording is that when it is illuminated by a readout beam, the signal beam is reproduced. In effect, some of the light is diffracted from the readout beam to "reconstruct" a weak copy of the signal beam. If the signal beam was created by reflecting light off a 3D object, then the reconstructed hologram makes the 3D object appear behind the holographic medium. When the hologram is recorded in a thin material, the readout beam can differ from the reference beam used for recording and the scene will still appear.


Volume Holograms
To make the hologram, the reference and object beams are overlapped in a photosensitive medium, such as a photopolymer or inorganic crystal. The resulting optical interference pattern creates chemical and/or physical changes in the absorption, refractive index or thickness of the storage media, preserving a replica of the illuminating interference pattern. Since this pattern contains information about both the amplitude and the phase of the two light beams, when the recording is illuminated by the readout beam, some of the light is diffracted to "reconstruct" a weak copy of the object beam .If the object beam originally came from a 3-D object, then the reconstructed hologram makes the 3-D object reappear. Since the diffracted wave front accumulates energy from throughout the thickness of the storage material, a small change in either the wavelength or angle of the readout beam generates enough destructive interference to make the hologram effectively disappear through Bragg selectivity.

As the material becomes thicker, accessing a stored volume hologram requires tight tolerances on the stability and repeatability of the wavelength and incidence angle provided by the laser and readout optics. However, destructive interference also opens up a tremendous opportunity: a small storage volume can now store multiple superimposed holograms, each one distributed throughout the entire volume. The destructive interference allows each of these stored holograms to be independently accessed with its original reference beam. To record a second, angularly multiplexed hologram, for instance, the angle of the reference beam is changed sufficiently so that the reconstruction of the first hologram effectively disappears. The new incidence angle is used to record a second hologram with a new object beam. The two holograms can be independently accessed by changing the readout laser beam angle back and forth. For a 2-cm hologram thickness, the angular sensitivity is only 0.0015 degrees. Therefore, it becomes possible to store thousands of holograms within the allowable range of reference arm angles (typically 20-30 degrees). The maximum number of holograms stored at a single location to date7 is 10,000.


Organic Display


With the imaging appliance revolution underway, the need for more advanced handheld devices that will combine the attributes of a computer, PDA, and cell phone is increasing and the flat-panel mobile display industry is searching for a display technology that will revolutionize the industry. The need for new lightweight, low-power, wide viewing angled displays has pushed the industry to revisit the current flat-panel digital display technology used for mobile applications. Struggling to meet the needs of demanding applications such as e-books, smart networked household appliances, identity management cards, and display-centric handheld mobile imaging devices, the flat panel industry is now looking at new and revolutionary form of displays known as Organic Light Emitting Diodes (OLED).


OLEDs offer higher efficiency and lower weight than many other types of displays, and are present in myriad forms that lend themselves to various applications. Many exciting virtual imaging applications will become a reality as new advanced OLED - on - silicon micro displays enter the market place over the next few years.
The field of semi conducting polymers has its root in the 1977 discovery of the semi conducting properties of polyacetylene. This breakthrough earned Alan Heeger, Alan MacDiarmid, and Hideki Shirakawa the 2000 Nobel Prize in Chemistry for 'the discovery and development of conductive polymers'. The physical and chemical understanding of these novel materials has led to new device applications as active and passive electronic and optoelectronic devices ranging from diodes and transistors to polymer LEDs, photodiodes, lasers, and solar cells. Much interest in plastic devices derives from the opportunities to use clever control of polymer structure combined with relatively economical polymer synthesis and processing techniques to obtain simultaneous control over electronic, optical, chemical, and mechanical features.


With the imaging appliance revolution underway, the need for more advanced handheld devices that will combine the attributes of a computer, PDA, and cell phone is increasing and the flat-panel mobile display industry is searching for a display technology that will revolutionize the industry. The need for new lightweight, low-power, wide viewing angled, handheld portable communication devices have pushed the display industry to revisit the current flat-panel digital display technology used for mobile applications. Struggling to meet the needs of demanding applications such as e-books, smart networked household appliances, identity management cards, and display-centric handheld mobile imaging devices, the flat panel industry is now looking at new displays For the preparation of the latest materials to prepare against this onslaught of demand for lighter and less power hungry display technologies, electrical engineers have enlisted the help of the humble jellyfish in their efforts to develop better light-emitting diodes (LEDs),Moreover, the jellyfish accomplishes this with great efficiency: its lightcomes from a substance dubbed green fluorescent protein (GFP), which collects the energy produced in a certain cellular chemical reaction and emits it as green light from a molecular package known as a chromophore.

An OLED is an electronic device made by placing a series of organic thin films between two conductors. When electrical current is applied, a bright light is emitted. This process is called electro phosphorescence. Even with the layered system, these systems are very thin, usually less than 500 nm (0.5 thousandths of a millimeter). known as Organic Light Emitting Diodes (OLED).

Symbian OS


Definition
Symbian OS is designed for the mobile phone environment. It addresses constraints of mobile phones by providing a framework to handle low memory situations, a power management model, and a rich software layer implementing industry standards for communications, telephony and data rendering. Even with these abundant features, Symbian OS puts no constraints on the integration of other peripheral hardware. This flexibility allows handset manufacturers to pursue innovative and original designs. Symbian OS is proven on several platforms. It started life as the operating system for the Psion series of consumer PDA products (including Series 5mx, Revo and netBook), and various adaptations by Diamond, Oregon Scientific and Ericsson. The first dedicated mobile phone incorporating Symbian OS was the Ericsson R380 Smartphone, which incorporated a flip-open keypad to reveal a touch screen display and several connected applications.

Most recently available is the Nokia 9210Communicator, a mobile phone that has a QWERTY keyboard and color display, and is fully open to third-party applications written in Java or C++. The five key points - small mobile devices, mass-market, intermittent wireless connectivity, diversity of products and an open platform for independent software developers - are the premises on which Symbian OS was designed and developed. This makes it distinct from any desktop, workstation or server operating system. This also makes Symbian OS different from embedded operating systems, or any of its competitors, which weren't designed with all these key points in mind. Symbian is committed to open standards. Symbian OS has a POSIX-compliant interface and a Sun-approved JVM, and the company is actively working with emerging standards, such as J2ME, Bluetooth, MMS, SyncML, IPv6 and WCDMA.


As well as its own developer support organization, books, papers and courses, Symbian delivers a global network of third-party competency and training centers - the Symbian Competence Centers and Symbian Training Centers. These are specifically directed at enabling other organizations and developers to take part in this new economy. Symbian has announced and implemented a strategy that will see Symbian OS running on many advanced open mobile phones. Small devices come in many shapes and sizes, each addressing distinct target markets that have different requirements. The market segment we are interested in is that of the mobile phone. The primary requirement of this market segment is that all products are great phones. This segment spans voice-centric phones with information capability to information-centric devices with voice capability. These advanced mobile phones integrate fully-featured personal digital assistant (PDA) capabilities with those of a traditional mobile phone in a single unit.

There are several critical factors for the need of operating systems in this market. It is important to look at the mobile phone market in isolation. It has specific needs that make it unlike markets for PCs or fixed domestic appliances. Scaling down a PC operating system, or bolting communication capabilities onto a small and basic operating system, results in too many fundamental compromises. Symbian believes that the mobile phone market has five key characteristics that make it unique, and result in the need for a specifically designed operating system:


1) mobile phones are both small and mobile.
2) mobile phones are ubiquitous - they target a mass-market of consumer, enterprise and professional users.
3) mobile phones are occasionally connected - they can be used when connected to the wireless phone network, locally to other devices, or on their own.
4) manufacturers need to differentiate their products in order to innovate and compete in a fast-evolving market.


Ovonic Unified Memory (OUM)


Definition
Ovonyx is developing a microelectronics memory technology called Ovonic Unified Memory (OUM). This technology is originally developed by Mr. Stanford Ovshinsky and exclusively licensed from Energy Conversion Devices (ECD) Inc. Ovonic unified memory -- its name is derived from ''Ovshinsky'' and ''electronic''. OVM is also known as phase change memory because it uses unique thin-film phase change material to store information economically and with excellent solid-state memory properties. It would be the replacement of conventional memories like Magnetic Random Access Memory (MRAM), Ferro electric Random Access Memory (FeRAM or FRAM), Dynamic Random Access Memory (DRAM), and Static Random Access Memory (SRAM).


OVM allows the rewriting of CD & DVDs .CD & DVD drives read or write ovonic material with laser , but OVM uses electric current to change the phase of the material. The thin-film material is a phase-change chalcogenide alloy similar to the film used to store information on commercial CD-RW and DVD-RAM optical disks, based on proprietary technology originally developed by and exclusively licensed from Energy Conversion Devices.


Evolution Of OUM
Magnetic Random Access Memory (MRAM), a technology first developed in the 1970's, but rarely commercialized, has attracted by the backing of I.B.M. Motorola and others. MRAM stores information by flip flopping two layers of magnetic material in and out of alignment with an electric current. For reading and writing data, MRAM can be as fast as a few nanoseconds, or billionths of a second, best among the next three generation memory candidates. And if promises to integrate easily with the industry's existing chip manufacturing process. MRAM is built on top of silicon circuitry. The biggest problem with MRAM is a relatively small distance, difficult to detect, between it's ON and OFF states.


The second potential successor to flash, Ferro - electric Random Access Memory (FeRAM / FRAM), has actually been commercially available for nearly 15 years, has attracted by the backing of Fujitsu, Matsushita, I.B.M. and Ramtron. FRAM relies on the polarization of what amount to tiny magnets inside certain materials like perouikite, from basaltic rocks. FRAM memory cells do not wear out until they have been read or written to billions of times, while MRAM and OUM would require the addition of six to eight "masking" layers in the chip manufacturing process, just like Flash, FRAM might require as little as two extra layers.


OUM is based on the information storage technology developed by Mr.Ovshinsky that allows rewriting of CD's and DVD's. While CD and DVD drives read and write ovonic material with lasers, OUM uses electric current to change the phase of memory cells. These cells are either in crystalline state, where electrical resistance is low or in amorphous state, where resistance is high. OUM can be read and write to trillionths of times making its use essentially nondestructive, unlike MRAM or FRAM. OUM's dynamic range, difference between the electrical resistance in the crystalline state and in the amorphous state - is wide enough to allow more than one set of ON and OFF values in a cell, dividing it into several bits and multiplying memory density by two, four potential even 16 times. OUM is not as fast as MRAM.The OUM solid-state memory has cost advantages over conventional solid-state memories such as DRAM or Flash due to its thin-film nature, very small active storage media, and simple device structure. OUM requires fewer steps in an IC manufacturing process resulting in reduced cycle times, fewer defects, and greater manufacturing flexibility.


Spintronics


Spintronics can be fairly new term for you but the concept isn't so very exotic .This technological discipline aim to exploit subtle and mind bending esoteric quantum property of electron to develop a new generation of electronics devices. The ability to exploit spin in semiconductor promise a new logical devices as spin transistor etc with enhanced functionality higher speed and reduction power conception and might have a spark revolution in semiconductor industry. so far the problem of injecting electron with controlled spin direction has held up the realization of such spintronics

Spintronics is an emergent technology that exploits the quantum propensity of the electrons to spin as well as making use of their charge state. The spin itself is manifested as a detectable weak magnetic energy state characterised as "spin up" or "spin down".


Conventional electronic devices rely on the transport of electrical charge carriers - electrons - in a semiconductor such as silicon. Device engineers and physicists are now trying to exploit the spin of the electron rather than its charge.
Spintronic-devices combine the advantages of magnetic materials and semiconductors. They are expected to be non-volatile, versatile, fast and capable of simultaneous data storage and processing, while at the same time consuming less energy. Spintronic-devices are playing an increasingly significant role in high-density data storage, microelectronics, sensors, quantum computing and bio-medical applications, etc.

Bio-Molecular Computing


Definition
Molecular computing is an emerging field to which chemistry, biophysics, molecular biology, electronic engineering, solid state physics and computer science contribute to a large extent. It involves the encoding, manipulation and retrieval of information at a macromolecular level in contrast to the current techniques, which accomplish the above functions via IC miniaturization of bulk devices. The biological systems have unique abilities such as pattern recognition, learning, self-assembly and self-reproduction as well as high speed and parallel information processing. The aim of this article is to exploit these characteristics to build computing systems, which have many advantages over their inorganic (Si,Ge) counterparts.

DNA computing began in 1994 when Leonard Adleman proved thatDNA computing was possible by finding a solution to a real- problem, a Hamiltonian Path Problem, known to us as the Traveling Salesman Problem,with a molecular computer. In theoretical terms, some scientists say the actual beginnings of DNA computation should be attributed to Charles Bennett's work. Adleman, now considered the father of DNA computing, is a professor at the University of Southern California and spawned the field with his paper, "Molecular Computation of Solutions of Combinatorial Problems." Since then, Adleman has demonstrated how the massive parallelism of a trillion DNA strands can simultaneously attack different aspects of a computation to crack even the toughest combinatorial problems.

Adleman's Traveling Salesman Problem:
The objective is to find a path from start to end going through all the points only once. This problem is difficult for conventional computers to solve because it is a "non-deterministic polynomial time problem" . These problems, when they involve large numbers, are intractable with conventional computers, but can be solved using massively parallel computers like DNA computers. The Hamiltonian Path problem was chosen by Adleman because it is known problem.


The following algorithm solves the Hamiltonian Path problem:
1.Generate random paths through the graph.
2.Keep only those paths that begin with the start city (A) and conclude with the
end city (G).
3.If the graph has n cities, keep only those paths with n cities. (n=7)
4.Keep only those paths that enter all cities at least once.
5.Any remaining paths are solutions.


The key was using DNA to perform the five steps in the above algorithm. Adleman's first step was to synthesize DNA strands of known sequences, each strand 20 nucleotides long. He represented each of the six vertices of the path by a separate strand, and further represented each edge between two consecutive vertices, such as 1 to 2, by a DNA strand which consisted of the last ten nucleotides of the strand representing vertex 1 plus the first 10 nucleotides of the vertex 2 strand. Then, through the sheer amount of DNA molecules (3x1013 copies for each edge in this experiment!) joining together in all possible combinations, many random paths were generated. Adleman used well-established techniques of molecular biology to weed out the Hamiltonian path, the one that entered all vertices, starting at one and ending at six. After generating the numerous random paths in the first step, he used polymerase chain reaction (PCR) to amplify and keep only the paths that began on vertex 1 and ended at vertex 6. The next two steps kept only those strands that passed through six vertices, entering each vertex at least once. At this point, any paths that remained would code for a Hamiltonian path, thus solving the problem.


4G Wireless Systems


Definition
Fourth generation wireless system is a packet switched wireless system with wide area coverage and high throughput. It is designed to be cost effective and to provide high spectral efficiency . The 4g wireless uses Orthogonal Frequency Division Multiplexing (OFDM), Ultra Wide Radio Band (UWB),and Millimeter wireless. Data rate of 20mbps is employed. Mobile speed will be up to 200km/hr.The high performance is achieved by the use of long term channel prediction, in both time and frequency, scheduling among users and smart antennas combined with adaptive modulation and power control. Frequency band is 2-8 GHz. it gives the ability for world wide roaming to access cell anywhere.


Wireless mobile communications systems are uniquely identified by "generation designations. Introduced in the early 1980s, first generation (1G) systems were marked by analog frequency modulation and used primarily for voice communications. Second generation (2G) wireless communications systems, which made their appearance in the late 1980s, were also used mainly for voice transmission and reception The wireless system in widespread use today goes by the name of 2.5G-an "in between " service that serves as a stepping stone to 3G. Whereby 2G communications is generally associated with Global System for Mobile (GSM) service, 2.5G is usually identified as being "fueled " by General Packet Radio Services (GPRS) along with GSM. In 3G systems, making their appearance in late 2002 and in 2003, are designed for voice and paging services, as well as interactive media use such as teleconferencing, Internet access, and other services. The problem with 3G wireless systems is bandwidth-these systems provide only WAN coverage ranging from 144 kbps (for vehicle mobility applications) to 2 Mbps (for indoor static applications). Segue to 4G, the "next dimension " of wireless communication. The 4g wireless uses Orthogonal Frequency Division Multiplexing (OFDM), Ultra Wide Radio Band (UWB), and Millimeter wireless and smart antenna. Data rate of 20mbps is employed. Mobile speed will be up to 200km/hr.Frequency band is 2 ]8 GHz. it gives the ability for world wide roaming to access cell anywhere.


Features:
o Support for interactive multimedia, voice, streaming video, Internet, and other broadband services
o IP based mobile system
o High speed, high capacity, and low cost per bit
o Global access, service portability, and scalable mobile services
o Seamless switching, and a variety of Quality of Service driven services
o Better scheduling and call admission control techniques
o Ad hoc and multi hop networks (the strict delay requirements of voice make multi hop network service a difficult problem)
o Better spectral efficiency
o Seamless network of multiple protocols and air interfaces (since 4G will be all ]IP, look for 4G systems to be compatible with all common network technologies, including802.11, WCDMA, Blue tooth, and Hyper LAN).
o An infrastructure to handle pre existing 3G systems along with other wireless technologies, some of which are currently under development.


Code Division Duplexing


Introduction
Reducing interference in a cellular system is the most effective approach to increasing radio capacity and transmission data rate in the wireless environment. Therefore, reducing interference is a difficult and important challenge in wireless communications.


In every two-way communication system it is necessary to use separate channels to transmit information in each direction. This is called duplexing. Currently there exist only two duplexing technologies in wireless communications, Frequency division duplexing (FDD) and time division duplexing (TDD). FDD has been the primary technology used in the first three generations of mobile wireless because of its ability to isolate interference. TDD is seemingly a more spectral efficient technology but has found limited use because of interference and coverage problems.


Code-division duplexing (CDD) is an innovative solution that can eliminate all kinds of interference. CDMA is the best multiple access scheme when compared to all others for combating interference. However, the codes in CDMA can be more than one type of code. A set of smart codes can make a high-capacity CDMA system very effective without adding other technologies. The smart code plus TDD is called CDD. This paper will elaborate on a set of smart codes that will make an efficient CDD system a reality. The CDMA system based on this is known as the LAS-CDMA, where LAS is a set of smart codes. LAS-CDMA is a new coding technology that will increase the capacity and spectral efficiency of mobile networks. The advanced technology uses a set of smart codes to restrict interference, a property that adversely affects the efficiency of CDMA networks.

To utilize spectrum efficiently, two transmission techniques need to be considered: one is a multiple access scheme and the other a duplexing system. There are three multiple access schemes namely TDMA, FDMA and CDMA. The industry has already established the best multiple access scheme, code-division multiple access (CDMA), for 3G systems. The next step is to select the best duplexing system. Duplexing systems are used for two-way communications. Presently, there are only two duplexing systems used: frequency-division duplexing (FDD), and time-division duplexing (TDD). The former uses different frequencies to handle incoming and outgoing signals. The latter uses a single frequency but different time slots to handle incoming and outgoing signals.

In the current cellular duplexing systems, FDD has been the appropriate choice, not TDD. Currently, all cellular systems use frequency-division duplexing in an attempt to eliminate interference from adjacent cells. The use of many technologies has limited the effects of interference but still certain types of interference remain. Time-division duplexing has not been used for mobile cellular systems because it is even more susceptible to different forms of interference. TDD can only be used for small confined area systems. Code-division duplexing is an innovative solution that can eliminate all kinds of interference. Eliminating all types of interference makes CDD the most spectrum efficient duplexing system.


CDMA overview


Interference and Capacity
One of the key criteria in evaluating a communication system is its spectral efficiency, or the system capacity, for a given system bandwidth, or sometimes, the total data rate supported by the system. For a given bandwidth, the system capacity for narrow band radio systems is dimension limited, while the system capacity of a traditional CDMA system is interference limited. Traditional CDMA systems are all self-interference system. Three types of interference are usually considered. By ISI we mean Inter Symbol Interference, which is created by the multi-path replica of the useful signal itself; MAI, or Mutual Access Interference, which is the interference created by the signals and their multi-path replica from the other users onto the useful signal; and ACI, or Adjacent Cell Interference, which is all the interfering signals from the adjacent cells onto the useful signal.


VLSI Computations


Definition
Over the past four decades the computer industry has experienced four generations of development, physically marked by the rapid changing of building blocks from relays and vacuum tubes (1940-1950s) to discrete diodes and transistors (1950-1960s), to small- and medium-scale integrated (SSI/MSI) circuits (1960-1970s), and to large- and very-large-scale integrated (LSI/VLSI) devices (1970s and beyond). Increases in device speed and reliability and reductions in hardware cost and physical size have greatly enhanced computer performance. However, better devices are not the sole factor contributing to high performance. Ever since the stored-program concept of von Neumann, the computer has been recognized as more than just a hardware organization problem. A modern computer system is really a composite of such items as processors, memories, functional units, interconnection networks, compilers, operating systems, peripherals devices, communication channels, and database banks.

To design a powerful and cost-effective computer system and to devise efficient programs to solve a computational problem, one must understand the underlying hardware and software system structures and the computing algorithm to be implemented on the machine with some user-oriented programming languages. These disciplines constitute the technical scope of computer architecture. Computer architecture is really a system concept integrating hardware, software algorithms, and languages to perform large computations. A good computer architect should master all these disciplines. It is the revolutionary advances in integrated circuits and system architecture that have contributed most to the significant improvement of computer performance during the past 40 years. In this section, we review the generations of computer systems and indicate the general tends in the development of high performance computers.
Generation of Computer Systems

The division of computer systems into generations is determined by the device technology, system architecture, processing mode, and languages used. We consider each
generation to have a time span of about 10 years. Adjacent generations may overlap in several years as demonstrated in the figure. The long time span is intended to cover both development and use of the machines in various parts of the world. We are currently in the fourth generation, while the fifth generation is not materialized yet.
The Future
Computers to be used in the 1990s may be the next generation. Very large-scale integrated (VLSI) chips will be used along with high-density modular design. Multiprocessors like the 16 processors in the S-1 project at Lawrence Livermore National Laboratory and in the Denelcor's HEP will be required. Cray-2 is expected to have four processors, to be delivered in 1985. More than 1000 mega float-point operations per second (megaflops) are expected in these future supercomputers.




Need For Parallel Processing
Achieving high performance depends not only on using faster and more reliable hardware devices, but also on major improvements in computer architecture and processing techniques. State - of - the art parallel computer systems can be characterized into three structural classes: pipelined computers, array processors and multi-processor systems. Parallel processing computers provide a cost-effective means to achieve high system performance through concurrent


Tunable lasers


Definition
Tunable lasers as the name suggests are lasers whose wavelengths can be tuned or varied. They play an important part in optical communication networks. Recent improvements in tunable laser technologies are enabling highly flexible and effective utilization of the massive increases in optical network capacity brought by large-scale application of dense wavelength division multiplexing. Several tunable laser technologies have emerged, each with its own set of tradeoffs with respect to the needs of particular optical networking applications. Tunable lasers are produced mainly in 4 ways: The distributed feedback laser (DFB), the external cavity diode laser, the vertical cavity diode laser and the micro electro mechanical system (MEMS) technology. Tunable lasers help network administrators to save a lot of cost, by allowing them to efficiently manage the network with lesser number of spares. They also enable reliable functioning of the optical network. Changing traffic patterns, customer requirements, and new revenue opportunities require greater flexibility than static OADMs can provide, complicating network operations and planning. Incorporating tunable lasers removes this constraint altogether by allowing any channel to be added by the OADM at any time.

In a wavelength-division multiplexed (WDM) network carrying 128 wavelengths of information, we have 128 different lasers giving out these wavelengths of light. Each laser is designed differently in order to give the exact wavelength needed. Even though the lasers are expensive, in case of a breakdown, we should be able to replace it at a moment's notice so that we don't lose any of the capacity that we have invested so much money in. So we keep in stock 128 spare lasers or maybe even 256, just to be prepared for double failures.
What if we have a multifunctional laser for the optical network that could be adapted to replace one of a number of lasers out of the total 128 wavelengths? Think of the money that could be saved, as well as the storage space for the spares. What is needed for this is a "tunable laser,"


Tunable lasers are still a relatively young technology, but as the number of wavelengths in networks increases so will their importance. Each different wavelength in an optical network will be separated by a multiple of 0.8 nanometers (sometimes referred to as 100GHz spacing. Current commercial products can cover maybe four of these wavelengths at a time. While not the ideal solution, this still cuts your required number of spare lasers down. More advanced solutions hope to be able to cover larger number of wavelengths, and should cut the cost of spares even further.
The devices themselves are still semiconductor-based lasers that operate on similar principles to the basic non-tunable versions. Most designs incorporate some form of grating like those in a distributed feedback laser. These gratings can be altered in order to change the wavelengths they reflect in the laser cavity, usually by running electric current through them, thereby altering their refractive index. The tuning range of such devices can be as high as 40nm, which would cover any of 50 different wavelengths in a 0.8nm wavelength spaced system. Technologies based on vertical cavity surface emitting lasers (VCSELs) incorporate moveable cavity ends that change the length of the cavity and hence the wavelength emitted. Current designs of tunable VCSELs have similar tuning ranges.


Lasers are devices giving out intense light at one specific color. The kinds of lasers used in optical networks are tiny devices - usually about the size of a grain of salt. They are little pieces of semiconductor material, specially engineered to give out very precise and intense light. Within the semiconductor material are lots of electrons - negatively charged particles.


High Altitude Aeronautical Platforms


Definition
Affordable bandwidth will be as essential to the Information Revolution in the21 st century as inexpensive power was to the Industrial Revolution in the 18 th and 19 th centuries. Today's global communications infrastructures of landlines, cellular towers, and satellites are inadequately equipped to support the increasing worldwide demand for faster, better, and less expensive service. At a time when conventional ground and satellite systems are facing increasing obstacles and spiraling costs, a low cost solution is being advocated.

This paper focuses on airborne platforms- airships, planes, helicopters or some hybrid solutions which could operate at stratospheric altitudes for significant periods of time, be low cost and be capable of carrying sizable multipurpose communications payloads. This report briefly presents an overview about the internal architecture of a High Altitude Aeronautical Platform and the various HAAPS projects.

High Altitude Aeronautical Platform Stations (HAAPS) is the name of a technology for providing wireless narrowband and broadband telecommunication services as well as broadcasting services with either airships or aircrafts. The HAAPS are operating at altitudes between 3 to 22 km. A HAPS shall be able to cover a service area of up to 1'000 km diameter, depending on the minimum elevation angle accepted from the user's location. The platforms may be airplanes or airships (essentially balloons) and may be manned or un-manned with autonomous operation coupled with remote control from the ground. While the term HAP may not have a rigid definition, we take it to mean a solar-powered and unmanned airplane or airship, capable of long endurance on-station -possibly several years.

Various types of platform options exist: SkyStation™, the Japanese Stratospheric Platform Project, the European Space Agency (ESA) and others suggest the use of airships/blimps/dirigibles. These will be stationed at 21km and are expected to remain aloft for about 5 years. Angel Technologies (HALO™), AeroVironment/ NASA (Helios) and the European Union (Heliplat) propose the use of high altitude long endurance aircraft. The aircraft are either engine or solar powered and are stationed at 16km (HALO) or 21km (Helios). Helios is expected to stay aloft for a minimum of 6 months whereas HALO will have 3 aircraft flying in 8- hour shifts. Platforms Wireless International is implementing a tethered aerostat situated at ~6km.

A high altitude telecommunication system comprises an airborne platform - typically at high atmospheric or stratospheric altitudes - with a telecommunications payload, and associated ground station telecommunications equipment. The combination of altitude, payload capability, and power supply capability makes it ideal to serve new and metropolitan areas with advanced telecommunications services such as broadband access and regional broadcasting. The opportunities for applications are virtually unlimited. The possibilities range from narrowband services such as paging and mobile voice to interactive broadband services such as multimedia and video conferencing. For future telecommunications operators such a platform could provide blanket coverage from day one with the added advantage of not being limited to a single service. Where little or unreliable infrastructure exists, traffic could be switched through air via the HAPS platform. Technically, the concept offers a solution to the propagation and rollout problems of terrestrial infrastructure and capacity and cost problems of satellite networks.


Daknet


Introduction
Now a day it is very easy to establish communication from one part of the world to other. Despite this even now in remote areas villagers travel to talk to family members or to get forms which citizens in-developed countries an call up on a computer in a matter of seconds. The government tries to give telephone connection in very village in the mistaken belief that ordinary telephone is the cheapest way to provide connectivity. But the recent advancements in wireless technology make running a copper wire to an analog telephone much more expensive than the broadband wireless Internet connectivity. Daknet, an ad hoc network uses wireless technology to provide digital connectivity. Daknet takes advantages of the existing transportation and communication infrastructure to provide digital connectivity. Daknet whose name derives from the Hindi word "Dak" for postal combines a physical means of transportation with wireless data transfer to extend the internet connectivity that a uplink, a cyber café or post office provides.

Real time communications need large capital investment and hence high level of user adoption to receiver costs. The average villager cannot even afford a personnel communications device such as a telephone or computer. To recover cost, users must share the communication infrastructure. Real time aspect of telephony can also be a disadvantage. Studies show that the current market for successful rural Information and Communication Technology (ICT) services does not appear to rely on real-time connectivity, but rather on affordability and basic interactivity. The poor not only need digital services, but they are willing and able to pay for them to offset the much higher costs of poor transportation, unfair pricing, and corruption. It is useful to consider non real-time infrastructures and applications such as voice mail, e-mail, and electronic bulletin boards. Technologies like store- and forward or asynchronous modes of communication can be significantly lower in cost and do not necessarily sacrifice the functionality required to deliver valuable user services. In addition to non real-time applications such as e-mail and voice messaging , providers can use asynchronous modes of communication to create local information repositories that community members can add to and query.


Wireless Catalyst
Advances in the IEEE 802 standards have led to huge commercial success and low pricing for broadband networks. These techniques can provide broadband access to even the most remote areas at low price. Important considerations in a WLAN are

Security: In a WLAN, access is not limited to the wired PCs but it is also open to all the wireless network devices, making it for a hacker to easily breach the security of that network.


Reach: WLAN should have optimum coverage and performance for mobile users to seamlessly roam in the wireless network


Interference: Minimize the interference and obstruction by designing the wireless network with proper placement of wireless devices.


Interoperability: Choose a wireless technology standard that would make the WLAN a truly interoperable network with devices from different vendors integrated into the same.


Reliability: WLAN should provide reliable network connection in the enterprise network.


Manageability: A manageable WLAN allows network administrators to manage, make changes and troubleshoot problems with fewer hassles. Wireless data networks based on the IEEE 802.11 or wifi standard are perhaps the most promising of the wireless technologies. Features of wifi include ease of setup, use and maintenance, relatively high bandwidth; and relatively low cost for both users and providers.


Daknet combines physical means of transportation with wireless data transfer to extend the internet connectivity. In this innovative vehicle mounted access points using 802.11b based technology to provide broadband, asynchronous, store and forward connectivity in rural areas.


Digital Light Processing


Definition
Large-screen, high-brightness electronic projection displays serve four broad areas of application: (1) electronic presentations (e.g., business, education, advertising), (2) entertainment (e.g., home theater, sports bars, theme parks, electronic cinema), (3) status and information (e.g., military, utilities, transportation, public, sports) and (4) simulation (e.g., training, games). The electronic presentation market is being driven by the pervasiveness of software that has put sophisticated presentation techniques (including multimedia) into the hands of the average PC user.


A survey of high-brightness (>1000 lumens) electronic projection displays for comparing the already existing three types of projection display technologies namely, Oil film, CRT-LCD, and AM-LCD was conducted. Developed in the early 1940s at the Swiss Federal Institute of Technology and later at Gretag AG, oil film projectors (including the GE Talaria) have been the workhorse for applications that require projection displays of the highest brightness. But the oil film projector has a number of limitations including size, weight, power, setup time, stability, and maintenance. In response to these limitations, LCD-based technologies have challenged the oil film projector. These LCD-based projectors are of two general types: (1) CRT-addressed LCD light valves and (2) active-matrix (AM) LCD panels. LCD-based projectors have not provided the perfect solution for the entire range of high-brightness applications.

CRT-addressed LCD light valves have setup time and stability limitations. Most active-matrix LCDs used for high-bright-ness applications are transmissive and, because of this, heat generated by light absorption cannot be dissipated with a heat sink attached to the substrate. This limitation is mitigated by the use of large-area LCD panels with forced-air cooling. However, it may still be difficult to implement effective cooling at the highest brightness levels.
In response to these and other limitations, as well as to provide superior image quality under the most demanding environmental conditions, high-brightness projection display systems have been developed based on Digital Light Processing technology. DLP is based on a micro electro mechanical system (MEMS) device known as the Digital Micro mirror Device (DMD). The DMD, invented in 1987 at Texas Instruments, is a semiconductor-based array of fast, reflective digital light switches that precisely control a light source using a binary pulse modulation technique. It can be combined with image processing, memory, a light source, and optics to form a DLP system capable of projecting large, bright, seamless, high-contrast color images.


The Mirror as a Switch
The DMD light switch is a member of a class of devices known as micro electromechanical systems. Other MEMS devices include pressure sensors, accelerometers, and micro actuators. The DMD is monolithically fabricated by CMOS-like processes over a CMOS memory. Each light switch has an aluminum mirror, 16 µm square that can reflect light in one of two directions depending on the state of the underlying memory cell. Rotation of the mirror is accomplished through electrostatic attraction produced by voltage differences developed between the mirror and the underlying memory cell. With the memory cell in the on state, the mirror rotates to +10 degrees. With the memory cell in the off state, the mirror rotates to .10 degrees. A close-up of DMD mirrors operating in a scanning electron microscope (SEM). By combining the DMD with a suitable light source and projection optics (Figure 6), the mirror reflects incident light either into or out of the pupil of the projection lens by a simple beam-steering technique. Thus, the state of the mirror appears bright and the state of the mirror appears dark. Compared to diffraction-based light switches, the beam-steering action of the DMD light switch provides a superior tradeoff between contrast ratio and the overall brightness efficiency of the system.


By electrically addressing the memory cell below each mirror with the binary bit plane signal, each mirror on the DMD array is electrostatically tilted to the on or off positions. The technique that determines how long each mirror tilts in either direction is called pulse width modulation (PWM). The mirrors are capable of switching on and off more than 1000 times a second. This rapid speed allows digital gray scale and color reproduction. At this point, DLP becomes a simple optical system. After passing through condensing optics and a color filter system, the light from the projection lamp is directed at the DMD. When the mirrors are in the on position, they reflect light through the projection lens and onto the screen to form a digital, square-pixel projected image.


Free Space Laser Communications


Definition
Lasers have been considered for space communications since their realization in 1960. However, it was soon recognized that, although the laser had potential for the transfer of data at extremely high rates, specific advancements were needed in component performance and systems engineering, particularly for space-qualified hardware. Advances in system architecture, data formatting, and component technology over the past three decades have made laser communications in space not only a viable but also a attractive approach to intersatellite link applications. The high data rate and large information throughput available with laser communications are many times greater than in radio frequency (RF) systems.

The small antenna size requires only a small increase in the weight and volume of host vehicle. In addition, this feature substantially reduces blockage of fields of view of the most desirable areas on satellites. The smaller antennas, with diameters typically less than 30cm, create less momentum disturbance to any sensitive satellite sensors. Fewer onboard consumables are required over the long lifetime because there is less disturbance to the satellite compared with larger and heavier RF systems. The narrow beam divergence of affords interference-free and secure operation.


Features Of Laser Communications System
A block diagram of typical terminal is illustrated in Fig 1. Information, typically in the form of digital data, is input to data electronics that modulates the transmitting laser source. Direct or indirect modulation techniques may be employed depending on the type of laser employed. The source output passes through an optical system into the channel. The optical system typically includes transfer, beam shaping, and telescope optics. The receiver beam comes in through the optical system and is passed along to detectors and signal processing electronics. There are also terminal control electronics that must control the gimbals and other steering mechanisms, and servos, to keep the acquisition and tracking system operating in the designed modes of operation.


Operation
Free space laser communications systems are wireless connections through the atmosphere. They work similar to fiber optic cable systems except the beam is transmitted through open space. The carrier used for the transmission of this signal is generated by either a high power LED or a laser diode. The laser systems operate in the near infrared region of the spectrum. The laser light across the link is at a wavelength of between 780 - 920 nm. Two parallel beams are used, one for transmission and one for reception.


Acquisition And Tracking
There are three basic steps to laser communication: acquisition, tracking, and communications. Of the three, acquisition is generally the most difficult; angular tracking is usually the easiest. Communications depends on bandwidth or data rate, but is generally easier than acquisition unless very high data rates are required. Acquisition is the most difficult because laser beams are typically much smaller than the area of uncertainty. Satellites do not know exactly where they are or where the other platform is located, and since everything moves with some degree of uncertainty, they cannot take very long to search or the reference is lost. Instability of the platforms also causes uncertainty in time. In the ideal acquisition method, the beam width of the source is greater than the angle of uncertainty in the location of receiver. The receiver field of includes the location uncertainty of the transmitter. Unfortunately, this ideal method requires a significant amount of laser power.

It is possible to operate a number of laser types at high peak power and low duty cycle to make acquisition easier. This is because a lower pulse rate is needed for acquisition than for tracking and communications. High peak power pulses more easily overcome the receiver set threshold and keep the false alarm rate low. A low duty cycle transmitter gives high peak power, yet requires less average power, and is thus a suitable source for acquisition. As the uncertainty area becomes less, it becomes more feasible to use a continues source of acquisition, especially if the acquisition time does not have to be short.


Distributed Integrated Circuits


Definition
"Divide and conquer" has been the underlying principle used to solve many engineering and social problems. Over many years engineers have devised systematic ways to divide a design objective into a collection of smaller projects and tasks defined at multiple levels of abstraction. This approach has been quite successful in an environment where a large number of people with different types and levels of expertise work together to realize a given objective in a limited time. Communication system design is a perfect example of this process, where the communication system is initially defined atthe application level, then descried using system level terms, leading to an architecture using a number of cascaded sub blocks that can be implemented as integrated circuits.

The integrated circuit design process is then divided further by defining the specifications for circuit building blocks and their interfaces that together form the system. The circuit designer works with the specifications at a lower level of abstraction dealing with transistors and passive components whose models have been extracted from the measurements, device simulations, or analytical calculations based on the underlying physical principles of semiconductor physics and electrodynamics.

This process of breaking down the ultimate objective into smaller, more manageable projects and tasks has resulted in an increased in the number of experts with more depth yet in more limited sublevels of abstraction. While this divide-and-conquer process has been quite successful in streamlining innovation, the overspecialization and short time specifications associated with today's design cycles sometimes result in suboptimal designs in the grand scheme of things. Also, in any reasonably mature field many of the possible innovations leading to useful new solutions within a given level of abstraction have already been explored. Further advancements beyond these local optima can be achieved by looking at the problem across multiple levels of abstraction to find solutions not easily seen when one confines one's search space to one level ( e.g., transistor-level circuit design).

This explains why most of today's research activities occurs at the boundaries between different levels of abstractions artificially created to render the problem more tractable. Distributed circuit design is a multilevel approach allowing a more integral co-design of the building blocks at the circuit and device levels. Unlike most conventional circuits, it relies on multiple parallel signal paths operating in harmony to achieve the design objective. This approach offers attractive solutions to some of the more challenging problems in high speed communication circuit design.


Issues In High-Speed Integrated Communication Circuits
Integration of high-speed circuits for wireless (e.g., cellular phones) and wired applications (e.g., optical fiber communications) poses several challenges. High-speed analog integrated circuits used in wireless and wired communication systems have to achieve tight and usually contradictory specifications. Some of the most common specifications are the frequency of operation, power dissipation, dynamic range, and gain. Once in a manufacturing setting, additional issues, such as cost, reliability, and repeatability, also come into play. To meet these specifications, the designer usually has to deal with physical and topological limitations caused by noise, device non-linearity, small power supply, and energy loss in the components.

Frequency of operation is perhaps one of the most important properties of communication integrated circuits since a higher frequency of operation is one of the more evident methods of achieving larger bandwidth, and hence higher bit rates in digital communication systems. A transistor in a given process technology is usually characterized by its unity-gain frequency shown as fT. This is the frequency at which the current gain of a transistor drops to unity. While the unity-gain frequency of a transistor provide a approximate measure to compare transistors in different process technologies, the circuit built using these transistors scarcely operate close to the fT and usually operate at frequencies 3-100 times smaller depending on the complexity of their function.

There are two main reasons for this behavior. First, analog building blocks and systems usually relay on closed loop operation based on negative feedback to perform a given function independent of these parameter variations. An open loop gain much higher than one is thus required for the negative feedback to be effective. Even if no feedback is present and open loop operation is acceptable, a higher gain usually improves the noise and power efficiency of the circuits. Therefore the transistor has to operate at a frequency lower than the fT to provide the desired gain. Second, passive devices (e.g. capacitors and inductors), necessary in most high-speed analog circuits, have their on frequency limitation due to parasitic components that can become the bottleneck of the design. The combination of these two effects significantly lowers the maximum frequency of reliable operation in most conventional circuit building blocks and provides a motivation to pursue alternative approaches to alleviate the bandwidth limitations.

AC Performance Of Nanoelectronics


Definition
Nano electronic devices fall into two classes: tunnel devices and ballistic transport devices. In Tunnel devices single electron effects occur if the tunnel resistance is larger than h/e = 25 K §Ù. In Ballistic devices with cross sectional dimensions in the range of quantum mechanical wavelength of electrons, the resistance is of order h/e = 25 K §Ù. This high resistance may seem to restrict the operational speed of nano electronics in general. However the capacitance values and drain source spacing are typically small which gives rise to very small RC times and transit times of order of ps or less. Thus the speed may be very large, up to THz range. The goal of this seminar is to present the models an performance predictions about the effects that set the speed limit in carbon nanotube transistors, which form the ideal test bed for understanding the high frequency properties of Nano electronics because they may behave as ideal ballistic 1d transistors.


Ballistic Transport- An Outline
When carriers travel through a semiconductor material, they are likely to be scattered by any number of possible sources, including acoustic and optical phonons, ionized impurities, defects, interfaces, and other carriers. If, however, the distance traveled by the carrier is smaller than the mean free path, it is likely not to encounter any scattering events; it can, as a result, move ballistically through the channel. To the first order, the existence of ballistic transport in a MOSFET depends on the value of the characteristic scattering length (i.e. mean free path) in relation to channel length of the transistor.


This scattering length, l , can be estimated from the measured carrier mobility where t is the average scattering time, m* is the carrier effective mass, and vth is the thermal velocity. Because scattering mechanisms determine the extent of ballistic transport, it is important to understand how these depend upon operating conditions such as normal electric field and ambient temperature.


Dependence On Normal Electric Field
In state-of-the-art MOSFET inversion layers, carrier scattering is dominated by phonons, impurities (Coulomb interaction), and surface roughness scattering at the Si-SiO2 interface. The relative importance of each scattering mechanism is dependent on the effective electric field component normal to the conduction channel. At low fields, impurity scattering dominates due to strong Coulombic interactions between the carriers and the impurity centers. As the electric field is increased, acoustic phonons begin to dominate the scattering process. At very high fields, carriers are pulled closer to the Si-SiO2 gate oxide interface; thus, surface roughness scattering degrades carrier mobility. A universal mobility model has been developed to relate field strength with the effective carrier mobility due to phonon and surface roughness scattering:


Dependence On Temperature
When the temperature is changed, the relative importance of each of the aforementioned scattering mechanisms is altered. Phonon scattering becomes less important at very low temperatures. Impurity scattering, on the other hand, becomes more significant because carriers are moving slower (thermal velocity is decreased) and thus have more time to interact with impurity centers. Surface roughness scattering remains the same because it does not depend on temperature. At liquid nitrogen temperatures (77K) and an effective electric field of 1MV/cm, the electron and hole mobilities are ~700 cm2/Vsec and ~100 cm2/Vsec, respectively. Using the above equations, the scattering lengths are approximately 17nm and 3.6nm.These scattering lengths can be assumed to be worst-case scenarios, as large operating voltages (1V) and aggressively scaled gate oxides (10Å) are assumed. Thus, actual scattering lengths will likely be larger than the calculated values.

Further device design considerations in maximizing this scattering length will be discussed in the last section of this paper. Still, the values calculated above are certainly in the range of transistor gate lengths currently being studied in advanced MOSFET research (<50nm). Ballistic carrier transport should thus become increasingly important as transistor channel lengths are further reduced in size. In addition, it should be noted that the mean free path of holes is generally smaller than that of electrons. Thus, it should be expected that ballistic transport in PMOS transistors is more difficult to achieve, since current conduction occurs through hole transport. Calculation of the mean scattering length, however, can only be regarded as a first-order estimation of ballistic transport.

To accurately determine the extent of ballistic transport evident in a particular transistor structure, Monte Carlo simulation methods must be employed. Only by modeling the random trajectory of each carrier traveling through the channel can we truly assess the extent of ballistic transport in a MOSFET.


High Performance DSP Architectures


Definition
Digital Signal Processing is carried out by mathematical operations. Digital Signal Processors are microprocessors specifically designed to handle Digital Signal Processing tasks. These devices have seen tremendous growth in the last decade, finding use in everything from cellular telephones to advanced scientific instruments. In fact, hardware engineers use "DSP" to mean Digital Signal Processor, just as algorithm developers use "DSP" to mean Digital Signal Processing. DSP has become a key component in many consumer, communications, medical, and industrial products. These products use a variety of hardware approaches to implement DSP, ranging from the use of off-the-shelf microprocessors to field-programmable gate arrays (FPGAs) to custom integrated circuits (ICs).

Programmable "DSP processors," a class of microprocessors optimized for DSP, are a popular solution for several reasons. In comparison to fixed-function solutions, they have the advantage of potentially being reprogrammed in the field, allowing product upgrades or fixes. They are often more cost-effective than custom hardware, particularly for low-volume applications, where the development cost of ICs may be prohibitive. DSP processors often have an advantage in terms of speed, cost, and energy efficiency.


DSP Algorithms Mould DSP Architectures
From the outset, DSP algorithms have moulded DSP processor architectures. For nearly every feature found in a DSP processor, there are associated DSP algorithms whose computation is in some way eased by inclusion of this feature. Therefore, perhaps the best way to understand the evolution of DSP architectures is to examine typical DSP algorithms and identify how their computational requirements have influenced the architectures of DSP processors.


Fast Multipliers
The FIR filter is mathematically expressed as a vector of input data, along with a vector of filter coefficients. For each "tap" of the filter, a data sample is multiplied by a filter coefficient, with the result added to a running sum for all of the taps . Hence, the main component of the FIR filter algorithm is a dot product: multiply and add, multiply and add. These operations are not unique to the FIR filter algorithm; in fact, multiplication is one of the most common operations performed in signal processing convolution, IIR filtering, and Fourier transforms also all involve heavy use of multiply-accumulate operations. Originally, microprocessors implemented multiplications by a series of shift and add operations, each of which consumed one or more clock cycles. As might be expected, faster multiplication hardware yields faster performance in many DSP algorithms, and for this reason all modern DSP processors include at least one dedicated single- cycle multiplier or combined multiply-accumulate (MAC) unit.

Multiple Execution Units
DSP applications typically have very high computational requirements in comparison to other types of computing tasks, since they often must execute DSP algorithms in real time on lengthy segments of signals sampled at 10-100 KHz or higher. Hence, DSP processors often include several independent execution units that are capable of operating in parallel for example, in addition to the MAC unit, they typically contain an arithmetic- logic unit (ALU) and a shifter.

Efficient Memory Accesses
Executing a MAC in every clock cycle requires more than just a single-cycle MAC unit. It also requires the ability to fetch the MAC instruction, a data sample, and a filter coefficient from memory in a single cycle. To address the need for increased memory bandwidth, early DSP processors developed different memory architectures that could support multiple memory accesses per cycle. Often, instructions were stored in the memory bank, while data was stored in another. With this arrangement, the processor could fetch an instruction and a data operand in parallel in every cycle.
Since many DSP algorithms consume two data operands per instruction, a further optimization commonly used is to include a small bank of RAM near the processor core that is used as an instruction cache. When a small group of instructions is executed repeatedly, the cache is loaded with those instructions, freeing the instruction bus to be used for data fetches instead of instruction fetches thus enabling the processor to execute a MAC in a single cycle. High memory bandwidth requirements are often further supported via dedicated hardware for calculating memory addresses. These address generation units operate in parallel with the DSP processor's main execution units, enabling it to access data at new locations in memory without pausing to calculate the new address. Memory accesses in DSP algorithms tend to exhibit very predictable patterns; for example, for each sample in an FIR filter, the filter coefficients are accessed sequentially from start to finish for each sample, then accesses start over from the beginning of the coefficient vector when processing the next input sample.


FinFET Technology


Definition
Since the fabrication of MOSFET, the minimum channel length has been shrinking continuously. The motivation behind this decrease has been an increasing interest in high-speed devices and in very large-scale integrated circuits. The sustained scaling of conventional bulk device requires innovations to circumvent the barriers of fundamental physics constraining the conventional MOSFET device structure. The limits most often cited are control of the density and location of dopants providing high I on /I off ratio and finite sub threshold slope and quantum-mechanical tunneling of carriers through thin gate from drain to source and from drain to body.

The channel depletion width must scale with the channel length to contain the off-state leakage I off. This leads to high doping concentration, which degrade the carrier mobility and causes junction edge leakage due to tunneling. Furthermore, the dopant profile control, in terms of depth and steepness, becomes much more difficult. The gate oxide thickness tox must also scale with the channel length to maintain gate control, proper threshold voltage VT and performance. The thinning of the gate dielectric results in gate tunneling leakage, degrading the circuit performance, power and noise margin.

Alternative device structures based on silicon-on-insulator (SOI) technology have emerged as an effective means of extending MOS scaling beyond bulk limits for mainstream high-performance or low-power applications .Partially depleted (PD) SOIwas the first SOI technology introduced for high-performance microprocessor applications. The ultra-thin-body fully depleted (FD) SOI and the non-planar FinFET device structures promise to be the potential "future" technology/device choices. In these device structures, the short-channel effect is controlled by geometry, and the thin Si film limits the off-state leakage. For effective suppression of the off-state leakage, the thickness of the Si film must be less than one quarter of the channel length. The desired VT is achieved by manipulating the gate work function, such as the use of midgap material or poly-SiGe. Concurrently, material enhancements, such as the use of a) high-k gate material and b) strained Si channel for mobility and current drive improvement, have been actively pursued. As scaling approaches multiple physical limits and as new device structures and materials are introduced, unique and new circuit design issues continue to be presented. In this article, we review the design challenges of these emerging technologies with particular emphasis on the implications and impacts of individual device scaling elements and unique device structures on the circuit design. We focus on the planar device structures, from continuous scaling of PD SOI to FD SOI, and new materials such as strained-Si channel and high-k gate dielectric.


Partially Depleted [PD] SOI
The PD floating-body MOSFET was the first SOI transistor generically adopted for high-performance applications, primarily due to device and processing similarities to bulk CMOS device.
The PD SOI device is largely identical to the bulk device, except for the addition of a buried oxide ("BOX") layer. The active Si film thickness is larger than the channel depletion width, thus leaving a quasi-neutral "floating" body region underneath the channel. The V T of the device is completely decoupled from the Si film thickness, and the doping profiles can be tailored for any desired VT. The device offers several advantages for performance/ power improvement:

1) Reduced junction capacitance,

2) Lower average threshold due to positive V BS during switching.


3) Dynamic loading effects, in which the load device tends to be in high VT state during switching The performance comes at the cost of some design complexity resulting from the floating body of the device, such as


1) Parasitic bipolar effect and


2) Hysteretic VT variation.


Stream Processor


Definition
For many signal processing applications programmability and efficiency is desired. With current technology either programmability or efficiency is achievable, not both. Conventionally ASIC's are being used where highly efficient systems are desired. The problem with ASIC is that once programmed it cannot be enhanced or changed, we have to get a new ASIC for each modification. Other option is microprocessor based or dsp based applications. These can provide either programmability or efficiency. Now with stream processors we can achieve both simultaneously. A comparison of efficiency and programmability of Stream processors and other techniques are done. We will look into how efficiency and programmability is achieved in a stream processor. Also we will examine the challenges faced by stream processor architecture.


The complex modern signal and image processing applications requires hundreds of GOPS (giga, or billions, of operations per second) with a power budget of a few watts, an efficiency of about 100 GOPS/W (GOPS per watt), or 10 pJ/op (Pico Joules per operation). To meet this requirement current media processing applications use ASICs that are tailor made for a particular application. Such processors require significant design efforts and are difficult to change when a new media processing application or algorithm evolve. The other alternative to meet the changing needs is to go for a dsp or microprocessor, which are highly flexible. But these do not provide the high efficiency needed by the application. Stream processors provide a solution to this problem by giving efficiency and programmability simultaneously. They achieve this by expressing the signal processing problems as signal flow graphs with streams flowing between computational kernels. Stream processors have efficiency comparable to ASICs (200 GOPS/W), while being programmable in a high-level language.


Many signal processing applications require both efficiency and programmability. The complexity of modern media processing, including 3D graphics, image compression, and signal processing, requires tens to hundreds of billions of computations per second. To achieve these computation rates, current media processors use special-purpose architectures tailored to one specific application. Such processors require significant design effort and are thus difficult to change as media-processing applications and algorithms evolve. Digital television, surveillance video processing, automated optical inspection, and mobile cameras, camcorders, and 3G cellular handsets have similar needs. The demand for flexibility in media processing motivates the use of programmable processors. However, very large-scale integration constraints limit the performance of traditional programmable architectures. In modern VLSI technology, computation is relatively cheap - thousands of arithmetic logic units that operate at multi gigahertz rates can fit on a modestly sized 1 cm 2 die. The problem is that delivering instructions and data to those ALUs is prohibitively expensive.

For example, only 6.5 percent of the Itanium 2 die is devoted to the 12 integer and two floating-point ALUs and their register files; communication, control, and storage overhead consume the remaining die area. In contrast, the more efficient communication and control structures of a special purpose graphics chip, such as the NVIDIA GeForce4, enable the use of many hundreds of floating-point and integer ALUs to render 3D images. Conventional signal processing solutions can provide high efficiency or programmability, but are unable to provide both at the same time. In applications that demand efficiency, a hardwired application-specific processor-ASIC (application-specific integrated circuit) or ASSP (application-specific standard part)-has an efficiency of 50 to 500 GOPS/W, but offers little if any flexibility.

At the other extreme, microprocessors and DSPs (digital signal processors) are completely programmable but have efficiencies of less than 10 GOPS/W. DSP (digital signal processor) arrays and FPGAs (field-programmable gate arrays) offer higher performance than individual DSPs, but have roughly the same efficiency. Moreover, these solutions are difficult to program-requiring parallelization, partitioning, and, for FPGAs, hardware design. Applications today must choose between efficiency and programmability.


General Packet Radio Service


Definition
Wireless phone use is taking off around the world. Many of us would no longer know how to cope without our cell phones. Always being connected offers us flexibility in our lifestyles, makes us more productive in our jobs, and makes us feel more secure. So far, voice has been the primary wireless application. But with the Internet continuing to influence an increasing proportion of our daily lives, and more of our work being away from the office, it is inevitable that the demand for wireless data is going to ignite. Already, in those countries that have cellular-data services readily available, the number of cellular subscribers taking advantage of data has reached significant proportions.

But to move forward, the question is whether current cellular-data services are sufficient, or whether the networks need to deliver greater capabilities. The fact is that with proper application configuration, use of middleware, and new wireless-optimized protocols, today's cellular-data can offer tremendous productivity enhancements. But for those potential users who have stood on the sidelines, subsequent generations of cellular data should overcome all of their objections. These new services will roll out both as enhancements to existing second-generation cellular networks, and an entirely new third generation of cellular technology.

In 1999, the primary cellular based data services were Cellular Digital Packet Data (CDPD), circuit-switched data services for GSM networks, and circuit-switched data service for CDMA networks. All of these services offer speeds in the 9.6 Kbps to 14.4 Kbps range. The basic reason for such low speeds is that in today's cellular systems, data is allocated to the same radio bandwidth as a voice call.

Since voice encoders (vocoders) in current cellular networks digitize voice in the range of 8 to 13 Kbps,
that's about the amount available for data. Back then, 9.6 Kbps was considered more than adequate. Today, it can seem slow with graphical or multimedia content, though it is more than adequate for text-based applications and carefully configured applications.

There are two basic ways that the cellular industry is currently delivering data services. One approach is
with smart phones, which are cellular phones that include a microbrowser. With these, you can view
specially formatted Internet information. The other approach is through wireless modems, supplied either in
PC Card format or by using a cell phone with a cable connection to a computer.


The GPRS services will reflect the GSM services with an exception that the GPRS will have a tremendous transmission rate which will make a good impact in the most of the existing services and a possibility of introduction of new services as operators and users (business/private) appreciate the newly introduced technology.
Services such as the Internet, videoconferencing and on-line shopping will be as smooth as talking on the phone, moreover we'll be able to access these services whether we are at work, at home or traveling. In the new information age, the mobile phone will deliver much than just voice calls. It will become a multi-media communications device, capable of sending and receiving graphic images and video.


The most common methods used for data transfer are circuit-switching and packet-switching. With circuit-switched transmission the dedicated circuit is first established across a sequence of links and then the whole channel is allocated to a single user for the whole duration of the call. With packet switched transmission, the data is first cut in to small parts called packages which are then sent in sequence to the receiver, which again builds the packages back together. This ensures that the same link resources can be shared at the same time buy many different users. The link is used only when the user has something to send. When there is no data to be sent the link is free to be used by another call. Packet switching is ideal for bursty traffic, e.g. voice.


Free Space Optics


Definition
Mention optical communication and most people think of fiber optics. But light travels through air for a lot less money. So it is hardly a surprise that clever entrepreneurs and technologists are borrowing many of the devices and techniques developed for fiber-optic systems and applying them to what some call fiber-free optical communication. Although it only recently, and rather suddenly, sprang into public awareness, free-space optics is not a new idea. It has roots that go back over 30 years--to the era before fiber-optic cable became the preferred transport medium for high-speed communication. In those days, the notion that FSO systems could provide high-speed connectivity over short distances seemed futuristic, to say the least. But research done at that time has made possible today's free-space optical systems, which can carry full-duplex (simultaneous bidirectional) data at gigabit-per-second rates over metropolitan distances of a few city blocks to a few kilometers.

FSO first appeared in the 60's, for military applications. At the end of 80's, it appeared as a commercial option but technological restrictions prevented it from success. Low reach transmission, low capacity, severe alignment problems as well as vulnerability to weather interferences were the major drawbacks at that time. The optical communication without wire, however, evolved! Today, FSO systems guarantee 2.5 Gb/s taxes with carrier class availability. Metropolitan, access and LAN networks are reaping the benefits.


The use of free space optics is particularly interesting when we perceive that the majority of customers does not possess access to fibers as well as fiber installation is expensive and demands long time. Moreover, right-of-way costs, difficulties in obataining government licenses for new fiber installation etc. are further problems that has turned FSO into the option of choice for short reach applications.
FSO uses lasers, or light pulses, to send packetized data in the terahertz (THz) spectrum range. Air, ot fiber, is the transport medium. This means that urban businesses needing fast data and Internet access have a significantly lower-cost option.

FSO
FSO technology is implemented using a laser device .These laser devices or terminals can be mounted on rooftops ,Corners of buidings or even inside offices behind windows. FSOdevices look like security video cameras.

Low-power infrared beams, which do not harm the eyes, are the means by which free-space optics technology transmits data through the air between transceivers, or link heads, mounted on rooftops or behind windows. It works over distances of several hundred meters to a few kilometers, depending upon atmospheric conditions.
Commercially available free-space optics equipment provides data rates much higher than digital subscriber lines or coaxial cables can ever hope to offer. And systems even faster than the present range of 10 Mb/s to 1.25 Gb/s have been announced, though not yet delivered.

Fiber Distributed Data Interface


Definition
The Fiber Distributed Data Interface (FDDI) standard was produced by the ANSI X3T9.5 standards committee in the mid-1980s. During this period, high-speed engineering workstations were beginning to tax the capabilities of existing local-area networks (LANs) (primarily Ethernet and Token Ring). A new LAN was needed that could easily support these workstations and their new distributed applications. At the same time, network reliability was becoming an increasingly important issue as system managers began to migrate mission-critical applications from large
computers to networks. FDDI was developed to fill these needs.


After completing the FDDI specification, ANSI submitted FDDI to the International Organization for Standardization (ISO). ISO has created an international version of FDDI that is completely compatible with the ANSI standard version.


Today, although FDDI implementations are not as common as Ethernet or Token Ring, FDDI has gained a substantial following that continues to increase as the cost of FDDI interfaces diminishes. FDDI is frequently used as a backbone technology as well as a means to connect high-speed computers in a local area.

Technology Basics
FDDI specifies a 100-Mbps, token-passing, dual-ring LAN using a fiber-optic transmission medium. It defines the physical layer and media-access portion of the link layer, and so is roughly analogous to IEEE 802.3 and IEEE 802.5 in its relationship to the Open System Interconnection (OSI) reference model.


Although it operates at faster speeds, FDDI is similar in many ways to Token Ring. The two networks share many features, including topology (ring), media-access technique (token passing), reliability features (redundant rings, for example), and others. For more information on Token Ring and related technologies.


One of the most important characteristics of FDDI is its use of optical fiber as a transmission medium. Optical fiber offers several advantages over traditional copper wiring, including security (fiber does not emit electrical signals that can be tapped), reliability (fiber is immune to electrical interference), and speed (optical fiber has much higher throughput potential than copper cable). FDDI defines use of two types of fiber: single mode (sometimes called monomode) and multimode. Modes can be thought of as bundles of light rays entering the fiber at a particular angle. Single-mode fiber allows only one mode of light to propagate through the fiber, while multimode fiber allows multiple modes of light to propagate through the fiber. Because multiple modes of light propagating through the fiber may travel different distances (depending on the entry angles), causing them to arrive at the destination at different times (a phenomenon called modal dispersion), single-mode fiber is capable of higher bandwidth and greater cable run distances than multimode fiber. Due to these characteristics, single-mode fiber is often used for interbuilding connectivity, while multimode fiber is often used for intrabuilding connectivity. Multimode fiber uses light-emitting diodes (LEDs) as the light-generating devices, while single-mode fiber generally uses lasers.


E-Nose


Definition
In an ever-developing world, where electronic devices are duplicating every other sense of perception, the sense of smell is lagging behind. Yet, recently, there has been an urgent increase in the need for detecting odours, to replace the human job of sensing and quantification.

Some of the most important applications fall in the category where human beings cannot afford to risk smelling the substance. Other important applications are continuous monitoring, medical applications, etc. These applications allow man to perform tasks that were once considered impossible.The fast paced technology has helped develop sophisticated devices that have brought the electronic nose to miniature sizes and advanced capabilities. The trend is such that there will be accurate, qualitative and quantitative measurements of odour in the near future.
Living beings interact with the surrounding environment through particular interfaces called senses, which can be divided in two groups: those detecting physical quantities and those detecting chemical quantities.

Physical interfaces (that deals with acoustic, optic, temperature and mechanic interaction mechanisms) are sufficiently well known and a wealth of successful studies to construct their artificial counterparts has been done in the past years. On the other side the chemical interfaces (bio transducers of chemical species in air: olfaction, and in solution: taste) even if well described in literature, present some aspects of their physiological working principal that are still unclear. It has also to be remarked a psychological difference, in human beings, between the two groups. Indeed the information from the physical senses can be adequately elaborated, verbally expressed, firmly memorized and fully communicated. On the contrary chemical information, coming from nose and tongue, are surrounded by vagueness and this is reflected in the poor description and memorization capacity in reporting olfactory and tasting experiences. Chemical information is of primary importance for the major part of the animals; for many of them, indeed, chemistry is the unique realm of which they are concerned, while for human beings evolution has enhanced about exclusively the physical interfaces, leaving little care of the chemical interface, if we exclude unconscious acquisition and side behaviours. For these intrinsic difficulties toward the understanding of the nature of these senses for many years only sporadic research on the possibility of fabricating artificial olfactory systems were performed. Only at the end of the eighties a new and promising approach was introduced. It was based on the assumption that an array of non-selective chemical sensors, matched with a suitable data processing method, could mimic the functions of olfaction.

In the past decade, electronic nose instrumentation has generated much interest internationally for its potential to solve a wide variety of problems in fragrance and cosmetics production, food and beverages manufacturing, chemical engineering, environmental monitoring, and more recently, medical diagnostics and bioprocesses. Several dozen companies are now designing and selling electronic nose units globally for a wide variety of expanding markets. An electronic nose is a machine that is designed to detect and discriminate among complex odours using a sensor array. The sensor array of consists of
broadly tuned (non-specific) sensors that are treated with a variety of odour-sensitive biological or chemical materials. An odour stimulus generates a characteristic fingerprint (or smell-print) from the sensor array. Patterns or fingerprints from known odours are used to construct a database and train a pattern recognition system so that unknown odours can subsequently be classified and identified. Thus, electronic nose instruments are comprised of hardware components to collect and transport odours to the sensor array - as well as electronic circuitry to digitise and stored the sensor responses for signal processing.



Embryonics Approach Towards Integrated Circuits


Definition
Embryonics is embryonic electronics. Working of multicellular organization in living beings suggests that concepts from biology can be applied to development of new "embryonic" integrated circuits. The final objective is the development of VLSI circuits that can partially reconstruct themselves in case of a minor fault (self-repair) or completely reconstruct the original device in case of major fault (self-replication). These features are advantageous for applications depending on high reliability, like avionics and medical electronics. The basic primitive of the system is the molecule: the element of new FPGA- essentially a multiplexer associated with a programmable connection network. A finite set of molecules comprises a cell, i.e., a very simple processor associated to some memory resources. A finite set of cells comprises an organism, i.e., an application- specific multiprocessor system. The organism itself can self-replicate, giving rise to a population of identical organisms. The self-repair and self-replication are achieved by providing spare cells. This seminar report tries to bring out the basic concepts in the embryonics approach to realize VLSI circuits.

The growth and operation of all living beings are directed by the interpretation, in each of the their cells, of a chemical program, the DNA string or genome.This process is the source of inspiration for Embryonics (embryonic electronics),whose final objective is the design of highly roubst integrated circuits, endowed with properties usually associated with the living world: self repair (cicatrisation) and self-replication.The embryonics architecture is based on four hierarchical levels of organization.


1. The basic primitive of our system is the molecule, a multiplexer-based element of a novel programmable cicuit.
2. A finite set of molecules makes up a cell, essentially a small processor with an associated memory.
3. A finite set of cells makes up an organism,an application specific multiprocessor system.
4. The organism can itself replicate,giving rise to a population of identical organisms, capable of self replication and repair.


Each of the artificial cell is characterized by a fixed architecture .Multicellular arrays can realize a variety of different organisms, all capable of self replication and self repair.In order to allow for a wide range of application we then introduce a flexible architeture, realized using a new type of fine-grained field-programmable gate array whose basic element, our molecule, is essentially a programmable multiplexer.

Toward Embryonics
A human being consists of approximately 60 trillion cells.At each instant, in each of these 60 trillion cells, the genome, a ribbon of 2 billion characters, is decoded to produce the proteins needed for survival of the organism.The genome contains the ensemble of the genetic inheritance of the individual and, at the same time, the instructions for both the construction and operation of the organism.the parallel execution of 60 trillion genomes in as many cells occurs ceaselessly from conception to death of the individual.Faults are rare, and in majority of cases, successfully detected and repaired.This process is remarkable for its complexity and its precision.Moreover, it relies on completely discrete information :the struture of DNA (the chemical substrate of the genome) is a sequence of four bases, usually designated with letters A(adenine),C(cytosine),G(guanine) and T(thymine).


Embedded Systems and Information Appliances


Definition
Embedded system is a combination of computer hardware, software and, perhaps, additional mechanical parts, designed to perform a specific function.

Embedded systems are usually programmed in high level language that is compiled (and/or assembled) into an executable ("machine") code. These are loaded into Read Only Memory (ROM) and called "firmware", "microcode" or a "microkernel". The microprocessor is 8-bit or 16-bit.The bit size refers to the amount of memory accessed by the processor. There is usually no operating system and perhaps 0.5k of RAM. The functions implemented normally have no priorities. As the need for features increases and/or as the need to establish priorities arises, it becomes more important to have some sort of decision making mechanism be part of the embedded system. The most advanced systems actually have a tiny, streamlined OS running the show, executing on a 32-bit or 64-bit processor. This is called RTOS.



Embedded Hardware
All embedded system has a microprocessor or microcontroller for processing of information and execution of programs, memory in the form of ROM/RAM for storing embedded software programs and data, and I/O interfaces for external interface. Any additional requirement in an embedded system is dependent on the equipment it is controlling. Very often these systems have a standard serial port, a network interface, I/O interface, or hardware to interact with sensors and activators on the equipment.



Embedded Software
C has become the language of choice for embedded programmers, because it has the benefit of processor independence, which allows the programmer to concentrate on algorithms and applications, rather than on the details of processor architecture. However, many of its advantages apply equally to other high-level languages as well. Perhaps the greatest strength of C is that it gives embedded programmers an extraordinary degree of direct hardware control without sacrificing the benefits of high-level languages. Compilers and cross compilers are also available for almost every processor with C.


Any source code written in C or C++ or Assembly language must be converted into an executable image that can be loaded onto a ROM chip. The process of converting the source code representation of your embedded software into an executable image involves three distinct steps, and the system or computer on which these processes are executed is called a host computer.First, each of the source files that make an embedded application must be compiled or assembled into distinct object files.Second, all of the object files that result from the first step must be linked into a final object file called the relocatable program.

Electronic Data Interchange (EDI)


Definition
Prosperity, and even survival, for small businesses depends as never before on the ability to respond with speed and certainty to the challenges and opportunities that are presented by competitors and customers. Electronic Commerce provides an opportunity to increase competitive edge and consolidate and enhance both business to business and business to consumer trading relationships.

In the current competitive & fast moving world of E-commerce & Electronic data transfer , comes a highly relevant , yet , under-utilised system of data exchange -the Electronic Data Interchange , or the EDI.


EDI has no single consensus definition .Two generally accepted definitions are :

1.Standardized format for communication of business information between computer applications .

2.Computer- to- computer exchange of information between companies, using an industry standard format .

In short , Electronic Data Interchange (EDI) is the computer-to-computer exchange of business information using a public standard. EDI is a central part of Electronic Commerce (EC), because it enables businesses to exchange business information electronically much faster, cheaper and more accurately than is possible using paper-based systems.

Electronic Data Interchange, consists of data that has been put into a standard format and is electronically transferred between trading partners.Often ,an acknowledgement is returned to the sender informing them that the data was received. The term EDI is often used synonymously with the term EDT. These two terms are indeed different and should not be used interchangeably.




EDI vs EDT
The terms EDI and EDT are often misused .


1.EDT, Electronic Data Transfer, is simply sending a file electronically to a trading partner.

2.Although EDI documents are sent electronically, they are sent in a standard format.

This standard format is what makes EDI different than EDT.




EDI vs E-Commerce
EDI is also often confused with E-commerce itself , though , of course by those who are relatively novices to the technology . However, they may not be faulted as, even now, this method has not found use in many such areas where it may work wonders .


DSP Processor


Definition
The best way to understand the requirements is to examine typical DSP algorithms and identify how their compositional requirements have influenced the architectures of DSP processor. Let us consider one of the most common processing tasks the finite impulse response filter.

For each tap of the filter a data sample is multiplied by a filter coefficient with result added to a running sum for all of the taps .Hence the main component of the FIR filter is dot product: multiply and add .These options are not unique to the FIR filter algorithm; in fact multiplication is one of the most common operation performed in signal processing -convolution, IIR filtering and Fourier transform also involve heavy use of multiply -accumulate operation. Originally, microprocessors implemented multiplication by a series of shift and add operation, each of which consumes one or more clock cycle .First a DSP processor requires a hardware which can multiply in one single cycle. Most of the DSP algorithm require a multiply and accumulate unit (MAC).

In comparison to other type of computing tasks, DSP application typically have very high computational requirements since they often must execute DSP algorithms in real time on lengthy segments ,therefore parallel operation of several independent execution units is a must -for example in addition to MAC unit an ALU and shifter is also required .
Executing a MAC in every clock cycle requires more than just single cycle MAC unit. It also requires the ability to fetch the MAC instruction, a data sample, and a filter coefficient from a memory in a single cycle. Hence good DSP performance requires high memory band width-higher than that of general microprocessors, which had one single bus connection to memory and could only make one access per cycle. The most common approach was to use two or more separate banks of memory, each of which was accessed by its own bus and could be written or read in a single cycle. This means programs are stored in a memory and data in another .With this arrangement, the processor could fetch and a data operand in parallel in every cycle .since many DSP algorithms consume two data operands per instruction a further optimization commonly used is to include small bank of RAM near the processor core that is used as an instruction cache. When a small group of instruction is executed repeatedly, the cache is loaded with those instructions, freeing the instruction bus to be used for data fetches instead of instruction fetches -thus enabling the processor to execute a MAC in a single cycleHigh memory bandwidth requirements are often further supported by dedicated hard ware for calculating memory address. These memory calculating units operate in parallel with DSP processors main execution units, enabling it to access data in new location in the memory without pausing to calculate the new address.


Memory accesses in DSP algorithm tend to exhibit very predictable pattern: for example For sample in FIR filter , the filter coefficient are accessed sequentially from start to finish , then accessed start over from beginning of the coefficient vector when processing the next input sample .This is in the contrast of other computing tasks ,such as data base processing where accesses to memory are less predictable .DSP processor address generation units take advantage of this predictability of supporting specialize addressing modes that enable the processor to efficiently access data in the patterns commonly found in DSP algorithms .The most common of these modes is register indirect addressing with post increment , which is used to automatically increment the address pointer for the algorithms where repetitive computations are performed on a series of data stored sequentially in the memory .Without this feature , the programmer would need to spend instruction explicitly incrementing the address pointer .



Direct to home television (DTH)


Definition
Direct to home (DTH) television is a wireless system for delivering television programs directly to the viewer's house. In DTH television, the broadcast signals are transmitted from satellites orbiting the Earth to the viewer's house. Each satellite is located approximately 35,700 km above the Earth in geosynchronous orbit. These satellites receive the signals from the broadcast stations located on Earth and rebroadcast them to the Earth.

The viewer's dish picks up the signal from the satellite and passes it on to the receiver located inside the viewer's house. The receiver processes the signal and passes it on to the television.The DTH provides more than 200 television channels with excellent quality of reception along with teleshopping, fax and internet facilities. DTH television is used in millions of homes across United States, Europe and South East Asia. Direct to home television is a wireless system for delivering television programming directly to a viewer's house. Usually broadcasting stations use a powerful antenna to transmit radio waves to the surrounding area. Viewer's can pickup the signal with a much smaller antenna. The main limitation of broadcast television is range. The radio signal used to broadcast television shoot out from the broadcast antenna in a straight line. Inorder to receive these signals, you have to be in the direct "line of sight" of the antenna. Small obstacles like trees or small buildings aren't a problem; but a big obstacle, such as Earth, will reflect these waves. If the Earth were perfectly flat, you could pickup broadcast television thousands of miles from the source. But because the planet is curved, it eventually breaks the signal's line of sight. The other problem with broadcast television is that the signal is often distorted even in the viewing area. To get a perfectly clear signal like you find on the cable one has to be pretty close to the broadcast antenna without too many obstacles in the wave.


DTH Television solves both these problems by transmitting broadcast signals from satellites orbiting the Earth. Since satellites are high in the sky there are a lot more customers in the line of sight. Satellites television systems transmit and receive radio signals using specialized antennas called satellite dishes.
The television satellites are all in geosynchronous orbit approximately 35,700 km above the Earth. In this way you have to direct the dish at the satellite only once, and from then on it picks up the signal without adjustment.
More than 200 channels with excellent audio and video are made available. The dish required is quite small (30 to 95 cm in diameter).



The Overall System
Early satellite TV viewers were explorers of sorts. They used their expensive dishes to discover unique programming that wasn't necessarily intended for mass audiences. The dish and receiving equipment gave viewers the tools to pick up foreign stations, live feeds between different broadcast stations, NASA activities and a lot of other stuff transmitted using satellites. Some satellite owners still seek out this sort of programming on their own, but today, most Direct to home TV customers get their programming through a direct broadcast satellite (DBS) provider, such as DirecTV or the Dish Network. The provider selects programs and broadcasts them to subscribers as a set package. Basically, the provider's goal is to bring dozens or even hundreds of channels to your television in a form that approximates the competition, cable TV. Unlike earlier programming, the provider's broadcast is completely digital, which means it has much better picture and sound quality. Early satellite television was broadcast in C-band radio -- radio in the 3.4-gigahertz (GHz) to 7-GHz frequency range. Digital broadcast satellite transmits programming in the Ku frequency range (12 GHz to 14 GHz ).


Digital Subscriber Line (DSL)


Definition


The accelerated growth of content-rich applications that demand high bandwidth has changed the nature of information networks. High-speed communication is now an ordinary requirement throughout business, government, academic, and "work-at-home" environments. High-speed Internet access, telecommuting, and remote LAN access are three services that network access providers clearly must offer. These rapidly growing applications are placing a new level of demand on the telephone infrastructure, in particular, the local loop portion of the network (i.e., the local connection from the subscriber to the local central office). The local loop facility is provisioned with copper cabling,
which cannot easily support high bandwidth transmission. This environment is now being stressed by the demand for increasingly higher bandwidth capacities. Although this infrastructure could be replaced by a massive rollout of fiber technologies, the cost to do so is prohibitive in today's business models.

More importantly, the time to accomplish such a transition is unacceptable, because the market demand exists today!
This demand for data services has created a significant market opportunity for providers that are willing and able to invest in technologies that maximize the copper infrastructure. Both incumbent and competitive Local Exchange Carriers (ILECs and CLECs) are capitalizing on this opportunity by embracing such technologies. The mass deployment of high-speed Digital Subscriber Line (DSL) has changed the playing field for service providers. DSL, which encompasses several different technologies, essentially allows the extension of megabit bandwidth capacities from the service provider central office to the customer premises. Utilizing existing copper cabling, DSL is available at
very reasonable costs without the need for massive infrastructure replacement.

These new DSL solutions satisfy the business need to provision the network in a fast, cost-effective manner, while both preserving the infrastructure and allowing a planned migration into newer technologies. DSL has the proven ability to meet the customer demand for high bandwidth right now, at costs that make sense. ADSL, or Asymmetric DSL, has emerged as thetechnology of choice for delivering greater throughputto the desktop. Currently, the ADSL Lite specification,also known as g.lite, is expected to be standardized bythe end of June, 1999 as a low-cost, easy-to-installversion of ADSL specifically designed for the consumer marketplace. While g.lite is expected to become the
predominant standard for consumer services, HDSL2 is becoming the protocol of choice for business services
more on HDSL2 to come).








The Telecommunications Infrastructure
The telecommunications industry has developed and deployed cost-effective technologies and created global, high-bandwidth, interoffice networks capable of supporting the demands of the information age. This network infrastructure, however, has been lacking one significant component—a ubiquitous low-cost, high-bandwidth access circuit for the local loop. This fact, more than any other, has slowed the growth and availability of high-bandwidth network services. The pervasive copper cable infrastructure deployed throughout the local loop was historically incapable of supporting the throughput required by growing consumer traffic. In response, the industry embraced DSL, which has proven to be the most significant technological development for solving the local loop demand for higher bandwidth.


Crusoe


Definition
The Crusoe processor solutions consist of a hardware engine logically surrounded by a software layer. The engine is a very long instruction word (VLIW) CPU capable of executing up to four operations in each clock cycle. The VLIW's native instruction set bears no resemblance to the x86 instruction set; it has been designed purely for fast lowpower
implementation using conventional CMOS fabrication. The surrounding software layer gives x86 programs the impression that they are running on x86 hardware. The software layer is called Code Morphing software because it dynamically "morphs" x86 instructions into VLIW instructions. The Code Morphing software includes a number of
advanced features to achieve good system-level performance. Code Morphing support facilities are also built into the underlying CPUs. In other words, the Transmeta designers have judiciously rendered some functions in hardware and some in software, according to the product design goals and constraints. Transmeta's Code Morphing technology changes the entire approach to designing microprocessors. By demonstrating that practical microprocessors can be implemented as hardware-software hybrids, Transmeta has dramatically expanded the design space that microprocessor designers can explore for optimum solutions. Upgrades to the software portion of a microprocessor can be rolled out independently from the chip. Finally, decoupling the hardware design from the system and application software that use it frees hardware designers to evolve and eventually replace their designs without perturbing legacy software.



Crusoe processor
Mobile computing has been the buzzword for quite a long time.Mobile computing devices like laptops,webslates & notebook PCs are becoming common nowadays.The heart of every PC whether a desktop or mobile PC is the microprocessor.Several microprocessors are available in the market for desktop PCs from companies like Intel ,
AMD , Cyrix etc.The mobile computing market has never had a microprocesor specifically designed for it.The microprocessors used in mobile PCs are optimized versions of the desktop PC microprocessor.

The concept of Crusoe is well understood from the simple sketch of the proceesor architecture , called 'amoeba'.In this concept , the x86 architecture is an ill-defined amoeba containing features like segmentation, ASCII arithmetic ,variable-length instructions etc. The amoeba explained how a traditional microprocessor was, in their design, to be divided up into hardware and software.Thus Crusoe was conceptualised as a hybrid microprocessor , that is it has a software part and a hardware part with the software layer surrounding the hardware unit.The role of software is to act as an emulator to translate x86 binaries into native code at run time. Crusoe is a 128-bit microprocessor fabricated using the CMOS process.The chip's design is based on a technique called VLIW to ensure design simplicity and high
performance.Besides this it also uses Transmeta's two pateneted technologies , namely , Code Morphing Software and LongRun Power Management.It is a highly integrated processor available in different vesions for different market segments.

Bio-metrics


Definition
Biometrics refers to the automatic identification of a person based on his/her physiological or behavioral characteristics such as finger scan, retina, iris, voice scan, signature scan etc. This method of identification is preferred over traditional
methods involving passwords and PIN numbers for various reasons: the person to be identified is required to be physically present at the point-of-identification; identification based on biometric techniques obviates the need to remember a password or carry a token. With the increased use of computers as vehicles of information technology, it is necessary to restrict access to sensitive/personal data. By replacing PINs, biometric techniques can potentially prevent unauthorized access to or fraudulent use of ATMs, cellular phones, smart cards, desktop PCs, workstations, and computer networks. A biometric system is essentially a pattern recognition system, which makes a personal identification by determining the authenticity of a specific physiological, or behavioral characteristics possessed by the user. An important issue in designing a practical system is to determine how an individual is identified. Depending
on the context, a biometric system can be either a verification (authentication) system or an identification system.


Biometrics is a rapidly evolving technology, which is being widely used in forensics such as criminal identification and prison security, and has the potential to be used in a large range of civilian application areas. Biometrics can be used to prevent unauthorized access to ATMs, cellular phones, smart cards, desktop PCs, workstations, and computer networks. It can be used during transactions conducted via telephone and Internet (electronic commerce and electronic banking). In automobiles, biometrics can replace keys with key-less entry devices Biometrics technology allows determination and verification of one's identity through physical characteristics. To put it simply, it turns your body into your password. These characteristics can include face recognition, voice recognition, finger/hand print scan, iris scans and even retina scans. Biometric systems have sensors that pick up a physical characteristic, convert it into a digital pattern and compare it to stored patterns for identification

Identification And Verification Systems
A person’s identity can be resolved in two ways: identification and verification. The former involves identifying a person from all biometric measurements collected in a database and this involves a one-to-many match also referred to as a ‘cold search’. “Do I know who you are?” Is the inherent question this process seeks to answer. Verification involves authenticating a person’s claimed identity from his or her previously enrolled pattern and this involves a one-to-one match. The question it seeks to answer is, “Are you claim to be?”


Verification
Verification requires comparing a person’s fingerprint to one that pass previously recorded in the system database. The person claiming an identity provided a fingerprint, typically by placing a finger on an optical scanner. The computer locates the previous fingerprint by looking up the person’s identity. This process is relatively easy because the computer needs to compare two-fingerprint record (although most systems use two fingerprints from each person to provide a safety factor). The verification process is referred as a ‘closed search’ because the search field is limited. The second question is “who is this person?” This is the identification function, which is used to prevent duplicate application or enrollment. In this case a newly supplied fingerprint is supplied to all others in the database. A match indicates that the person has already enrolled/applied.


Identification
The identification process, also known as an ‘open search’, is much more technically demanding. It involves many more comparisons and may require differentiating among several database fingerprints that are similar to the objects.


Augmented reality (AR)


Definition
Augmented reality (AR) refers to computer displays that add virtual information to a user's sensory perceptions. Most AR research focuses on see-through devices, usually worn on the head that overlay graphics and text on the user's view of his or her surroundings. In general it superimposes graphics over a real world environment in real time.
Getting the right information at the right time and the right place is key in all these applications. Personal digital assistants such as the Palm and the Pocket PC can provide timely information using wireless networking and Global Positioning System (GPS) receivers that constantly track the handheld devices. But what makes augmented reality different is how the information is presented: not on a separate display but integrated with the user's perceptions. This kind of interface minimizes the extra mental effort that a user has to expend when switching his or her attention back and forth between real-world tasks and a computer screen. In augmented reality, the user's view of the world and the computer interface literally become one.


Between the extremes of real life and Virtual Reality lies the spectrum of Mixed Reality, in which views of the real world are combined in some proportion with views of a virtual environment. Combining direct view, stereoscopic video, and stereoscopic graphics, Augmented Reality describes that class of displays that consists primarily of a real environment, with graphic enhancements or augmentations.In Augmented Virtuality, real objects are added to a virtual environment. In Augmented reality, virtual objects are added to real world. An AR system supplements the real world with virtual (computer generated) objects that appear to co-exist in the same space as the real world. Virtual Reality is a synthetic environment Comparison between AR and virtual environments.The overall requirements of AR can be summarized by comparing them against the requirements for Virtual Environments, for the three basic subsystems that they require.


1) Scene generator: Rendering is not currently one of the major problems in AR. VE systems have much higher requirements for realistic images because they completely replace the real world with the virtual environment. In AR, the virtual images only supplement the real world. Therefore, fewer virtual objects need to be drawn, and they do not necessarily have to be realistically rendered in order to serve the purposes of the application.


2) Display device: The display devices used in AR may have less stringent requirements than VE systems demand, again because AR does not replace the real world. For example, monochrome displays may be adequate for some AR applications, while virtually all VE systems today use full color. Optical see-through HMDs with a small field-of-view may be satisfactory because the user can still see the real world with his peripheral vision; the see-through HMD does not shut off the user's normal field-of-view. Furthermore, the resolution of the monitor in an optical see-through HMD might be lower than what a user would tolerate in a VE application, since the optical see-through HMD does not reduce the resolution of the real environment.


3) Tracking and sensing: While in the previous two cases AR had lower requirements than VE, that is not the case for tracking and sensing. In this area, the requirements for AR are much stricter than those for VE systems. A major reason for this is the registration problem.


Asynchronous Transfer Mode (ATM)


Definition
These computers include the entire spectrum of PCs, through professional workstations up to super-computers. As the performance of computers has increased, so too has the demand for communication between all systems for exchanging data, or between central servers and the associated host computer system.The replacement of copper with fiber and the advancement sin digital communication and encoding are at the heart of several developments that will change the communication infrastructure. The former development has provided us with huge amount of transmission bandwidth. While the latter has made the transmission of all information including voice and video through a packet switched network possible.


With continuously work sharing over large distances, including international communication, the systems must be interconnected via wide area networks with increasing demands for higher bit rates.
For the first time, a single communications technology meets LAN and WAN requirements and handles a wide variety of current and emerging applications. ATM is the first technology to provide a common format for bursts of high speed data and the ebb and flow of the typical voice phone call. Seamless ATM networks provide desktop-to-desktop multimedia networking over single technology, high bandwidth, low latency network, removing the boundary between LAN WAN.


ATM is simply a Data Link Layer protocol. It is asynchronous in the sense that the recurrence of the cells containing information from an individual user is not necessarily periodic. It is the technology of choice for evolving B-ISDN (Board Integrated Services Digital Network), for next generation LANs and WANs. ATM supports transmission speeds of 155Mbits / sec. In the future, Photonic approaches have made the advent of ATM switches feasible, and an evolution towards an all packetized, unified, broadband telecommunications and data communication world based on ATM is taking place.


These computers include the entire spectrum of PCs, through professional workstations upto super-computers. As the performance of computers has increased, so too has the demand for communication between all systems for exchanging data, or between central servers and the associated host computer system.
The replacement of copper with fiber and the advancement sin digital communication and encoding are at the heart of several developments that will change the communication infrastructure. The former development has provided us with huge amount of transmission bandwidth. While the latter has made the transmission of all information including voice and video through a packet switched network possible.

With continuously work sharing over large distances, including international communication, the systems must be interconnected via wide area networks with increasing demands for higher bit rates.For the first time, a single communications technology meets LAN and WAN requirements and handles a wide variety of current and emerging applications. ATM is the first technology to provide a common format for bursts of high speed data and the ebb and flow of the typical voice phone call. Seamless ATM networks provide desktop-to-desktop multimedia networking over single technology, high bandwidth, low latency network, removing the boundary between LAN WAN.


Artificial Eye


Definition
The retina is a thin layer of neural tissue that lines the back wall inside the eye. Some of these cells act to receive light, while others interpret the information and send messages to the brain through the optic nerve. This is part of the process that enables us to see. In damaged or dysfunctional retina, the photoreceptors stop working, causing blindness. By some estimates, there are more than 10 million people worldwide affected by retinal diseases that lead to loss of vision.


The absence of effective therapeutic remedies for retinitis pigmentosa (RP) and age-related macular degeneration (AMD) has motivated the development of experimental strategies to restore some degree of visual function to affected patients. Because the remaining retinal layers are anatomically spared, several approaches have been designed to artificially activate this residual retina and thereby the visual system.


At present, two general strategies have been pursued. The "Epiretinal" approach involves a semiconductor-based device placed above the retina, close to or in contact with the nerve fiber layer retinal ganglion cells. The information in this approach must be captured by a camera system before transmitting data and energy to the implant. The "Sub retinal" approach involves the electrical stimulation of the inner retina from the sub retinal space by implantation of a semiconductor-based micro photodiode array (MPA) into this location. The concept of the sub retinal approach is that electrical charge generated by the MPA in response to a light stimulus may be used to artificially alter the membrane potential of neurons in the remaining retinal layers in a manner to produce formed images.
Some researchers have developed an implant system where a video camera captures images, a chip processes the images, and an electrode array transmits the images to the brain. It's called Cortical Implants.



The Visual System
The human visual system is remarkable instrument. It features two mobile acquisition units each has formidable preprocessing circuitry placed at a remote location from the central processing system (brain). Its primary task include transmitting images with a viewing angle of at least 140deg and resolution of 1 arc min over a limited capacity carrier, the million or so fibers in each optic nerve through these fibers the signals are passed to the so called higher visual cortex of the brain


The nerve system can achieve this type of high volume data transfer by confining such capability to just part of the retina surface, whereas the center of the retina has a 1:1 ration between the photoreceptors and the transmitting elements, the far periphery has a ratio of 300:1. This results in gradual shift in resolution and other system parameters.
At the brain's highest level the visual cortex an impressive array of feature extraction mechanisms can rapidly adjust the eye's position to sudden movements in the peripherals filed of objects too small to se when stationary. The visual system can resolve spatial depth differences by combining signals from both eyes with a precision less than one tenth the size of a single photoreceptor.


AI for Speech Recognition


Definition
AI is the study of the abilities for computers to perform tasks, which currently are better done by humans. AI has an interdisciplinary field where computer science intersects with philosophy, psychology, engineering and other fields. Humans make decisions based upon experience and intention. The essence of AI in the integration of computer to mimic this learning process is known as Artificial Intelligence Integration
When you dial the telephone number of a big company, you are likely to hear the sonorous voice of a cultured lady who responds to your call with great courtesy saying "welcome to company X. Please give me the extension number you want" .You pronounces the extension number, your name, and the name of the person you want to contact. If the called person accepts the call, the connection is given quickly. This is artificial intelligence where an automatic call-handling system is used without employing any telephone operator.



The Technology
Artificial intelligence (AI) involves two basic ideas. First, it involves studying the thought processes of human beings. Second, it deals with representing those processes via machines (like computers, robots, etc).AI is behaviour of a machine, which, if performed by a human being, would be called intelligence. It makes machines smarter and more useful, and is less expensive than natural intelligence.

Natural language processing (NLP) refers to artificial intelligence methods of communicating with a computer in a natural language like English. The main objective of a NLP program is to understand input and initiate action.The input words are scanned and matched against internally stored known words. Identification of a keyword causes some action to be taken. In this way, one can communicate with the computer in one's language. No special commands or computer language are required. There is no need to enter programs in a special language for creating software.

Voice XML takes speech recognition even further. Instead of talking to your computer, you're essentially talking to a web site, and you're doing this over the phone.OK, you say, well, what exactly is speech recognition? Simply put, it is the process of converting spoken input to text. Speech recognition is thus sometimes referred to as speech-to-text.Speech recognition allows you to provide input to an application with your voice. Just like clicking with your mouse, typing on your keyboard, or pressing a key on the phone keypad provides input to an application; speech recognition allows you to provide input by talking. In the desktop world, you need a microphone to be able to do this. In the Voice XML world, all you need is a telephone.

The speech recognition process is performed by a software component known as the speech recognition engine. The primary function of the speech recognition engine is to process spoken input and translate it into text that an application understands. The application can then do one of two things:The application can interpret the result of the recognition as a command. In this case , the application is a command and control application. If an application handles the recognized text simply as text, then it is considered a dictation application.
The user speaks to the computer through a microphone, which in turn, identifies the meaning of the words and sends it to NLP device for further processing. Once recognized, the words can be used in a variety of applications like display, robotics, commands to computers, and dictation.

Treating Cardiac Disease With Catheter-Based Tissue Heating


Definition
In microwave ablation, electromagnetic energy would be delivered via a catheter to a precise location in a coronary artery for selective heating of a targeted atherosclerotic lesion. Advantageous temperature profiles would be obtained by controlling the power delivered, pulse duration, and frequency. The major components of an apparatus for microwave ablation apparatus would include a microwave source, a catheter/transmission line, and an antenna at the distal end of the catheter .The antenna would focus the radiated beam so that most of the microwave energy would be deposited within the targeted atherosclerotic lesion. Because of the rapid decay of the electromagnetic wave, little energy would pass into, or beyond, the adventitia. By suitable choice of the power delivered, pulse duration, frequency, and antenna design (which affects the width of the radiated beam), the temperature profile could be customized to the size, shape, and type of lesion being treated.

For decades, scientists have been using electromagnetic and sonic energy to serve medicine. But, aside from electro surgery, their efforts have focused on diagnostic imaging of internal body structures-particularly in the case of x-ray, MRI, and ultrasound systems. Lately, however, researchers have begun to see acoustic and electromagnetic waves in a whole new light, turning their attention to therapeutic-rather than diagnostic-applications. Current research is exploiting the ability of radio-frequency (RF) and microwaves to generate heat, essentially by exciting molecules. This heat is used predominantly to ablate cells. Of the two technologies, RF was the first to be used in a marketable device. And now microwave devices are entering the commercialization stage. These technologies have distinct strengths weaknesses that will define their use and determine their market niches. The depth to which microwaves can penetrate tissues is primarily a function of the dielectric properties of the tissues and of the frequency of the micro waves.


The tissue of the human body is enormously varied and complex, with innumerable types of structures, components, and cells. These tissues vary not only with in an individual, but also among people of different gender, age, physical condition, health and even as a function of external in puts, such as food eaten, air breathed, ambient temperature, or even state of minds. From the point of view of RF and Microwaves in the frequency range 10 MHz ~ 10GHz, however biological tissue can be viewed macroscopically in terms of its bulk shape and electromagnetic characteristic: dielectric constant and electrical conductivity . These are dependent on frequency and very dependent on the particular tissue type.

All biological tissue is somewhat electrically conductive, absorbing microwave power and converting it to heat as it penetrates the tissue. Delivering heat at depth is not only valuable for cooking dinner, but it can be quite useful for many therapeutic medical applications as well. These includes: diathermy for mild orthopedic heating, hyperthermia cell killing for cancer therapy, microwave ablation and microwave assisted balloon angioplasty. These last two are the subject of this article. It should also be mention that based on the long history of hi power microwave exposure in human, it is reasonable certain that, barring overheating effects, microwave radiation is medically safe. There have been no credible reported carcinogenic , muragenic or poisonous effects of microwave exposure.


Surround Sound System


Definition
There are many surround systems available in the market .They use different technologies for produce surround effect. Some Surround sound is based on using audio compression technology (for example Dolby ProLogic® or Digital AC-3®) to encode and deliver a multi-channel soundtrack, and audio decompression technology to decode the soundtrack for delivery on a surround sound 5-speaker setup. Additionally, virtual surround sound systems use 3D audio technology to create the illusion of five speakers emanating from a regular set of stereo speakers, therefore enabling a surround sound listening experience without the need for a five speaker setup.
We are now entering the Third Age of reproduced sound. The monophonic era was the First Age, which lasted from the Edison's invention of the phonograph in 1877 until the 1950s. during those times, the goal was simply to reproduce the timbre of the original sound. No attempts were made to reproduce directional properties or spatial realism.

The stereo era was the Second Age. It was based on the inventions from the 1930s, reached the public in the mid-'50s, and has provided great listening pleasure for four decades. Stereo improved the reproduction of timbre and added two dimensions of space: the left - right spread of performers across a stage and a set of acoustic cues that allow listeners to perceive a front-to-back dimension.

In two-channel stereo, this realism is based on fragile sonic cues. In most ordinary two-speaker stereo systems, these subtle cues can easily be lost, causing the playback to sound flat and uninvolved. Multichannel surround systems, on the other hand, can provide this involving presence in a way that is robust, reliable and consistent.

The purpose of this seminar is to explore the advances and technologies of surround sound in the consumer market.
Human hearing is binaural (based on two ears), yet we have the ability to locate sound spatially. That is, we can determine where a sound is coming from, and in most cases, from how far away. In addition, humans can distinguish multiple sound sources in relation to the surrounding environment. This is possible because our brains can determine the location of each sound in the three-dimensional environment we live in by processing the information received by our two ears.

The principal localization cues used in binaural human hearings are Interaural Intensity Difference ( IID ) and Interaural Time Difference ( ITD ). IID refers to the fact that if a sound is closer to one ear than the other, its intensity at that ear is greater than at the other ear, which is not only farther away but also receives the sound shadowed by the listener's head. ITD is related to the fact that unless the sound is located at exactly the same distance from both ears (i.e. directly in front or back of the listener), it arrives at one ear sooner than the other. If the sound reaches the right ear first, the source is somewhere to the right, and vice-versa. By combining these two cues and other related to the reflection of the sound as they travel to our eardrums, our brains are able to determine the position of an individual sound source.


The principal format for digital discrete surround is the "5.1 channel" system. The 5.1 name stands for five channels (see figure 1 below) (in front: left, right and centre, and behind: left surround and right surround)of full bandwidth audio (20 Hz to 20 kHz) plus a sixth channel which will, at times, contain additional bass information to maximize the impact of scenes such as explosions, etc.

Space Time Adaptive Processing


Definition
Space-Time Adaptive Processing (STAP) refers to a class of signal processing techniques used to process returns of an antenna array radar system. It enhances the ability of radars to detect targets that might otherwise be obscured by clutter or jamming.
. The output of STAP is a linear combination or weighted sum of the input signal samples .The "adaptive" in STAP refers to the fact that STAP weights are computed to reflect the actual noise, clutter and jamming environment in which the radar finds itself. The "space" in STAP refers to the fact that STAP the STAP weights (applied to the signal samples at each of the elements of the antenna array) at one instant of time define an antenna pattern in space. If there are jammers in the field of view, STAP will adapt the radar antenna pattern by placing nulls in the directions those jammers thus rejecting jammer power. The "time" in STAP refers to the fact that the STAP weights applied to the signal samples at one antenna element over the entire dwell define a system impulse response and hence a system frequency response.

STAP is a multi-dimensional adaptive signal processing technique over spatial and temporal samples. In this approach, the input data collected from several antenna sensors has a cubic form. Depending on how this input data cube is processed, STAP is classified into Higher Order Post-Doppler (HOPD), Element Space Pre-Doppler, Element Space Post-Doppler, Beam Space Pre-Doppler, and Beam Space Post-Doppler. STAP consists of three major computation steps. First, a set of rules called the training strategy is used to select data which will be processed in the subsequent computation. The second step is weight computation. It requires solving a set of linear equations. This is the most computationally intensive step. Finally, thresholding operation is performed after applying the computed weights. In HOPD processing, Doppler processing (FFT computations) is followed by solving least square problems (QR decompositions).



Introduction To Radar
Radar is an electromagnetic system for the detection and location of objects. RADAR is nothing but Radio Detection And Ranging. It operates by transmitting a particular type of waveform and detects the nature of the echo signal. An elementary form of radar consists of a transmitting antenna emitting electromagnetic radiation generated by an oscillator of some sort, a receiving antenna, and an energy detecting device or receiver .A portion of the transmitted signal is intercepted by a reflecting object (target) and is reradiated in all directions. It is the energy reradiated in the back direction that is of prime interest to the radar. The receiving antenna collects the returned energy and delivers it to a receiver, where it is processed to detect the presence of the target and to extract its location and relative velocity.

The transmitter may be an oscillator such as magnetron, which is pulsed by the modulator to generate a repetitive train of pulses. The waveform generated by the transmitter travels via a transmission line to the antenna where it is radiated into space. A single antenna is generally used for both transmitting and receiving. The receiver must be protected from damage caused by the high power of the transmitter. This is the function of the duplexer. The duplexer also serves to channel the returned echo signals to the receiver and not to the transmitter. The receiver is usually of the superhetrodyne type.

Real- Time Systems and Real- Time Operating Systems


Definition
Real-time systems play a considerable role in our society, and they cover a spectrum from the very simple to the very complex. Examples of current real-time systems include the control of domestic appliances like washing machines and televisions, the control of automobile engines, telecommunication switching systems, military command and control systems, industrial process control, flight control systems, and space shuttle and aircraft avionics.

All of these involve gathering data from the environment, processing of gathered data, and providing timely response. A concept of time is the distinguishing issue between real-time and non-real-time systems. When a usual design goal for non-real-time systems is to maximize system's throughput, the goal for real-time system design is to guarantee, that all tasks are processed within a given time. The taxonomy of time introduces special aspects for real-time system research.

Real-time operating systems are an integral part of real-time systems. Future systems will be much larger, more widely distributed, and will be expected to perform a constantly changing set of duties in dynamic environments. This also sets more requirements for future real-time operating systems
Timeliness is the single most important aspect of a real -time system. These systems respond to a series of external inputs, which arrive in an unpredictable fashion. The real-time systems process these inputs, take appropriate decis ions and also generate output necessary to control the peripherals connected to them. As defined by Donald Gillies "A real-time system is one in which the correctness of the computations not only depends upon the logical correctness of the computation but also upon the time in which the result is produced. If the timing constraints are not met, system failure is said to have occurred."

It is essential that the timing constraints of the system are guaranteed to be met. Guaranteeing timing behaviour requires that the system be predictable.

Most real -time systems interface with and control hardware directly. The software for such systems is mostly custom -developed. Real -time Applications can be either embedded applications or non -embedded (desktop) applications. Real -time systems often do not have standard peripherals associated with a desktop computer, namely the keyboard, mouse or conventional display monitors. In most instances, real-time systems have a customized version of these devices.




Real-time Programs: The Computational Model
A simple real -time program can be defined as a program P that receives an event from a sensor every T units of time and in the worst case, an event requires C units of computation time.

Assume that the processing of each event must always be completed before the arrival of the next event (i.e., when there is no buffering). Let the deadline for completin g the computation be D. If D < C, the deadline cannot be met. If T < D, the program must still process each event in a time O/ T, if no events are to be lost. Thus the deadline is effectively bounded by T and we need to handle those cases where C O/ D O/ T.

Radio frequency identification (RFID)


Definition
Radio frequency identification (RFID) is a contactless form of automatic identification and data capture. Dating back to World War II, RFID transponders were used to identify friendly aircraft. The RFID system consists of a reader, transponder, and antenna utilizing several frequency ranges. Over 40 million RFID tags will be used in 1999 with sales projected to break the one billion-dollar mark before 2003 (Frost & Sullivan, 1997). Radio frequency identification is used in access control, asset control, and animal identification. The advantages of RFID are the capability for multiple reads, ability to be used in almost any environment, and the accuracy. The Automatic Identification Manufacturers, International Standards Organization, and the American National Standards Institute are currently developing standards.

Barcodes have been developed in the railroad business to keep track of the various cars. Out of this system of identification grew the U.P.C. (Universal Product Code) which is now used in almost all manufactured goods. UPC is used to store the manufacturer code as well as the product code in a form that can be easily read by various scanners - even from a distance. But there are limits to the use of barcodes. There must be a direct line of sight between the reader and the code. The barcode can be obscured, for example by paint. One only has read-access to the data, i.e., one cannot add new data without adding another label.


This is the point where a relatively new technology comes in: RFID (Radio Frequency IDentification). In RFID electronic chips are used to store data that can be broadcast via radio waves to the reader, eliminating the need for a direct line of sight and making it possible for "tags" to be placed anywhere on or in the product. One can even write to tags made of semiconductor chips, thus enabling updating of data. This write function introduces new capabilities, such as the updating of the manufacturing process of the attached item.


RFID first appeared in tracking and access applications during the 1980s. These wireless AIDC systems allow for non-contact reading and are effective in manufacturing and other hostile environments where bar code labels could not survive. RFID has established itself in livestock identification and automated vehicle identification (AVI) systems because of its ability to track moving objects.


To understand and appreciate the capabilities of RFID systems it is necessary to consider their constituent parts. It is also necessary to consider the data flow requirements that influence the choice of systems and the practicalities of communicating across the air interface. By considering the system components and their function within the data flow chain it is possible to grasp most of the important issues that influence the effective application of RFID.

The RFID reader is designed for fast and easy system integration without losing performance, functionality or security. The RFID reader consists of a real time processor, operating system, virtual portable memory, and transmitter/receiver unit in one small self-contained module that is easily installed in the ceiling or in any other convenient location.



Quantum Dot Lasers


Definition
Quantum Dot Lasers can be considered as a quantum leap in the development of lasers. Quantum Dots improve basically the laser emissions. This property of Quantum Dots is well utilized for fiber optic communication, which is now the leading subject under research and development. Quantum Dots are thus very well used in applications fiber optic communication. The remaining major division of the field of quantum electronics deals with the interactions of coherent light with matter and again leads to a wide range of all-optical and optoelectronic devices.

Basically Quantum Dots are made of InGaAs or simply GaAs structures. Also the possibility for extended wave length (>1.1µm) emission from GaAs based devices is an important characteristic of Quantum Dots. The QDs are formed by an optimized growth approach of alternating sub-monolayer deposition of column III and column V, constituents for optoelectronic device fabrication. Thus there is a large energy separation between states.The infrastructure of the Information Age has to date relied upon advances in microelectronics to produce integrated circuits that continually become smaller, better, and less expensive. The emergence of photonics, where light rather than electricity is manipulated, is posed to further advance the Information Age. Central to the photonic revolution is the development of miniature light sources such as the Quantum dots(QDs).

Today, Quantum Dots manufacturing has been established to serve new datacom and telecom markets. Recent progress in microcavity physics, new materials, and fabrication technologies has enabled a new generation of high performance QDs. This presentation will review commercial QDs and their applications as well as discuss recent research, including new device structures such as composite resonators and photonic crystals Semiconductor lasers are key components in a host of widely used technological products, including compact disk players and laser printers, and they will play critical roles in optical communication schemes. The basis of laser operation depends on the creation of non-equilibrium populations of electrons and holes, and coupling of electrons and holes to an optical field, which will stimulate radiative emission. . Other benefits of quantum dot active layers include further reduction in threshold currents and an increase in differential gain-that is, more efficient laser operation.


Since the 1994 demonstration of a quantum dot (QD) semiconductor laser, the research progress in developing lasers based on QDs has been impressive. Because of their fundamentally different physics that stem from zero-dimensional electronic states, QD lasers now surpass the established planar quantum well laser technology in several respects. These include their minimum threshold current density, the threshold dependence on temperature, and range of wavelengths obtainable in given strained layer material systems. Self-organized QDs are formed from strained-layer epitaxy. Upon reaching such conditions, the growth front can spontaneously reorganize to form 3-dimensional islands. The greater strain relief provided by the 3-dimensionally structured crystal surface prevents the formation of dislocations. When covered with additional epitaxy, the coherently strained islands form the QDs that trap and isolate individual electron-hole pairs to create efficient light emitters.


Optimizing the QD characteristics for use as practical, commercial light sources is based on controlling their density, shape, and uniformity during epitaxy. In particular, the QD's shape plays a large role in determining its dynamic response, as well as the temperature sensitivity of the laser's characteristics. Their density, shape, and uniformity also establish the optical gain of a QD ensemble. All three physical characteristics can be engineered through the precise deposition conditions in which temperature, growth rate, and material composition are carefully controlled.

Plasma Antennas


Definition
Plasma antennas are radio frequency antennas that employ plasma as the guiding medium for electromagnetic radiation.

The concept is to use plasma discharge tubes as the antenna elements. When the tubes are energized, they become conductors, and can transmit and receive radio signals. When they are de-energised, they revert to non-conducting elements and do not reflect probing radio signals. Plasma antenna can be "Steered" electronically. Another feature of the plasma antenna is that it can be turned off rapidly, reducing ringing on pulse transmission.On earth we live upon an island of "ordinary" matter. The different states of matter generally found on earth are solid, liquid, and gas. Sir William Crookes, an English physicist identified a fourth state of matter, now called plasma, in 1879. Plasma is by far the most common form of matter. Plasma in the stars and in the tenuous space between them makes up over 99% of the visible universe and perhaps most of that which is not visible. Important to ASI's technology, plasmas are conductive assemblies of charged and neutral particles and fields that exhibit collective effects. Plasmas carry electrical currents and generate magnetic fields.


When the Plasma Antenna Research Laboratory at ANU investigated the feasibility of plasma antennas as low radar cross-section radiating elements, Redcentre established a network between DSTO ANU researchers, CEA Technologies, Cantec Australasia and Neolite Neon for further development and future commercialization of this technology. The plasma antenna R & D project has proceeded over the last year at the Australian National University in response to a DSTO (Defence Science and Technology Organisation) contract to develop a new antenna solution that minimizes antenna detectability by radar. Since then, an investigation of the wider technical issues of existing antenna systems has revealed areas where plasma antennas might be useful. The project attracts the interest of the industrial groups involved in such diverse areas as fluorescent lighting, telecommunications and radar. Plasma antennas have a number of potential advantages for antenna design.


When a plasma element is not energized, it is difficult to detect by radar. Even when it is energized, it is transparent to the transmissions above the plasma frequency, which falls in the microwave region. Plasma elements can be energized and de-energized in seconds, which prevents signal degradation. When a particular plasma element is not energized, its radiation does not affect nearby elements. HF CDMA Plasma antennas will have low probability of intercept( LP) and low probability of detection( LPD ) in HF communications.



Plasma Antenna Technology
Since the discovery of radio frequency ("RF") transmission, antenna design has been an integral part of virtually every communication and radar application. Technology has advanced to provide unique antenna designs for applications ranging from general broadcast of radio frequency signals for public use to complex weapon systems. In its most common form, an antenna represents a conducting metal surface that is sized to emit radiation at one or more selected frequencies. Antennas must be efficient so the maximum amount of signal strength is expended in the propogated wave and not wasted in antenna reflection.
Plasma antenna technology employs ionized gas enclosed in a tube (or other enclosure) as the conducting element of an antenna.


Organic Light Emitting Diodes (OLED)


Definition
Scientific research in the area of semiconducting organic materials as the active substance in light emitting diodes (LEDs) has increased immensely during the last four decades. Organic semiconductors was first reported in the 60:s and then the materials where only considered to be merely a scientific curiosity. (They are named organic because they consist primarily of carbon, hydrogen and oxygen.). However when it was recognized in the eighties that many of them are photoconductive under visible light, industrial interests were attracted. Many major electronic companies, such as Philips and Pioneer, are today investing a considerable amount of money in the science of organic electronic and optoelectronic devices. The major reason for the big attention to these devices is that they possibly could be much more efficient than todays components when it comes to power consumption and produced light. Common light emitters today, Light Emitting Diodes (LEDs) and ordinary light bulbs consume more power than organic diodes do. And the strive to decrease power consumption is always something of matter. Other reasons for the industrial attention are i.e. that eventually organic full color displays will replace todays liquid crystal displays (LCDs) used in laptop computers and may even one day replace our ordinary CRT-screens.

Organic light-emitting devices (OLEDs) operate on the principle of converting electrical energy into light, a phenomenon known as electroluminescence. They exploit the properties of certain organic materials which emit light when an electric current passes through them. In its simplest form, an OLED consists of a layer of this luminescent material sandwiched between two electrodes. When an electric current is passed between the electrodes, through the organic layer, light is emitted with a color that depends on the particular material used. In order to observe the light emitted by an OLED, at least one of the electrodes must be transparent.


When OLEDs are used as pixels in flat panel displays they have some advantages over backlit active-matrix LCD displays - greater viewing angle, lighter weight, and quicker response. Since only the part of the display that is actually lit up consumes power, the most efficient OLEDs available today use less power.
Based on these advantages, OLEDs have been proposed for a wide range of display applications including magnified microdisplays, wearable, head-mounted computers, digital cameras, personal digital assistants, smart pagers, virtual reality games, and mobile phones as well as medical, automotive, and other industrial applications.




OLED Versus LED
Electronically, OLED is similar to old-fashioned LEDs -- put a low voltage across them and they glow. But that's as far as the similarity goes: instead of being made out of semiconducting metals, OLEDs are made from polymers, plastics or other carbon-containing compounds. These can be made very cheaply and turned into devices without all the expensive palaver that goes with semiconductor fabrication.

Light-emitting diodes, based upon semiconductors such as Gallium Arsenide, Gallium Phosphide, and, most recently, Gallium Nitride, have been around since the late '50s. They are mostly used as indicator lamps, although they were used in calculators before liquid crystals, and are used in large advertising signs, where they are valued for very long life and high brightness. Such crystalline LEDs are not inexpensive, and it is very difficult to integrate them into small high-resolution displays.


Narrow Band & Broad Band ISDN


Definition
The most important development in the computer communications industry in the 1990s is the evolution of the integrated services digital network (ISDN) and broadband ISDN (B-ISDN). The ISDN and B-ISDN have had a dramatic impact on the planning and deployment of intelligent digital networks providing integrated services for voice, data and video. Further, the work on the ISDN and B-ISDN standards has led to the development of two major new networking technologies; frame relay and asynchronous transfer mode (ATM). Frame relay and ATM have become the essential ingredients in developing high-speed networks for local, metropolitan and wider area applications.

The ISDN is intended to be a worldwide public telecommunications network to replace existing public telecommunication networks and deliver a wide variety of services. The ISDN is defined by the standardization of user interfaces and implemented as a set of digital switches and paths supporting a broad range of traffic types and providing value added processing services. In practice, there are multiple networks, implemented within national boundaries but from the user's point of view, the eventual widespread deployment of ISDN will lead to a single, uniformly accessible, worldwide network.

The narrowband ISDN is based on the use of a 64 kbps channel as the basic unit of switching and has a circuit switching orientation. The major technical contribution of the narrowband ISDN effort has been frame relay. The B-ISDN supports very high data rates (100s of Mbps) and has a packet switching orientation. The major technical contribution of the B-ISDN effort has been asynchronous transfer mode, also known as cell relay.
CIRCUIT SWITCHING
The circuit switching is the dominant technology for both voice and data communications. Communication via circuit switching implies that there is a dedicated communication path between two stations. That path is a connected sequence of links between network nodes. On each physical link, a channel is dedicated to the connection. The three phases involved in a communication via circuit switching are circuit establishment, information transfer and circuit disconnect.

PACKET SWITCHING
In a typical data connection much of the time the line is idle. Thus circuit switched approach is inefficient. In packet switching data are transmitted in short packets. Each packet contains a portion of the user's data plus some control information. The control information, at a minimum, includes the information that the network requires to be able to route the packet through the network and deliver it to the intended destination. At each node enroute, the packet is received, stored briefly, and passed on the next node. The advantages of packet switching are line efficiency is greater, data rate conversion is possible and priorities can be used.


FRAME RELAY
With modern, high-speed telecommunication systems, the overhead in error control is unnecessary and counter productive. To take advantages of the high data rates and low error rates of contemporary networking facilities, frame relay was developed. Whereas the original packet switching networks were designed with a data rate to the end user of about 64 kbps, Frame relay networks are designed to operate at user data rates of up to 2 Mbps. The key to achieving these high data rates are to strip out most of the overhead involved with error control.



Nanotechnology


Definition
Nanotechnology is defined as fabrication of devices with atomic or molecular scale precision. Devices with minimum feature sizes less than 100 nanometers (nm) are considered to be products of nanotechnology. A nanometer is one billionth of a meter (10-9 m) and is the unit of length that is generally most appropriate for describing the size of single molecules. The nanoscale marks the nebulous boundary between the classical and quantum mechanical worlds; thus, realization of nanotechnology promises to bring revolutionary capabilities. Fabrication of nanomachines, nanoelectronics and other nanodevices will undoubtedly solve an enormous amount of the problems faced by mankind today.

Nanotechnology is currently in a very infantile stage. However, we now have the ability to organize matter on the atomic scale and there are already numerous products available as a direct result of our rapidly increasing ability to fabricate and characterize feature sizes less than 100 nm. Mirrors that don't fog, biomimetic paint with a contact angle near 180°, gene chips and fat soluble vitamins in aqueous beverages are some of the first manifestations of nanotechnology. However, immenant breakthroughs in computer science and medicine will be where the real potential of nanotechnology will first be achieved.

Nanoscience is an interdisciplinary field that seeks to bring about mature nanotechnology. Focusing on the nanoscale intersection of fields such as physics, biology, engineering, chemistry, computer science and more, nanoscience is rapidly expanding. Nanotechnology centers are popping up around the world as more funding is provided and nanotechnology market share increases. The rapid progress is apparent by the increasing appearance of the prefix "nano" in scientific journals and the news. Thus, as we increase our ability to fabricate computer chips with smaller features and improve our ability to cure disease at the molecular level, nanotechnology is here.



History of Nanotechnology
The amount of space available to us for information storage (or other uses) is enormous. As first described in a lecture titled, 'There's Plenty of Room at the Bottom' in 1959 by Richard P. Feynman, there is nothing besides our clumsy size that keeps us from using this space. In his time, it was not possible for us to manipulate single atoms or molecules because they were far too small for our tools. Thus, his
speech was completely theoretical and seemingly fantastic. He described how the laws of physics do not limit our ability to manipulate single atoms and molecules. Instead, it was our lack of the appropriate methods for doing so. However, he correctly predicted that the time would come in which atomically precise manipulation of matter would inevitably arrive.

Prof. Feynman described such atomic scale fabrication as a bottom-up approach, as opposed to the top-down approach that we are accustomed to. The current top-down method for manufacturing involves the construction of parts through methods such as cutting, carving and molding.


LED wireless


Definition
Billions of visible LEDs are produced each year, and the emergence of high brightness AlGaAs and AlInGaP devices has given rise to many new markets. The surprising growth of activity in, relatively old, LED technology has been spurred by the introduction of AlInGaP devices. Recently developed AlGaInN materials have led to the improvements in the performance of bluish-green LEDs, which have luminous efficacy peaks much higher than those for incandescent lamps. This advancement has led to the production of large-area full-color outdoors LED displays with diverse industrial applications.

The novel idea of this article is to modulate light waves from visible LEDs for communication purposes. This concurrent use of visible LEDs for simultaneous signaling and communication, called iLight, leads to many new and interesting applications and is based on the idea of fast switching of LEDs and the modulation visible-light waves for free-space communications. The feasibility of such approach has been examined and hardware has been implemented with experimental results. The implementation of an optical link has been carried out using an LED traffic-signal head as a transmitter. The LED traffic light (fig 1 below) can be used for either audio or data transmission.
Audio messages can be sent using the LED transmitter, and the receiver located at a distance around 20 m away can play back the messages with the speaker. Another prototype that resembles a circular speed-limit sign with a 2-ft diameter was built. The audio signal can be received in open air over a distance of 59.3 m or 194.5 ft. For data transmission, digital data can be sent using the same LED transmitter, and the experiments were setup to send a speed limit or location ID information.

The work reported in this article differs from the use of infrared (IR) radiation as a medium for short-range wireless communications. Currently, IR links and local-area networks available. IR transceivers for use as IR data links are widely available in the markets. Some systems are comprised of IR transmitters that convey speech messages to small receivers carried by persons with severe visual impairments. The Talking Signs system is one such IR remote signage system developed at the Smith-Kettlewell Rehabilitation Engineering Research center. It can provide a repeating, directionally selective voice message that originates at a sign. However, there has been very little work on the use of visible light as a communication medium.

The availability of high brightness LEDs make the visible-light medium even more feasible for communications. All products with visible-LED components (like an LED traffic signal head) can be turned into an information beacon. This iLight technology has many characteristics that are different from IR. The iLight transceivers make use of the direct line-of-sight (LOS) property of visible light, which is ideal in applications for providing directional guidance to persons with visual impairments. On the other hand, IR has the property of bouncing back and forth in a confined environment. Another advantage of iLight is that the transmitter provides easy targets for LOS reception by the receiver. This is because the LEDs, being on at all times, are also indicators of the location of the transmitter. A user searching for information has only to look for lights from an iLight transmitter. Very often, the device is concurrently used for illumination, display, or visual signage. Hence, there is no need to implement an additional transmitter for information broadcasting. Compared with an IR transmitter, an iLight transmitter has to be concerned with even brightness. There should be no apparent difference to a user on the visible light that emits from an iLight device.

It has long been realized that visible light has the potential to be modulated and used as a communication channel with entropy. The application has to make use of the directional nature of the communication medium because the receiver requires a LOS to the audio system or transmitter. The locations of the audio signal broadcasting system and the receiver are relatively stationary. Since the relative speed between the receiver and the source are much less than the speed of light, the Doppler frequency shift observed by the receiver can be safely neglected. The transmitter can broadcast with viewing angle close to 180 . The frequency of an ON period followed by an OFF period to transmit information is short enough to be humanly unperceivable; so that it does not affect traffic control. This article aims to present an application of high-brightness visible LEDs for establishing optical free-space links.



Laser Communication Systems


Definition
Lasers have been considered for space communications since their realization in 1960. Specific advancements were needed in component performance and system engineering particularly for space qualified hardware. Advances in system architecture, data formatting and component technology over the past three decades have made laser communications in space not only viable but also an attractive approach into inter satellite link applications.

Information transfer is driving the requirements to higher data rates, laser cross -link technology explosions, global development activity, increased hardware, and design maturity. Most important in space laser communications has been the development of a reliable, high power, single mode laser diode as a directly modulable laser source. This technology advance offers the space laser communication system designer the flexibility to design very lightweight, high bandwidth, low-cost communication payloads for satellites whose launch costs are a very strong function of launch weigh. This feature substantially reduces blockage of fields of view of most desirable areas on satellites. The smaller antennas with diameter typically less than 30 centimeters create less momentum disturbance to any sensitive satellite sensors. Fewer on board consumables are required over the long lifetime because there are fewer disturbances to the satellite compared with heavier and larger RF systems. The narrow beam divergence affords interference free and secure operation.



Background
Until recently, the United States government was funding the development of an operational space laser cross-link system employing solid-state laser technology. The NASA is developing technology and studying the applicability of space laser communication to NASA's tracking and data relay network both as cross-link and for user relay links. NASA's Jet Propulsion Laboratory is studying the development of large space and ground-base receiving stations and payload designs for optical data transfer from interplanetary spacecraft. Space laser communication is beginning to be accepted as a viable and reliable means of transferring data between satellites. Presently, ongoing hardware development efforts include ESA's Space satellite Link Experiment (SILEX) and the Japanese's Laser Communication Experiment (LCE). The United States development programs ended with the termination of both the production of the laser cross-link subsystem and the FEWS satellite program
.
Satellite use from space must be regulated and shared on a worldwide basis. For this reason, frequencies to be used by the satellite are established by a world body known as the International Telecommunications Union (ITU) with broadcast regulations controlled by a subgroup known as World Administrative Radio Conference (WARC). An international consultative technical committee (CCIR) provides specific recommendations on satellite frequencies under consideration by WARC. The basic objective is to allocate particular frequency bands for different types of satellite services, and also to provide international regulations in the areas of maximum radiation's level from space, co-ordination with terrestrial systems and the use of specific satellite locations in a given orbit. Within these allotments and regulations an individual country can make its own specific frequency selections based on intended uses and desired satellite services.

Josephson Junction


Definition
The 20th century saw many developments in the field of electronics because of basically two reasons

1. The development of transistors, which forms the basics of everything that is electronics.
2. The development of IC, which helped in the fabrication of fast, compact & sophisticated electronic circuits.

In the 21st century we are going to see some radical changes in the approach towards electronics. These are :
1. The replacement of semiconducting devices with superconducting devices.
2. The use of new classical theories in physics like the relative physics & quantum mechanics to explain various phenomenon, application & working of electronic devices.

The first step to integrate the previously separate branches, electronics &super conductivity was done by the scientist called Brian Josephson by the invention of the JJ in the year 1962 for which he received the Nobel prize in the year 1973.The analysis of the device is impossible using classical theories of physics. The device has immense potential & numerous applications in almost all fields of applied electronics.


The Josephson junction (JJ) is basically an insulator sandwitched between the two semiconductor layers. Hence the device is also called as a SIS (Superconductor-Insulator-superconductor). A tunneling phenomenon called Josephson tunneling takes place through the insulator when the thickness of the insulator is very thin (less than 1.5 nm) and the insulator turns into a superconductor due to the tunneling of charge carriers from the 1st to the 2nd super conductor; through the insulator.
To explain the working of the device we need to analyze the principles of superconductivity & the principles of tunneling. The superconductivity is explained in terms of BCS theory & tunneling in terms of the uncertainity principle.




Superconductivity
It is a remarkable property in which there is a complete loss of resistivity in a metal or alloy, usually at temperature close to the absolute zero & this property was discovered by Kammerlingh Onnes. As perfect conductors, superconductors will carry current without resistance loss, i.e, the current applied will persist forever without any loss of power. These materials are also perfect diamagnetic & magnet placed above the super conductor will levitate under its own magnetic field.

Low temperature superconductors exhibit property at temperature near-250?C. LBCO &certain alloys of La & Ba shows this property near 35k, RBa2Cu3O7, Bi2Sr2ca2Cu3O10 can show the property near 90k. Thallium based & mercury based cuprates can show superconductivity at 134k. Progress in the development of high temperature superconductivity & particular cuprate based superconductors has made significant advances. Some organic compounds have lately been developed as Superconductors.


Imagine


Definition
The focus of the Imagine is to develop a programmable architecture that achieves the performance of special purpose hardware on graphics and image/signal processing. This is accomplished by exploiting stream-based computation at the application, compiler, and architectural level. At the application level, we have cast several complex media applications such as polygon rendering, stereo depth extraction, and video encoding into streams and kernels. At the compiler-level, we have developed programming languages for writing stream-based programs and have developed software tools that optimize their execution on stream hardware. Finally, at the architectural level, we have developed the Imagine stream processor, a novel architecture that executes stream-based programs and is able to sustain over tens of GFLOPs over a range of media applications with a power dissipation of less than 10 Watts.



Research Contributions
Stream Architecture
The Imagine Stream Architecture is a novel architecture that executes stream-based programs. It provides high performance with 48 floating-point arithmetic units and a area- and power-efficient register organization. A streaming memory system loads and stores streams from memory. A stream register file provides a large amount of on-chip intermediate storage for streams. Eight VLIW arithmetic clusters perform SIMD operations on streams during kernel execution. Kernel execution is sequenced by a micro-controller. A network interface is used to support multi-Imagine systems and I/O transfers. Finally, a stream controller manages the operation of all of these units.

Stream Programming Model
Applications for Imagine are programmed using the stream programming model. This model consists of streams and kernels. Streams are sequences of similar data records. Kernels are small programs which operate on a set of input streams and produce a set of output streams.

Software Tools
Imagine is programmed with a set of languages and software tools that implement the stream programming model. Applications are programmed in StreamC and KernelC. A stream scheduler maps StreamC to stream instructions for Imagine and a kernel scheduler maps KernelC to VLIW kernel instructions for Imagine. Imagine applications have been tested using a cycle accurate simulator, named ISim, and are currently being tested on a prototype board.

Programmable Graphics and Real-time Media Applications
The Imagine stream processor combines full programmability with high performance. This has enabled research into new real-time media applications such as programmable graphics pipelines.

VLSI Prototype
A prototype Imagine processor was design and fabricated in conjunction with Texas Instruments.and received by Stanford on April 9, 2002. Imagine contains 21 million transistors and has a die size of 16mm x 16mm in a 0.15 micron standard cell technology.

Stream Processor Development Platform
A prototype development board was designed and fabricated in conjunction with ISI-East Dynamic Systems Division. This board has enabled experimental measurements of the prototype Imagine processor, experiments on performance of multi-Imagine systems, and additional application and software tool development.



Synchronous Optical Networking


The Synchronous optical network, commonly known as SONET, is a standard for communicating digital information using lasers or light emitting diodes (LEDs) over optical fiber as defined by GR-253-CORE from Telcordia. It was developed to replace the PDH system for transporting large amounts of telephone and data traffic and to allow for interoperability between equipment from different vendors.


The more recent Synchronous Digital Hierarchy (SDH) standard developed by ITU (G.707 and its extension G.708) is built on experience in the development of SONET. Both SDH and SONET are widely used today; SONET in the U.S. and Canada, SDH in the rest of the world. SDH is growing in popularity and is currently the main concern with SONET now being considered as the variation.

SONET differs from PDH in that the exact rates that are used to transport the data are tightly synchronized to network based clocks. Thus an entire network can operate synchronously, though the presence of different timing sources allow for different circuits within a SONET signal to be timed off of different clocks (through the use of pointers and buffers.) SDH was made possible by the existence of atomic clocks.

Both SONET and SDH can be used to encapsulate earlier digital transmission standards, such as the PDH standard, or used directly to support either ATM or so-called Packet over SONET networking. As such, it is inaccurate to think of SONET as a communications protocol in and of itself, but rather as a generic and all-purpose transport container for moving both voice and data.


Digital Watermarking


With the rapid growth of Internet and networks technique, multimedia data transforming and sharing is common to many people. Multimedia data is easily copied and modified, so necessity for copyright protection is increasing. It is the imperceptible marking of multimedia data to "brand" ownership. Digital watermarking has been proposed as technique for copyright protection of multimedia data. Digital watermarking invisibly embeds copyright information into multimedia data. Thus, digital watermarking has been used for copyright protection, finger printing, copy protection and broadcast monitoring. Indeed, a watermarking algorithm requires both invisibility and robustness, which exist in a trade-off relation. Thus good watermarking algorithm must be satisfied the requirements.


The process of digital watermarking involves the modification of the original multimedia data to embed a watermark containing key information such as authentication or copyright codes. The embedding method must leave the original data perceptually un-changed, yet should impose modifications which can be detected by using an appropriate extraction algorithm. Common types of signals to watermark are images, music clips and digital video. The application of digital watermarking to still images is concentrated here. The major technical challenge is to design a highly robust digital watermarking technique, which discourages copyright infringement by making the process of watermarking removal tedious and costly.

Satellite Radio/TV System
Satellite systems are ideally suited for television and radio distribution, providing high-quality, high-reliability, low-maintenance, flexible alternatives to terrestrial systems. Unlike terrestrial microwave systems, there are no towers or repeaters to maintain, no radio fades to degrade performance, no extensive troubleshooting to diagnose problems and far less land to lease. Your capital investment for a satellite network is also much lower, especially in areas with difficult terrain. Receive stations can be deployed in a fraction of the time it would take to install a terrestrial system
With the advent of digital modulation and compression techniques, crystal clarity can be achieved with both video and audio, while at the same time minimizing transmission costs and ensuring the privacy of your network.

The signals you receive are virtually identical to those generated at the studio. With newer-generation satellites, occupied satellite bandwidths can be as little as 9 MHz for a TV signal and its associated (stereo) audio channels. Stereo radio signals can be multiplexed with the TV signal or transmitted on separate narrowband digital carriers. Only stations designated by your control center will be able to decode your transmissions, thus ensuring privacy.


Solid-state transmitter equipment is rapidly becoming the standard for new installations. Although initially more expensive, solid-state equipment enjoys the advantage of reduced maintenance costs for the life of the equipment.




Robotics


Over the course of human history the emergence of certain new technologies have globally transformed life as we know it. Disruptive technologies like fire, the printing press, oil, and television have dramatically changed both the planet we live on and mankind itself, most often in extraordinary and unpredictable ways. In pre-history these disruptions took place over hundreds of years. With the time compression induced by our rapidly advancing technology, they can now take place in less than a generation.

We are currently at the edge of one such event. In ten years robotic systems will fly our planes, grow our food, explore space, discover life saving drugs, fight our wars, sweep our homes and deliver our babies. In the process, this robotics driven disruptive event will create a new 200 billion dollar global industry and change life as you now know it, forever. Just as my children cannot imagine a world without electricity, your children will never know a world without robots. Come take a bold look at the future and the opportunities for Mechanical Engineers that wait there.


The Three Laws of Robotics are:


1. A robot may not injure a human being, or, through inaction, allow a human being to come to harm.
2. A robot must obey the orders given it by human beings except where such orders would conflict with the First Law.
3. A robot must protect its own existence as long as such protection does not conflict with the First or Second Law


Plasma Display


A type of flat-panel display that works by sandwiching a neon/xenon gas mixture between two sealed glass plates with parallel electrodes deposited on their surfaces. The plates are sealed so that the electrodes form right angles, creating pixels. When a voltage pulse passes between two electrodes, the gas breaks down and produces weakly ionized plasma, which emits UV radiation. The UV radiation activates color phosphors and visible light is emitted from each pixel.


Also called "gas discharge display," a flat-screen technology that uses tiny cells lined with phosphor that are full of inert ionized gas (typically a mix of xenon and neon). Three cells make up one pixel (one cell has red phosphor, one green, one blue). The cells are sandwiched between x- and y-axis panels, and a cell is selected by charging the appropriate x and y electrodes. The charge causes the gas in the cell to emit ultraviolet light, which causes the phosphor to emit color. The amount of charge determines the intensity, and the combination of the different intensities of red, green and blue produce all the colors required.

Today, Plasma displays are becoming more and more popular. Compared to conventional CRT displays, plasma displays are about one-tenth the thickness--around 4'', and one-sixth the weight--less than 67 pounds for a 40" display. They use over 16 million colors and have a 160 degree-viewing angle.
Companies such as Panasonic, Fujitsu, and Pioneer manufacture plasma displays.

Plasma displays were initially monochrome, typically orange, but color displays have become very popular and are used for home theater and computer monitors as well as digital signs. The plasma technology is similar to the way neon signs work combined with the red, green and blue phosphor technology of a CRT. Plasma monitors consume significantly more current than LCD-based monitors.


Wireless Intellegent Network (WIN)


(WIN) is a concept being developed by the Telecommunications Industry Association (TIA) Standards Committee TR45.2. The charter of this committee is to drive intelligent network (IN) capabilities, based on interim standard (IS)-41, into wireless networks. IS-41 is a standard currently being embraced by wireless providers because it facilitates roaming. Basing WIN standards on this protocol enables a graceful evolution to an IN without making current network infrastructure obsolete.

Today's wireless subscribers are much more sophisticated telecommunications users than they were five years ago. No longer satisfied with just completing a clear call, today's subscribers demand innovative ways to use the wireless phone. They want multiple services that allow them to handle or select incoming calls in a variety of ways.
Enhanced services are very important to wireless customers. They have come to expect, for instance, services such as caller ID and voice messaging bundled in the package when they buy and activate a cellular or personal communications service (PCS) phone. Whether prepaid, voice/data messaging, Internet surfing, or location-sensitive billing, enhanced services will become an important differentiator in an already crowded, competitive service-provider market.


Enhanced services will also entice potentially new subscribers to sign up for service and will drive up airtime through increased usage of PCS or cellular services. As the wireless market becomes increasingly competitive, rapid deployment of enhanced services becomes critical to a successful wireless strategy.
Intelligent network (IN) solutions have revolutionized wireline networks. Rapid creation and deployment of services has become the hallmark of a wireline network based on IN concepts. Wireless intelligent network (WIN) will bring those same successful strategies into the wireless networks.





NRAM


Definition
Nano-RAM, is a proprietary computer memory technology from the company Nantero and NANOMOTOR is invented by University of bologna and California nano systems.NRAM is a type of nonvolatile random access memory based on the mechanical position of carbon nanotubes deposited on a chip-like substrate. In theory the small size of the nanotubes allows for very high density memories. Nantero also refers to it as NRAM in short, but this acronym is also commonly used as a synonym for the more common NVRAM, which refers to all nonvolatile RAM memories.Nanomotor is a molecular motor which works continuously without the consumption of fuels. It is powered by sunlight. The research are federally funded by national science foundation and national academy of science.

Carbon Nanotubes
Carbon nanotubes (CNTs) are a recently discovered allotrope of carbon. They take the form of cylindrical carbon molecules and have novel properties that make them potentially useful in a wide variety of applications in nanotechnology, electronics, optics, and other fields of materials science. They exhibit extraordinary strength and unique electrical properties, and are efficient conductors of heat. Inorganic nanotubes have also been synthesized.
A nanotube is a member of the fullerene structural family, which also includes buckyballs. Whereas buckyballs are spherical in shape, a nanotube is cylindrical, with at least one end typically capped with a hemisphere of the buckyball structure. Their name is derived from their size, since the diameter of a nanotube is on the order of a few nanometers (approximately 50,000 times smaller than the width of a human hair), while they can be up to several millimeters in length. There are two main types of nanotubes: single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs).


Manufacturing a nanotube is dependent on applied quantum chemistry, specifically, orbital hybridization. Nanotubes are composed entirely of sp2 bonds, similar to those of graphite. This bonding structure, stronger than the sp3 bonds found in diamond, provides the molecules with their unique strength. Nanotubes naturally align themselves into "ropes" held together by Van der Waals forces. Under high pressure, nanotubes can merge together, trading some sp2 bonds for sp3 bonds, giving great possibility for producing strong, unlimited-length wires through high-pressure nanotube linking.


Fabrication Of NRAM
This nano electromechanical memory, called NRAM, is a memory with actual moving parts, with dimensions measured in nanometers. Its carbon nanotube based technology makes advantage of vaanderwaals force to create basic on off junctions of a bit. Vaanderwaals forces interaction between atoms that enable noncovalant binding. They rely on electron attractions that arise only at nano scale levels as a force to be reckoned with. The company is using this property in its design to integrate nanoscale material property with established cmos fabrication technique.


Storage In NRAM
NRAM works by balancing the on ridges of silicon. Under differing electric charges, the tubes can be physically swung into one or two positions representing one and zeros. Because the tubes are very small-under a thousands of time-this movement is very fast and needs very little power, and because the tubes are a thousand times conductive as copper it is very to sense to read back the data. Once in position the tubes stay there until a signal resets them.
The bit itself is not stored in the nano tubes, but rather is stored as the position of the nanotube. Up is bit 0 and down is bit 1.Bits are switched between the states by the application of the electric field.


The technology work by changing the charge placed on a latticework of crossed nanotube. By altering the charges, engineers can cause the tubes to bind together or separate, creating ones and zeros that form the basis of computer memory. If we have two nano tubes perpendicular to each other one is positive and other negative, they will bend together and touch. If we have two similar charges they will repel. These two positions are used to store one and zero. The chip will stay in the same state until you make another change in the electric field. So when you turn the computer off, it doesn't erase the memory .We can keep all the data in the NRAM and gives your computer an instant boot.


Landmine Detection Using Impulse Ground Penetrating Radar


Definition
Landmines are affecting the lives and livelihood of millions of people around the world. The video impulse ground penetrating radar system for detection for small and shallow buried objects has been developed. The hardware combines commercially available components with components specially developed or modified for being used in the system. The GPR system has been desired to measure accurately electromagnetic field backscattered from subsurface targets in order to allow identification of detected targets through the solution of the inverse scattering problem. The GPR has been tested in different environmental conditions and has proved its ability to detect small and shallow buried targets.


Landmines and unexploded ordnance (UXO) are a legacy of war, insurrection, and guerilla activity. Landmines kill and maim approximately 26,000 people annually. In Cambodia, whole areas of arable land cannot be farmed due to the threat of landmines. United Nations relief operations are made more difficult and dangerous due to the mining of roads. Current demining techniques are heavily reliant on metal detectors and prodders.

Technologies are used for landmine detection are:
• Metal detectors--- capable of finding even low-metal content mines in mineralized soils.
• Nuclear magnetic resonance, fast neutron activation and thermal neutron activation.
• Thermal imaging and electro-optical sensors--- detect evidence of buried objects.
• Biological sensors such as dogs, pigs, bees and birds.
• Chemical sensors such as thermal fluorescence--- detect airborne and waterborne presence of explosive vapors.


In this seminar, we will concentrate on Ground Penetrating Radar (GPR). This ultra wide band radar provides centimeter resolution to locate even small targets. There are two distinct types of GPR, time-domain and frequency domain. Time domain or impulse GPR transmits discrete pulses of nanosecond duration and digitizes the returns at GHz sample rates. Frequency domain GPR systems transmit single frequencies either uniquely, as a series of frequency steps, or as a chirp. The amplitude and phase of the return signal is measured. The resulting data is converted to the time domain. GPR operates by detecting the dielectric contrasts in the soils, which allows it to locate even non-metallic mines.

In this discussion we deal with buried anti-tank (AT) and anti-personnel (AP) landmines, which require close approach or contact to activate. AT mines range from about 15 to 35 cm in size. They are typically buried up to 40cm deep, but they can also be deployed on the surface of a road to block a column of machinery. AP mines range from about 5 to 15cm in size. AT mines, which are designed to impede, the progress of destroy vehicles and AP mines which are designed to kill and maim people.

Micro-electro Mechanical Systems (MEMS)


The satellite industry could experience its biggest revolution since it joined the ranks of commerce, thanks to some of the smallest machines in existence. Researchers are performing experiments designed to convince the aerospace industry that microelectromechanical systems (MEMS) could open the door to low-cost, high-reliability, mass-produced satellites.MEMS combine conventional semiconductor electronics with beams, gears, levers, switches, accelerometers, diaphragms, microfluidic thrusters, and heat controllers, all of them microscopic in size.
"We can do a whole new array of things with MEMS that cannot be done any other way," said Henry Helvajian, a senior scientist with Aerospace Corp., a nonprofit aerospace research and development organization in El Segundo, Calif.

Microelectromechanical Systems, or MEMS, are integrated micro devices or systems combining electrical and mechanical components. They are fabricated using integrated circuit (IC) batch processing techniques and can range in size from micrometers to millimeters. These systems can sense, control and actuate on the micro scale, and function individually or in arrays to generate effects on the macro scale.


MEMS is an enabling technology and current applications include accelerometers, pressure, chemical and flow sensors, micro-optics, optical scanners, and fluid pumps. Generally a satellite consists of battery, internal state sensors, communication systems and control units. All these can be made of MEMS so that size and cost can be considerably reduced. Also small satellites can be constructed by stacking wafers covered with MEMS and electronics components. These satellites are called 'I' Kg class satellites or Picosats. These satellites having high resistance to radiation and vibration compared to conventional devices can be mass-produced there by reducing the cost. These can be used for various space applications.Also small satellites can be constructed by stacking wafers covered with MEMS and electronics components. These satellites are called 'I' Kg



Integrated Voice & Data


IBM has created evolutionary solutions for data networks in anticipation of the dynamic trends and business advantages of integrating voice onto data networks. IBM's strategy is to provide high quality equipment and services with cost saving implementations that enable networks either to be upgraded using the installed base or architected to start simple and grow fast in cost-effective steps while accommodating new technologies or standards.


Voice and data integration is currently a hot topic within the business community, with its promise of major cost savings and consolidation of data and voice infrastructures. But there remains some skepticism and the old adage 'if it ain't broke, don't fix it' certainly has a few adherents. However, while PBX based telephone systems have certainly proved their worth in the past, there is growing evidence that the demands of modern business will increasingly necessitate the implementation of integrated voice and data systems. Up to now, small sites were the ones that showed themselves willing to adopt the new standard, but now it is the large enterprise sites with existing PBX based systems that are beginning to be seduced by the significant business and cost benefits that a migration to VoIP technology can bring.


Voice and data integration, or convergence, is the next mission-critical, must-have technology, according to many telecommunications experts. As businesses upgrade their networks or build new infrastructure, many are turning to integrated networking solutions that use packet-switched networks to accommodate voice and video in addition to data. Examples of integrated solutions include Frame Relay, ATM (Asynchronous Transfer Mode) and voice over IP. From a pure business perspective, moving toward integration seems wise, especially as com-petition becomes more fierce and operating costs continue to rise. Networking voice and data can help your business to be more productive and efficient, enabling you to use the same technology and personnel for different operations.





Smart Quill


Definition
Lyndsay Williams of Microsoft Research's Cambridge UK lab is the inventor of the Smartquill,a pen that can remember the words that it is used to write, and then transform them into computer text . The idea that "it would be neat to put all of a handheld-PDA type computer in a pen," came to the inventor in her sleep . "It's the pen for the new millennium," she says. Encouraged by Nigel Ballard, a leading consultant to the mobile computer industry, Williams took her prototype to the British Telecommunications Research Lab, where she was promptly hired and given money and institutional support for her project. The prototype, called SmartQuil, has been developed by world-leading research laboratories run by BT (formerly British Telecom) at Martlesham, eastern England. It is claimed to be the biggest revolution in handwriting since the invention of the pen.


The sleek and stylish prototype pen is different from other electronic pens on the market today in that users don't have to write on a special pad in order to record what they write. User could use any surface for writing such as paper, tablet, screen or even air. The SmartQuill isn't all space-age, though -- it contains an ink cartridge so that users can see what they write down on paper. SmartQuill contains sensors that record movement by using the earth's gravity system, irrespective of the platform used. The pen records the information inserted by the user. Your words of wisdom can also be uploaded to your PC through the "digital inkwell", while the files that you might want to view on the pen are downloaded to SmartQuill as well.


It is an interesting idea, and it even comes with one attribute that makes entire history of pens pale by comparison-if someone else picks your SmartQuill and tries to write with it- it won't. Because user can train the pen to recognize a particular handwriting. Hence SmartQuill recognizes only the owner's handwriting. SmartQuill is a computer housed within a pen which allows you to do what a normal personal organizer does .It's really mobile because of it's smaller size and one handed use. People could use the pen in the office to replace a keyboard, but the main attraction will be for users who usually take notes by hand on the road and type them up when returning to the office. SmartQuill will let them skip the step of typing up their notes.


WORKING

SmartQuill is slightly larger than an ordinary fountain pen. Users can enter information into these applications by pushing a button on the pen and writing down what they would like to enter .The SmartQuill does not need a screen to work. The really clever bit of the technology is its ability to read handwriting not only on paper but on any flat surface - horizontal or vertical. There is also a small three-line screen to read the information stored in the pen; users can scroll down the screen by tilting the pen slightly. The user trains the pen to recognize a particular handwriting style - no matter how messy it is, as long as it is consistent, the pen can recognize it. The handwritten notes are stored on hard disk of the pen. The pen is then plugged into an electronic "inkwell" ,text data is transmitted to a desktop computer, printer, or modem or to a mobile telephone to send files electronically. Up to 10 pages of notes can be stored locally on the pen . A tiny light at the tip allows writing in the dark. When the pen is kept idle for some time ,power gets automatically off.


FEATURES

" Display technology used in SmartQuill

" Handwriting recognition and signature verification

" Display scrolls using tilt sensors

" Communication with other devices

" Memory and power

Automatic Number Plate Recognition


Definition
Automatic Number Plate Recognition or ANPR is a technology that uses pattern recognition to 'read' vehicle number plates.

" work by tracking vehicles' travel time between two fixed points, and therefore calculate the average speed


"In simple terms ANPR cameras 'photograph' the number plates of the vehicles that pass them. This 'photograph' is then fed in a computer system to find out details about the driver and owner of the vehicle and details about the vehicle itself


"ANPR consists of cameras linked to a computer.


"As a vehicle passes, ANPR 'reads' Vehicle Registration Marks - more commonly known as number plates - from digital images, captured through cameras located either in a mobile unit, in-built in traffic vehicles or via Closed Circuit Television (CCTV).


"The digital image is converted into data, which is processed through the ANPR system.



ANPR is used for Detecting crime through the use of intelligence monitoring.
o Identifying stolen vehicles.
oDetecting vehicle document crime
oelectronic toll collection etc.

There are six primary algorithms that the software requires for identifying a licence plate:
1.Plate localisation - responsible for finding and isolating the plate on the picture
2.Plate orientation and sizing - compensates for the skew of the plate and adjusts the dimensions to the required size
3.Normalisation - adjusts the brightness and contrast of the image
4.Character segmentation - finds the individual characters on the plates
5.5.Optical character recognition6.Syntactical/Geometrical analysis - check characters and positions against country specific rules


oPoor image resolution, usually because the plate is too far away but sometimes resulting from the use of a low-quality camera.
oBlurry images, particularly motion blur and most likely on mobile units
oPoor lighting and low contrast due to overexposure, reflection or shadows
oAn object obscuring the plate, quite often a tow bar, or dirt on the plate
oA different font, popular for vanity plates
oCircumvention techniques

oAutomatic number plate recognition (ANPR) is a mass surveillance method that uses optical character recognition on images to read the licence plates on vehicles. As of 2006 systems can scan number plates at around one per second on cars travelling up to 100 mph (160 km/h). They can use existing closed-circuit television or road-rule enforcement cameras, or ones specifically designed for the task. They are used by various police forces and as a method of electronic toll collection on pay-per-use roads, and monitoring traffic activity such as red light adherence in an intersection.


Optical Camouflage


Definition
Optical camouflage is a hypothetical type of active camouflage currently only in a very primitive stage of development. The idea is relatively straightforward: to create the illusion of invisibility by covering an object with something that projects the scene directly behind that object. Although optical is a term that technically refers to all forms of light, most proposed forms of optical camouflage would only provide invisibility in the visible portion of the spectrum. Prototype examples and proposed designs of optical camouflage devices range back to the late eighties at least, and the concept began to appear in fiction in the late nineties.


The most intriguing prototypes of optical camouflage yet have been created by the Tachi Lab at the University of Tokyo, under the supervision of professors Susumu Tachi, Masahiko Inami and Naoki Kawakami. Their prototype uses an external camera placed behind the cloaked object to record a scene, which it then transmits to a computer for image processing. The computer feeds the image into an external projector which projects the image onto a person wearing a special retroreflective coat. This can lead to different results depending on the quality of the camera, the projector, and the coat, but by the late nineties, convincing illusions were created. The downside is the large amount of external hardware required, along with the fact that the illusion is only convincing when viewed from a certain angle.


Creating complete optical camouflage across the visible light spectrum would require a coating or suit covered in tiny cameras and projectors, programmed to gather visual data from a multitude of different angles and project the gathered images outwards in an equally large number of different directions to give the illusion of invisibility from all angles. For a surface subject to bending like a flexible suit, a massive amount of computing power and embedded sensors would be necessary to continuously project the correct images in all directions. This would almost certainly require sophisticated nanotechnology, as our computers, projectors, and cameras are not yet miniaturized enough to meet these conditions.


Although the suit described above would provide a convincing illusion to the naked eye of a human observer, more sophisticated machinery would be necessary to create perfect illusions in other electromagnetic bands, such as the infrared band. Sophisticated target-tracking software could ensure that the majority of computing power is focused on projecting false images in those directions where observers are most likely to be present, creating the most realistic illusion possible.
Creating a truly realistic optical illusion would likely require Phase Array Optics, which would project light of a specific amplitude and phase and therefore provide even greater levels of invisibility. We may end up finding optical camouflage to be most useful in the environment of space, where any given background is generally less complex than earthly backdrops and therefore easier to record, process, and project.


Active camouflage

Active camouflage is a group of camouflage technologies which allow an object to blend into its surroundings by use of panels or coatings capable of altering their appearance, color, luminance and reflective properties. Active camouflage has the potential to achieve perfect concealment from visual detection.Active camouflage differs from conventional means of concealment in two important ways. First, it makes the object appear not merely similar to its surroundings, but invisible through the use of perfect mimicry. Second, active camouflage changes the appearance of the object in real time. Ideally, active camouflage mimics nearby objects as well as objects as distant as the horizon. The effect should be similar to looking through a pane of glass, making the camouflaged object practically invisible.


Active camouflage has its origins in the diffused lighting camouflage first tested on Canadian Navy corvettes during World War II, and later in the armed forces of the United Kingdom and the United States of America.
Current systems began with a United States Air Force program which placed low-intensity blue lights on aircraft. As night skies are not pitch black, a 100 percent black-colored aircraft might be rendered visible. By emitting a small amount of blue light, the aircraft blends more effectively into the night sky.

Smart Fabrics


Definition
Based on the advances in computer technology, especially in the field of miniaturization, wireless technology and worldwide networking, the vision of wearable computers emerged. We already use a lot of portable electronic devices like cell phones, notebooks and organizers. The next step in mobile computing could be to create truly wearable computers that are integrated into our daily clothing and always serve as our personal assistant. This paper explores this from a textile point of view. Which new functions could textiles have? Is a combination of textiles and electronics possible? What sort of intelligent clothing can be realized? Necessary steps of textile research and examples of current developments are presented as well as future challenges.


Introduction
Today, the interaction of human individuals with electronic devices demands specific user skills. In future, improved user interfaces can largely alleviate this problem and push the exploitation of microelectronics considerably. In this context the concept of smart clothes promises greater user-friendliness, user empowerment, and more efficient services support. Wearable electronics responds to the acting individual in a more or less invisible way. It serves individual needs and thus makes life much easier. We believe that today, the cost level of important microelectronic functions is sufficiently low and enabling key technologies are mature enough to exploit this vision to the benefit of society. In the following, we present various technology components to enable the integration of electronics into textiles.


Electronic textiles (e-textiles) are fabrics that have electronics and interconnections woven into them. Components and interconnections are a part of the fabric and thus are much less visible and, more importantly, not susceptible to becoming tangled together or snagged by the surroundings. Consequently, e-textiles can be worn in everyday situations where currently available wearable computers would hinder the user. E-textiles also have greater flexibility in adapting to changes in the computational and sensing requirements of an application.


The number and location of sensor and processing elements can be dynamically tailored to the current needs of the user and application, rather than being fixed at design time. As the number of pocket electronic products (mobile phone, palm-top computer, personal hi-fi, etc.) is increasing, it makes sense to focus on wearable electronics, and start integrating today's products into our clothes. The merging of advanced electronics and special textiles has already begun. Wearable computers can now merge seamlessly into ordinary clothing. Using various conductive textiles, data and power distribution as well as sensing circuitry can be incorporated directly into wash-and-wear clothing.


Java Ring


Definition
A Java Ring is a finger ring that contains a small microprocessor with built-in capabilities for the user, a sort of smart card that is wearable on a finger. Sun Microsystem's Java Ring was introduced at their JavaOne Conference in 1998 and, instead of a gemstone, contained an inexpensive microprocessor in a stainless-steel iButton running a Java virtual machine and preloaded with applets (little application programs). The rings were built by Dallas Semiconductor.

Workstations at the conference had "ring readers" installed on them that downloaded information about the user from the conference registration system. This information was then used to enable a number of personalized services. For example, a robotic machine made coffee according to user preferences, which it downloaded when they snapped the ring into another "ring reader."

Although Java Rings aren't widely used yet, such rings or similar devices could have a number of real-world applications, such as starting your car and having all your vehicle's components (such as the seat, mirrors, and radio selections) automatically adjust to your preferences.

The Java Ring is an extremely secure Java-powered electronic token with a continuously running, unalterable real-time clock and rugged packaging, suitable for many applications. The jewel of the Java Ring is the Java iButton -- a one-million transistor, single chip trusted microcomputer with a powerful Java Virtual Machine (JVM) housed in a rugged and secure stainless-steel case. The Java Ring is a stainless-steel ring, 16-millimeters (0.6 inches) in diameter, that houses a 1-million-transistor processor, called an iButton. The ring has 134 KB of RAM, 32 KB of ROM, a real-time clock and a Java virtual machine, which is a piece of software that recognizes the Java language and translates it for the user's computer system.

The Ring, first introduced at JavaOne Conference, has been tested at Celebration School, an innovative K-12 school just outside Orlando, FL. The rings given to students are programmed with Java applets that communicate with host applications on networked systems. Applets are small applications that are designed to be run within another application. The Java Ring is snapped into a reader, called a Blue Dot receptor, to allow communication between a host system and the Java Ring.

Designed to be fully compatible with the Java Card 2.0 standard the processor features a high-speed 1024-bit modular exponentiator fro RSA encryption, large RAM and ROM memory capacity, and an unalterable real time clock. The packaged module has only a single electric contact and a ground return, conforming to the specifications of the Dallas Semiconductor 1-Wire bus. Lithium-backed non-volatile SRAM offers high read/write speed and unparallel tamper resistance through near-instantaneous clearing of all memory when tampering is detected, a feature known as rapid zeroization. Data integrity and clock function are maintained for more than 10 years. The 16-millimeter diameter stainless steel enclosure accomodates the larger chip sizes needed for up to 128 kilobytes of high-speed nonvolatile static RAM. The small and extremely rugged packaging of the module allows it to attach to the accessory of your choice to match individual lifestyles, such as key fob, wallet, watch, necklace, bracelet, or finger ring!!!!!


A Java Ring--and any related device that houses an iButton with a Java Virtual Machine--goes beyond a traditional smart card by providing real memory, more power, and a capacity for dynamic programming. On top of these features, the ring provides a rugged environment, wear-tested for 10-year durability. You can drop it on the floor, step on it, forget to take it off while swimming and the data remains safe inside. Today iButtons are primarily used for authentication and auditing types of applications. Since they can store data, have a clock for time-stamping, and support for encryption and authentication, they are ideal for audit trails



Internet Protocol Television (IPTV)


Definition
Over the last decade, the growth of satellite service, the rise of digital cable, and the birth of HDTV have all left their mark on the television landscape. Now, a new delivery method threatens to shake things up even more powerfully. Internet Protocol Television (IPTV) has arrived, and backed by the deep pockets of the telecommunications industry, it's poised to offer more interactivity and bring a hefty dose of competition to the business of selling TV.

IPTV describes a system capable of receiving and displaying a video stream encoded as a series of Internet Protocol packets. If you've ever watched a video clip on your computer, you've used an IPTV system in its broadest sense. When most people discuss IPTV, though, they're talking about watching traditional channels on your television, where people demand a smooth, high-resolution, lag-free picture, and it's the Telco's that are jumping headfirst into this market. Once known only as phone companies, the Telco's now want to turn a "triple play" of voice, data, and video that will retire the side and put them securely in the batter's box. In this primer, we'll explain how IPTV works and what the future holds for the technology. Though IP can (and will) be used to deliver video over all sorts of networks, including cable systems.
How It Works

First things first: the venerable set-top box, on its way out in the cable world, will make resurgence in IPTV systems. The box will connect to the home DSL line and is responsible for reassembling the packets into a coherent video stream and then decoding the contents. Your computer could do the same job, but most people still don't have an always-on PC sitting beside the TV, so the box will make a comeback. Where will the box pull its picture from? To answer that question, let's start at the source.

Most video enters the system at the Telco's national head end, where network feeds are pulled from satellites and encoded if necessary (often in MPEG-2, though H.264 and Windows Media are also possibilities). The video stream is broken up into IP packets and dumped into the Telco's core network, which is a massive IP network that handles all sorts of other traffic (data, voice, etc.) in addition to the video. Here the advantages of owning the entire network from stem to stern (as the Telco's do) really come into play, since quality of service (QoS) tools can prioritize the video traffic to prevent delay or fragmentation of the signal. Without control of the network, this would be dicey, since QoS requests are not often recognized between operators. With end-to-end control, the Telco's can guarantee enough bandwidth for their signal at all times, which is key to providing the "just works" reliability consumers have come to expect from their television sets.

The video streams are received by a local office, which has the job of getting them out to the folks on the couch. This office is the place that local content (such as TV stations, advertising, and video on demand) is added to the mix, but it's also the spot where the IPTV middleware is housed. This software stack handles user authentication, channel change requests, billing, VoD requests, etc.-basically, all of the boring but necessary infrastructure.

All the channels in the lineup are multicast from the national headend to local offices at the same time, but at the local office, a bottleneck becomes apparent. That bottleneck is the local DSL loop, which has nowhere near the capacity to stream all of the channels at once. Cable systems can do this, since their bandwidth can be in the neighborhood of 4.5Gbps, but even the newest ADSL2+ technology tops out at around 25Mbps (and this speed drops quickly as distance from the DSLAM [DSL Access Multiplier] grows).


FireWire


Definition
FireWire, originally developed by Apple Computer, Inc is a cross platform implementation of the high speed serial data bus -define by the IEEE 1394-1995 [FireWire 400],IEEE 1394a-2000 [FireWire 800] and IEEE 1394b standards-that move large amounts of data between computers and peripheral devices. Its features simplified cabling, hot swapping and transfer speeds of up to 800 megabits per second. FireWire is a high-speed serial input/output (I/O) technology for connecting peripheral devices to a computer or to each other. It is one of the fastest peripheral standards ever developed and now, at 800 megabits per second (Mbps), its even faster .

Based on Apple-developed technology, FireWire was adopted in 1995 as an official industry standard (IEEE 1394) for cross-platform peripheral connectivity. By providing a high-bandwidth, easy-to-use I/O technology, FireWire inspired a new generation of consumer electronics devices from many companies, including Canon, Epson, HP, Iomega, JVC, LaCie, Maxtor, Mitsubishi, Matsushita (Panasonic), Pioneer, Samsung, Sony and FireWire has also been a boon to professional users because of the high-speed connectivity it has brought to audio and video production systems.

In 2001, the Academy of Television Arts & Sciences presented Apple with an Emmy award in recognition of the contributions made by FireWire to the television industry. Now FireWire 800, the next generation of FireWire technology, promises to spur the development of more innovative high-performance devices and applications. This technology brief describes the advantages of FireWire 800 and some of the applications for which it is ideally suited.


TOPOLOGY
The 1394 protocol is a peer-to-peer network with a point-to-point signaling environment. Nodes on the bus may have several ports on them. Each of these ports acts as a repeater, retransmitting any packets received by other ports within the node. Figure 1 shows what a typical consumer may have attached to their 1394 bus. Because 1394 is a peer-to-peer protocol, a specific host isn't required, such as the PC in USB. In Figure 1, the digital camera could easily stream data to both the digital VCR and the DVD-RAM without any assistance from other devices on the bus
FireWire uses 64-bit fixed addressing, based on the IEEE 1212 standard. There are three parts to each packet of information sent by a device over FireWire:


" A 10-bit bus ID that is used to determine which FireWire bus the data came from
" A 6-bit physical ID that identifies which device on the bus sent the data
" A 48-bit storage area that is capable of addressing 256 terabytes of information for each node!


The bus ID and physical ID together comprise the 16-bit node ID, which allows for 64,000 nodes on a system. Individual FireWire cables can run as long as 4.5 meters. Data can be sent through up to 16 hops for a total maximum distance of 72 meters. Hops occur when devices are daisy-chained together. Look at the example below. The camcorder is connected to the external hard drive connected to Computer A. Computer A is connected to Computer B, which in turn is connected to Computer C. It takes four hops for Computer C to access camera.
The 1394 protocol supports both asynchronous and isochronous data transfers.


Isochronous transfers: Isochronous transfers are always broadcast in a one-to-one or one-to-many fashion. No error correction or retransmission is available for isochronous transfers. Up to 80% of the available bus bandwidth can be used for isochronous transfers.
Asynchronous transfers: Asynchronous transfers are targeted to a specific node with an explicit address. They are not guaranteed a specific amount of bandwidth on the bus, but they are guaranteed a fair shot at gaining access to the bus when asynchronous transfers are permitted. This allows error-checking and retransmission mechanisms to take place.

Night Vision Technology


Definition
Night vision is a spy or action movie you've seen, in which someone straps on a pair of night-vision goggles to find someone else in a dark building on a moonless night. With the proper night-vision equipment, you can see a person standing over 200 yards (183 m) away on a moonless, cloudy night. Night vision can work in two very different ways, depending on the technology used.

" Image enhancement - This works by collecting the tiny amounts of light, including the lower portion of the infrared light spectrum, that are present but may be imperceptible to our eyes, and amplifying it to the point that we can easily observe the image.
" Thermal imaging - This technology operates by capturing the upper portion of the infrared light spectrum, which is emitted as heat by objects instead of simply reflected as light. Hotter objects, such as warm bodies, emit more of this light than cooler objects like trees or buildings.


To study about night vision technology we should first know about ligt.
The amount of energy in a light wave is related to its wavelength: Shorter wavelengths have higher energy. Of visible light, violet has the most energy, and red has the least. Just next to the visible light spectrum is the infrared spectrum.
Night vision technology consists of two major types: light amplification (or intensification) and thermal (infrared).
Most consumer night vision products are light amplifying devices. All ITT Night Vision products use light-amplifying technology.

This technology takes the small amount of light that's in the surrounding area (such as moonlight or starlight), and converts the light energy (scientists call it photons) into electrical energy (electrons).
These electrons pass through a thin disk that's about the size of a quarter and contains more than 10 million channels. As the electrons go through the channels, they strike the channel walls and thousands more electrons are released. These multiplied electrons then bounce off of a phosphor screen which converts the electrons back into photons and lets you see an impressive nighttime view even when it's really dark.


In night vision, thermal imaging takes advantage of this infrared emission.

Thermal imaging works as
1. A special lens focuses the infrared light emitted by all of the objects in view.
2. The focused light is scanned by a phased array of infrared-detector elements. The detector elements create a very detailed temperature pattern called a thermogram. It only takes about one-thirtieth of a second for the detector array to obtain the temperature information to make the thermogram. This information is obtained from several thousand points in the field of view of the detector array.
3. The thermogram created by the detector elements is translated into electric impulses.
4. The impulses are sent to a signal-processing unit, a circuit board with a dedicated chip that translates the information from the elements into data for the display.
5. The signal-processing unit sends the information to the display, where it appears as various colors depending on the intensity of the infrared emission. The combination of all the impulses from all of the elements creates the image.

Types Of Thermal Imaging Devices

Most thermal-imaging devices scan at a rate of 30 times per second. They can sense temperatures ranging from -4 degrees Fahrenheit (-20 degrees Celsius) to 3,600 F (2,000 C), and can normally detect changes in temperature of about 0.4 F (0.2 C).
RD RAM


Definition
During the last two decades, there has been an exponential growth in the operational speed of microprocessors. Also RAM capacities have been improving at more than fifty percent per year. However the speed and access time of the memory have been improving at slower rate. In order to keep up in performance and reliability with processor technology it is necessary to make considerable improvements in the memory access time.

The Rambus founders emerged with a memory technology-RD RAM. RDRAM memory provides the highest bandwidth -2.1GB/sec. per pin- from the fewest pins at five-times the speed of industry available DRAM. The RDRAM memory channel achieves its high-speed operation through several innovative techniques including separate control and address buses, highly efficient protocol, low voltage signaling, and precise clocking to minimize skew between clock and data lines. A single RDRAM device is capable of transferring data at 1066Mb/sec. per-pin to Rambus-compatible ICs. Data rate per-pin will increase beyond 1066Mb/sec per pin in the future.

Implementation Of Zoom FFT in Ultrasonic Blood Flow Analysis


An adequate blood flow supply is necessary for all organs of the body. Analysis of the blood flow finds its importance in the diagnoses of diseases. There are many techniques for analyzing the blood flow. These techniques are not affordable by the poor people because of their high expense. So we have implemented a technique called Zoom-FFT. This technique is simple and affordable to detect the blood clots and other diseases.


Human with his potential tries to get whichever is unexplored, explored, and till now we are managing and succeeding using some technical ways. In the same way this is one of the explorations made for scanning the intra details of some specific objects using ultrasound named SONOGRAPHY, which is used as an alternative to x-ray photography. In this paper, the method to zoom the image or the scanned data-using zoom FFT has been discussed. It also explains the algorithm to get ZOOM FFT and how it can be obtained via simulation. Real time experimentation and its applications, with basics of ultrasound scanning are also explained. Here a specific application will be dealt i.e., ultrasonic blood flow analyzer using ZOOM FFT.


Blood flow analysis is done by passing a high frequency ultrasonic wave in the blood vessels through a transducer (transmitter) .The reflected signal; from the receiver transducer has a different frequency due to the Doppler principle. This signal is passed to a DSP processor to find the frequency spectrum. Because of the high frequency of the ultrasonic wave, the resolution of the frequency spectrum output will not be good. Therefore we go for advanced Zoom FFT technique, wherein a very small frequency change due to the clot formation can be obtained with a good resolution. It can be used to locate the initial presence of a blood clot. All of these tasks must be achieved with a single DSP chip in order for the system to be both cost-effective and power
efficient and thus widely accepted.


This paper proposes:
1.Study of Bio-medical signal processing
2.Mixing down the input signal to the base band frequency using Hilbert Transform
3. Finding the down sampling using the decimation process
4.Obtaining the spectrum output using fast Fourier transform
5.Simulation is done by Matlab/C.
6.TMS320C5X/6X DSP processor does real time implementation.

Steps involved:
" Sound generation: The ultrasonic sound is generated using the piezoelectric transducer
" Number of transducer may vary from 1 to many.
" Narrow beam of wave is to be feed in.
" Continuous mode of operation with no timed switching is applied in real time to measure Frequency and Amplitude
" Doppler shift analysis for frequency content is to be done.
" Creation of image - to plot in 2 Dimension.
" Display using color differentiation.


REAL BLOOD FLOW ANALYSIS:
In an Ultrasonic blood flow analysis, a beam of ultrasonic energy is directed through a blood vessel at a shallow angle and its transit time is then measured.. More common are the ultrasonic analyzers based on the Doppler principle. An oscillator, operating at a frequency of several Mega Hertz, excites a piezoelectric transducer. This transducer is coupled to the wall of an exposed blood vessel and sends an ultrasonic beam with a frequency F into the flowing blood. A small part of the transmitted energy is scattered back and is received by a second transducer arranged opposite the first one.


Military Radars


RADAR (Radio Detection and Ranging) is basically a means of gathering information about distant objects by transmitting electromagnetic waves at them and analyzing the echoes. Radar has been employed on the ground, in air, on the sea and in space. Radar finds a number of applications such as in airport traffic control, military purposes, coastal navigation, meteorology and mapping etc.

The development of the radar technology took place during the World War II in which it was used for detecting the approaching aircraft and then later for many other purposes which finally led to the development of advanced military radars being used these days. Military radars have a highly specialized design to be highly mobile and easily transportable, by air as well as ground.


INTRODUCTION
Military radar should be an early warning, altering along with weapon control functions. It is specially designed to be highly mobile and should be such that it can be deployed within minutes.


Military radar minimizes mutual interference of tasks of both air defenders and friendly air space users. This will result in an increased effectiveness of the combined combat operations. The command and control capabilities of the radar in combination with an effective ground based air defence provide maximum operational effectiveness with a safe, efficient and flexible use of the air space. The increased operational effectiveness is obtained by combining the advantages of centralized air defence management with decentralized air defence control.

ADVANCED FEATURES AND BENEFITS
Typical military radar has the following advanced features and benefits: -


¢ All-weather day and night capability.
¢ Multiple target handling and engagement capability.
¢ Short and fast reaction time between target detection and ready to fire moment.
¢ Easy to operate and hence low manning requirements and stress reduction under severe conditions.
¢ Highly mobile system, to be used in all kind of terrain
¢ Flexible weapon integration, and unlimited number of single air defence weapons can be provided with target data.
¢ High resolution, which gives excellent target discrimination and accurate tracking.


The identification of the targets as friend or hostile is supported by IFF, which is an integral part of the system.
During the short time when the targets are exposed accurate data must be obtained. A high antenna rotational speed assures early target detection and a high data update rate required for track accuracy.


The radar can use linear (horizontal) polarization in clear weather. During rains, to improve the suppression of rain clutter, provision exists to change to circular polarization at the touch of the button from the display console.


Military Radars


RADAR (Radio Detection and Ranging) is basically a means of gathering information about distant objects by transmitting electromagnetic waves at them and analyzing the echoes. Radar has been employed on the ground, in air, on the sea and in space. Radar finds a number of applications such as in airport traffic control, military purposes, coastal navigation, meteorology and mapping etc.

The development of the radar technology took place during the World War II in which it was used for detecting the approaching aircraft and then later for many other purposes which finally led to the development of advanced military radars being used these days. Military radars have a highly specialized design to be highly mobile and easily transportable, by air as well as ground.


INTRODUCTION
Military radar should be an early warning, altering along with weapon control functions. It is specially designed to be highly mobile and should be such that it can be deployed within minutes.


Military radar minimizes mutual interference of tasks of both air defenders and friendly air space users. This will result in an increased effectiveness of the combined combat operations. The command and control capabilities of the radar in combination with an effective ground based air defence provide maximum operational effectiveness with a safe, efficient and flexible use of the air space. The increased operational effectiveness is obtained by combining the advantages of centralized air defence management with decentralized air defence control.

ADVANCED FEATURES AND BENEFITS
Typical military radar has the following advanced features and benefits: -


¢ All-weather day and night capability.
¢ Multiple target handling and engagement capability.
¢ Short and fast reaction time between target detection and ready to fire moment.
¢ Easy to operate and hence low manning requirements and stress reduction under severe conditions.
¢ Highly mobile system, to be used in all kind of terrain
¢ Flexible weapon integration, and unlimited number of single air defence weapons can be provided with target data.
¢ High resolution, which gives excellent target discrimination and accurate tracking.


The identification of the targets as friend or hostile is supported by IFF, which is an integral part of the system.
During the short time when the targets are exposed accurate data must be obtained. A high antenna rotational speed assures early target detection and a high data update rate required for track accuracy.


The radar can use linear (horizontal) polarization in clear weather. During rains, to improve the suppression of rain clutter, provision exists to change to circular polarization at the touch of the button from the display console.


Modern Irrigation System Towards Fuzzy


In the past few years, there has been an increasing interest in the application of the fuzzy set theory to many control problems. For many complex control systems, the construction of an ordinary model is difficult due to nonlinear and time varying nature of the system. Fuzzy Control has been applied in traditional control systems, which yields promising results, It is applied for the processes, which yields promising results, it is applied for the processes, which are too complex to be analyzed by conventional techniques or where the available information is uncertain. In fact, fuzzy logic controller (FLC) is easier to prototype, simple to describe and verify, can be maintained and also extended with grater accuracy in less time. These advantages make fuzzy logic technology to be used for irrigation system also.


NEED FOR MODERN IRRIGATION SYSTEM
Water and electricity should be optimally utilized in an agricultural like India. The development in the filed of science and technology should be appropriately used in the field of agriculture for better yields. Irrigation has traditionally resulted in excessive labour and nonuniformity in water application across the filed. Hence, an automatic irrigation system is required to reduce the labour cost and to give uniformity in water application across the field.


PHYSIOLOGICAL PROCESSING
In the irrigation system, plant take-varying quantities of water at different stages of plant growth. Unless adequate and timely supply of water is assured, the physiological activities taking place within the plant are bound to be adversely affected, thereby resulting in reduced yield of crop. The amount of water to be irrigated in an irrigation schedule depends upon the evapotranspiration(ET) from adjacent soil and from plant leaves at that specified time. The rate of ET of a given crop is influenced by its growth stages, environmental conditions and crop management. The consumptive use or evapotranspiration for a given crop at a given place may vary through out the day, through out the month and through out the crop period. Values of daily consumptive use or monthly consumptive use are determined for a given crop and at a given place. It also varies from crop to crop. There are several elimatological factors, which will influence and decide the rate of evaporation. Some of the important factors of elimate influencing the evaporation are radiation, temperature, humidity and wind speed. In this work, the input variables chosen for the system are evapotranspiration and rate of change of evapotranspiration called as error and the output variable is water amount.

FUZZIFICATION UNIT
It converts a crisp process state into a fuzzy state so that it is compatible with the fuzzy set representation of the process required by the inference unit.


KNOWLEDGE BASE
The Knowledge base consists of two components. A rule base, which describes the behaviour of control surfaces, which involves writing the rules that tie the input values to the output model properties. Rule formation can be framed by discussing with the experts. A database contains the definition of the fuzzy sets representing the linguistic terms used in the rules. The knowledge base is generally represented by a fuzzy associative memory.


INFERENCE UNIT
This unit is the core of the fuzzy controller. It generates fuzzy control actions applying the rules in the knowledge base to the current process state. It determines the degree to which each measured valued is a member of a given labeled group. A given measurement can be classified simultaneously as belonging to several linguistic groups. The degree of fulfillment (DOF) of each rule is determined by applying the rules of Boolean algebra to each linguistic group that is part of the rule. This is done for all the rules in the system. Finally the net control action is determined by weighting action associated with each rule by degree of fulfillment.

Smart Cameras in Embedded Systems


A smart camera performs real-time analysis to recognize scenic elements. Smart cameras are useful in a variety of scenarios: surveillance, medicine, etc.We have built a real-time system for recognizing gestures. Our smart camera uses novel algorithms to recognize gestures based on low-level analysis of body parts as well as hidden Markov models for the moves that comprise the gestures. These algorithms run on a Trimedia processor. Our system can recognize gestures at the rate of 20 frames/second. The camera can also fuse the results of multiple cameras

Overview
Recent technological advances are enabling a new generation of smart cameras that represent a quantum leap in sophistication. While today's digital cameras capture images, smart cameras capture high-level descriptions of the scene and analyze what they see. These devices could support a wide variety of applications including human and animal detection, surveillance, motion analysis, and facial identification.

Video processing has an insatiable demand for real-time performance. Fortunately, Moore's law provides an increasing pool of available computing power to apply to real-time analysis. Smart cameras leverage very large-scale integration (VLSI) to provide such analysis in a low-cost, low-power system with substantial memory. Moving well beyond pixel processing and compression, these systems run a wide range of algorithms to extract meaning from streaming video.

Because they push the design space in so many dimensions, smart cameras are a leading-edge application for embedded system research.


Detection and Recognition Algorithms
Although there are many approaches to real-time video analysis, we chose to focus initially on human gesture recognition-identifying whether a subject is walking, standing, waving his arms, and so on. Because much work remains to be done on this problem, we sought to design an embedded system that can incorporate future algorithms as well as use those we created exclusively for this application.

Our algorithms use both low-level and high-level processing. The low-level component identifies different body parts and categorizes their movement in simple terms. The high-level component, which is application-dependent, uses this information to recognize each body part's action and the person's overall activity based on scenario parameters.

Low-level processing
The system captures images from the video input, which can be either uncompressed or compressed (MPEG and motion JPEG), and applies four different algorithms to detect and identify human body parts.

Region extraction: The first algorithm transforms the pixels of an image into an M ¥ N bitmap and eliminates the background. It then detects the body part's skin area using a YUV color model with chrominance values down sampled
Nextthe algorithm hierarchically segments the frame into skin-tone and non-skin-tone regions by extracting foreground regions adjacent to detected skin areas and combining these segments in a meaningful way.


Contour following: The next step in the process involves linking the separate groups of pixels into contours that geometrically define the regions. This algorithm uses a 3 ¥ 3 filter to follow the edge of the component in any of eight different directions.


Ellipse fitting: To correct for deformations in image processing caused by clothing, objects in the frame, or some body parts blocking others, an algorithm fits ellipses to the pixel regions to provide simplified part attributes. The algorithm uses these parametric surface approximations to compute geometric descriptors for segments such as area, compactness (circularity), weak perspective invariants, and spatial
relationships.


Graph matching: Each extracted region modeled with ellipses corresponds to a node in a graphical representation of the human body. A piecewise quadratic Bayesian classifier uses the ellipses parameters to compute feature vectors consisting of binary and unary attributes. It then matches these attributes to feature vectors of body parts or meaningful combinations of parts that are computed offline. To expedite the branching process, the algorithm begins with the face, which is generally easiest to detect.



Spin Valve Transistor


In a world of ubiquitous presence of electrons can you imagine any other field displacing it? It may seem peculiar, even absurd, but with the advent of spintronics it is turning into reality.

In our conventional electronic devices we use semi conducting materials for logical operation and magnetic materials for storage, but spintronics uses magnetic materials for both purposes. These spintronic devices are more versatile and faster than the present one. One such device is spin valve transistor.

Spin valve transistor is different from conventional transistor. In this for conduction we use spin polarization of electrons. Only electrons with correct spin polarization can travel successfully through the device. These transistors are used in data storage, signal processing, automation and robotics with less power consumption and results in less heat. This also finds its application in Quantum computing, in which we use Qubits instead of bits.


INTRODUCTION

Two experiments in 1920's suggested spin as an additional property of the electron. One was the closely spaced splitting of Hydrogen spectralines, called fine structure. The other was Stern -Gerlach experiment, which in 1922 that a beam of silver atoms directed through an inhomogeneous magnetic field would be forced in to two beams. These pointed towards magnetism associated with the electrons.

Spin is the root cause of magnetism that makes an electron tiny magnet. Magnetism is already been exploited in recording devices. Where data is recorded and stored as tiny areas of magnetized iron or chromium oxide. To access that information the head detects the minute changes in magnetic field. This induces corresponding changes in the head's electrical resistance - a phenomenon called Magneto Resistance.


EVOLUTION OF SPINTRONICS:

Spintronics came into light by the advent of Giant Magneto Resistance (GMR) in 1988. GMR is 200 times stronger than ordinary Magneto Resistance. It results from subtle electron - spin effects in ultra multilayers of magnetic materials that cause a huge change in electrical resistance.

The discovery of Spin Valve Transistor (GMR in magnetic multilayers) has let to a large number of studies on GMR systems. Usually resistance of multilayer is measured with the Current in Plane (CIP). For instance, Read back magnetic heads uses this property. But this suffers from several drawbacks such as; shunting and channeling, particularly for uncoupled multilayers and for thick spaced layers diminish the CIP magneto resistance. Diffusive surface scattering reduces the magneto resistance for sandwiches and thin multilayers.
In spin valve transistor (SVT) electrons are injected in to metallic base across a Schottky barrier (Emitter side) pass through the spin valve and reach the opposite side (Collector side) of transistor. When these injected electrons traverse the metallic base electrons are above Fermi level, hence hot electron magneto transport should be considered in Spin Valve Transistor (SVT).

The transport properties of hot electrons are different from Fermi electrons .For example spin polarisation of Fermi electrons mainly depends on Density Of States (DOS) at Fermi level, while the spin polarisation of hot electron is related to the density of unoccupied states above the fermi level.

For the preparations of transistor we apply direct bonding, both to obtain device quality semiconductor material for the emitter and to allow room temperature processes.The starting material for both emitter and collector is a 380um, 5-10Ocm, n-si (100) wafer. After back side n++ implantation ,wafer is dry oxidised to anneal the implant and to form a SIO2 layer .After depositing a Pt ohmic contact on to the back side, wafer is sawn in to 10X10mm collector and 1.6X1.6mm emitters. Collector is subsequently dipped in HNO3, 2% HF to remove the native oxide on silicon fragments,5% Tetra methyl Ammonium Hydroxide at 90°, and buffered HF to remove thermal oxide .following each step the collector is rinsed in demineralised water.




Moletronics- an invisible technology


As a scientific pursuit, the search for a viable successor to silicon computer technology has garnered considerable curiosity in the last decade. The latest idea, and one of the most intriguing, is known as molecular computers, or moletronics, in which single molecules serve as switches, "quantum wires" a few atoms thick serve as wiring, and the hardware is synthesized chemically from the bottom up.


The central thesis of moletronics is that almost any chemically stable structure that is not specifically disallowed by the laws of physics can in fact be built. The possibility of building things atom by atom was first introduced by Richard Feynman in 1959.


An "assembler", which is little more than a submicroscopic robotic arm can be built and be controlled. We can use it to secure and position compounds in order to direct the precise location at which chemical reactions occur. This general approach allows the construction of large, atomically precise objects by initiating a sequence of controlled chemical reactions. In order for this to function as we wish, each assembler requires a process for receiving and executing the instruction set that will dictate its actions. In time, molecular machines might even have onboard, high speed RAM and slower but more permanent storage. They would have communications capability and power supply.

Moletronics is expected to touch almost every aspect of our lives, right down to the water we drink and the air we breathe. Experimental work has already resulted in the production of molecular tweezers, a carbon nanotube transistor, and logic gates. Theoretical work is progressing as well. James M. Tour of Rice University is working on the construction of a molecular computer. Researchers at Zyvex have proposed an Exponential Assembly Process that might improve the creation of assemblers and products, before they are even simulated in the lab. We have even seen researchers create an artificial muscle using nanotubes, which may have medical applications in the nearer term.


Teramac computer has the capacity to perform 1012 operations in one seconds but it has 220,000 hardware defects and still has performed some tasks 100 times faster than single-processor .The defect-tolerant computer architecture and its implications for moletronics is the latest in this technology. So the very fact that this machine worked suggested that we ought to take some time and learn about it.
Such a 'defect-tolerant' architecture through moletronics could bridge the gap between the current generation of microchips and the next generation of molecular-scale computers.


Moletronic circuit--QCA basics
The interaction between cells is Coulombic, and provides the necessary computing power. No current flows between cells and no power or information is delivered to individual internal cells. Local interconnections between cells are provided by the physics of cell-cell interaction. The links below describes the QCA cell and the process of building up useful computational elements from it. The discussion is mostly qualitative and based on the intuitively clear behavior of electrons in the cell.


Fundamental Aspects of QCA
A QCA cell consists of 4 quantum dots positioned at the vertices of a square and contains 2 extra electrons. The configuration of these electrons is used to encode binary information. The 2 electrons sitting on diagonal sites of the square from left to right and right to left are used to represent the binary "1" and "0" states respectively. For an isolated cell these 2 states will have the same energy. However for an array of cells, the state of each cell is determined by its interaction with neighboring cells through the Coulomb interaction.



Solar Power Satellites


The new millennium has introduced increased pressure for finding new renewable energy sources. The exponential increase in population has led to the global crisis such as global warming, environmental pollution and change and rapid decrease of fossil reservoirs. Also the demand of electric power increases at a much higher pace than other energy demands as the world is industrialized and computerized. Under these circumstances, research has been carried out to look into the possibility of building a power station in space to transmit electricity to Earth by way of radio waves-the Solar Power Satellites. Solar Power Satellites(SPS) converts solar energy in to micro waves and sends that microwaves in to a beam to a receiving antenna on the Earth for conversion to ordinary electricity.

SPS is a clean, large-scale, stable electric power source. Solar Power Satellites is known by a variety of other names such as Satellite Power System, Space Power Station, Space Power System, Solar Power Station, Space Solar Power Station etc. One of the key technologies needed to enable the future feasibility of SPS is that of Microwave Wireless Power Transmission.WPT is based on the energy transfer capacity of microwave beam i.e, energy can be transmitted by a well focused microwave beam. Advances in Phased array antennas and rectennas have provided the building blocks for a realizable WPT system.

Increasing global energy demand is likely to continue for many decades. Renewable energy is a compelling approach - both philosophically and in engineering terms. However, many renewable energy sources are limited in their ability to affordably provide the base load power required for global industrial development and prosperity, because of inherent land and water requirements. The burning of fossil fuels resulted in an abrupt decrease in their .it also led to the green house effect and many other environmental problems. Nuclear power seems to be an answer for global warming, but concerns about terrorist attacks on Earth bound nuclear power plants have intensified environmentalist opposition to nuclear power.

Moreover, switching on to the natural fission reactor, the sun, yields energy with no waste products. Earth based solar panels receives only a part of the solar energy. It will be affected by the day & night effect and other factors such as clouds. So it is desirable to place the solar panel in the space itself, where, the solar energy is collected and converted in to electricity which is then converted to a highly directed microwave beam for transmission. This microwave beam, which can be directed to any desired location on Earth surface, can be collected and then converted back to electricity. This concept is more advantageous than conventional methods. Also the microwave energy, chosen for transmission, can pass unimpeded through clouds and precipitations.


SPS- THE BACKGROUND
The concept of a large SPS that would be placed in geostationary orbit was invented by Peter Glaser in 1968. The SPS concept was examined extensively during the late 1970s by the U.S Department of Energy (DOE) and the National Aeronautics and Space Administration (NASA). The DOE-NASA put forward the SPS Reference System Concept in 1979. The central feature of this concept was the creation of a large scale power infrastructure in space, consisting of about 60 SPS, delivering a total of about 300GW.But, as a result of the huge price tag, lack of evolutionary concept and the subsiding energy crisis in 1980-1981, all U.S SPS efforts were terminated with a view to re-asses the concept after about ten years. During this time international interest in SPS emerged which led to WPT experiments in Japan.




MIMO Wireless Channels: Capacity and Performance Prediction


Multiple-input multiple-output (MIMO) communication techniques make use of multi-element antenna arrays at both the TX and the RX side of a radio link and have been shown theoretically to drastically improve the capacity over more traditional single-input multiple output (SIMO) systems [2, 3, 5, 7]. SIMO channels in wireless networks can provide diversity gain, array gain, and interference canceling gain among other benets. In addition to these same advantages, MIMO links can offer a multiplexing gain by opening Nmin parallel spatial channels, where Nmin is the minimum of the number of TX and RX antennas. Under certain propagation conditions capacity gains proportional to Nmin can be achieved [8]. Space-time coding [14] and spatial multiplexing [1, 2, 7, 16] (a.k.a. \BLAST") are popular signal processing techniques making use of MIMO channels to improve the performance of wireless networks.

Previous work and open problems. The literature on realistic MIMO channel models is still scarce. For the line-of-sight (LOS) case, previous work includes [13]. In the fading case, previous studies have mostly been conned to i.i.d. Gaussian matrices, an idealistic assumptions in which the entries of channel matrix are independent complex Gaussian random variables [2, 6, 8]. The influence of spatial fading correlation on either the TX or the RX side of a wireless MIMO radio link has been addressed in [3, 15]. In practice, however, the realization of high MIMO capacity is sensitive not only to the fading correlation between individual antennas but also to the rank behavior of the channel. In the existing literature, high rank behavior has been loosely linked to the existence of a dense scattering environment. Recent successful demonstrations of MIMO technologies in indoor-to-indoor channels, where rich scattering is almost always guaranteed.


Here we suggest a simple classification of MIMO channel and devise a MIMO channel model whose generality encompasses some important practical cases. Unlike the channel model used in [3, 15], our model suggests that the impact of spatial fading correlation and channel rank are decoupled although not fully independent, which allows for example to describe MIMO channels with uncorrelated spatial fading at the transmitter and the receiver
but reduced channel rank (and hence low capacity). This situation typically occurs when the distance between transmitter and receiver is large. Furthermore,our model allows description of MIMO channels with scattering at both the transmitter and the receiver.

We use the new model to describe the capacity behavior as a function of the wavelength, the scattering radii at the transmitter and the receiver, the distance between TX and RX arrays, antenna beamwidths, and antenna spacing. Our model suggests that full MIMO capacity gain can be achieved for very realistic values of scattering radii, antenna spacing and range. It shows, in contrast to usual intuition, that large antenna spacing has only limited impact on capacity under fairly general conditions. Another case described by the model is the "pin-hole" channel where spatial fading is uncorrelated and yet the channel has low rank and hence low capacity.We show that this situation typically occurs for very large distances between transmitter and receiver. In the 1 * 1 case (i.e. one TX and one RX antenna), the pinhole channel yields capacities worse than the traditional Rayleigh fading channel. Our results are validated by comparing with a ray tracing-based channel simulation. We find a good match between the two models over a wide range of situations.

Fractal Robots


Definition
In order to respond to rapidly changing environment and market, it is imperative to have such capabilities as flexibility, adaptability, reusability, etc. for the manufacturing system. The fractal manufacturing system is one of the new manufacturing paradigms for this purpose. A basic component of fractal manufacturing system, called a basic fractal unit (BFU), consists of five functional modules such as an observer, an analyzer, an organizer, a resolver, and a reporter. Each module autonomously cooperates and negotiates with others while processing its jobs by using the agent technology. The resulting architecture has a high degree of self-similarity, one of the main characteristics of the fractal. What this actually means in this case is something that when you look at a part of it, it is similar to the whole object.

Some of the fractal specific characteristics are:
Self-similarity
Self-organization
Goal-orientation

FRACTAL ROBOTS

Fractal Robot is a science that promises to revolutionize technology in a way that has never been witnessed before. Fractal Robots are objects made from cubic bricks that can be controlled by a computer to change shape and to reconfigure themselves into objects of different shapes. These cubic motorized bricks can be programmed to move and shuffle themselves to change shape to make objects like a house potentially in few seconds. It is exactly like kids playing with Lego bricks and making a toy house or a toy bridge by snapping together Lego bricks, except that here we are using a computer.

This technology has the potential to penetrate every field of human work like construction, medicine, research and others. Fractal robots can enable buildings to build within a day, help perform sensitive medical operations and can assist in laboratory experiments. Also, Fractal Robots have built-in self repair which means they continue to work without human intervention. Also, this technology brings down the manufacturing price down dramatically.

A Fractal Robot resembles itself, i.e. wherever you look at, any part of its body will be similar to the whole object. The robot can be animated around its joints in a uniform manner. Such robots can be straight forward geometric patterns/images that look more like natural structures such as plants. This patented product however has a cubical structure.A fractal cube can be of any size. The smallest expected size is between 1000 and 10,000 atoms wide. These cubes are embedded with computer chips that control their movement.

FRACTAL ROBOT MECHANISM

SIMPLE CONSTRUCTION DETAILS

Considerable effort has been spent in making the robotic cube as simple as possible after the invention had been conceived. The design is such that it has the fewest possible moving parts so that they can be mass produced. Materials requirements have been made as flexible as possible so that they can be built from metals and plastics which are cheaply available in industrial nations but also from ceramics and clays which are environmentally friendlier and more readily available in developing nations.

The cube therefore is hollow and the plates have all the mechanisms. Each of these face plates have electrical contact pads that allow power and data signals to be routed from one robotic cube to another. They also have 45 degree petals that push out of the surface to engage the neighboring face that allows one robotic cube to lock to its neighbors.
The contact pads are arranged symmetrically around four edges to allow for rotational symmetry .

Stereoscopic Imaging


Definition
A stereoscopic motion or still picture in which the right component of a composite image usually red in color is superposed on the left component in a contrasting color to produce a three-dimensional effect when viewed through correspondingly colored filters in the form of spectacles. The modes of 3D presentation you are most familiar with are the paper glasses with red and blue lenses. The technology behind 3D, or stereoscopic, movies is actually pretty simple. They simply recreate the way humans see normally.


Since your eyes are about two inches apart, they see the same picture from slightly different angles. Your brain then correlates these two images in order to gauge distance. This is called binocular vision - ViewMasters™ and binoculars mimic this process by presenting each eye with a slightly different image. Now you're learning! Need to know more about how do 3D glasses work? Read on. The binocular vision system relies on the fact that our two eyes are spaced about 2 inches (5 centimeters) apart. Therefore, each eye sees the world from a slightly different perspective, and the binocular vision system in your brain uses the difference to calculate distance. Your brain has the ability to correlate the images it sees in its two eyes even though they are slightly different. If you've ever used a ViewMaster™ or a stereoscopic viewer, you have seen yourbinocular vision system in action. In a View-Master, each eye is presented with an image. Two cameras photograph the same image from slightly different positions to create these images. Your eyes can correlate these images automatically because each eye sees only one of the images.


A 3D film viewed without glasses is a very strange sight and may appear to be out of focus, fuzzy or out of register. The same scene is projected simultaneously from two different angles in two different colors, red and cyan (or blue or green). Here's where those cool glasses come in -- the colored filters separate the two different images so each image only enters one eye. Your brain puts the two pictures back together and now you're dodging a flying meteor!
3D glasses make the movie or television show you're watching look like a 3-D scene that's happening right in front of you. With objects flying off the screen and careening in your direction, and creepy characters reaching out to grab you, wearing 3-D glasses makes you feel like you're a part of the action - not just someone sitting there watching a movie. Considering they have such high entertainment value, you'll be surprised at how amazingly simple 3-D glasses are.


The binocular vision system relies on the fact that our two eyes are spaced about 2 inches (5 centimeters) apart. Therefore, each eye sees the world from a slightly different perspective, and the binocular vision system in your brain uses the difference to calculate distance. Your brain has the ability to correlate the images it sees in its two eyes even though they are slightly different.
If you've ever used a View-Master or a stereoscopic viewer, you have seen your binocular vision system in action. In a View-Master, each eye is presented with an image. Two cameras photograph the same image from slightly different positions to create these images. Your eyes can correlate these images automatically because each eye sees only one of the images.


The reason why you wear 3-D glasses in a movie theater is to feed different images into your eyes just like a View-Master does. The screen actually displays two images, and the glasses cause one of the images to enter one eye and the other to enter the other eye. There are two common systems for doing this:


Although the red/green or red/blue system is now mainly used for television 3-D effects, and was used in many older 3-D movies. In this system, two images are displayed on the screen, one in red and the other in blue (or green). The filters on the glasses allow only one image to enter each eye, and your brain does the rest. You cannot really have a color movie when you are using color to provide the separation, so the image quality is not nearly as good as with the polarized system.

Ultra-Wideband


Definition
UWB is a wireless technology that transmits binary data-the 0s and 1s that are the digital building blocks of modern information systems. It uses low-energy and extremely short duration (in the order of pico seconds) impulses or bursts of RF (radio frequency) energy over a wide spectrum of frequencies, to transmit data over short to medium distances, say about 15-100 m. It doesn't use carrier wave to transmit data.

UWB is fundamentally different from existing radio frequency technology. For radios today, picture a guy watering his lawn with a garden hose and moving the hose up and down in a smooth vertical motion. You can see a continuous stream of water in an undulating wave. Nearly all radios, cell phones, wireless LANs and so on are like that: a continuous signal that's overlaid with information by using one of several modulation techniques.

Now picture the same guy watering his lawn with a swiveling sprinkler that shoots many, fast, short pulses of water. That's typically what UWB is like: millions of very short, very fast, precisely timed bursts or pulses of energy, measured in nanoseconds and covering a very wide area. By varying the pulse timing according to a complex code, a pulse can represent either a zero or a one: the basis of digital communications.

Wireless technologies such as 802.11b and short-range Bluetooth radios eventually could be replaced by UWB products that would have a throughput capacity 1,000 times greater than 802.11b (11M bit/sec). Those numbers mean UWB systems have the potential to support many more users, at much higher speeds and lower costs, than current wireless LAN systems. Current UWB devices can transmit data up to 100 Mbps, compared to the 1 Mbps of Bluetooth and the 11 Mbps of 802.11b. Best of all, it costs a fraction of current technologies like Blue-tooth, WLANs and Wi-Fi.


The concepts of communication and computation are so close that their tight connection is obvious even for PR departments of major IT companies. Quite often it makes no sense to separate these concepts. Today, speaking about growing power of computing devices we imply both growing performance of their processors and growing throughput of their communication channels. The communication channels include internal:


" caches
" system buses
" memory interfaces
" interfaces of storage devices
...and external:
" interfaces of peripherals
" wireless network channels
" wired network channels
structures of data transfer.

External wired communication channels are developing mainly in two directions - cost reduction and increase of availability of optical channels (top-down) and growth of throughput (bottum-up). However, the two physical carriers are not so close yet (first of all, in prices) to be involved in direct competition - in 90% of cases a character of a problem to be solved determines the technology to be preferred.

Internal wired channels are switching over from specialized parallel interfaces to high-level serial packet interface (Serial ATA, 3GIO/PCI Express, Hyper Transport). It fosters a convergence of external and internal communication technologies: in future separate components of a computer case will be combined into a normal network. It's quite a logical solution - a modern chipset, thus, works as a network switch equipped with multiple interfaces such as a DDR memory bus or a processor bus and AGP/PCI.


Universal Asynchronous Receiver Transmitter


Introduction

The Universal Asynchronous Receiver Transmitter (UART) is the most widely used serial data communication circuit ever. UARTs allow full duplex communication over serial communication links as RS232. UARTs are available as inexpensive standard products from many semiconductor suppliers, making it unlikely that this specific design is useful by itself.

The basic functions of a UART are a microprocessor interface, double buffering of transmitter data, frame generation, parity generation, parallel to serial conversion, double buffering of receiver data, parity checking, serial to parallel conversion. The data is transmitted asynchronously one bit at a time and there is no clock line.
The frame format of used by UARTs is a low start bit, 5-8 data bits, optional parity bit, and 1 or 2 stop bits. Universal Asynchronous Receive/Transmit consists of baud rate generator, transmitter and receiver. The number of bits transmitted per second is called baud rate and the baud rate generator generates the transmitter and receiver clocks separately. UART synchronizes the incoming bit stream with the local clock.

Transmitter interfaces to the data bus with the transmitter data register empty (TDRE) and write signals. When transmitting, UART takes eight bits of parallel data and converts it into serial bit stream and transmit them serially.
Receiver interfaces to the data bus with the receiver ready and the read signals. When UART detects the start bit, it receives the data serially and converts it into parallel form and when stop bit (logic high) is detected, data is recognized as a valid data.



UART Transmitter

The UART transmitter mainly consists of two eight bit registers the Transmit Data Register (TDR) and Transmit Shift Register (TSR) along with the Transmitter Control. The transmitter control generates the TDRE and TSRE signals which controls the data transmission through the UART transmitter. The write operation into the TDR is based on the signals generated from the microprocessor.