TOUCH SCREEN

First computers became more visual, then they took a step further to understand vocal commands and now they have gone a step further and became ‘TOUCHY’, that is skin to screen.

A touchscreen is an easy to use input device that allows users to control PC software and DVD video by touching the display screen. A touch system consists of a touch Sensor that receives the touch input, a Controller, and a Driver. The most commonly used touch technologies are the Capacitive & Resistive systems. The other technologies used in this field are Infrared technology, Near Field Imaging & SAW (surface acoustic wave technology). These technologies are latest in this field but are very much expensive.

The uses of touch systems as Graphical User Interface (GUI) devices for computers continues to grow popularity. Touch systems are used for many applications such as ATM’s, point-of–sale systems, industrial controls, casinos & public kiosks etc. Touch system is basically an alternative for a mouse or keyboard.

The market for touch system is going to be around $2.5 billion by 2004. Various companies involved in development of touch systems mainly are Philips, Samsung etc. Even touch screen mobile phones have been developed by Philips.

INTRODUCTION

A touchscreen is an easy to use input device that  allows users to control PC software and DVD video by touching the display screen. We manufacture and distribute a variety of touch screen related products.

A touch system consists of a touch

Sensor that receives the touch input, a Controller, and a Driver. The touch screen sensor is a clear panel that is designed to fit over a PC. When a screen is touched, the sensor detects the voltage change and passes the signal to the touch screen controller. The controller that reads & translates the sensor input into a conventional bus protocol (Serial, USB) and a software driver which converts the bus information to cursor action as well as providing systems utilities.

As the touch sensor resides between the user and the display while receiving frequent physical input from the user vacuum deposited transparent conductors serve as primary sensing element. Vacuum coated layers can account for a significant fraction of touch system cost. Cost & application parameters are chief criteria for determining the appropriate type determining the system selection. Primarily, the touch system integrator must determine with what implement the user will touch the sensor with & what price the application will support.

Applications requiring activation by a

gloved finger or arbitrary stylus such as a plastic pen will specify either a low cost resistive based sensor or a higher cost infra-red (IR) or surface acoustic wave (SAW) system. Applications anticipating bare finger input or amenable to a tethered pen comprises of the durable & fast capacitive touch systems. A higher price tag generally leads to increased durability better optical performance & larger price.

The most commonly used systems are

generally the capacitive & resistive systems. The other technologies used in this field are Infrared technology & SAW (surface acoustic wave technology) these technologies are latest in this field but are very much expensive.

1. Introduction

To avoid shoot-though in voltage source inverters (VSI), dead-time, a small interval during which both the upper and lower switches in a phase-leg are off, is introduced into the standard pulse width modulation (PWM) control of VSIs. How­ever, such a blanking time can cause problems such as output waveform distortion and fundamental voltage loss in VSIs, es­pecially when the output voltage is low.

To overcome dead-time effects, most solutions focus on dead-time compensation  by introducing complicated PWM compensators and expensive current detection hardware. In practice, the dead-time varies with the gate drive path propa­gation delay, device characteristics and output current, as well as temperature, which makes the compensation less effective, especially at low output current, low frequency, and zero current crossing. Several switching strategies for PWM power converters have been proposed to minimize the dead-time effect. A dead-time minimization algorithm was also discussed earlier to improve the inverter output performance. A phase-leg configu­ration topology proposed prevented shoot through. However, an additional diode in series in the phase-leg increases complexity and causes more loss in the inverter. Also, this phase-leg configuration is not suitable for high-power inverters because the upper device gate turn-off voltage is reversely clamped by a diode turn on voltage. Such a low voltage, usually less than 2 V, is not enough to ensure that a device is in its off-state during the activation of its complement device.

High-power inverters usually need longer dead-time than those low-power counterparts. Also due to complicated struc­tures and severe parasitic parameter variations, in practice, the dead-time for high-power inverters requires specific adjustment and/or compensation, and usually this process is time-con­suming. For general applications, automatically eliminating dead-time by gate drive technology is a desired and complete solution. Gate drives with intelligent functions are in high demand due to the emerging technology of power electronics building blocks (PEBB) and intelligent power modules (IPM) because smart functions can improve power devices’ modu­larity, flexibility and reliability.

In this work, an effective dead-time elimination method is proposed. This method is based on decomposing of a generic phase-leg into two basic switching cells, which are configured with a controllable switch in series with an uncontrollable diode. Therefore, dead-time is not needed. In this paper, the effect of dead-time in VSIs will be first introduced. The prin­ciple of the proposed method to eliminate dead-time effect is explained in detail. Simulation and experimental results are provided to demonstrate the validity and features of the proposed novel method. Flexible implementation methods are also discussed.

ABSTRACT

The Remote Media Immersion (RMI) system is the result of a unique blend of multiple cutting-edge media technologies to create the ultimate digital media delivery platform. The main goal is to provide an immersive user experience of the highest quality. RMI encompasses all end-to-end aspects from media acquisition, storage, transmission up to their final rendering. Specifically, the Yima streaming media server delivers multiple high bandwidth streams, transmission error and flow control protocols ensure data integrity, and high-definition video combined with immersive audio provide highest quality rendering. The RMI system is operational and has been successfully demonstrated in small and large venues. Relying on the continued advances in electronics integration and residential broadband improvement, RMI demonstrates the future of on-demand home entertainment.

INTRODUCTION

The charter of the Integrated Media Systems Center (IMSC) at the University of Southern California (USC) is to investigate new methods and technologies that combine multiple modalities into highly effective, immersive technologies, applications and environments. One of the results of these research efforts is the Remote Media Immersion (RMI) system. The goal of the RMI is to create and develop a complete aural and visual environment that places a participant or group of participants in a virtual space where they can experience events that occurred in different physical locations. RMI technology can effectively overcome the barriers of time and space to enable, on demand, the realistic recreation of visual and aural cues recorded in widely separated locations.

The focus of the RMI effort is to enable the most realistic recreation of an event possible while streaming the data over the Internet. Therefore, we push the technological boundaries much beyond what current video-on-demand or streaming media systems can deliver. As a consequence, high-end rendering equipment and significant transmission bandwidth are required. The RMI project integrates several technologies that are the result of research efforts at IMSC. The current operational version is based on four major components that are responsible for the acquisition, storage, transmission, and rendering of high quality media.

STAGES OF RMI

Acquisition of high-quality media streams

This authoring component is an important part of the overall chain to ensure the high quality of the rendering result as experienced by users at a later time. As the saying “garbage in, garbage out” implies, no amount of quality control in later stages of the delivery chain can make up for poorly acquired media.

Real-time digital storage and playback of multiple independent streams

Yima Scalable Streaming Media Architecture provides real-time storage, retrieval and transmission capabilities. The Yima server is based on a scalable cluster design. Each cluster node is an off-the-shelf personal computer with attached storage devices and, for example, a Fast or Gigabit Ethernet connection. The Yima server software manages the storage and network resources to provide real-time service to the multiple clients that are requesting media streams. Media types include, but are not limited to, MPEG-2 at NTSC and HDTV resolutions, multichannel audio (e.g., 10.2 channel immersive audio), and MPEG-4

Protocols for synchronized, efficient real time transmission of multiple media streams

A selective data retransmission scheme improves playback quality while maintaining realtime properties. A flow control component reduces network traffic variability and enables streams of various characteristics to be synchronized at the rendering location. Industry standard networking protocols such as Real-Time Protocol (RTP) and Real-Time Streaming Protocol (RTSP) provide compatibility with commercial systems.

Rendering of immersive audio and high resolution video

Immersive audio is a technique developed at IMSC for capturing the audio environment at a remote site and accurately reproducing the complete audio sensation and ambience at the client location with full fidelity, dynamic range and directionality for a group of listeners (16 channels of uncompressed linear PCM at a data rate of up to 17.6Mb/s). The RMI video is rendered in HDTV resolutions (1080i or 720p format) and transmitted at a rate of up to 45 Mb/s.

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Download Full Article Cocoa.doc

ABSTRACT

Cocoa is one of Apple Inc.’s native object-oriented application program environments for the Mac OS X operating system. It is one of five major APIs available for Mac OS X; the others are Carbon, POSIX (for the BSD environment), X11 and Java.

Cocoa applications are typically developed using the development tools provided by Apple, specifically Xcode (formerly Project Builder) and Interface Builder, using the Objective-C language. However, the Cocoa-programming environment can be accessed using other tools, such as Object Pascal, Python, Perl and Ruby, with the aid of bridging mechanisms such as PasCocoa, PyObjC, CamelBones and RubyCocoa, respectively. Also, under development by Apple, is an implementation of the Ruby language, called MacRuby, which does away with the requirement for a bridging mechanism. It is also possible to write Objective-C Cocoa programs in a simple text editor and build it manually with GCC or GNUstep’s makefile scripts. For end-users, Cocoa applications are considered to be those written using the Cocoa-programming environment. Such applications usually have a distinctive feel, since the Cocoa-programming environment automates many aspects of an application to comply with Apple’s human interface guidelines.

Main frameworks

Cocoa consists primarily of two Objective-C object libraries called frameworks. Frameworks are functionally similar to shared libraries, a compiled object that can be dynamically loaded into a program’s address space at runtime, but frameworks add associated resources, header files, and documentation.

Foundation Kit, or more commonly simply Foundation, first appeared in OpenStep. On Mac OS X, it is based on Core Foundation. Foundation is a generic object-oriented library providing string and value manipulation, containers and iteration, distributed computing, run loops, and other functions that are not directly tied to the graphical user interface. The “NS” prefix, used for all classes and constants in the framework, comes from Cocoa’s NeXTSTEP heritage.

Application Kit or AppKit is directly descended from the original NeXTSTEP Application Kit. It contains code with which programs can create and interact with graphical user interfaces. AppKit is built on top of Foundation, and uses the same “NS” prefix. A key part of the Cocoa architecture is its comprehensive views model. This is organized along conventional lines for an application framework, but is based on the PDF drawing model provided by Quartz. This allows creation of custom drawing content using PostScript-like drawing commands, which also allows automatic printer support and so forth. Since the Cocoa framework manages all the clipping, scrolling, scaling and other chores of drawing graphics, the programmer is freed from implementing basic infrastructure and can concentrate only on the unique aspects of an application’s content.

Technology Overview

Cocoa helps you create commercial-grade applications quickly and efficiently. It is an advanced, mature object- oriented development environment that enables you to create complex software with surprisingly few lines of code. Through a seamless integration of tools and Cocoa API, the design and construction of a user interface is largely a matter of dragging windows, buttons, and other objects from palettes, initializing their attributes, and connecting them to other objects. Cocoa also defines a model for applications and implements most aspects of application behavior; you simply fit into this model the code that makes your application unique.

The programmatic interfaces of the core Cocoa frameworks, Foundation and Application Kit, simplify access to most of the technologies on which Mac OS X is based, such as Quartz, Bonjour networking, Core Text, and the printing system. Although these interfaces are in Objective-C, you can integrate code written in other languages into your Cocoa projects, including C++ code and C code. Because Objective-C is a superset of ANSI C, frameworks with C APIs are compatible with Objective-C.

Implementations

The Cocoa frameworks are written in Objective-C, and hence Objective-C is the preferred language for development of Cocoa applications. Java bindings for the Cocoa frameworks (known as the “Java bridge”) are also available but have not proven popular amongst Cocoa developers. Further, the need for runtime binding means many of Cocoa’s key features are not available with Java. In 2005, Apple announced that the Java bridge was to be deprecated, meaning that features added to Cocoa in Mac OS X versions later than 10.4 would not be added to the Cocoa-Java programming interface. AppleScript Studio, part of Apple’s Xcode Tools makes it possible to write (less complex) Cocoa applications using AppleScript. Third party bindings available for other languages include PyObjC (Python), RubyCocoa (Ruby), CamelBones (Perl), Cocoa#, Monobjc (C#) and NObjective(C#).There are also open source implementations of major parts of the Cocoa framework that allows cross- platform (including Microsoft Windows) Cocoa application development, such as GNUstep, and Cocotron

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DSTATCOM-Distribution SATATic COMpensator

INTRODUCTION

Shunt Connected Controllers at distribution and transmission levels usually fall under two catogories – Static Synchronous Generators (SSG) and Static VAr Compensators (SVC).

A Static Synchronous Generator (SSG) is defined by IEEE as a self-commutated switching power converter supplied from from an appropriate electric energy source and operated to produce a set of adjustable multiphase voltages , which may be coupled to an ac power system for the purpose of exchanging independently controllable real and reactive power. When the active energy source (usually battery bank, Superconducting Magnetic Energy Storage etc) is dispensed with and replaced by a DC Capacitor which can not absorb or deliver real power except for short durations the SVG becomes a Static Synchronous Compensator (STATCOM) . STATCOM has no long term energy support in the DC Side and can not exchange real power with the ac system ; however it can exchange reactive power. Also , in principle, it can exchange harmonic power too. But when a STATCOM is designed to handle reactive power and harmonic currents together it gets a new name – Shunt Active Power Filter. So a STATCOM handles only fundamental reactive power exchange with the ac system.

STATCOMs are employed at distribution and transmission levels – though for different purposes. When a STATCOM is employed at the distribution level or at the load end for power factor improvement and voltage regulation alone it is called DSTATCOM. When it is used to do harmonic filtering in addition or exclusively it is called Active Power Filter. In the transmission system STATCOMs handle only fundamental reactive power and provide voltage support to buses. In addition STATCOMs in transmission system are also used to modulate bus voltages duting transient and dynamic disturbances in order to improve transient stability margins and to damp dynamic oscillations.

IEEE defines the second kind of Shunt Connected Controller called Static VAr Compensator (SVC) as a shunt connected static var generator or absorber whose output is adjusted to exchange capacitive or inductive current so as to maintain or control specific parameters of the electrical power system (typically bus voltage).Thyristor-switched or thyristor-controlled capacitors/inductors and combinations of such equipment with fixed capacitors and inductors come under this.This has been covered in an earlier lecture and this lecture focusses on STACOMs at distribution and transmission levels.

PWM Voltage Source Inverter based Static VAr Compensators (referred to as SVC here onwards) began to be considered a viable alternative to the existing passive shunt compensators and Thyristor Controlled Reactor (TCR ) based compensators from mid-eighties onwards. The disadvantages of capacitor/inductor compensation are well known. TCRs could overcome many of the disadvantages of passive compensators. However they suffered from two major disadvantages ;namely slow response to a VAr command and injection of considerable amount of harmonic currents into the power system which had to be cancelled by special transformers and filtered by heavy passive filters.

It became clear in the early eighties that apart from the mundane job of pumping lagging/leading VArs into the power system at chosen points ,VAr generators can assist in enhancing stability of the power system during large signal and small signal disturbances if only they were faster in the time domain. Also ,they can provide reactive support against a fluctuating load to maintain the bus voltage regulation and to reduce flicker problems,provide reactive support to control bus voltages against sag and swell conditions and provide reactive support to correct the voltage unbalance in the source – if only they were fast enough. PWM STATCOMs covered in this lecture are capable of delivering lagging/leading VArs to a load or to a bus in the power system in a rapidly controlled manner.

High Power STATCOMs of this type essentially consist of a three phase PWM Inverter using GTOs,Thyristors or IGBTs, a D.C. side capacitor which provides the D.C. voltage required by the inverter,filter components to filter out the high frequency components of inverter output voltage,a link inductor which links the inverter output to the a.c supply side,interface magnetics (if required) and the related control blocks. The Inverter generates a three-phase voltage, which is synchronized with the a.c supply ,from the D.C. side capacitor and the link inductance links up this voltage to the a.c source. The current drawn by the Inverter from the a.c supply is controlled to be mainly reactive(leading or lagging as per requirement) with a small active component needed to supply the losses in the Inverter and Link Inductor (and in the magnetics,if any).The D.C. side capacitor voltage is maintained constant( or allowed to vary with a definite relationship maintained between its value and the reactive power to be delivered by the Inverter) by controlling this small active current component. The currents are controlled indirectly by controlling the phase angle of Inverter output Voltage with respect to the a.c side source voltage in the “Synchronous Link Based Control Scheme” whereas they are controlled directly by current feedback in the case of “Current Controlled Scheme”.In the latter case the Inverter will be a Current Regulated one ,i.e. its switches are controlled in such a way that the Inverter delivers a commanded current at its output rather than a commanded voltage (the voltage required to see that the commanded current flows out of Inverter will automatically be synthesized by the Inverter).Current Control Scheme results in a very fast STATCOM which can adjust its reactive output within tens of microseconds of a sudden change in the reactive demand.

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INTRODUCTION

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 9210 Communicator, 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.

INTRODUCTION

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 seeral 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.
5) the platform has to be open to enable independent technology and software
vendors to develop third-party applications, technologies and services.

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INTRODUCTION

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 subthreshold 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) SOI was 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 off-state leakage is limited by the thin Si film. 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 .

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ABSTRACT

The General Packet Radio Service (GPRS) is a new non-voice value added service that allows information to be sent and received across a mobile telephone network. It supplements today’s Circuit Switched Data and Short Message Service. GPRS is NOT related to GPS (the Global Positioning System), a similar acronym that is often used in mobile contexts. GPRS has several unique features which can be summarized as:

SPEED: Theoretical maximum speeds of up to 171.2 kilobits per second (kbps) are achievable with GPRS using all eight timeslots at the same time. This is about three times as fast as the data transmission speeds possible over today’s fixed telecommunications networks and ten times as fast as current Circuit Switched Data services on GSM networks.

IMMEDIACY: GPRS facilitates instant connections whereby information can be sent or received immediately as the need arises, subject to radio coverage. No dial-up modem connection is necessary. This is why GPRS users are sometimes referred to be as being “always connected”.

NEW APPLICATIONS, BETTER APPLICATIONS: GPRS facilitates several new applications that have not previously been available over GSM networks due to the limitations in speed of Circuit Switched Data (9.6 kbps) and message length of the Short Message Service (160 characters). GPRS will fully enable the Internet applications you are used to on your desktop from web browsing to chat over the mobile network.

INTRODUCTION

The General Packet Radio Service (GPRS) is a new service that provides actual packet radio access for Global System for Mobile Communications (GSM) and Time-Division Multiple Access (TDMA) users. It provides for the transmission of IP packets over existing cellular networks, bringing the Internet to the mobile phone. Anything the Internet offers, from web browsing to chat and email, will be available from GSM and TDMA service providers via GPRS-enabled devices..

The main benefits of GPRS are that it reserves radio resources only when there is data to send and it reduces reliance on traditional circuit-switched network elements. The increased functionality of GPRS will decrease the incremental cost to provide data services, an occurrence that will, in turn, increase the penetration of data services among consumer and business users. In addition, GPRS will allow improved quality of data services as measured in terms of reliability, response time, and features supported. The unique applications that will be developed with GPRS will appeal to a broad base of mobile subscribers and allow operators to differentiate their services. These new services will increase capacity requirements on the radio and base-station subsystem resources. One method GPRS uses to alleviate the capacity impacts is sharing the same radio resource among all mobile stations in a cell, providing effective use of the scarce resources. In addition, new core network elements will be deployed to support the increased use of data services more efficiently.

In addition to providing new services for today’s mobile user, GPRS is important as a migration step toward third-generation (3G) networks. GPRS will allow network operators to implement an IP-based core architecture for data applications, which will continue to be used and expanded upon for 3G services for integrated voice and data applications. In addition, GPRS will prove a testing and development area for new services and applications, which will also be used in the development of 3G services.

GPRS is a non-voice, value added, packet-switched, mobile communication system. GPRS is implemented over the existing GSM network. So it shares GSM frequency bands and makes use of many properties of physical layer of the original GSM system, most importantly time-division multiple access frame structure, modulation techniques, and structure of GSM time slots.

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ABSTRACT

Digital Subscriber Lines (DSL) are used to deliver high-rate digital data over existing ordinary phone-lines. A new modulation technology called Discrete Multitone (DMT) allows the transmission of high speed data. DSL facilitates the simultaneous use of normal telephone services, ISDN, and high speed data transmission, e.g., video. DMT-based DSL can be seen as the transition from existing copper-lines to the future fiber-cables. This makes DSL economically interesting for the local telephone companies. They can offer customers high speed data services even before switching to fiber-optics.

DSL is a newly standardized transmission technology facilitating simultaneous use of normal telephone services, data transmission of 6 M bit/s in the downstream and Basic-rate Access (BRA). DSL can be seen as a FDM system in which the available bandwidth of a single copper-loop is divided into three parts. The base band occupied by POTS is split from the data channels by using a method which guarantees POTS services in the case of ADSL-system failure (e.g. passive filters).

INTRODUCTION

The past decade has seen extensive growth of the telecommunications industry, with the increased popularity of the Internet and other data communication services. While offering the world many more services than were previously available, they are limited by the fact that they are being used on technology that was not designed for that purpose..

The majority of Internet users access their service via modems connects to the Plain Old Telephone System (POTS). In the early stages of the technology, modems were extremely slow by today’s standards, but this was not a major issue. A POTS connection provided an adequate medium for the relatively small amounts of data that required transmission, and so was the existing system was the logical choice over special cabling.

Technological advances have seen these rates increase up to a point where the average Internet user can now download at rates approaching 50Kbps, and send at 33.6Kps. However, POTS was designed for voice transmission, at frequencies below 3kHz, and this severely limits the obtainable data rates of the system. To increase performance of new online services, such as steaming audio and video, and improve general access speed, the bandwidth hungry public must therefore consider other alternatives. Technologies, such as ISDN or cable connections, have been in development for sometime but require special cabling. This makes them expensive to set up, and therefore have not been a viable alternative for most people.

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ABSTRACT

Brain fingerprinting is based on finding that the brain generates a unique brain wave pattern when a person encounters a familiar stimulus Use of functional magnetic resonance imaging in lie detection derives from studies suggesting that persons asked to lie show different patterns of brain activity than they do when being truthful. Issues related to the use of such evidence in courts are discussed. The author concludes that neither approach is currently supported by enough data regarding its accuracy in detecting deception to warrant use in court.

In the field of criminology, a new lie detector has been developed in the United States of America. This is called “brain fingerprinting”. This invention is supposed to be the best lie detector available as on date and is said to detect even smooth criminals who pass the polygraph test (the conventional lie detector test) with ease. The new method employs brain waves, which are useful in detecting whether the person subjected to the test, remembers finer details of the crime. Even if the person willingly suppresses the necessary information, the brain wave is sure to trap him, according to the experts, who are very excited about the new kid on the block.

INTRODUCTION

Brain Fingerprinting is a controversial proposed investigative technique that measures recognition of familiar stimuli by measuring electrical brain wave responses to words, phrases, or pictures that are presented on a computer screen. Brain fingerprinting was invented by Lawrence Farwell. The theory is that the suspect’s reaction to the details of an event or activity will reflect if the suspect had prior knowledge of the event or activity. This test uses what Farwell calls the MERMER (“Memory and Encoding Related Multifaceted Electroencephalographic Response”) response to detect familiarity reaction. One of the applications is lie detection. Dr. Lawrence A. Farwell has invented, developed, proven, and patented the technique of Farwell Brain Fingerprinting, a new computer-based technology to identify the perpetrator of a crime accurately and scientifically by measuring brain-wave responses to crime-relevant words or pictures presented on a computer screen. Farwell Brain Fingerprinting has proven 100% accurate in over 120 tests, including tests on FBI agents, tests for a US intelligence agency and for the US Navy, and tests on real-life situations including actual crimes..

What is Brain Fingerprinting?

Brain Fingerprinting is designed to determine whether an individual recognizes specific information related to an event or activity by measuring electrical brain wave responses to words, phrases, or pictures presented on a computer screen. The technique can be applied only in situations where investigators have a sufficient amount of specific information about an event or activity that would be known only to the perpetrator and investigator. In this respect, Brain Fingerprinting is considered a type of Guilty Knowledge Test, where the “guilty” party is expected to react strongly to the relevant detail of the event of activity.

Existing (polygraph) procedures for assessing the validity of a suspect’s “guilty” knowledge rely on measurement of autonomic arousal (e.g., palm sweating and heart rate), while Brain Fingerprinting measures electrical brain activity via a fitted headband containing special sensors. Brain Fingerprinting is said to be more accurate in detecting “guilty” knowledge distinct from the false positives of traditional polygraph methods, but this is hotly disputed by specialized researchers.

Technique:

The person to be tested wears a special headband with electronic sensors that measure the electroencephalography from several locations on the scalp. In order to calibrate the brain fingerprinting system, the testee is presented with a series of irrelevant stimuli, words, and pictures, and a series of relevant stimuli, words, and pictures. The test subject’s brain response to these two different types of stimuli allow the testor to determine if the measured brain responses to test stimuli, called probes, are more similar to the relevant or irrelevant responses.

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