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SENIOR EDITORS HABIBULLAH PAGARKAR (BE IT)SHREYAN SARKAR (BE ELECTRONICS)

JUNIOR EDITORS PRIYA SAWANT (TE COMPUTERS)KAPIL ASHER (TE TELECOM)

LAYOUT & DESIGN DEVDATT LAD (BE ELECTRONICS)ASST. EDITORS SMRUTI PATEL (TE COMPUTERS)

LUBAINA KITABI (TE COMPUTERS)COVER PAGE APURVA PANGAM (TE IT)PROOF READERS ARAVIND KAILAS (EX-VICE-CHAIR, IEEE-VESIT)

SUDHIR SHUKLA (BE ELECTRONICS)

BRANCH COUNSELOR PROF. J A GOKHALEEXECUTIVE COMMITTEECHAIRPERSON DEVDATT LAD (BE ELECTRONICS)VICE-CHAIRPERSON NEELESH MUNDRA (BE ELECTRONICS)SECRETARY LUBAINA KITABI (TE COMPUTERS)TREASURER SUYOG LAKESHRI (TE IT)TECHNICAL ACTIVITIES BOARDCHAIRPERSON ADITYA SANE (BE INSTRUMENTATION)VICE-CHAIRPERSON YOGESH JASHNANI (BE TELECOMMUNICATIONS)BOARD MEMBERS APURVA PANGAM (TE IT)

SHWETHA VIJAY (TE IT)ABHISHEK SRIVASTAVA (TE ELECTRONICS)

MEMBERSHIP AND PUBLICITYSENIOR OFFICERS CHINMAY SHAH (BE IT)

ADITYA AGARWAL (BE TELECOMMUNICATIONS)JUNIOR OFFICERS SMRUTI PATEL (TE COMPUTERS)

TARUN MAKHIJA (TE IT)SARITA JAPTIWALE (TE IT)

EDITORIAL BOARDSENIOR EDITORS M. HABIBULLAH PAGARKAR (BE IT)

SHREYAN SARKAR (BE ELECTRONICS)JUNIOR EDITORS PRIYA SAWANT (TE COMPUTERS)

KAPIL ASHER (TE TELECOMMUNICATIONS)WEB DESIGNING TEAMSENIOR DESIGNER PARIMAL KALE (BE TELECOMMUNICATIONS)JUNIOR DESIGNERS YASH DOSHI (TE ELECTRONICS)

ABHIJIT AKHAWE (TE ELECTRONICS)

CO-ORDINATORS JIMMY DESAI (SE ELECTRONICS)SHILPA MENON (SE ELECTRONICS)SAURABH RANADIVE (SE ELECTRONICS)MANAS KHADILKAR (SE COMPUTERS)DARSHAN MEHTA (SE COMPUTERS)HARSHAD MANDE (SE COMPUTERS)ADITYA NARVEKAR (SE INSTRUMENTATION)SNEHA NAIR (SE TELECOMMUNICATIONS)POOJA SHAH (SE IT)BHAVNA SACHDEV (SE IT)SUMEET ADVANI (SE IT)ABHISHEK PANDEY (SE IT)

IEEEIEEEIEEEIEEEIEEEVESITA Student Branch of the Institute of Electrical AndElectronics Engineers, Inc. School Code 33011Vivekanand Education Society’s Institute ofTechnology, Sindhi Society, Chembur, Mumbai 71

SHORT CIRCUITa p u b l i c a t i o n o f i e e e - v e s i t

2 0 0 3

reat people don’t do different things; they do thingsdifferently.

At IEEE-VESIT, we take this adage very seriously.Hence, we have come out with a new-look to the BombaySection Newsletter ‘Short Circuit’. The changesincorporated in Short Circuit go way beyond the cover.

As is a tradition, this magazine too is a collection ofprize-winning articles as well as short, excellent write-upsby our student members and our working council. Aproper balance between technical and non-technicalarticles has been maintained, all the while keeping an eyeon quality. Also, we have tried to suit the very differenttastes of our readers; therefore articles from a broadspectrum of topics have also been included.

We would sincerely like to thank our Junior Councilfor putting up with all our threats and our frenziedattempts to complete this magazine. You guys are thebest! Also, we would like to thank all those who havespent a lot of time to submit articles to us includingstudents from TSEC, RAIT, and VJTI.

Finally, we would like to thank our ex-vicechairperson, Aravind Kailas, whose pertinent suggestionshelped us to improve the magazine. Even though he isnot associated with IEEE-VESIT anymore, he gladlyhelped us out many a times. His enthusiasm has inspiredus to do the best we could.

Given the quality of magazines published by ourseniors, this was a tough act to follow; and we are surethat you will enjoy reading this magazine as much as weenjoyed getting it to you. To contribute an article for ournext publication or comment on our work, you arewelcome to send us an email at the addresses are givenbelow.

Last but definitely not the least, we are grateful tothe Bombay Section Chair Prof. B. R. Prabhu and theStudent Activities Chair Prof. M. M. Shah for their supportand encouragement to us. We hope to continue our long-standing relationship with our Section in the years tocome.

So till next time, Alt+F4 !!

The Editorial Team

M. Habibullah Pagarkar (BE IT) mhabibp@ieee.orgShreyan Sarkar (BE Electronics) shreyan_s@ieee.orgPriya Sawant (TE Computers) priye@ieee.orgKapil Asher (TE Telecommunications) kapil@ieee.org

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Conte

nts c o n t e n t sNEXT TRENDSStop! Put Your Pencils DownSay hello to Electronic Paper - a computermonitor that is so thin that you could roll itup and stick it in your pocket...SHILPA MENON(SE ELECTRONICS)SIDDHARTH SHETTY(SE ELECTRONICS)

13 Prize Winning Article

OPTO-ELECTRONICSVertical Cavity Surface Emitting LaserRevolutionizing Optical Communication LinksNINAD KULKARNI (TE COMPUTERS)GAURAV TAMHANKAR (TE COMPUTERS)

16 Prize Winning Article

BRANCH REPORTBranch At A GlanceA Recap of what was IEEE-VESIT. Includesphotos of the Industrial Visit to Pune.

5BRANCH PROJECTCSIDCA write-up on the IEEE-VESIT BluetoothProject that won the Best Design Award atthe International Level CSIDC 2002

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PERSPECTIVEWhy Are We Getting IT All Wrong?An Analysis of the supposed IT BubbleBurst. Is it really as harsh as they say it is?APURVA PANGAM (TE IT)

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COMMUNICATIONMommy, Can I Have MoreBandwidth?Orthogonal Frequency DivisionMultiplexingTARUN MAKHIJA (TE IT)

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PERIPHERALSVirtual Keyboard - Welcome ToThe Real WorldNo more clickety-clicks...ASHA KRISHNAN (TE COMPUTERS)

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DOCTOR DOCTORVirtual SurgeryNo squishy organs, no blood, noinstruments ...LUBAINA KITABI (TE COMPUTERS)

26COMPANY PROFILEInside IntelBe part of the journey that is IntelSMRUTI PATEL (TE COMPUTERS)

29 NET @ HOMELogging On To The Network...Through The Power LineHow about a network that runs throughyour home’s power lines itself?M. HABIBULLAH PAGARKAR (BE IT)

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MEMORY MARKETSToo Many Cooks? Great For The Broth!PISMA: Parallel vIrtually Shared MemoryArchitectureAdapted from a Technical Paper byPRIYA SAWANT (TE COMPUTERS)ASHA KRISHNAN (TE COMPUTERS)SMRUTI PATEL (TE COMPUTERS)

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ContentsENGG. & SOCIETYEthics In EngineeringTo do or not to do...That is the questionYOGESH JASHNANI (BE TELECOMMUNICATIONS)

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Jobs Ahoy!What you should know before youstep into that Interview RoomSHWETA VENGSARKAR (Cornell University)

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ALGO-RYTHMSWill You Start The Maze Please!The objective is to learn the sciencebehind generating and solving mazes.ABHIJIT AKHAWE (TE ELECTRONICS)

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GAMES GALORERaiding The GamesJourney through the fantasticevolution of computer games and alook into the gaming industryMIHIR SHAH (B.E. COMPUTERS, VJTI)

40BATTLE FRONTReady...Aim...Transmit43 Arms and ammunition alone nolonger win wars. Electronic warfarehas become an essential weapon inevery combatSACHIN DASNURKAR(TE TELECOMMUNICATIONS)JIMMY DESAI(SE ELECTRONICS)

NUMBER-O-LOGYFacts About Factorials47VIRAG SHAH(BE INFORMATION TECHNOLOGY)

Random number generation usingfactorials of large numbers

HUMOUR & SATIREConfessions Of A DigitalizingWoman61A satirical insight to our modern daylife.APARNA JAYAKUMAR (S.Y.B.A.,ST. XAVIER’S COLLEGE)

The Management Express65 The road well-travelled ...gettinginto a b-schoolKUNAL MUNDRA(BE TELECOMMUNICATIONS)

COMPUTER SECURITYHacking The HackersIntrusion Detection - How do youdetect and stop system intrusions?SACHIN BAHADUR (BE COMPUTERS)

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MULTIMEDIAMultimedia Choreographed50 SMIL - A revolutionary tool that will leadus to a multimedia universe on the Web!SHIVANI SAHI (TE INFORMATION TECHNOLOGY, RAIT)

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the branch... at a glanceI E E E V E S I T

One Ring to rule them all, One Ring to find them,One Ring to bring them all and in the darkness bind them.- The Lord of the Rings (Book 1)

The IEEE-VESIT Student Branch Members outside the Giant Meterwave Radio Telescope (GMRT)Complex on the outskirts of Pune

Udey Pyrocable Pvt. Ltd. (19th February 2003)• Visit to the manufacturing plant for cables used in telecommunications.• Detailed explanation and demonstration of the entire process from tinning, extruding,

twisting to smoking of the cables.

INTEL Electronics (19th February 2003)• Visit to the manufacturing unit which supplies parts used in the defense instruments to

the government of India.• Explanation of the process of conversions of conventional drawings provided by the

government to gadgets meeting the required standards.• Tour of their R&D department.• Detailed explanation of working of the generators and object detectors in tanks, a

ndus t r i a l V is i tI

continued...

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gadget used to simulate the functionality of a missile and other paraphernalia such ashermitically sealing chamber etc.

GMRT (20th February 2003)• Visit The Giant Metre Radio Telescope - the largest in the world.• Introduction by the director, Prof. S. Ananthakrishnan, who explained the reasons and

the technical details of the construction of the radio telescopes.• Tour of the control rooms which remotely monitor the telescopes.• Visit to the base of the antenna.

With Prof. Ananthakrishnan, Director of GMRT against the backdrop of the giant telescopes

At the Udey Pyrocables Complex

o r k s h o p sW• Computer Assembly workshop• Matlab Workshop• Networking & Linux Workshop

(upcoming)

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p e c i a l I n t e r e s t G r o u p sS√Do-It-Yourself (DIY) SIG√Robotics SIG√Software SIG√Animation SIG√Bulls N’ Bears (Business) SIG

i r e l e s s C o n f e r e n c eW• Orientation to members by the CSIDC-2002 team

of IEEE-VESIT.• Announcement of Blue Tooth contest 2002-2003.• Introduction to the emerging Blue tooth technol-

ogy.• Presentation by the winners of the Best Project

Idea 2002-2003 on Free Space laser Communi-cation

The students at the telescopes

c h i e v e m e n t sAThe branch was one of 70 branches world-wide which was selected to participate inthe CSIDC 2002 and won the ‘Outstand-ing Design Award’. For the prize-winningreport refer page 9.

Was one of 8 branches world-wide to beawarded the AT&T Student EnterpriseAward in 2000-2001

Was selected to host the National Students’Congress in 2000-2001

The branch has won the InternationalWebsite Design Award three times in a rowand the third prize last year.

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n n u a l A c t i v i t i e sACSIDC 2003Computer Society’s International Design Com-petition - Submission of interesting and inno-vative ideas with the theme ‘Add Value To Com-puters by third year students. The best proposalwill be forwarded to the international level.

Hardware ContestTo encourage the members to participate inhardware related activities, the branch came upwith a very novel and unconventional hardwarecontest On the Spot Hardware Contest. Follow-ing the paper eliminations was a ‘3-LabTriathlon’, which tested their hardware skillsin microprocessors, communication and elec-tronics. The contest not only gave the studentsan opportunity to learn more, but also instilledin their minds the fact that mutual understand-ing, team spirit and co-ordination are impera-tive to succeed.

Software ContestAims to develop a Theme based software andhas three different levels of difficulty.

Best Project IdeaSoftware and hardware are two different worlds

in engineering and interfacing between thetwo is imperative for most of the systems tofunction efficiently. To introduce the studentsto this interfacing and interdependence of thetwo worlds, ‘Best Project Idea’ contest wasannounced for the students of all branches ofthe second year. The members had to comeup with original and innovative ideas for thiscontest and develop working models of thesame.

Paper Writing ContestAn explosion of technical ideas tempered withastounding writing skills and polished withthe precision and finesse of a perfectionist.

Article Writing ContestGetting acquainted with the ever revolution-izing world of technology is one of the aimsof all IEEE members. To encourage this arti-cle writing contest was held for all the mem-bers.

QuizzesComputer based technical quizCryptographic quizBrand equity quiz

SHANTI Book CentreDealers in Technical, Medical, Dental, Computer

and Pharmarcy books.All kinds of educational book suppliers.

89 Mahavir Building CompoundMatunga CRMumbai-400019Phone- 24010274 24099888

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The goal of Computer Society’s International Design Competition(CSIDC) is to advance excellence in education by having studentteams design and implement computer-based solutions to real-world problems. The competition emphasizes teamwork in thedesign, implementation, and testing of a computer-based system.

CSIDCIT IS A MATTER OF GREAT PRIDE FOR IEEE-VESIT to be

2002

amongst 70 teams, the world over, to

be selected to participate in the third

Annual IEEE Computer Society’s In-

ternational Design Competition

(CSIDC 2002). We received hardware

kits of the emerging Bluetooth radio

link. IEEE-VESIT developed a medi-

cal telemetry system named Critical

Healthcare Link. Primary financial

support for CSIDC 2002 was pro-

vided by Microsoft Corporation.

Shankar SomasundaramNeelesh MundraYogesh JashnaniKunal MundraAditya Sane

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Overview Of The ProjectIndia stands as the second most populated coun-try in the world with over a billion occupants; asimple fact – but one when combined with thelow per capita income, creates a potentially for-midable situation when it comes to providingquality health care to the masses. The answer liesin the system designed by the CSIDC-2002 team

of IEEE VESIT. The system can also be designedfor several applications due to its inherent flex-ibility.

The critical medical parameters- Res-piration rate, Oxygen Saturation and ECG canbe discretely and non-invasively monitored us-ing the Critical Healthcare Link. The proposalincludes the design of the necessary hardwarefor the measurement of the initial two parametersand a software analysis technique of the ECGsignal using Wavelet Transforms so as to extractthe necessary information from the waveform.At the receiving end, after de-multiplexing thedata the various signals are processed independ-ently to compare them with their respectivedatabases and give appropriate warnings. Thissystem overcomes one of the drawbacks of thecurrent systems, namely that they are not suit-able for an ambulatory patient since the patientis wired into the system.

The Hardware segment is designed toaccurately monitor the respiration rate and thepulse of the patient along with the ECG signal sothat these can be transmitted via the Bluetooth

module to a personal computer or mobile unit asper the application .The inputs are then comparedwith standard values in a database and analyzedusing various software techniques. The softwarechecks for abnormalities within the received sig-nals and triggers an alarm to alert the necessaryauthorities, may it be the family of the patientsor the hospital net-

works.

Data Acquisition TechniquesThe respiration rate is measured using a circuitemploying a highly sensitive thermistor affectedby the changes in the temperature of the air dur-ing inhalation and exhalation. The oxygen satu-ration level in the blood is measured using anoptocoupler circuit.

The ECG of the patient is monitored us-ing the conventional method of placing elec-trodes on the body that record the electrical im-pulses of the heart. The micro-controller deter-mines the respiration rate by using the inbuilttimer. It also calculates the oxygen saturation byusing Lambert-Bayer law. It then multiplexes thethree signals and sends the bit stream to a levelshifter. The level shifter is used to convert theTTL levels to RS232 standard, so as feed data tothe Bluetooth module via the RS232 to PCMCIAconverter. Data received from the transmitter isfirst fed to software which de-multiplexes it soas to get the three parameters: Breathing rate,Oxygen saturation level and the ECG signal.

Technical Overview

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.....”””””

“““““The parameters are then compared with

standard values in their respective databases andthe necessary actions are taken after analyzingthe results. The ECG in particular is first fed to aprogram that finds its Wavelet Transform andcompares it with standard values. The WaveletTransform is preferred over conventional FFTas it allows multi-resolution analysis, which isdone at a constant number of levels with a lowernumber of coefficients.

Mechanism for Distance MonitoringThe Critical Healthcare Link needs data to betransferred over the Internet to a nearby hospitalto keep continuous track of a person’s health andfor detailed analysis of the information extracted.The parameters that are measured by data acqui-sition systems are first transmitted by theBluetooth system to the receiving computerwhere they are stored as cookies. Here no soft-ware is needed and by this methodology, theoverall cost of the system is reduced. Moreoverstoring the data as cookies i.e. simple text fileshelps in easier processing of the data.

The ASP software that runs on the hos-pital’s server acts on these cookies and transfersthem to an SQL database. The hospital can thenprocess the data, which is again displayed inHTML format on their servers. In this way realtime processing of information can be done.

Core Applications

Sudden Infant Death SyndromeEvery year, on an average, one in every thou-sand babies in the United States of America diesof crib death or Sudden Infant Death Syndrome.The reasons cited are- the child choking on hissaliva, suffocation in the bedding, heart irregu-larities, allergy, low blood sugar, sudden over-whelming infections and so on. However the only

valid conclusion remains that the child stopsbreathing, causing death soon after, due to suf-focation.

One way this can be prevented is bytimely intervention of parents. A modified ver-sion of Critical Healthcare Link can be used toconstantly monitor the respiration rate of thebaby and alert the parents if infant’s respirationstops, using a mobile unit irrespective of theirlocation in the house.

GeriatricsIn a country like India, where the population isgrowing exponentially coupled with the factsthat the health care facilities are not developingat even half the rate and nuclear families are be-coming more and more predominant; monitor-ing the health of elderly citizens is becoming adifficult task. This is very important especiallyif they have just recovered from a serious con-dition and have to be kept under constant obser-vation. Considering the health care link’s lowcost, inherent flexibility, it becomes extremelyfeasible to accomplish this particular task. Theinformation about the vital parameters is trans-ferred over the Internet to the hospital’s data-base where the required analysis is done and ifnecessary, appropriate warnings and the requiredamount of further action can be taken.

ParamedicsParamedics respond to emergencies over a vari-ety of situations with several of them requiringimmediate data collection and analysis. How-ever due to hostile terrain or unsupportive sce-narios it is not possible to transfer the measur-ing instruments to the immobile victim. This iswhere a modified version of the CriticalHealthcare Link steps in. The paramedic cancarry the mobile unit to the patient or victimwhere his critical parameters such as oxygensaturation level and ECG signal are measuredand transmitted to the ambulance using theBluetooth link. Here a prognosis is made usinganalyzing software and vital feedback is pro-vided to the paramedic on how to handle thevictim better. The information is then sent to thehospital via a radio link.

This system can also be used for Dis-aster Management. For example, in case of a firethe data cannot be transmitted immediately be-cause of the intense heat, smoke and suspendedparticles which cause severe distortion in the sig-nal along with drastically reducing the range.The Critical Healthcare Link facilitates the im-

Of the 3.8 million infants born each year, manysuffer from Sudden Infant Death Syndrome(SIDS).

Wirelessly,Powerfully,Efficiently.

BLUETOOTHTECHNOLOGYworks however

you work. Itworks whenev-

er you work,seamlessly

connecting allyour mobile

devices!

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mediate transfer of data, thus saving vital sec-onds that can save many lives.

The Critical Healthcare Link, thus, prom-ises to change the face of health care. Its wide-spread applications coupled with its low cost canprove highly beneficial for a developing countrylike India. Even though this system in itself is anindependent modular unit, further enhancementscan definitely be incorporated. With the help ofbiomedical experts, extensive analysis of everykind of medical condition can be done and in-

corporated into the running software at the pa-tient’s computer itself, making long distancemonitoring unnecessary and increasing speed.Acquisition systems for ECG with as less as 2electrodes can be developed which will help inreal time analysis of the data. With rapid im-provements taking place in the VLSI field, mini-aturizing the hardware to very small sizes willsoon be possible making the usage of the sys-tem as convenient as wearing a wrist watch. TheCritical Healthcare Link is one that signifies thebeginning of a new era in the ever-importantarea of Healthcare.

SmartShirt SmartpenA team of researchers at the GeorgiaInstitute of Technology School ofTextile and Fiber Engineering firstdeveloped a fabric interwoven withconductive fibers that looked andfelt like a regular T-shirt but couldprovide an ongoing stream of vitalsigns information about the wearer.The idea was to have the wearer goabout his daily business whileseveral integrated componentsenabled the measurement, collectionand wireless transmission of criticaldata for remote healthcare.

The Anoto pen enables one to storeand transmit basically anything onewrites or draws .The main parts ofthe Anoto pen are a digital camera,an advanced image-processingunit,Bluetooth radio transceiver andan ink cartridge so that one canactually see what one has written ordrawn.The Anoto pen does not haveany buttons or display. It looks andfeels like an ordinary ballpoint pen.The pen is activated by simplyremoving the cap and deactivated byreplacing the cap again.

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Stop! Put YourPencils Down!

The days of paper books and newspapers are numbered.Say hello to Electronic Paper - a computer monitor that is sothin that you could roll it up and stick it in your pocket...

THE GOAL IS TO CREATE AN ELECTRONIC DISPLAY on a material that has the

look and flexibility of paper, but, unlike paper, could be

erased, updated, and used over and over again. Paper has

many superior optical qualities. It can reflect about 80 per-

cent of the light that hits its surface (so-called photopic

reflection), it can provide satisfactory contrast (ratios ap-

proaching 20:1), and it disperses reflected light evenly in

all directions. It is also inexpensive, robust, flexible, and

foldable, and can provide full-colour images. What’s more,

paper retains images for long periods without consuming

any power. It has long-lasting memory. Nevertheless, pa-

S H I L P A M E N O N

Prize-WinningArticle

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per does have disadvantages. It is unable to in-stantly change images and text the way an elec-tronic display can, and thus cannot be reusedquickly over and over. This is where new elec-tronic displays enter the picture.

Apart from the need for high, even re-flectance, the ability to retain images withoutusing any power is the most challenging criteri-on that an ideal portable electronic display mustmeet. To do so, the reflective displays now indevelopment make use of materials with bista-ble memory. Because the materials are stable intwo different states, reflective and non-reflec-tive, they need no power to continue displayingimages and text, but require power only tochange their state. A new technology is beingdeveloped which not only does all this but muchmore. This new technology can be effectivelyused in electronic reusable displays. It is beingdeveloped by the XEROX Palo Alto ResearchCentre (PARC) and is called Gyricon. It was orig-inally invented in 1975 at Xerox PARC by NickSheridon.

The Technology UnveiledA Gyricon sheet is a thin layer of transparentplastic in which millions of small beads, some-what like toner particles, are randomly dis-

persed. The beads, each contained in an oil-filledcavity, are free to rotate within those cavities.The beads are “bichromal”, with hemispheresof two contrasting colours (e.g. black and white,red and white), and charged so they exhibit anelectrical dipole. When voltage is applied to thesurface of the sheet, the beads rotate to presentone coloured side to the viewer. Voltages canbe applied to the surface to create images suchas text and pictures. The image will persist un-til new voltage patterns are applied.

The technology at work

Advantages Over Conventional DisplaysGyricon displays don’t require backlighting orconstant refreshing, and are brighter than today’sreflective displays. These attributes will lead toGyricon’s utilisation in lightweight and lower-power applications. Gyricon displays have nu-merous advantages over conventional electrical-ly addressable visual displays, such as LCD andCRT displays. In particular, they are suitable forviewing in ambient light, retain an image indef-initely in the absence of an applied electric field,and can be made lightweight, flexible, foldable,and with many other familiar and useful char-acteristics of ordinary writing paper. Thus, atleast in principle, they are suitable both for dis-play applications and for so-called electric pa-per or interactive paper applications, in whichthey serve as an electrically addressable, reusa-ble substitute for ordinary paper.

The best way to improve the reflectanceof a gyricon display is to make the display froma thick arrangement of bichromal balls. It isthought that the thicker the arrangement of balls,the better the reflectance and the brighter theappearance of the display. To achieve high res-olution in a gyricon display, the cavities in whichthe balls rotate should be packed as closely to-gether as possible.

However Gyricon displays have uniqueoptical properties. Con-ventional approachesused to increase the re-flectance of diffuse scat-tering arrays do not workwell for gyricon displays.Conventional opticalmodels, which assumethat the bichromal ballssituated well below theviewing surface of agyricon display contrib-ute as much to overalldisplay brightness as dothe bichromal balls near-est the viewing surface,

do not accurately describegyricon display optics. It is seen that the displaysmade based on conventional beliefs of “thickeris better” (even those of high resolution), lackthe reflectance, brightness, and contrast quali-ties predicted by the conventional wisdom.

A New Invention-Monolayer GyriconThe bichromal balls used in a gyricon displayare white on one hemispherical surface and black

Gyricon Media Inc.(GMI) is spun outto commercializePARC’s “electronicreusable paper,” adocument displaytechnology that isthin, flexible andportable like paperbut can beconnected to anetwork andreused thousandsof times. When anelectric charge isapplied to it, thematerial displaysand changes textand graphics, sothe display can beupdated with aclick of a mouse.

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SENSORS

on the other. When a portion of the display is inthe “white” state, the balls therein are orientedso that their white hemispheres face up. Lightcoming in from above the display is diffuselyscattered in many directions from the tops ofthe balls. When light strikes a given point onthe white hemisphere of agiven ball, scattering takesplace at all angles boundedby the tangent plane (a planetangent to the surface of theball at the point where thelight strikes the ball). For apoint at the top of the ball,this means that all light isscattered backward. If noother balls are between thegiven ball and the viewingsurface of the gyricon dis-play, light scattered from thetop of the ball is free to re-turn outward from the view-ing surface and so contributestoward observed whiteness ofthe display. However, if thereare other balls between thegiven ball and the viewingsurface, light scattered fromthe top of the ball cannotleave the display immediately, because the scat-tered light is partly intercepted by the black hem-ispherical surfaces of balls above it. The bot-tom surfaces are black, so this light is immedi-ately absorbed. Thus, much of the light thatreaches the lower layers of balls is lost forever.

The new invention instead proposes agyricon display having a tightly packed singlelayer or monolayer of bichromal balls. The onlygaps between balls are the spaces that arise whenspheres are packed into a planar array. Prefera-

bly, to minimize these gaps, a hexagonal arrayis used, so that adjacent ball surfaces are as closeto one another as possible. The light reflectedfrom the gyricon display is reflected substan-tially entirely from the monolayer of balls, sothat lower layers are not needed. By eliminat-

ing the lower layers, the dis-play can be made much thin-ner.

A monolayer gyricon dis-play has advantages in addi-tion to improved reflectance.The operating voltage need-ed for such a display is lessthan the voltage needed for aconventional thick gyricondisplay. This is because therotation of gyricon balls un-der the influence of an elec-tric field depends on the fieldstrength. Electric field is thederivative of voltage with re-spect to distance. Thus a giv-en electric field strength canbe achieved with a lower ap-plied voltage, other thingsbeing equal, by reducing thedistance over which the volt-age is applied. Accordingly,by using the thinnest config-uration possible, which is a

monolayer, the operating voltage of the gyri-con display is minimized. A lower operatingvoltage has many advantages, including lowerpower consumption, less expensive drive elec-tronics, and increased user safety.

It is hoped that the new gyricon displaywill go a long way toward making the promiseof electric paper come true.

Shilpa MenonSiddharth Shetty

SE Electronics

E-Paper In Use

This Polymer-DispersedLiquid-Crystal Display

(PDLCD), 64 pixels by 64pixels wide, is driven by anactive matrix of polymer-

based thin-film transistors.The image contains 256

levels of grey paper.

SMARTSENSORS

You are walking across a street at noon and your cell phonerings. You realize that the McDonalds outlet nearby has sentyou a couple of electronic coupons saying that they“sensed” your presence and would offer you a special mealif you dropped in. Now that’s exactly the way sensors aregoing to take over the marketplace.

Smart sensors contain an embedded memory chipwith standardized transducer electronic data sheets thatstore sensor information and parameters for identificationand self description. These sensors include serial digitallinks for accessing this information for plug and playoperation as well as analog signals. The future will have

interactions between machines on behalf of people. Forexample, appliances or cars etc. may be tagged with sensorsthat tell the factory they were made in, that they have justbeen bought!

Smart sensors can be designed to monitor all sortsof environmental conditions such as, traffic congestion, airpollution, or even magnetic fields. They can prove to beextremely useful for disaster mitigation by monitoring themotion of buildings during an earthquake. Monitoring thepulse and the blood pressure can also be done by these“smart” ones.So behold.... the sensors are coming....

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The Vertical Cavity Surface EmittingLaser (VCSEL) emits light perpendicular to the substrate and offerssignificant advantages when comparedto the edge-emitting lasers which is in

common use in optic communications devices.VCSELs can be fabricated efficiently on a 3-inchdiameter wafer & this enables the integration ofVCSELs on-board with other components withoutrequiring pre-packaging. VCSELs have intrinsicproperties that enable simpler fabrication, lower cost,and easier integration than traditional lasers. VCSELswill be the key enabler for next generation opticalnetworking equipment. VCSELs are the ideal lasersource for a variety of fiber optic applications and

have become the preferred choice for gigabit speedoptical links at 850 nm wavelengths. It is also pre-dicted that the 1310 nm VCSEL will revolutionizeoptical component design for the Telecom market.

Manufacture of VCSELsTwo important parts of the laser are the gain section,or active region, and the mirrors. In a VCSEL, thesestructures are stacked on top of one another, verti-cally, creating a “sandwich” of the active region be-tween a set of mirrors. Layers of semiconductor withdiffering compositions create these mirrors, and eachmirror reflects a narrow range of wavelengths backinto the cavity in order to cause light emission at justone wavelength. By using metal-organic chemicalvapour deposition or Molecular Beam Epitaxy , aVCSEL is effectively “grown” when these processesdeposit crystalline semiconducting materials onto awafer that will later be scribed and broken to pro-duce individual laser die.

Vertical CavitySurface Emitting

Lasers

Prize-WinningArticle

N I N A D K U L K A R N I

G A U R A V T A M H A N K A R&&&&&

Revolutionizing opticalcommunication links!

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Through additionalprocesses, the wave-length of the VCSELcan be tuned to oper-ate well within theData Communicationsand Telecommunica-tions wavelength win-dows. The emission

wavelength is control-led through precise en-gineering of the crystal-line materials in combi-

nations of column III and V elements. Quantumwells, extremely thin layers of III-V materials,are incorporated in the active region to furtherimprove the performance of the laser. Most of-ten VCSELs are fabricated with a circular aper-ture of between 5 to 25 microns in diameter toenable single or multiple mode operation. TheVCSELs are so small that as many as 20,000individual laser die can be fabricated on a single3 inch wafer.

Structure Of VCSELsThere are many designs of VCSEL structurehowever, they all have certain aspects in com-mon. The cavity length of VCSELs is very short

typically 1-3 wavelengths of the emitted light.As a result, in a single pass of the cavity, a pho-ton has a small chance of a triggering a stimu-lated emission event at low carrier densities.Therefore, VCSELs require highly reflectivemirrors to be efficient. For VCSELs, the reflec-tivity required for low threshold currents isgreater than 99.9%. Such a high reflectivity can-not be achieved by the use of metallic mirrors.VCSELs make use Distributed Bragg Reflec-tors. (DBRs). These are formed by laying downalternating layers of semiconductor or dielec-tric materials with a difference in refractive in-dex. At the dispersion minima for optical fibres,semiconductor materials used for DBRs have asmall difference in refractive index thereforemany periods are required. Since the DBR lay-ers also carry the current in the device, morelayers increase the resistance of the device there-fore dissipation of heat and growth may becomea problem if the device is poorly designed.

Working Of VCSELsSemiconductor lasers emit light when a smallcurrent is applied across the device. This cur-rent injection creates light in the active regionof the laser. The reduced cavity length inVCSELs and the addition of quantum wells sig-

nificantly reduces theprobability of stimu-lated emission in a sin-gle pass of the cavity.The light within thecavity must be reflectedback into the cavitymany more times thanwith a Fabry Perot la-ser.. The reflectivity ofthe mirrors must be veryhigh to increase thephoton lifetime and thusthe time of interactionwith the excited elec-tron states. As the lightis reflected back andforth between the mir-rors it is both amplifiedand locked into coher-ence. A small percent-age of the light “leaks”through the mirrors toform the laser beam.Due to the high gain andsmall volume of theVCSEL structure, the

Fig A - Airpost VCSEL Fig B - Buried Re-growthVCSEL

Fig C - Etched growth VCSEL Fig D - Metallic reflectorVCSEL

The first success-fully optical laser

constructed byMaiman (1960),consisted of a

ruby crystalsurrounded by a

helicoidal flashtube enclosed

within a polishedaluminum cylin-

drical cavitycooled by forced

air.

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lasers are very efficient, have low turn onvoltages, high modulation frequencies and sin-gle longitudinal mode operation. By turning thecurrent on and off the laser can be directly modu-lated at speeds beyond 10 Gbps.

ApplicationsVCSELs are promising emitter for fiber datacommunication in the speed range of 100Mbs

and 1Gbs. They enable high performance sys-tems in Gigabit Ethernet, Fiber Channel, andATM markets. Through their integration withoriginal equipment manufacturer’s (OEM) sys-tems design, 850nm VCSELs provide enhancedperformance benefits to a variety of applications,such as local area networks(LAN), telecommu-nication switches, optical storage and otheroptoelectronic systems. Other applications in-clude fiber channel, gigabit ethernet, access net-working, instruments’ calibration, free-space linkand sensing

SignificanceAlthough VCSELs have been a reality since theearly 1980’s, their true potential was not real-ized until the growth of the Internet and fiber

The VCSEL is currently the de facto laser source of choice forthe short haul Data Communication links, and comprisesapproximately 85% of the optical links in that market.

optics.. VCSELs were first introduced in theData Communications market in the mid-1990’s.However, the VCSEL with its numerous advan-tages, especially in the areas of cost, speed, andreliability displaced the use of edge-emittinglasers within a quick two years of its introduc-tion. The VCSEL is currently the de facto lasersource of choice for the short haul Data Com-munication links, and comprises approximately

85% of the opticallinks in that mar-ket.

Of themany performanceparameters thatd i f f e r e n t i a t e

VCSELs from other laser sources, two key prop-erties make them compelling as the laser sourcefor next generation networks. First, VCSELs arecapable of extremely fast direct modulationspeeds, which means no additional external com-ponents, like modulators, are required. The sec-ond area of importance is the wavelength. Al-though VCSELs were confined to short distanceapplications, recent advancements in VCSELtechnology, described above, have yielded a1310 nm VCSEL. Thus, the 1310 nm VCSELhas the potential to turn the optical communica-tions market upside-down by replacing the 1310nm DFB laser in telecommunication optical linksthe way the 850 nm VCSELs replaced the CDlaser in Data Communications.

Ninad Kulkarni, Gaurav TamhankarTE Computers

Ever wondered what was so special about Neo from Matrixthat he could bend a spoon, and the kid Matilda who couldhurl her 200 pound Principal a good 50 metres?!! Welcometo the intriguing world to Telekinesis.

Telekinesis is the movement of objects from oneplace to another or reshaping of objects without any physicalcontact. In telekinesis one taps into the universal life forceenergy or psychic energy and combines it with the physicalenergy created by electromagnetic impulses. The brain is thehardware that is utilized by the Mind. Our brain is capable ofgenerating a neural network that when ‘pushed’ can actuallystep up energy ready to be utilized beyond our 5 senses.Neurons do communicate with each other since low levelsubatomic and atomic dialogue occurs all the time. Even at acellular level there is communication going on. A documenta-ry on Cellular Communication depicted how a scientistscraped some cells from the inside of several participants’mouths and placed them in a petri dish. They connectedthose cells to a lie-detector type looking device and took thesubjects into another room several feet away from ‘their’

cells. As the participants were introduced to different stimuli,naturally their bodies would react. What was amazing - so didtheir cells in the other room!

So, who can do Telekinesis?? Everyone with a brainhas the potential to be able to be telekinetic. There aredifferent things that can have a psychotropic affect on thebrain which affect the mental activity and behavior percep-tion. Even stress and abuse can cause one to cultivatecertain psycho-kinetic abilities.

However, telekinesis can not be created by ‘wishingit’ to happen on the physical level. The energy to move orbend an object is created by a person’s thoughts in hissubconscious mind. The ability to bend spoons, moveobjects, levitate occurs during the ‘off’ phase of Conscious-ness but is being only manifested as a physical event uponthe space-time shell frame which we interpret as our reality.There is also a good deal of illusion present. One must beable to discern the reality of both. Sometimes there is a vastdifference in what we THINK we see and what IS actuallyhappening. But whatever it is... it IS possible!!

TELEKINESIS TELEKINESIS TELEKINESIS TELEKINESIS TELEKINESIS - BELIEVE IT ... (Or Not)

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ITAll Wrong ?!Why are we getting

“The matrix isall around you -when you go to

church, whenyou pay your

taxes. It is thereevery time you

look out of yourwindow.” - The

Matrix, 1999.

t’s been two whole years that the dotcom bubble has burst.And we still dwell in the misconception that Information Tech-nology is on a slowdown as if two whole years hadn’t reallybeen enough for us to realize. It is reflected in junta choos-ing different vocations for their B.E. People in 2000 AD ex-pected the dotcoms to rise, rise and rise and never fall. Littledid they realize that it was an “Irrational Exuberance”.

Fundamental physics says that bodies possessing excessenergy will try to lose it and become stable. Ditto with fundamen-tal economics - Every aberration in the system is corrected. So,from the beginning of the industrial revolution, the rule that “Any

fleeting and baseless money minting industry will die soon” canbe well applied here. All such bubbles have been busted. Be it thetulip bubble (when for handful of tulips, people were selling theirhouses) some centuries ago, or be it the railway industry bubble atthe turn of the century. The dotcoms however, for the people whodon’t know, do not represent IT industry in the entirety (thoughcan be proclaimed to be a part of it). Along with it, the commonman (and others too) failed to see the rise of software services,web-services, and the sort.

Let us see some reasons for the boom, and the bust. Theimportant thing to be noticed was that during 1997-1999 the In-ternet came of commercial age globally, and large companies useddotcoms as a showcase to their products (B2C) and enhance pro-ductivity (B2B). So a huge number of people simply started in-vesting into such net related businesses. Other companies observedthat these were profitable, and hence jumped on to the bandwag-on. Obviously the first few, and lucky few, generated profits. TheInternet existed before this, but it came into focus only after major

non-commercial applications like e-mail. After applications for the com-mon man were launched, several peo-ple realized that it was a Pandora’s Boxwaiting to be opened. Any company orsmall startup that could cook up a webapplication, which common peoplecould use, profited (only on valuationterms, not in actual cash-flows). That’swhere the entire “valuation-rigging”making started. The companies thatprovided software were automaticallyhyped, valuation of their share pricesrigged up by couple of biggies to as-tronomical limits and the people ob-served a steady exponential curve onstock prices.

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Also, the sites that kept on cropping upstarted providing hackneyed ideas. All of themseemed to be made from the same basic tem-plate and all of them provided the same features.A shake out was imminent and “boys” had to beseparated from the “men”. Websites were nomore valued as much for the number of ‘hits’on the webpage as before. This led to a suddendecline in valuations of such businesses. Thosewho still continued with such businesses, madevery little profit, many of them incurred losses,though there are cases of dotcoms and alliedbusinesses with positive cash flows. For everydotcom that survived, nine were ‘dotgones’.

What Is IT?Information Technology is the application ofcomputer systems and their use in a wide rangeof businesses to increase produc-tivity. In all such applications, therole of the computer is to proc-ess data or information and tosolve problems or take decisionsusing information. IT broughtalong with it networking, newersoftware platforms, the Open-Source Movement, miniaturiza-tion of product lines rangingfrom mobile units to computersand has completely changed thelifestyle of people all around the world. IT helpsto ensure that computers work to increase effi-ciency of the organizations. Nearly every com-pany, from a software design firm, to the big-gest manufacturer, to the smallest ‘shop aroundthe corner’, needs IT to keep their business run-ning smoothly.

So IT wasn’t, isn’t and won’t be onlyabout the www. For all those web-aficionados,we’re riding the wave of an industry whose en-tire base is application of logic, mathematics andtechnology to improve biz-processes and thequality of life. IT is an omnipresent entity, onethat has amalgamated into every field and with-out which, all the industries would collapse.Don’t believe us? Remove computers and soft-ware from banking, finance, telecom, teaching,entertainment, etc. and then the effect of IT willbe truly felt. A similar example given by Timemagazine emphasizes importance of IT in a moreheuristic manner: Remove IBM and the wholeof North America and Europe will come to astandstill.

Much of the excitement in IT is due to

the dramatic pace of dynamism. The result ofthis startling dynamic nature is that ever morenew applications have become economicallyfeasible. Whenever a new industry springs up,if it is not IT-ised, then quicker developmentswill be retarded. The telecom sector has bur-geoned, it is not just because we demanded tel-ecom, but it was the need to spread and gaininformation, that lead us to this stage of askingfor faster connections, smaller cell phones, andsleeker devices. Some say, “Well, in this case,IT has saturated.” What is meant by “satura-tion”? It is just a term used by some ill-informedpeople to give a general description of a fieldthey don’t know. The pitcher might have over-flowed, but that is not due to the shallowness ofthe pitcher, rather simply due to the speed withwhich it filled up. That just goes to show, how

powerful an industry it is and theeffect that it has on the worldaround us. At every instant, newtechnological advances are beingmade by people worldwide leadingto newer avenues never seen be-fore. The biotech sector, if expect-ed to grow, will seek similarservices. Actually, the more knowl-edgeable know that if there is any-thing called “saturation” , then thetelecom industry is the one which

is more saturated. Large telecom companiesworldwide are all loss-making. Be them fromJapan (HKT/NTT DoCoMo) or from Europe(Nokia and the like), all are in the red. Even inIndia, a supposedly good telecom company,Bharti Televentures, is a loss making company.This doesn’t imply that telecom is saturated. Ifanything at all, it may mean that the competi-tion has increased. Competition increases eve-rywhere. Without competition there cannot begrowth!

We’re not looking at an industry whichis all about glamour or making the ‘fast-buck’.IT is all about getting important informationacross; information that billions want to com-municate to others. Information has been thelife blood of businesses worldwide. In effect,IT has become indispensable to our lives in gen-eral and society at large. From the biggest busi-ness to the smallest farm, we just can’t do with-out IT.IT is here to stay. It’s like the matrix, all aroundyou and you can’t feel it. Unless it’s gone.

Apurva Pangam (VESIT)TE Information Technology

IT is an omnipresententity, one that hasamalgamated into

every field andwithout which, all the

industries wouldcollapse.

American firmshave invested30% of all capitalinvestments intoacquiring Infor-mation Technol-ogy.

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irst came in the computer, thenthe concept of a laptop and fi-nally WAP and bluetooth tech-nology brought in “smart” devic-es like the smart phones and

Virtual Keyboard

Welcome To TheA S H A K R I S H N A N

No more ‘clicketyclicks’ that keepyour family awakewhile you happilychat late at night!

PDAs (Personal Digital Assistant). With the in-troduction of PDAs of the size of the palm, alight pen was needed to use it. However, imag-ine having to needle a palm sized object with alight pen — the convenience of using a keyboardwas missing and it was obvious.This led to the advent of what is called the “vir-tual keyboard”. All that is needed to use the key-board is a flat surface. The flat surface can be adesktop, or the lap or even somebody’s back.Using laser technology, a bright red image of akeyboard is projected from a device such as ahandheld one. Detection technology based onoptical recognition allows users to tap the imag-es of the keys so the virtual keyboard behaveslike a real one. It can be designed to support anytyping speed.

Underlying TechnologyThe technology is based on timing the speed oflight to create a 3-D relief map of an image,which makes it easier to distinguish that imagefrom its background. The process works like this:The light source illuminates a subject; a sensor,stored in a chip, measures the distance that the

F

Real World...

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tionality can be given to the keyboard when cer-tain functions are needed and used very oftenby incorporating them in the keyboard layout.The position of certain keys can also be changeddepending upon the user. Also the letters canbe customized to make commonly used prefix-es or suffixes like “an”, “pre” etc. so that theycan be obtained at the press of a single key andthe physical feel of the keys can be changed.

LimitationsLike every emerging technology, usage of a vir-tual keyboard also possesses some problems.Firstly the virtual keyboard employs a wholeclass of analog-to-digital conversion technolo-gies. The analog-world is highly variable andthe problem arises during the process of distin-guishing the input from all the other analogitems in the analog world. Thus, filtering is abig problem. Also, there’s the apparent ease-of-use issue. It is easier to type on a keyboardthan to type on light. Unless the virtual keyscan give the right kind of feedback it might seema little problematic.This does not mean that the virtual keyboard isnot in use today. It is certainly used by pocketsof people but if it has to be made available on alarge scale it has to be developed to counter theproblems it faces currently. Again by doing sowe will be opening the doors to the future –that is virtual reality. The electronic perceptiontechnology can also be extended to include vir-tual reality games in which the computer sens-es the body movements of the human players,as well as blind-spot detectors for automobiles,wherein the car’s computer will be able to seevehicles that the driver does not. But until thefuture arrives and the “physical” world meta-morphoses to “virtual” reality we need to makedo with the “clickety clicks” of the physicalworld.

Asha Krishnan (VESIT)TE Computers

light has traveled between the subject and eachcorresponding pixel of the image in the chip;imaging software maps the subject in real time;and the computer in the end-user device reactsaccordingly.This process when extended to a virtual key-board idea can be translated as follows - the elec-tronic perception technology explained can beused to project an image of a keyboard from amobile device onto the surface in front of it. Theuser can then “type” on the image of the key-board, and the device will respond accordingly.

Defying ConventionsThe fact that the keyboard is virtual also givesroom to modifications in the layout of the key-board according to the user’s desire. The key-board no longer has fixed physical keys. Instead,it is a pin-matrix - a grid of small pins whichcan move up and down, right and left. Thesepins are also coloured, presumably by feedingfibres through them. The pins detect pressureon them, and provide relevant feedback to sim-ulate physical keys.The result is that it can quickly reshape itself toany keyboard layout, and simultaneously lightup to show that layout. The layout can be con-trolled by software, and can change from pro-gram to program. When software is used to mod-el hardware the possibilities are endless. Onespeaks of software in terms of something that isuser-dependant and that which can be modified.If the rugged concept of “hardware’ can be doneaway with the help of software we will be look-ing at more user-customized and friendly de-vices. As it is obvious the flexibility of the “vir-tual keyboard” is immense. Typing in French,German, Italian etc. would be much easier andsimpler if the keyboard not just changes the po-sition of the keys but also changes their labels.The same applies to languages like Chinese, Jap-anese, Korean etc. where the script is complete-ly different from the English script. Added func-

Jerusalemstartup VKB hasdesigned avirtual keyboard.The companyalso isdemonstrating avirtual mouse,and they say thetechnology couldreplace othereverydayinterfaces suchas phonekeypads or on-offswitches forlights.

KeyboardStressCarpal tunnel syndrome is a painful debiliating conditioncommon among computer keyboard users. Working understress (deadline pressure, anger, or other anxiety) canmake matters even worse. Symptoms include numbness

of hand, mainly thumb, index and middle fingers, tingling of fingers and trouble holding onto objects.Many studies recommend a 10-15 minute break each hour to give yourself the recovery time you need. Thisneedn’t be a break from productive activities just a break from your keyboard. Exercises can help, too. Try thefollowing - make tight fists, hold for one second, then stretch your fingers out wide and hold for five seconds.Variety is the key. CTS occurs most frequently in workers whose motions are not only repetitious but are kept upfor hours at a time. If you use a keyboard, structure your workdays to include a mix of activities each hour. Forexample, instead of typing all morning and filing all afternoon, mix typing and filing throughout the day.

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Mommy, Can I Have

More Bandwidth?NO!NO!NO!NO!NO! No more bandwidth. Learn to do with what’s given to you.

With the burden on communication networks increasing withevery passing day, engineers are continuously looking for waysto utilize the available spectrum more efficiently. One of thenewest solutions to this challenge is OFDM. Orthogonal Fre-quency Division Multiplexing (OFDM) is a block modula-tion scheme. It is a multi-carrier transmission technique usedin applications catering to both Wired and Wireless Commu-nications. The OFDM technique divides the frequency spec-trum available into many closely spaced carriers, which areindividually modulated by low-rate data streams. In this sense,OFDM is similar to FDMA (Frequency Division MultipleAccess) (the bandwidth is divided into many channels, so that,in a multi-user environment, each channel is allocated to auser). However, the difference lies in the fact that the carrierschosen in OFDM are much more closely spaced than in FDMA(1kHz in OFDM as opposed to about 30kHz in FDMA), there-by increasing its spectral usage efficiency. The orthogonalitybetween the carriers is what facilitates the close spacing ofcarriers.

The orthogonality principle essentially implies that eachcarrier has a null at the center frequency of each of the othercarriers in the system while also maintaining an integer numberof cycles over a symbol period. The motivation for usingOFDM techniques over TDMA (Time Division Multiple Ac-cess) techniques is two-fold. Firstly, TDMA limits the totalnumber of users that can be sent efficiently over a channel. In

T A R U N M A K H I J A

OFDM: Orthogonal Frequency Division Multiplexing - Anew method of modulation, which works on the principleof division of bandwidths to increase the usage of theavailable spectrum efficiently.

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addition, since the symbol rate of each channelis high, problems with multi-path delay spreadinvariably occur. In stark contrast, each carrierin an OFDM sig-nal has a very nar-row bandwidth(i.e. 1 kHz); thusthe resulting sym-bol rate is low.This results in thesignal having ahigh degree oftolerance to mul-ti-path delayspread, as the de-lay spread mustbe very long tocause significantinter-symbol interference (e.g. > 500usec).

OrthoganalityTo generate OFDM signals successfully, the re-lationship between all carriers must be careful-ly controlled in order to maintain orthogonality.Rectangular windowing of transmitted pulsesresults in a sine-shaped frequency response foreach channel. Whenever any particular carrierfrequency attains peak amplitude, the remain-ing carriers have a null point.

OFDM GenerationTo generate OFDM success-fully the relationship betweenall the carriers must be care-fully controlled to maintainthe orthogonality of the carri-ers. For this reason, OFDM isgenerated by firstly choosing the spectrum re-quired, based on the input data, and modulationscheme used. Each carrier to be produced is as-signed some data to transmit. The required am-plitude and phase of the carrier is then calculat-

ed based on the modulation scheme (typicallydifferential BPSK or Binary Phase Shift Key-ing, QPSK or Quadrature Phase Shift Keying,

or QAMwhich isQuadratureAmpl i tudeModulation).The requiredspectrum isthen convert-ed back to itstime domainsignal usingan InverseF o u r i e r

Transform. In most applications, an Inverse FastFourier Transform (IFFT) is used. The IFFT per-forms the transformation very efficiently, andprovides a simple way of ensuring the carriersignals produced are orthogonal.

The Fast Fourier Transform (FFT) trans-forms a cyclic time domain signal into its equiva-lent frequency spectrum. This is done by find-ing the equivalent waveform, generated by a sumof orthogonal sinusoidal components. The am-plitude and phase of the sinusoidal componentsrepresent the frequency spectrum of the time do-main signal. The IFFT performs the reverse proc-ess, transforming a spectrum (amplitude and

phase of each component) into a time domainsignal. An IFFT converts a number of complexdata points, of length that is a power of 2, intothe time domain signal of the same number ofpoints. Each data point in frequency spectrum

used for an FFT or IFFT is called abin.

The orthogonal carriers requiredfor the OFDM signal can be easilygenerated by setting the amplitudeand phase of each frequency bin, thenperforming the IFFT. Since each binof an IFFT corresponds to the ampli-tude and phase of a set of orthogonalsinusoids, the reverse process guar-antees that the carriers generated areorthogonal. The signal generated is atbase-band and so to generate an RF

OFDM Spectrum

The carriers for each channel are made orthogonalto one another, allowing them to be spaced very

close together, with no overhead as in FDMA

In the old dayswhen the radiospectrum was notas crowded withradio, pagers, cellphones andsatellite signalsetc., it was notunusual to pick upa radio signal fromthe past. Findsome old hamradio amateur orask some agedcommunicationsengineer and hewill confirm this.These are called'refractions' andare not supernatu-ral, instead thesewere and still aresignals thatsomehow gotlocked betweentwo layers of theatmosphere(ionosphere andstratosphere) andthen in some waybroke loose onlyto be picked up bysome radio andmisinterpreted assupernatural. Thisway you could talkto Elvis...

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signal the signal must be filtered and mixed tothe desired transmission frequency.

Advantages of OFDM over otherMultiple Access TechniquesOFDM is similar to FDMA in that the multipleuser access is achieved by subdividing the avail-able bandwidth into multiple channels, which arethen allocated to users. However, OFDM usesthe spectrum much more efficiently by spacingthe channels much closer together. This isachieved by making all the carriers orthogonalto one another, preventing interference betweenthe closely spaced carriers.

TDMA partly overcomes this problem byusing wider bandwidth channels, which are usedby several users. Multiple users access the samechannel by transmitting in their data in time slots.Thus, many low data rate users can be combinedtogether to transmit in a single channel that has abandwidth sufficient so that the spectrum can beused efficiently. There are however, two mainproblems with TDMA. There is an overhead as-sociated with the change over between users dueto time slotting on the channel. A change overtime must be allocated to allow for any tolerancein the start time of each user, due to propagationdelay variations and synchronization errors. Thislimits the number of users that can be sent effi-

ciently in each channel. In addition, the symbolrate of each channel is high (as the channel han-dles the information from multiple users) result-ing in problems with multi path delay spread.

OFDM overcomes most of the problemswith both FDMA and TDMA. OFDM splits theavailable bandwidth into many narrow bandchannels as already mentioned above. The car-riers for each channel are made orthogonal toone another, allowing them to be spaced veryclose together, with no overhead as in the FDMAexample. There is no need for users to be timemultiplex as in TDMA, thus there is no over-head associated with switching between users.

OFDM out-performs CDMA in many ar-eas for a single and multi cell environment.OFDM allows upto 2 - 10 times more users thanCDMA in a single cell environment and from0.7 - 4 times more users in a multi-cellular en-vironment. The difference in user capacity be-tween OFDM and CDMA was dependent onwhether cell sectorization and voice activity de-tection is used. It is found that CDMA only per-forms well in a multi-cellular environmentwhere a single frequency is used in all cells. Thisincreases the comparative performance againstother systems that require a cellular pattern offrequencies to reduce inter-cellular interference.

Tarun Makhija (VESIT)TE Information Technology

Future full of energy

HINDUSTAN PETROLEUM LTD.

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Whenever a dramatic change occurs, there is theperception that the old is cast aside to be replaced by the entirely new. In a technologicsense, this is occurring today in medicine. Fromone perspective, it could be said that there is

no medicine, but rather information infrastructure with a medi-cal flavour. And of the many disciplines arising from this newinformation era, virtual reality (VR) holds the greatest promise.

Rapid improvements in computing power today haveopened the way for desktop virtual reality trainers that incorpo-rate realistic graphics and, in some cases, the sense of touch. Af-

fordable commercial simulators are now available for practisingvery complicated tasks such as threading flexible endoscopesdown a virtual patient’s throat or manipulating the long surgicalinstruments used in laparoscopy. Companies and universities arealso developing systems that simulate more complex procedures,such as suturing tissue and inserting a catheter into a vein usinglaparoscopic tools.

For the most part, they are designed to do very specifictasks—sewing veins together,inserting catheters, and the like.It turns out, though, that model-ling the myriad textures and re-sponses of the human body isvastly complicated and existingdata relatively scant. All thisleads us to the inevitable ques-tion.

So Why Virtual Reality?Not only does virtual surgerypave the way for surgeons tohone their skills but simulatorsprovide virtual cadavers “near-ly indistinguishable from a realperson” on which students canoperate. These VR trainers canbe adjusted to the user, to pin-

v i r t u a l s u r g e r y

MEDICALMEDICALMEDICALMEDICALMEDICALthe

university

L U B A I N A K I T A B I

No squishy organs, no blood, noinstruments ... it’s like flying inside

the human body. Surgery is nowonly a combination of robotics andsimulation with a nuance of medi-

cal knowledge...

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point areas of weakness, and they can be usedat any time, without the need for supervision.In a sense they prepare the student psychologi-cally for surgical tasks, because complicationscan be simulated in a safe manner. They can alsogive objective scores of a student’s ability. In-deed, studies show that computer-based train-ing simulations are at least as good as standardtraining methods.

How The Simulators WorkSimulating human tissue—be it tooth

enamel, skin, or blood vessel—often starts witha sample from a flesh-and-blood person. De-pending on the simulation needed, anatomical

images can be derived from magnetic resonanceimages, video recordings, or the Visible HumanProject, a computer model of a human devel-oped by the National Library of Medicine. Theimage can then be digitally mapped onto a po-lygonal mesh representing whatever body partor organ is being examined. Each vertex of thepolygon is assigned attributes like color and re-flectivity from the image of the organ. The 3-Dimages can also be color-enhanced to highlight,say, bone or blood vessels. Imagery of this kindrelies on a technique called ray tracing: an al-gorithm calculates which rays of light from thevolume image would enter a virtual eye locatedat a point that will give the surgeon the desiredperspective. The virtual eye can, for example,be induced to move down an oesophagus, sim-ulating the path an endoscopic probe would take.

For the user to interact with the graphicsthere must be software algorithms that can cal-culate the whereabouts of the virtual instrumentand determine whether it has collided with abody part or anything else. Also needed aremodels of how various tissues behave when cut,prodded, punctured, and so on. Here, too, VRdesigners often portray the tissue as a polygo-nal mesh that reacts like an array of masses con-nected by springs and dampers. The parame-ters of these models can then be tweaked tomatch what a physician experiences during anactual procedure. To create graphics that movewithout flickering, collision detection and tis-sue deformation must be calculated at least 30

times per second.Advances in med-

ical graphics maysoon allow ordinarymedical scans of a pa-tient’s anatomy to beenhanced into virtualthree-dimensionalviews—a clear ad-vantage for surgeonswho are preparing todo a complicated pro-cedure. Scans frommagnetic resonanceimaging (MRI) andcomputed tomogra-phy (CT) produce aseries of thin slices ofthe anatomy dividedinto volume data

points, or voxels; these slices can be restackedand turned into 3-D images by a computer

The 3-D images can also be color-en-hanced to highlight, say, bone or blood vessels.Imagery of this kind relies on a technique calledray tracing: an algorithm calculates which raysof light from the volume image would enter avirtual eye located at a point that will give thesurgeon the desired perspective. The virtual eyecan, for example, be induced to move down anoesophagus, simulating the path an endoscopicprobe would take. Three-dimensional render-ings provide a concise way of depicting an en-tire data set, instead of flipping through lots andlots of [two-dimensional] images. A surgeonsearching for, say, an abdominal aneurysmwould quickly spot it in a volume-rendered dis-play. Thus planning a procedure to fix it wouldalso be easier.

Virtual Surgery

Surgeons in NewYork removed a

68-year oldwoman’s gall

bladder as shelay across the

ocean in Stras-bourg, France,

more than 7,000kms away. This

is an illustrationof Tele-Surgery,

i.e. computerassisted surgery

involving greatdistance.

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Physicians rely a great deal on their senseof touch for everything from routine diagnosisto complex, life-saving surgical procedures. Sohaptics, or the ability to simulate touch, goes along way to making VR simulators more life-like. It also adds a layer of technology that canstump the standard microprocessor. While thebrain can be tricked into seeing seamless mo-tion by flipping through 30 or so images per sec-ond, touch signals need to be refreshed up toonce a millisecond.

The precise rate at which a computermust update a haptic interface varies, depend-ing on what type of virtual surface is encoun-

tered. Softer objects require lower update ratesthan harder objects. A low update rate may notprevent a user’s surgical instrument from sink-ing into the virtual flesh, but in soft tissue, thatsinking is what is expected. If an abrupt stop isrequired, it requires a higher update rate thanbumping into something a little squishy. Still,simulating squish is no easy task, either. Thenumber of collision points between a virtualsquishy object and a virtual instrument is largerand more variable than between a virtual rigidobject and an instrument. In addition, the me-chanics of such an interaction are complicated,because each object may deform the other.

A Clearer PictureA heated debate in the field today is how fardevelopers should go to reproduce the look andfeel of true surgery. Current technology allows

for the simulation of touch and sound (such asa patient expressing discomfort), as well as forlifelike images. But the cost of greater realismcan be prohibitive. So some companies haveturned to simple graphics-only VR simulationsthat can be run on low-end PCs.

In the coming years, VR designers hopeto gain a better understanding of the true me-chanical behavior of various tissues and organsin the body. If a haptic device is to give a realis-tic impression of, say, pressing the skin on apatient’s arm, the mechanical contributions ofthe skin, the fatty tissue beneath it, muscle, andeven bone must be summed up. The equations

to solve such acomplex prob-lem areknown, but sofar the calcu-lations cannotbe made fastenough to up-date a displayat 30 Hz, let

alone update a haptic interface at 500-1000 Hz.Meanwhile, other research groups are at-

tempting to speed the calculation of complexfinite-element models of human tissue throughparallel computing and other techniques. Stillother labs are attempting to make spring anddamper models as well as simplified finite-ele-ment models that closely match the more com-plex and realistic finite-element models, but re-quire less computation.

VR methods may also prove useful inrobotic surgery, a new technique in which sur-geons remotely manipulate robotic tools insidethe patient’s body. Current robotic systems donot allow the surgeon to feel the patient’s body.The next step then will be to incorporate hapticinterfaces, like those used in surgical trainers.

Lubaina Kitabi (VESIT)TE Computers

A CD-R drive has two actions - recording onto and reading from compact discs. A CD-RWdrive has three actions - recording, rewriting (erasing and recording over) and reading.x = 150 KB of data transfer per second2 = Speed at which writing takes place i.e. at 2 x 150 KB per sec12 = Speed at which rewriting takes place i.e. at 12 x 150 KB per sec24 = Speed at which reading takes place i.e. 24 x 150 KB per sec

CDBurnerLINGO Ever wondered what thesenumbers mean?2x12x24

A heated debate in the field today is how far developers should go toreproduce the look and feel of true surgery. Current technologyallows for the simulation of touch and sound (such as a patientexpressing discomfort), as well as for lifelike images. But the cost ofgreater realism can be prohibitive.

“What this isallowing me todo is take myhands andliterally putthem inside apatient’sbody,” sayscardiac sur-geon MarkSuzuki

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insideintelFOR MORE THAN THREE DECADES, Intel Corporation has devel-

oped technology enabling the computer and Internet

revolution that has changed the world. Founded in

1968, by Robert Noyce & Gordon Moore to build sem-

iconductor memory products, Intel introduced the

world’s first microprocessor in 1971. Today, Intel sup-

plies the computing and communications industries

with chips, boards, systems, networking solutions and

software building blocks that are the “ingredients” of

computers, servers and networking and communica-

tions products. Intel, in addition, to being the compa-

ny that invented the microprocessor also helped es-

tablish Ethernet, and created the world’s first DRAM

integrated circuit.

“Do not be encumbered by history. Go offand do something wonderful."- Robert Noyce, Intel co-founder

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Operational Overview

ManufacturingIntel is a leader in semiconductor manu-

facturing and technology and has established acompetitive ad-vantage throughits scale of oper-ations, agility ofits factory net-work, and con-sistent executionworldwide. Intelhas 12 fabrica-tion facilities and

12 assembly and test facilities worldwide. It pro-duces the silicon for its high-performance mi-croprocessors, chipset and flash memory com-ponents in its fabrication facilities. After the sil-icon-based products are created, they are sent toIntel’s assembly and test facilities where eachwafer is cut into individual microprocessors,placed within external packages, and tested forfunctionality.

Research and DevelopmentIn 2001, Intel spent $3.8 billion on R&D.

The company’s technology investments differ-entiate Intel from competitors and provide thefoundation for future growth. Intel Labs, theR&D arm of Intel, comprises of more than 6,000researchers and scientists in labs around theworld.

e-BusinessThe company’s mission

is to be a world-wide, 100 per-cent e-corporation that maxi-mizes profitability, responsive-ness and innovation. Intel han-dles everything online, fromorder processing to materialsmanagement to accounts pay-able. More than 60 percent ofIntel’s materials transactionsand 85 percent of customer or-ders are processed electroni-cally.

WorkplaceBonus Programs: Intel has two bonus programsto reward its employees, the Employee CashBonus Plan (ECBP), a profit-sharing programtied directly to Intel’s financial performance andthe Employee Bonus which is based on individ-ual and business group performance, as well ascorporate earnings per share.

Stock options: At Intel, the employees own astake in the company based on their past per-formance and anticipated future contributions.Additionally, all employees are encouraged toenroll in the Stock Participation Plan, a pro-gram that offers employees an opportunity topurchase Intel stock at a price lower than thefair market value through convenient payrolldeductions.Intel University: Intel University is a world-wide internal training organization offeringmore than 7,000 courses which facilitate thedevelopment of its employees, managers andleaders. On an average, an Intel employee par-ticipates in six different courses each year.Employees are entitled to financial assistancefor work-related courses and/or degrees out-side Intel. In order to enhance work and per-sonal lives of the employees Intel provides arange of options which include flexible workschedules, telecommuting ,childcare assistance,Work / Life seminars and training, employeediscounts, fitness centers and recreation facili-ties, health and wellness benefits, family eventsand employee groups programs.

The Intel Inside ProgramFrom the dawn of the personal computer in thelate 1970s, marketing was mainly driven bycomputer vendors and software publishers. ButIntel relied on its PC vendor customers to con-vey this message.

Thus it had very littlebrand identification amongend-users. The computerusers were totally unawareof what advanced proces-sors were available or of thecontinually improving costperformance. So, in order toeducate the people about theprocessor and the companybehind it, Intel adopted anew tag line for their adver-tising: “Intel. The computerinside.” Using this to posi-tion the important role of theprocessor and at the sametime associating Intel with

“safety”, “leading technology” and “reliabili-ty,” the company’s following and consumerconfidence soared up. Later, this tagline wasshortened to “Intel Inside”. Thus Intel InsideProgram, which was launched in 1991 was anincentive-based cooperative advertising pro-gram channelled through television, print me-dia and the Web. Intel’s innovative marketing

Year foundedNumber of employees

Products & servicesFortune 500 ranking

Worldwide offices

196880,000over 4504145

CORPORATE SNAPSHOT

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helped broaden awareness of thePC, fueling consumer demand while prices con-tinued to plunge. Thispaved the way for thePC to becomemore commonplacein the home, emerg-ing as a business, en-tertainment and edu-cation tool.

Since its in-ception, the programhas seen an invest-ment of well over $7billion in advertisingthat carries the IntelInside logos. This hascreated an estimated500 billion impres-sions, while buildingIntel’s worldwide name. Today the Intel brandis one of the top ten known-brands in the world.

Envisioning the FutureFour fabrication facilities now operate using0.13-micron manufacturing process technology.This process shrinks line widths on silicon tran-sistors to just 1/1000th the width of a humanhair, which increases processor performancewhile requiring less power and lower cost perchip. Also, smaller die sizes are being explored.Intel also begun the manufacturing conversionfrom 200 mm silicon wafers to 300 mm silicon

Net RevenuesNet Income

R&D InvestmentStock Symbol

$26.5b$1.3b$3.8bINTC

CORPORATE SNAPSHOT 2

for 2001

Intel(R) Pentium(R) 4 Proc-essor on 0.13 Micron

wafers. Chip fabrication costs on 300 mm wa-fers will be at least 30 percent lower than on200 mm wafers.

Among the projects of future are embed-ding radio devices in all of Intel’s silicon prod-ucts and enabling “write once-execute any-where” applications that will allow the user toreceive the same data on different devices-fromcellular phones to PDAs to laptops.

Intel’s new business initiatives includeWeb hosting, data center services, photonic de-

sign and manu-facturing serv-ices for opticalc o m p o n e n t ,custom chip orapplication spe-cific integratedcircuit (ASIC),design andmanufacturingservices. In ad-dition to work-ing on specifict echno log ie sthat will keepone connected,Intel is workingbehind thescenes to helpbuild the wire-

less tomorrow. It works with a number of in-dustry groups to promote standards and speci-fications that will make wireless technologiesmore widely available and easy to use for eve-ryone.

Smruti Patel, Priya Sawant, Lubaina KitabiTE Computers

along withVinesh Paperwala

Internet Solutions GroupIntel India

Intel founders (left toright) Andy Grove,Robert Noyce andGordon Moore posearound a rubylith forthe Intel® 8080processor in 1978.

Because radio waves travel at186,000 miles per second andsound waves saunter at 700 milesper hour, a broadcast voice can beheard sooner 13,000 miles awaythan it can be heard at the back ofthe room in which it originated.

DidYOUKNOW

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ave you ever been troubled by your little sister whowants to surf the net exactly at the same time youare neck deep in completing an important assign-ment? You have a cable modem at home but youcannot connect your second computer to use it si-multaneously. The most reliable solution is to builda LAN using Cat-5 cable, but the installation in-volves extensive rewiring and purchasing newequipment. Another solution is to use systems basedon the IEEE 802.11b standard. They don’t needwires but instead expensive user and control mod-ules and transceivers for every computer. For a whileit seemed that networking at home would prove tobe a very expensive affair. Intimidated already?

Not any more. There are many technologieswhich allow you to network your house. These in-clude but are not limited to power line and phoneline networking. Of these, the simplest and most

Logging on to the network...

through thepower line

How about a network that runsthrough your home’s power lines

itself? Link up your computerswith a reliable network even your

grandmother can install!

H

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efficient method is power line networking. Inthis, computers are connected to one anotherthrough the same outlet. The convenience isvery obvious in this case because while not eve-ry room has a phone jack, there will always bean electrical outlet near a computer. Since it re-quires no new wiring, and the network doesn’tadd to the electricity bill,power line networking isthe cheapest method ofconnecting computers indifferent rooms.

Power line was de-vised for transmission ofpower at 50-60 Hz; the useof this medium for datatransmission presentssome technically challenging problems. Besideslarge attenuation, power line is one of the mostelectrically contaminated environments, whichmakes communication extremely difficult. Fur-ther more the restrictions imposed on the use ofvarious frequency bands in the power line spec-trum limit the achievable data rates. There aretwo competing power line technologies. Theoriginal technology is called Passport, by acompany named Intelogis. A new technologycalled PowerPacket, developed by Intellon, hasbeen chosen by the HomePlug Alliance as thestandard for power line networking. Devicesconforming to the HomePlug standard are easyto setup and use.

Power line technologies have many ad-vantages over telephone and other types of homenetworking technologies. They are compatiblewith many operating systems. They work inde-pendent of line voltage and frequency of cur-rent. Even printers can be connected to the net-work and in no way are the features limited.

The ScienceBehind ItDevices based onIntellon’s technol-ogy use Orthogo-nal Frequency Di-vision Multiplex-ing (OFDM). This

is very similar to the tech-nology found in DSL mo-

dems. OFDM modulates the digital informationonto multiple carriers with each carrier havingits own frequency. The available range of fre-quencies on the electrical subsystem (4.3 MHzto 20.9 MHz) is split into 84 separate carriers.

Multiple bits are sent on multiple channels atthe same time, thereby making efficient use ofthe available spectrum. Each frequency is con-tinuously monitored for interference and con-sequent data loss. If the channel’s SNR is de-graded, communication slows down but doesn’t

stop. The PowerPacket chip will sense this deg-radation and switch that data to another carri-er. This rate-adaptive design allows it to main-tain an Ethernet-class connection throughoutthe power line network without losing any data.The latest generation of PowerPacket technol-ogy is rated at 14 Mbps, which is faster thanexisting phone-line and wireless solutions.However, as broadband access and Internet-based content like streaming audio and videoand voice over - IP become more common-place, speed requirements will continue to in-crease. Along these lines, Intellon’s OFDM ap-proach to power-line networking is highly scal-able, eventually it will allow the technology tosurpass the speed barrier of 100 Mbps.

The older power-line technology usedby Intelogis relies on Frequency Shift Keying(FSK) to send data back and forth over the elec-trical wires. FSK uses two frequencies, one for1s and the other for 0s, to send digital informa-tion between the computers on the network.The frequencies used are in a narrow band justabove the level where most line noise occurs.Any noise that impinges on either frequencycan disrupt the data flow, causing the transmit-ting computer to resend the data. This can af-fect the performance of the network. For ex-ample, when more electricity is used in thehouse, such as running the washer and dryer,the network slows down.

Connections And PeripheralsPowerPacket devices connect via a USB or Eth-ernet cord from the computer to a small walladapter. Other devices will have the circuitrybuilt in, meaning the only connection neededwould be the power cord. Once the physical

Intellon’s homenetworking device

They are compatible with many operatingsystems. They work independant of linevoltage and frequency of current. Evenprinters can be connected to the network.

“““““.....”””””

I could gosit out inthe woodsnear myhouse andsurf, if Ihad just anextensioncord.

John EvansManassasResident

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connections are made, in-stallation of the software is

easy. The software automatically detects allnodes on the network. The proxy server soft-ware enables sharing the Internet connectionwith the other computers. New computers caneasily be added plugging a new adapter in andinstalling the software.

Additional printers can be added usingthe printer plug-in adapter. File and printer shar-ing is done through Windows. Intelogis Pass-port technology uses a client/server networkwhereas Intellon’s PowerPacket technology usesa peer-to-peer network. The problem here is thatISP’s don’t allow more than one computer toaccess the Internet using the same connection

because only one IP address is associ-ated with a connection. Hence a routerwith Network Address Translation(NAT) will also have to be purchased.NAT lets multiple computers to shareone IP address.

ScopePower line networking can also be usedas a complement to wireless network-ing, which gets weaker and slower asthe distance from the transmitter in-creases. Instead the wireless signal can

be spread by moving the access point to a cen-tral location. Power line networking does havesome disadvantages. It might not work wherethe outlets are far apart or on separate phasesof a power line. Other devices using the powerline may cause some interference resulting inlower throughput.

Building these home networks using ACelectrical wiring is easier than running wires,more secure and reliable than radio wireless sys-tem and the least expensive amongst them all.For home and small office applications this isan excellent solution to the networking prob-lems.

Habibullah Pagarkar (VESIT)BE Information Technology

Home Power LineNetworking

The currentstandard,HomePNA 2.0,offers 10 Mbpsfor Home Phone-line networks, asopposed to 1Mbps that waspossible underthe old standard.The market forhome networks isexpected toincrease from“$567 million in2000 to morethan $6 billion by2004.

‘Hacktivism’ refers to the merging of politicalactivism and computer hacking. It is the end productof a meeting of hackers (tech. skills) and political/social activists. The hackers provide the weaponryand the activists locate the target.

‘Hacktivism’ has roots and formative ideasthat go back nearlyto the beginning of themicrocomputer revolution. As a means of socialprotest, it also draws deeply on the techniques andmany years of experiences brought in by ‘real life’activists. This includes knowledge on conducting sit-ins, media events, acts of civil disobedience, etc.

However, instead of just adopting wholesalethese techniques, the new hacktivists have takenthese ideas as a basis from which to develop newand interesting techniques more suited to themedium in which they will conduct their protest. Civildisobedience was one of the first activist tools’ to betranslated into an electronic context.

The flow of information and technique hasnot been all one- way. Activists who have come from‘real life’ protests are also adopting the tools andtechniques of the hackers when working for a cause.Activists are finding that, by coming online, they areexpanding not only the range of tools at theirdisposal, but also the ways they can connect with

like-minded individuals and groups. Also, they canapproach their targets on a dual level, both throughreal-life and virtual forms of protest.

As a result, radical groups are discoveringwhat hackers have always known: Traditional socialinstitutions are more vulnerable in cyberspace thanthey are in the physical world. Likewise, somemembers of the hacker underground are findingmotivation in causes other than ego gratification.The reasons why hackers have taken to activismare as diverse as why activists have taken to theweb.

However, the main reasons that come upagain and again when conversing with thesehacker-activists themselves are threats against theirenvironment, and changes in their own worldview.To date, hacktivism as a concept has not trulyentered the public arena. However, early publiccoverage seems to suggest that hacktivists are anidealized faceless enemy. They seem capable ofthreatening security and stability of the averagecitizen, and they seem to have an almost mythicability to destroy a computer-dominated lifestyle.And as we shall see in the next chapter, theseattitudes are reinterpreted, challenged and in somecases appropriated by the hacktivists themselves.

Hacktivism

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he problem of information security is recognized now as one of the most com-plex and its importance is growing coherently with increasing network con-nectivity, size, and implementation of new information technologies. Intru-sion is defined as “any set of actions that attempt to compromise the integrity,confidentiality or availability of a resource”.

Many of the security problems witnessed today are related to faultycode. For example, the Morris Internet worm used a buffer overflow in a UNIXprogram to gain root access to computers which ran the program. Buffer over-flow attacs have been the most common attacks over the past ten years, andinvolve overwriting instructions in the program being run by overflowing theinput buffer. Specifically, a fixed amount of memory on the stack may beallocated for user input; if the user input is larger than this allocated space, theuser can overwrite program instructions. If this is done carefully, the user caninsert his own instructions into the program code, thus causing the target ma-chine to perform arbitrary operations as dictated by the attacker. While suchattacks can typically be prevented against with bounds checking (checkingthe size of the input before copying it to the input buffer), this is a matter ofprogramming practice which we trust the programmer himself will follow.The difficult aspect of buffer overflows is that they can occur in a large numberof places in any given program, and are difficult to prevent from happeningeverywhere.

According to recent reports, information theft is up over 250% since

Hacking TheHAHAHAHAHACKERSCKERSCKERSCKERSCKERS

T

S A C H I N B A H A D U R

INTRUSION DETECTIONHow do you know whensomeone is trying tobreak into a system?Can this be stopped inreal time?

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1999. 99% of all major companies report at leastone major incident. Telecom and computer fraudtotalled $10 billion in the US alone.

It is thus more important than ever beforethat since it seems obvious that we cannot pre-vent subversion, we should at least try to detectit and prevent similar attacks in future.

The most popular way to detect intrusionshas been by using the audit data generated bythe operating system. An audit trail is a record ofactivities on a system that are logged to a file inchronologically sorted order. Since almost allactivities are logged on a system, it is possiblethat a manual inspection of these logs would al-low intrusions to be detected. However, the in-credibly large sizes of audit data generated (onthe order of 100 Megabytes a day) make manualanalysis impossible. Some complex methodsautomate the drudgery of wading through theaudit data jungle.

Methods of Detection Two advanced techniques of intrusion detectionare:1. Anomaly Detection : Anomaly detection tech-niques assume that all intrusive activities are nec-essarily anomalous. This means that if we couldestablish a ‘normal activity profile’ for a system,we could, in theory, flag all system states vary-ing from the established profile by statisticallysignificant amounts as intrusion attempts.2. Misuse Detection : The concept behind mis-use detection schemes is that there are ways torepresent attacks in the form of a pattern or asignature so that even variations of the same at-tack can be detected. This means that these sys-tems are not unlike virus detection systems - theycan detect many or all known attack patterns, butthey are of little use for as yet unknown attackmethods.

Most computer systems use an authenti-cation method which requires the user to pro-vide a password. On inter-networked systems,the user’s password (and corresponding ID) mustbe passed over the network, as typed by the user,to the remote server. This passing of the infor-mation in plain-text makes it very susceptible toattack by network eavesdroppers. To provide se-curity and privacy for a user, systems need tosupport a method to determine the identities oftwo or more remote parties that wish to exchangeinformation. This shared process of identifica-tion is called mutual authentication.

AuthenticationThe Diffie-Hellman key exchange protocol isan example of the basic mutual authenticationprotocol . In this method two users can agree ona secret session key and then authenticate overan unsecured channel by encrypting the authen-tication information using the session key. Thisbasic mutual authentication protocol may be il-lustrated in an example involving two parties,Alice and Bob, who both agree on a primenumber p and a primitive element a in a finitefield called the Galois field, GF(p). Prime pshould be such that (p-1) has a large prime fac-tor. This agreement could be based on published,system-wide constants, or could result from pre-vious communications (the values must beknown reliably by both parties).

As the first step in deriving a key, Alicegenerates a random number x, 2 <= x <= (p-2).She then calculates a*mod(p) and sends thisvalue to Bob. Bob generates a random number

2 <= y <= (p-1)calculates aymod(p) and sends this value toAlice. Then Alice calculates (ay)xmod(p) andBob calculates (ax)ymod(p). Both parties nowknow a common key, axymod(p). This basic pro-tocol prevents an eavesdropper from compro-mising axmod(p) and/or aymod(p) and invertingthe function to determine the key k.

Another technique for providing confi-dentiality using authentication is called ‘chaff-ing and winnowing’. The scheme works bysending chaff (incorrect messages) that can onlybe differentiated from the real message by theintended receiver (who winnows the stream).The word winnow means to separate or elimi-nate useless parts and is derived from its com-mon meaning, to separate wheat from chaff (use-less plant parts) on a farm. We refer to goodpackets of information as ‘wheat’ and bad pack-ets of information as ‘chaff’.

ConclusionIntrusion Detection is still a fledgling field ofresearch. However, it is beginning to assumeenormous importance in today’s computing en-vironment. The combination of facts such as theunbridled growth of the Internet, the vast finan-cial possibilities opening up in electronic trade,and the lack of truly secure systems make it animportant and pertinent field of research.

Sachin Bahadur (VESIT)BE Computers

Firewalls havebeen called‘condoms forcorporate net-works.’ They aredigital protectionfor participants inthe packet-levelintercourse. Aswith condoms, alot of people haveheard about themor know theyexist, but fewactually use them.Some who do usethem are notusing themcorrectly.

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““When moralitycomes upagainst profit, itis seldom thatprofit loses.-SHIRLEY CHISHOLM

Ethics! We say it with such reverence! Everyone talks aboutethics today - in politics, in business, in reli-gion, in the family. We discuss the ethics ofeuthanasia, genetic cloning, and income taxpreparation. The society tends to hold the pro-fessionals to an elevated standard, and engi-neering is no exception. Engineers are increas-ingly examined and scrutinized by the public,the media, the government and the professionitself is questioned on moral and ethical issues.The society expects practicing engineers toperform on a higher ethical plane. Engineersare expected to use their education, training andexperience for the betterment of public healthand safety. This justifiable expectation is cre-ating a dilemma, especially for engineering

Y O G E S H J A S H N A N Ithics inngineeringE

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students and the young practicing engineers.Engineers cannot avoid the fact that they deal ina market-place economy, where competition,cost, and profit motives seem to be the bottomline. And as is well known, many times what ittakes to please the boss, the stockholders, theclient, and our conscience is not the same.

Clearly, the demands and conflicts of cap-italism inherent in the profession present the dif-ficult dilemma of balancing many interests. En-gineers look for guidance in determining the mostappropriate course of action in such cases. Onepossible source is the law. Regulations, courtdecisions, etc. certainly provide a basis to makecertain decisions concerning conduct and behav-ior. However, the law does not address many is-sues concerning appropriate professional con-duct. Another possible resource might be col-leagues, family members orfriends. While sometimesthese sources might be ex-tremely valuable as a soundsupport, in some cases, theymight lack the necessaryeducation and training toprovide useful feedback orthe feedback might be bi-ased or prejudiced by somefact or circumstance. Forthat reason, professional or-ganizations such as IEEE,develop codes of ethics toassist engineers in makingdecisions in their every daypractice and employment.Professional codes of ethics reflect basic ‘norms’of conduct that exist within a particular profes-sional and provide general guidance relating toa variety of issues.

But no one is likely to learn much abouta profession’s ethics except at a professionalschool or while practicing the profession. Thisis why professional ethics is as much a part ofwhat members of a profession know — and oth-ers do not—as their ‘technical’ knowledge. En-gineering ethics is part of thinking like an engi-neer. Teaching engineering ethics is part of teach-ing future engineers how to practice the profes-sion.

Engineering Ethics For StudentsThe technical education provided by many ac-credited engineering schools in our country isvery good. However, awareness of engineeringpractice pitfalls and an understanding of howthey can be avoided are lacking in the curricu-

lum, and for good reason. While engineering fac-ulty is well versed in technical areas, most fac-ulty members in our education system have lit-tle or no experience working in a professionalengineering organization. As a result, they arenot aware of the professional practice problemsthat can arise on a daily basis and therefore arenot equipped to teach students how to recog-nize and mitigate these issues. This makes theneed for a separate course on this topic all themore acute. Many institutions around the worldnow offer such a course for additional credits.While such courses serve their purpose, mostare not mandatory for engineering students. Wecan modify these courses to incorporate theminto our curriculum. Perhaps this could serve asthe starting point:

The American Society for EngineeringEducation’s ASEE State-ment on EngineeringEthics Education states,“…to educate students tocope with ethical prob-lems, the first task of theteacher is to make stu-dents aware of ethicalproblems and help themlearn to recognize them.A second task is to helpstudents understand thattheir projects affect peo-ple for good or ill, andthat, as ‘moral agents’they need to understandand anticipate these ef-

fects. A third task is to help students see that, asmoral agents, they are responsible for helpingto develop solutions to the ethical problems theyencounter…” January 31, 1999.

Whistle blowingA very important aspect of practicing ethics inthe profession of engineering, which should becovered in every course on the topic, is whistleblowing. What is whistle blowing? The wordcarries strong images – the sharp sound of awhistle giving a warning of harm or calling ahalt to actions that have gone out of bounds.Generally, the whistleblower’s action is forwardlooking. The term whistle blowing is reservedfor actions of disclosure when the whistleblow-er steps outside of approved organizational chan-nels to reveal a significant moral problem. Oc-casions when the whistle was not blown bringto mind yet another feature of whistle blowing— retaliation against the whistleblower. This is

“…to educate students to copewith ethical problems, the firsttask of the teacher is to make

students aware of ethical prob-lems... second task is to help

students understand that theirprojects affect people for good orill, ...third task is to help students

see that, as moral agents, theyare responsible for helping to

develop solutions to the ethicalproblems they encounter…”

“

“

Ours is a world ofnuclear giants andethical infants. Weknow more aboutwar than we knowabout peace, moreabout killing thanwe know aboutliving. We havegrasped themystery of theatom and rejectedthe Sermon on theMount.

- Omar N. Bradley

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a predictable sequel and a strong deterrent. Re-taliation may be the most predictable feature ofwhistle blowing, perhaps enough to make it adefining feature.

Why has whistle blowing drawn so muchattention in engineering? Part of the answer isthat it dramatizes the moral situation of manyengineers. Built into codes of ethics, engineer-ing education and technical practice is an orien-tation toward safety. The technical knowledgeand organizational positions of engineers ena-ble them to detect serious moral problems thataffect the public welfare. Yet, engineers’ organ-izational positions are such that they cannot bringappropriate attention to serious problems theydetect unless they can convince others to react.Whistle blowing so naturally comes up as an

option that instructors of engineering ethics mustpay careful attention to fostering in students theskills of persuading, negotiating, and allyingwith colleagues that support other options.

ConclusionThis article serves to introduce the topic of eth-ics in relation to engineering. There are manyother aspects to this topic as well, which are veryextensive themselves. Clearly, engineering eth-ics is an issue that goes to the heart of engineer-ing practice. It is necessary for us students tounderstand the same. Only then can we becomecomplete engineers and uphold the dignity ofthe profession we will soon be a part of.

Yogesh JashnaniB.E. Telecommunications

We, the members of the IEEE, in recognition of the importance of our tech-nologies in affecting the quality of life throughout the world, and in accepting apersonal obligation to our profession, its members and the communities weserve, do hereby commit ourselves to the highest ethical and professionalconduct and agree:

1. to accept responsibility in making engineering decisions consistent withthe safety, health and welfare of the public, and to disclose promptly fac-tors that might endanger the public or the environment;

2. to avoid real or perceived conflicts of interest whenever possible, and todisclose them to affected parties when they do exist;

3. to be honest and realistic in stating claims or estimates based on availabledata;

4. to reject bribery in all its forms;5. to improve the understanding of technology, its appropriate application,

and potential consequences;6. to maintain and improve our technical competence and to undertake tech-

nological tasks for others only if qualified by training or experience, or afterfull disclosure of pertinent limitations;

7. to seek, accept, and offer honest criticism of technical work, to acknowl-edge and correct errors, and to credit properly the contributions of others;

8. to treat fairly all persons regardless of such factors as race, religion, gen-der, disability, age, or national origin;

9. to avoid injuring others, their property, reputation, or employment by falseor malicious action;

10. to assist colleagues and co-workers in their professional development andto support them in following this code of ethics.

Approved by the IEEE Board of DirectorsAugust 1990

IEEE Code Of Ethics

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Raiding The GAMES

hose were the good old days… when a high-schoolnerd made a game because it was a fun thing to do.He distributed it for free, because seeing his bud-dies having a good time playing it was rewardenough. Before he knew it his game was a phenom-

enon! People wanted more and self-interest kicked in – ‘Send me$1 if you liked it’. Then it was ‘Send me $5 for the next stage’.Pretty soon it became ‘Send a cheque to GeekInc for $20 for 6stages of Commander Keen, and we’ll also send you a T-shirt,Comic Book, Game Guide and Commander Keen’s diapers abso-lutely free!!’ Pretty soon, gaming became an industry.

It still wasn’t a problem though. Copyrighted games didn’tmean I couldn’t copy them anyway. I could go to a friend’s housewith Dangerous Dave, Prince and Test Drive and come back withGolden Axe, LHX and Death Track… all on one floppy disk! Learn-ing how to play a game took five minutes of your time. A 512Megabyte hard-disk meant you could have a hundred games storedon it and a 486DX meant you were the God of the gaming world.A 3D-accelerator? Never heard of it. Wolfenstein and Doom werethe state of the art and all of it ran just fine without any fancy-schmancy hardware! Today playing a new game would mean re-defining up to a dozen controls. It could occupy well over 4 CDsand even a Pentium-4 CPU without a decent graphic card may not

be enough to run it at maximum detail. Those were thegood old days.

Today, gaming is big business. The PC gaming in-dustry earned 20 billion smackeroos in 2001. In the USA,movies earned 8.4 billion, while games earned a stagger-ing 9.4 billion dollars. Creating a game is not a casualgeeky pastime anymore – one person just cannot create agame today using his home PC. I mean he could, but itdoesn’t count if only his parents end up buying it out ofpity. Creating a game involves years of production, witha huge team of designers, programmers, artist, testers,quality assurance staff, public relations consultants andmarketing specialists. A lot of money is poured in andpromises are made to fans and investors. With releasedates being pushed further behind each time they comeclose, the developers find themselves working all impos-sible hours to meet the deadlines – and they still feel likethey’re always chasing the setting sun – all in all, not ajob for the weak-hearted.

The games being released today are enough to leaveanybody spellbound. Each time you see a new game inaction, you tell yourself that it’s going to be impossiblefor them to top this. And then they go and do exactlythat. One of the most striking features of any new gameis the quality of the graphics. The symbiosis of the hard-

TM I H I R S H A H

Lara Croft from ‘Tomb Raider’

Journey through the fantasticevolution of computer games rightfrom the ancient Commander Keen

to the latest Warcraft and take alook into the gaming industry

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ware and software industries that has emergedtoday ensures that games will keep pushing theenvelope. Every kid who has a computer morethan six months old will try his level best to con-vince his dad that its become obsolete, “Dad!We need a new machine… I can’t play N.O.L.F.2 on this one!’ You can surf the net, manage youraccounts, write a letter, watch movies and doprobably every task under the sun short of play-

ing the latest game. The newest games requirethe newest hardware. If you wanted to buy a newmachine with the latest video card, chances areyou could end up spending a whopping 50% ofyour budget on it. The meanest daddy on theblock the GeForce FX Ultra would cost you $400or roughly Rs. 20,000. To say that gaming actu-ally drives the PC industry is not an entirely un-fair statement to make. Why would anyone whoowns a Pentium-III CPU ever choose to upgradehis machine if all he wanted to do was print doc-uments and send faxes? In fact, I think a 486would perform these tasks just fine as well.

Good graphics aren’t enough to ensurethat a game will sell. More forgettable gameswere made using the Quake III Arena engine thanI’d like to list or you’d like to know about. We’vegrown extremely finicky – we want the amazinggraphics, the fantastic music, the cool sound ef-fects, the immersive game-play and the grippingstoryline and we gripe and groan if a game fallsshort on any of these. My, how far we’ve come– I don’t think Prince had any of these, and we

grinned while playing it anyway. Developers aretrying very hard to deliver to each and every oneof these expectations. With the kind of visualperformance the fan demands today, we actual-ly have computer farms crunching away thenumbers and churning out the fantastically ren-dered scenes we see in today’s games. And thankGod for that – the cinematics we see in WarcraftIII are nothing short of magic – an absolute treat

for theeyes. The hottest performers from the music in-dustry are being roped in to provide the musicfor games – ranging from The Crystal Methodin N2O to Robbie Williams in the FIFA series.Successful writers are also being used to devel-op storylines such as horror specialist CliveBarker’s story for Undying.

Serious gaming fans are as fanaticalabout their games as Indians are about cricket.A successful game means big bucks – not onlythrough sales, but also through merchandising– Diablo novels, Tomb Raider movies and Su-per Mario dolls.

Brand loyalty counts for a lot – West-wood, Blizzard, Eidos, Id, Sierra and the jug-gernaut of them all – EA. For a loyal fan, thetime till the release of a game from his favouritedeveloper is as slow as bullet-time in Max Payne,and the time spent playing it seems to be likethe Enterprise at Warp 9.2. The coming yearlooks exciting with games like Doom 3, Com-mandos 3 and The Matrix coming up for releaseand the queues that will form if and when

Starcraft 2 is developed and re-leased, could put cinemas toshame.

As a gamer, the future doeslook exciting. The games aregoing to get better with everyrelease. As long as humans re-

DOOM 3 DOOM 1Evolution of Graphics

The queues that will form if and whenStarcraft 2 is developed and released,could put cinemas to shame.

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main innovative, we will continue to be enter-tained. Though the same DVD player will con-tinue to work just fine for movies, when it comesto games, nothing seems to be enough. Whenyou buy a new PC, don’t ever tell yourself thatit’s all you’ll ever need. I assure you, your dreammachine is already obsolete. As long as we’redreaming, if I did have a wish and I were naïveenough to waste it on ‘The Computer’, I’d prob-ably go for a Pentium-4 processor running at 3.0

GigaHertz, an Asus P4T-533C motherboard, 1Gigabyte of PC 1066 RDRAM, two 180 Giga-byte IBM Deskstar harddrives, a Toshiba 16XDVD ROM drive, an ATI Radeon 9700 Pro AGP8X 128 MB video card, a 21 inch Sony monitor,a Creative Labs Audigy 2 Sound Card and 500Watt Klipsch Promedia 5.1 speakers. I think itmight even last an entire year! Life is not fair –especially if you’re into gaming. ;-)

Mihir Shah, VJTIBE Computers

Digitally Created Face andTextures using Maya Software

Characters from the movie ‘FinalFantasy - The Spirits Within’.

A Still from Fifa 2003

G R A P H I C SXTREME

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The control and dominance of the entire electromagnetic spectrum in thetheatre of war and beyond, for military purposes is the sole purpose ofElectronic Warfare (EW). Today,

most forms of communications, navigationequipment and radars etc. rely upon electromag-netic waves. If a warring side is able to control,

suppress or entirely change the electronic trans-missions of the enemy, then he is at an advan-tage. Electronic Warfare comprises of three ba-sic parts:• Electronic Attack (EA) involves activity

aimed at degrading the enemy’s ability toconduct EW.

• Electronic Protection (EP) is aimed at pro-tecting assets against attack by an EW sys-tem.

• Electronic Support Measures (ESM) in-volves actions taken to search for, intercept,identify, and locate radiated electromagneticenergy for the purpose of immediate threatrecognition.

Electronic Countermeasures (ECM) and Elec-tronic Counter-Countermeasures (ECCM) areprovided information required for immediate de-cisions through ESM. ESM data goes into pro-ducing Signals Intelligence (SIGINT) (mainlyin the areas of Communications Intelligence(COMINT) and Electronics Intelligence(ELINT)). Since the most prevalent use of thisspectrum for weapons/sensor’s/communications,etc. is in the radio frequency (RF) region, mostcounter measures and counter-countermeasuresalso operate in that region

Electronic Support Measures (ESM)Electronic support measures (ESM) search theRF spectrum for emissions and analyze the re-sults to exploit the weapons or sensors involved.Exploitation includes tactical early warning,

Ready... Aim...

TRANSMIT

identification for counter-weapon selection andrecording to support countermeasures develop-ment. The EW receiver is the primary ElectronicSupport Measures (ESM) equipment and func-tions as a sensor for, and as a means of identi-fying friendly, neutral, and enemy electronicemissions. It provides warning of potential at-tack, knowledge of enemy capabilities, and anindication of enemy use of active countermeas-ures to manipulate the electromagnetic spec-trum. No single antenna system or specific re-ceiver circuit can cover the entire range of theelectromagnetic spectrum. A set of componentscan be designed to provide maximum efficien-cy over a range of up to a few thousand mega-hertz; however, current requirements demandperformance from a few kHz to 50 GHz with awide range of signal strengths and other param-

S A C H I N D A S N U R K A R

J I M M Y D E S A I &&&&&

ELECTRONIC WARFAREi s o n t h e p r o w l . A r m s a n d

a m m u n i t i o n a l o n e , n o l o n g e rwin wars . Wi re less technologyh a s m a d e i t s b a s e i n t h e f i e l d

o f w a r f a r e w h i c h i s a ne s s e n t i a l w e a p o n r e q u i r e d i n

every combat .

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eters such as pulse width, PRF, scan rate, side-band characteristics, and modulation. The solu-tion has been to connect many different frequen-cy-sensitive circuits called tuners and their as-sociated preamplifiers to a common chain ofmain amplifiers and display or data-storageunits. The followingare the primary de-sign criteria for EWreceivers.Wide spectrum sur-veillance:• The frequency of

the enemy radaris not knownb e f o r e h a n d .This means,with presenttechnology, thatthe frequencyspectrum mustbe searchedfrom 30 kHz to50 GHz.

• The receiver mustbe able to re-ceive both veryweak and verystrong signals without changing its charac-teristics, for the receiver is not always op-erating at great distances from a radar, butmay in fact be very close. It would be un-desirable for the resulting strong signal todisable the analysis capability.

• Signal collection is a three-stage process ofwarning, sorting and analysis. Warningalerts the operator to the presence of a sig-nal by audio modulation, flashing light or aCRT bearing line. Sorting identifies signalsof immediate interest based on the frequen-cy and modulation of the warning signal.

Analysis determines the transmitter’s spe-cific location and frequency. Signal process-ing is an important stage in EW and hencelarge amount of computation power is usedfor it.

Electronic Counter Measures (ECM)The concepts and underlying principles in EWand ECM, whether today or in its infancy, re-

main the same. The means and equipment how-ever, continue to evolve. ECM is the most cru-cial part of EW. Other forms of EW, such as EPand ESM involve the use of existent assets, suchas radars, receivers etc. ECM calls for construc-tion of dedicated hardware and software. Elec-

tronic countermeasures basically involve jam-ming of radars so that no information can beobtained by the enemy. ECM attempts to reducethe information content of the signals the de-fense receives with its sensors. The objectiveof ECM, then, is to force the air/surface defensesystem to make mistakes.

This refers to ECM activity using emis-sion of energy in a special way to offset the en-emy’s detection or attack systems. Active ECMrelies on the use of jamming and ECM podsfitted either internally on the aircraft or attachedto a hardpoint – either under the wing or on the

belly. For a jammer to bemost effective it must con-tinuously obtain signalsfrom the receiver that is be-ing jammed. This is mostoften done by stopping the

jamming for brief periods of time for the re-ceiver to ‘look through’. The time that the jam-ming is stopped must be precise so that the lookthrough receiver has enough time to record thejammed receiver and must also not be longenough to decrease jamming effectiveness.There are some jammers that can look throughwhile jamming enemy radar. The capability tocover several different bands is important, be-

The objective of ECM is to force the air orsurface defence system to make mistakes

Blanket jammingis broad-spectrumjamming thateffects allcommunicationsin the areaexcept fordirectionalantenna commu-nications.

The disadvan-tage to this sortof jamming isthat while theenemy’s commu-nications mightbe jammed,so are yours!

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cause different radars work in different bandsof frequencies. There are also several types ofECM response modes. The effectiveness of anECM transmitter (jammer) depends, among oth-er things, upon the power output of the trans-mitter, losses in the transmission line, antennagain in the direction of the victim receiver, andtransmitter bandwidth. In addition, the amountof the ECM transmitter emission delivered intothe victim receiver is a function of the receiverbandwidth, its antenna gain, and the radar cross-sectional area of the tar-get. In order to be effec-tive, the ECM transmittermust be capable of emit-ting enough power in thebandwidth of the victimreceiver to mask (jam) itsintended signal or to sim-ulate a deceptive signalrealistically.

Major Noise Jam-ming TechniquesOne-way of preventing aradar receiver (or any oth-er receiver) from functioning correctly is to sat-urate it with noise. Noise is a continuous ran-dom signal and is dissimilar to the radar signal.The radar signal or echo is a periodic sequenceof pulses. The objective is to conceal the echo.Within the general class of jamming, there arethree different techniques for generating thenoise-like signal to be used. In spot jamming allthe power output of the jammer is concentratedin a very narrow bandwidth, ideally identical tothat of the radar. Barrage and sweep jammingspread their energy over a bandwidth much wid-er than that of the radar signal. Thus, spot jam-ming is usually directed against a specific radarand requires a panoramic receiver to match thejamming signal to the radar signal. The othertwo techniques, however, can be against anynumber of radars and only require a receiver totell them that there is a radar present.

DeceptionThe other major type of active ECM is decep-tion. In contrast to noise jamming, deceptiontries to mimic the radar echo so that the radarwill respond as if it is receiving an echo fromanother aircraft or ship. For a radar to direct afire control system correctly, it must accuratelymeasure target range, bearing, and elevation. Ifeither range or bearing is misrepresented with-

out the operator’s knowledge, the target’s loca-tion will be incorrectly established. DeceptionECM is generally accomplished by repeatersand transponders, and is sometimes also calledrepeater jamming.

The radar signal is received, delayed,amplified, modulated, and retransmitted backto the radar. Transponders are used for retrans-mitting data and confusing the radar. The trans-ponder plays back a stored replica of the radarsignal after it is triggered by the radar. The trans-

mitted signal is madeto resemble the radarsignal as closely aspossible. Delay maybe employed for de-ception.

Angle DeceptionRadar and commandcontrol systems canbe confused by caus-ing the radar to gen-erate incorrect targetbearing and elevationinformation. For this

to be successful, the deception device mustcause the radar to indicate the presence of a tar-get at some time other than when the radar is atthe target’s bearing and elevation.

CW Doppler and pulsed Doppler radarswere developed to track high-speed, low-fly-ing aircraft in the presence of ground clutter.The echo-return from these radars that enablesthe target to be tracked is the Doppler shift dueto the target’s velocity.• The deception of the CW Doppler requires

that the repeater retransmit the receivedCW signal with a spurious Doppler shift,gradually increasing its magnitude to causevelocity track breaking.

• Deception of the pulsed Doppler radar ismuch the same. The repeater introduces asimilar spurious Doppler shift when itretransmits the received pulses.

Echo/Blip EnhancerAnother type of deception repeater is the echoor “blip enhancer.” This repeater strengthens theretransmitted pulse in order to make a small ra-dar target, such as a destroyer, appear as a largecarrier apparently at formation center. This mayalso be done mechanically by using properlydesigned reflectors that will make a small tar-get look like a large one.Range-gate stealing

Spot jamming isselective jam-

ming of just theenemy’s commu-nication frequen-

cies.

Its advantage isthat the enemy’scommunications

can be jammedwhile still

retaining yourown capability to

use your com-municationsequipment.

The disadvan-tage is that the

frequency atwhich the enemy

is communicat-ing on must be

known.

The EW receiver is the primary Elec-tronic Support Measures (ESM) equip-ment and functions as a sensor for, and

as a means of identifying friendly,neutral, and enemy electronic emis-

sions. It provides warning of potentialattack, knowledge of enemy capabilities,

and an indication of enemy use ofactive countermeasures to manipulate

the electromagnetic spectrum.

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mode transponder, which sends out a ‘reflect-ed’ pulse much larger in amplitude than the nat-ural return of the aircraft. Such systems are alsoautomatically triggered by enemy radar signals.The result of their work is that the enemy in-stead of seeing the return from the aircraft seesa large pulse, which moves, slowly away fromthe aircraft’s true position. Such ECM pods areideal for deceiving radar-directed Anti-AircraftArtillery, SAMs and Air-to-Air Missiles and make themvirtually harmless.

The FutureA contact that remains un-detected until its terminalphase carries the highestprobability of successfullycompleting its mission. Inthe future, all the fighter air-craft are expected to incor-porate stealthy features intheir physical design itself.This ‘stealth’ is achieved bymaking the aircraft invisibleto enemy radar. The class ofweapons so engineered are termed ‘low observ-ables’ and they make use of the latest techniquesand materials for reducing their characteristicsignature-stealth technology.

Radar, like sonar, detects targets based onthe electromagnetic waves reflected back fromthe surface of the plane. However, if the planeis designed such that it reflects the beams in suchway that they don’t reach the radar receivers atall, then the plane can’t be seen on radar – ef-fectively invisible. This is achieved by construct-ing the surface of the aircraft with oblique an-gled surfaces and also coating them with radar-absorbing paint. Some stealth aircraft are alreadyused such as the B2 Bomber and F-117 NightHawk of the USAF. Alteration of Target Shapeis another way of changing the ‘radar signature’of an object making detection difficult. The con-figuration of the target must be modified accord-ing to the principles of geometrical optics suchthat the large reflections are diverted to unim-portant regions of space (i.e., not back to theradar). The designer should avoid flat, cylindri-cal, parabolic, or conical surfaces normal to thedirection of the radar illumination. These shapestend to concentrate the energy and provide alarge radar return. The target design should in-clude the use of doubly curved surfaces that re-sult in low radar cross section.

Another way of evading a radar is usingradar absorbent materials. In this case the ob-ject to be protected is given a coating of suc-cessive layers of magnetic composition materi-al such as Ni-Mn-Zn sandwiched with dielec-trics that convert 95% of incident RF energy toheat. This material can be made as thin as 1.75cm, which is practical for aircraft use; howev-er, the weight penalty of 24.9 kg per m2 is ex-

cessive. This would noteliminate their use aboardship or at ground-basedfacilities. Another ap-proach, involving contin-uing research, consists ofa phenolic - fiberglasssandwich material. Thisstructure again converts95% of incident RF ener-gy to heat by using a re-sistive material consistingof carbon black and silverpowder. This material iseffective over the range of2.5 to 13 GHz, which en-compasses many fire con-

trol and weapon-guidance radars. The disadvan-tage of this approach is that while it is light-weight and relatively thin, it is not able to han-dle the high temperature and erosion processesat supersonic speeds.

Other forms of active EW systems underdevelopment are ones, which can radiate ener-gy – to the tune of gigawatts and completely‘fry’ any electronic devices under its coverage.Such systems can disable entire cities – includ-ing factories, telephone exchanges etc. They candisable radar stations, the computers onboardplanes etc. More personal level EW systems areguns which can ‘shoot’ a large electric chargeand completely kill, maim or temporarily disa-ble humans, animals etc.

Airborne Electronic Countermeasuressystems are essential in the survival of modernaircraft. These systems also enhance the effec-tiveness of warplanes. An integrated systemcombining both offensive and defensive assetsin the electromagnetic spectrum will thus am-plify the weapon systems’ ability to fight a mod-ern electronic war.

Sachin DasnurkarTE Telecommunications

andJimmy Desai

SE Electronics

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FACTSABOUT

FACTORIALSactorials of large numbers have long been a mystery to humans.

As we look on the far side of the number line we tend to reach

astronomical quantities which go beyond our imagination. The fac-

torials of 0, 1, 2, 3, 4, 5, 6 and so on are 1, 1, 2, 6, 24, 120, 720...

This gives an idea of how fast can a factorial reach the largest

number you have ever known.

Mathematically, factorial of a whole number ‘n’ is defined as

n! = n * (n - 1)…2 * 1 for n = 1, 2…

= 1 for n = 0.

Its conventional use is for determining number possible ar-

rangements of various objects. For example, 3! = 6, since the six

possible permutations of {1,2,3} are {1,2,3}, {1,3,2}, {2,1,3},

{2,3,1}, {3,1,2}, {3,2,1}. Since there is a single permutation of

F

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zero elements (the empty set), 0! =1.In the early 90’s factorial found its new

application in the fields of Random Number Gen-eration and Cryptography. Calculation of facto-rial is a computationally complex problem. Butwith the easy availability of High Speed Micro-processors capable of performing operations innanoseconds, it’s now possible to calculate num-bers of the order 10100000 in a few seconds.

Simple recursive routines can be used tocalculate factorials of small numbers only, be-cause of the limitations of the existing integerdata types. Even the 32 bit unsigned long integerhas the upper bound of 4294967295 (10 digits),which is obviously insufficient. This is evidentfrom the fact that 18! = 6402373705728000 (16digits). However this limitation can be tackledby using “Register Logic” while multiplying alarge number with a comparatively small inte-ger. Large number can be stored in a characterarray with each digit stored in a separate indexedlocation of the array, where a[0] represents digitin its units place, a[1] ten’s place and so on. Forexample, how will you compute:

1234567890129303030815159196036378 * 38 =?

The answer is ‘simple’, you will use yourhigh school multiplication methods or in otherwords, the carry method. 38*8 = 304. So 4 nowbecomes your new unit digit, So we store a [0]=4 and remaining 30 goes as carry for the nextmultiplication. Next, you would calculate 38*7= 266, add the carry 266+30 = 296, Hence a [1]=6 and carry will be 29. This way we can get thewhole answer.

While calculating factorial of a number‘n’ this has to be done for n times, which makesthe problem computationally expensive. The fol-lowing C code snippet can be used to implementthe factorial calculation explained above:

for (i=1; i<=n; i++){

c=0;j=0;while (j<=stop){

temp= (a[j]*i+c) %10;c= (a[j]*i+c)/10;a[j] =temp;j++;

}}

Random Number GenerationThe number sequences generated for factorialgeneration are truly random. This is evident fromthe fact that frequency of occurrence of all the10 digits happens to be similar, once the trailingzeroes are truncated. In fact, number of trailingzeroes ‘z’ in n! can be calculated using the fol-lowing:

The C code given alongside is capable ofgenerating huge numbers which can ex-tend upto thousands of digits. The follow-ing output would give you an idea:Enter the no: 555

661408560927794670909833167124276990212353194561078966630610091508066518398462938708570165931453818774346806677937487622941296716409901122180791183381615199180133649323135568584492485536333258769584469786383591661922104266566863913614070698138881545530808522346156055053115762262612679476256481322688203567171111038254916285768948868390683387427561794062346854491689633073215348773710363218016157511181863057926134577070731221701301152592821760868454925199903505386017787199554004695300736714548162986647886019771379144075642172619449355885906311490931562018599832173006150698910081357711177369686310362939324425024584999311539904643730800189147272918915911770251276375152459026027462464002063813902395684537655374791000270699823191370607631655257869634515506590089013974314269381678319888713892407305906053693865079154285101747723299382026182512365914527438847783156831674629869733219475045947728356608604070725171727115599864469722301348700056888092787342824689113236014679770929700834913475709726807511726110607658874785711823552896770088837953463376048502815279955957922924689302538415337162205637471098765281762231617571867644711936978426265600000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

0 count: 247 1 count: 138 2 count: 1013 count: 114 4 count: 895 count: 109 6 count: 133 7 count: 1258 count: 115 9 count: 113

Number of trailing zeroes = 137Total Number of the digits for 555! = 1284

mEtRiCs

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One cannotescape thefeeling that themathematicalformulae havean independentexistence andan intelligenceof their own,that they arewiser than weare, wiser eventhan theirdiscoverers,that we getmore out ofthem than wasoriginally putinto them.

- Heinrich Hertz

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The following algorithm can be used for randomNumber generation:(Here we would generate random numbers oflength 7. But this might be changed according tothe application)1. Select the timestamp as the seed for the ran-dom number generator. This ensures that the samestart point do not occur more than once. e.g.: On10/03/03 at 2:00 pm we can have the seed as1003032.2. Consider the first 4 digits of the randomnumber as the handle and the next 3 digits asoffset.3. Take the factorial of the handle and then usethe offset to select the next random string of therequired length. e.g.: 1003! and then select thestring from the 32nd digit onwards.4. Repeat the above procedure.

The price to be paid for true randomnessis the computational complexity. However thestrings are truly random. For getting random num-bers in a particular range we can use Modulofunctions. E.g.: random number in the range of11 to 20 can be obtained as:

Rand = (N mod 10) + 11

CryptographyThe factorial logic can also be applied to Infor-mation Security. An innovative Symmetric keyalgorithm can be used. The Encryption/Decryp-

tion can be implemented using the algorithmwhich is similar to the one used for randomnumber generation. The security lies in the se-cret key which is same for both the sender andthe recipient. Hence inherent threats such as Rub-ber Hose attacks exist but nothing much can bedone about that. Probably, one can use a secretkey exchange protocol.

Let the key be denoted by K (more than 4digits) and the session key can be denoted by S.1. Initially a session key is established before anytransmission can be done. This can contain manyuseful data fields which include time, computerID, Operating System, etc. However two moredata fields are needed i.e. OFFSET Value (keylength) and the E-LENGTH encrypted length(10 to20).S = OFFSET + E-LENGTH + Additional Information2. Now the sender computes K! which is a verylarge number and uses the Offset value to locatethe string and extracts the string of the size stat-ed in the encryptor length which varies from 10to 20. Now this encryptor is used to code the data.3. Recipient knows all the 3 essential entities:OFFSET, E-LENGTH and the secret key. Hence know-ing the decryption algorithm with the requiredinputs data can be successfully decrypted.These mysterious numbers truly have widespreadapplications in many fields of growing impor-tance.

Virag ShahBE Information Technology

N U M B E R O L O G Y

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m u l t i m e d i a

S H I V A N I S A H I

he need for web-based applications is growingand a tool that allows web-developers to stream-line huge audio-video applications in a lighterformat on the web is being sought. Real timesynchronization and playing of multimedia clipswithin the web context, Internet Explorer 6.0,MMS technology, Real players and much moreis what Synchronized Multimedia IntegrationLanguage (an XML compliant language) is cre-ating. Standardized by the W3C, the Web Con-sortium, this powerful tool adds to the Web tech-nology, the much needed flexibility.

The needExperience from the CD-ROM and the Web mul-timedia community suggested that it would bebeneficial to adopt a declarative format for ex-pressing media synchronization on the Web asan alternative and complementary approach toscripting language. To bring about this facility,W3C established a working group on Synchro-nized Multimedia in March 1997, giving rise toSMIL1.0 ( pronounced as Smile).

SMIL is a World Wide Web Consortium(W3C) language that allows Web authors to po-sition and time media elements for display in aWeb multimedia browser. With SMIL, the Webis no longer a place of still text and images. Itbecomes a true multimedia universe.

SMIL is a language for choreographingmultimedia presentations where audio, video,text and graphics are combined in real time. Sim-ply put, it enables authors to specify what shouldbe presented when, enabling them to control theprecise time that a given sentence is spoken andmake it coincide with the display of a given im-age appearing on the screen. In order to providenew features compared to SMIL 1.0, such as,

author-defined windows, improvised event-han-dling, hierarchical layout and authoring adap-tive content, the animation subset of SMIL2.0became a W3C recommendation around Sep-tember 2001.The goal of SMIL 2.0 was to ex-tend the development of SMIL as a declarative,XML-based timing and synchronization lan-guage, and advance the corresponding timingmodel. SMIL2.0 covers the various areas offunctionality such as Animation, Content Con-trol, Layout, Linking, Integration of Media ob-jects, Meta-information, Structure, Timing andSynchronization, Time manipulations and Tran-sition effects.

Most of the SMIL enthusiasts were wellversed with W3C language even before it wasintroduced. Realnetworks one of the biggest on-going supporters of SMIL, rolled out their newG2 player. This second generation RealPlayershowed off the expected improvements in au-dio and video streaming. But weaving it all to-gether was SMIL. People understood SMIL asHTML for multimedia. Now a streaming mediadeveloper had much greater control of where andwhen media is played in the window. Low band-width solutions like streaming images and link-

tm u l t i m e d i a

CHOREOGRAPHEDCHOREOGRAPHED

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able text added sophistication. This was a lan-guage designed around the Internet and the vi-sion of things to come was tantalizing. Sure therewere still other important players. But to many,it seemed that SMIL was a one-format show. Ofcourse with a great idea, even a one-format showcan make it on the Internet. RealNetworks is adominant streaming browser. So while Micro-soft and Macromedia proposed their ownHTML+TIME version of SMIL to the W3C, Re-

alNetworks continued to integrate SMIL moretightly into their player. Most RealPlayer con-sumers use SMIL on a regular basis. They justhave no idea SMIL is the mechanism driving thelayout and timing of media in the RealPlayerwindow. Even then SMIL has gradually droppedoff the radar of all but the most dedicated Webmultimedia enthusiasts.

In the last several months, industry ac-ceptance of SMIL has begun to improve. WhileMicrosoft rolled out an HTML+TIME author-ing tool called Vizact 2000 and wrapped theirlanguage into their IE 5.0 browser, the publicityof their HTML+TIME language has receded.Later, they rejoined the process as the W3C rolledout their next version of SMIL (called ‘SMILBoston’). Following this, Apple announced thatSMIL support would be included in QuickTime4.1. So suddenly, SMIL is gaining new life as allthree major streaming players come on board.

CharacteristicsTo time the components, the basic idea is to namemedia components for text, images, audio andvideo with URLS and to schedule their presen-tation either in parallel or in sequence .A typicalSMIL presentation is composed from severalcomponents that are accessible via URLs, e.g.files stored on a web server. Also the compo-nents have different media types, such as audio,video, image or text. The begin and end times ofdifferent components are specified relative toevents in the other media components. For ex-ample in a slide show, a particular slide is dis-played when the narrator in the audio starts talk-ing about it.· Familiar looking control buttons such asstop, fast-forward and rewind allow the user tointerrupt the presentation and to move forwardor backwards to another point in the presenta-tion. Additional functions are ‘random access’,

i.e. the presentation can be started anywhere, and‘slow motion’, i.e. the presentation is playedslower than at its original speed. The user canalso follow hyperlinks embedded in the presen-tations.

ApplicationsPhotos taken with a digital camera can be coor-dinated with a commentary. Training courses canbe devised integrating voice and images. A Web

site showingitems for salemight showphotos of theproduct range

in turn on the screen, coupled with a voice talk-ing about each as it appears.

SMIL Vs FlashSMIL is not sensitive to the kind of media itworks with. The goal is to provide a frameworkto control the media used. There are a few sim-ilarities between SMIL and Flash, which needto be highlighted. In the big scheme of things,Flash is still an animation format. It has wideindustry acceptance by content creators and us-ers. SMIL, in the big picture, is more global innature. To SMIL, Flash is potentially just an-other media type to integrate with other mediatypes. But by outward appearances But by out-ward appearances today, Flash is better. For mostpractical Web multimedia projects today, thelook of a Flash piece can usually match SMILand often beat it. So what is it that Flash has butSMIL does not? And why hasn’t SMIL claimedits rightful Web multimedia throne? It is all aboutcontent creation software, which is present inFlash and not in SMIL. SMIL has and still con-tinues to be a creation of Web engineers. But forSMIL to survive and thrive, it desperately needsWeb designers. The structure is built, now itneeds artists to paint it. Flash is understandableand growing more polished with every release.In comparison, most SMIL authoring tools arecomplex and require some serious treatment. Theonly bright spot on the horizon has been Real-Networks’ Real slide show an intuitive stream-ing image tool that is designer friendly.

The futureThe Web is quickly becoming a multimedia uni-verse. With the right tools in the right hands,SMIL will be there to help start that revolutionand a footnote in Internet history.

Shivani Sahi (RAIT)TE Information Technology

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t first look this article might seem to undertake quite an easy task. Butin case you have never tried it before, generating a maze is a job easyenough in concept but implementing it stretches a programmer’s im-agination to the limit.

MAZE GENERATIONThe simplest type of mazes solved bycomputers is defined as a perfect mazebecause they are perfect for the com-puter to solve! Technically a perfectmaze is defined as a maze which hasone and only one path from any pointin the maze to any other point. Thismeans that the maze has no inaccessi-ble sections, no circular paths or loops and no open areas. In this arti-cle we shall be talking only about perfect mazes adhering to the NEWS

(North East West South) protocol i.e. allowing motion only in the 4directions. The method described here can make mazes of n dimen-sions and of any shape or size.

The picture shows a perfect maze which seems easy enough. Adeeper insight into the picture will reveal that the maze shown aboveis actually rendered from a 16x12 grid of cells. The horizontal andvertical lines of the grid represent the walls of the maze. It is this re-semblance that enables us to arrive at the maze in a manner quite sim-ilar to tree traversing algorithms. We start with a grid with all the wallsup and then knock the walls down depending on a criterion or in a

random manner. So in short we have to:1) Walk through the grid in a random manner choosing any startingpoint.2) At each cell determining if the wall between this cell and any ad-joining cell can be knocked off.There are three simple approaches employed in developing mazes.Technique 1: Depth First Search

Will you

Start The MazePlease!

A

The objective is to learn thetechniques and algorithms of

creating and conquering mazes.This is a two minute game from

the second I close the door...

A B H I J I T A K H A W EA Perfect Maze

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This method employs the widely used DFS al-gorithm to traverse randomly through the gridknocking down walls. Basically it involves twoiterative steps:i) Pick a random starting location as the “cur-

rent cell” and mark it as “visited”. Also, ini-tialize a stack of cells to empty (the stack willbe used for backtracking). Initialize VISIT-ED (the number of visited cells) to 1.

ii) While VISITED < the total number of cells,do the following:

• If the current cell has any neighbours whichhaven’t yet been visited, pick one at random.Push the current cell on the stack and set thecurrent cell to be the new cell, marking thenew cell as visited. Knock out the wall be-tween the two cells. Increment VISITED.

• If all the current cell’s neighbors have alreadybeen visited, then backtrack. Pop the previ-ous cell off the stack and make it the currentcell.

This algorithm is probably the simplest toimplement, but there are many mazes which itcannot generate. In particular, it will continuegenerating one branch of the maze as long asthere are unvisited cells in the area instead ofbeing able to give up and let the unvisited cellsget used by some different branch. This can bepartially remedied by allowing the algorithm torandomly backtrack even when there are unvis-ited neighbors or by limiting the stack size, butthis creates the possibility of (potentially large)dead spaces in the maze. For some applications,such as dungeon creation, this behavior mightbe desirable. A refinement which cuts down onthe amount of dead space is to vary the proba-bility of backtracking as an increasing functionon the number of iterations since the last back-track. This involves a lot of overhead calcula-tions which would considerably slow down thesystem if the size of the maze is huge. The algo-rithm demands heavy resources due to the stacksize.

Technique 2: Prim’s algorithmThis algorithm works by growing a single tree(without concentrating on any one particularbranch like the previous algorithm). The follow-ing iterative steps are used while implementingthis algorithm:i) Maintain three sets of cells: IN, OUT, and

FRONTIER. Initially, choose one cell at ran-dom and place it in IN. Place all of the cell’sneighbors in FRONTIER and all remaining

cells in OUT.ii) While FRONTIER is not empty do the fol-

lowing:• Remove one cell at random from FRONTIER

and place it in IN.• If the cell has any neighbours in OUT,

remove and place them in FRONTIER. Thecell is guaranteed to have at least one neigh-bour in IN (otherwise it would not have beenin FRONTIER); pick one such neighbor atrandom and connect it to the new cell (i.e.knock out a wall).

Technique 3: Kruskal’s AlgorithmThis is perhaps the most advanced of the mazegeneration algorithms, requiring some knowl-edge of the union-find algorithm. Basically whatthe union-find algorithm does is give a fast im-plementation of equivalence classes where twothings can be done:FIND which equivalence class a given objectbelongs toORUNION two equivalence classes into a singleclass. Any moderately advanced book on algo-rithms and data structures will have more de-tails.In this algorithm, the objects will be cells in themaze, and two objects will be in the same equiv-alence class if and only if they are (perhaps in-directly) connected. The maze building pro-ceeds as follows:i) Initialize the union-find structures so that eve-

ry cell is in its own equivalence class. Cre-ate a set containing all the interior walls ofthe maze (ie those walls which lie betweenneighbouring cells). Set COUNT to thenumber of cells. (COUNT is the number ofconnected components in the maze).

ii) While COUNT > 1 do the following:• Remove a wall from the set of walls at ran-

dom.• If the two cells that this wall separates are

already connected (test by doing a FIND oneach), then do nothing; otherwise, connectthe two cells (by UNIONing them and dec-rementing COUNT) and knock out the wall.

None of these algorithms make any assumptionsabout the topology of the maze. They will workwith 2-d or 3-d grids, toroids and hexagons.However, in the more highly connected topolo-gies (such as 3-d grids), the deficiencies of theDFS algorithm will become even more appar-

The easiest wayto traverse any

maze is to catchhold of any

boundary walland then

proceed in asingle direction.

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ent (it will tend to produce long, winding pathswith very little branching).So get your computers out to implement thesealgorithms and design mazes. After having gen-erated mazes let’s look at the second part; howdo we solve mazes being passed onto us?

MAZE SOLVING

Rat ApproachConventional maze solving algorithms haveevolved mainly around the “rat” approach inwhich a “rat” effectively runs through the mazeand backtracks only on approaching a dead-end;implying only a local knowledge of the maze

relative tothe “rat’s”p o s i t i o nsince itc a n n o t“ s e e ”around thec o r n e r s .These al-g o r i t h m sare inher-ently recur-

sive since at any point of in-tersection one path is selected and the intersec-tion remembered until a dead-end is reached.This DFS traversal becomes slow and cumber-some for higher order mazes.If the memory requirements are left for a mo-ment then we can have a global idea of the mazeby letting in more than 1 rat. This method makesthe job faster especially if we have a multitask-ing environment.

Spawning ThreadsAnother algorithm derived from the DFS makesuse of spawning threads from each intersectionby numbering the adjacent cells in consecutivenumbers. This is more like the reverse of Prim’sAlgorithm.

Cellular AutomataA more intuitive approach involves use of a Cel-lular Automata concept. A two dimensional ar-ray of cells is defined with each cell represent-ing a position in the maze. Then a state transi-tion rule determines the state that can be takenby a cell in each iteration. This rule dependsupon the current state of the cell and its imme-diate neighbours. 2 states are defined for eachcell in CA. A “free” cell corresponds to a free

The oldest European story about a labyrinth is The-seus and the Minotaur. This maze seemed to havebeen buildings with lots of rooms, joined in compli-cated ways, unlike any modern maze. However uni-cursal mazes are considered to be the oldest knownmaze. The oldest design of a reasonably complexmaze is the Cretan maze, although spirals and GreekKey patterns have been used before this. This late12th Century manuscript maze (13cm in diameter) isin the Bayerische Staatsbibliothek in Munich (Clm.14731, Fol 82 v.). The text above the maze reads CUMMINOTHAURO PUGNAT THESEUS [IN] LABORINTOwhich means Theseus fights with the Minotaur in theLabyrinth. The maze design was clearly intended tobe the 12-level simple, alternating, transit maze 0 3 21 4 7 6 5 8 11 10 9 12, a common maze in medievalmanuscripts, but the 11th level was taken over bythe center image (traces of it are still visible); level 8is led directly to the center; levels 9 and 10 are nowcut off from the rest of the path, and have been joinedseparately to the center. The topological meaning ofthe maze has been sacrificed to the visual impact ofthe composition. They can be as simple as a gamein a child’s coloring book, or as enveloping as ahouse of mirrors. They can be entertainment for aSunday afternoon stroll in a garden or a path alonga deep spiritual journey. They are mazes.

The first recorded maze in history wasthe Egyptian Labyrinth. Herodotus, a Greektraveller and writer, visited the Egyptian Labyrinthin the 5th century, BC. The building was locatedjust above Lake Moeris and opposite the city ofthe crocodiles (Crocodilopolis). Herodotus wasvery impressed by it, stating, “I found it greaterthan words could tell, for although the temple atEphesus and that at Samos are celebrated works,yet all the works and buildings of the Greeks puttogether would certainly be inferior to thislabyrinth as regards labour and expense.”Herodotus added that even the pyramids weresurpassed by the Egyptian Labyrinth.

Herodotus was told that the land of Egypthad been divided into twelve kingdoms, ornomes, each ruled by a king. The kings had cometogether to leave a memorial of themselvesthrough this temple which was called Arsinoë,which means “the temple at the entrance of thelake.” The entire building was surrounded by awall and contained 12 courts with 3,000chambers. The roof of the temple was composedof stone and the walls were covered withsculpture. On one side of the labyrinth was apyramid 243 feet high. The temple was in twolevels with half of the rooms above ground andthe rest below. Herodotus was guided through theupper part of the labyrinth, but was not permittedto go underground. He was told that the roomsbelow contained the bodies of the kings thatconstructed the temple and the tombs of sacredcrocodiles.

T H E O L D E S T T Y P E O F M A Z E

The Cretan Maze

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location and a “wall” cell implies presence of awall at that position. The state transition rulesapplied to each cell every iteration are as fol-lows:

1. If I am a free cell and I’m surroundedby 3 or 4 NEWS wall cells then I willbecome a wall cell.

2. If I am a wall cell then I will alwaysremain a wall cell.

3. A free cell surrounded by less than 3EWS wall cells remains a free cell dur-ing the iteration.

The advantages of this method are quite appar-ent. Unlike previous methods it is fast and itcan even handle imperfect mazes. Also the so-lution is iteratively attained. As a result at anypoint the solution set is a narrowed version ofthe previous solutions. In addition the memoryrequirements are very less as at any point as onlya small part of maze needs to be analyzed at any

time and no stacks are used. Also if the mazecells are allowed to be overwritten then the so-lution is permanent for future access unlike othermethods wherein the whole algorithm wouldhave to be run again or a huge stack be built upfor storing the path.

The biggest disadvantage of this meth-od is the fact that it is not applicable in real lifesituations. This is because it requires the knowl-edge of entire maze beforehand; somethingwhich is not possible in case one’s aim for us-ing this algorithm is to try and get out of a maze!Thus we have seen that a simple topic like MazeGeneration requires a lot of in-depth explana-tion. So get your computers running and con-vert the above algorithms to programs or if youare more on the theoretical side then rack yourbrains and evolve your own methodologies todevelop mazes.

Abhijit AkhaweTE Electronics

IN COMPUTER JARGON, A BOUNCED E-mail is one that never arrives in the recipient’sinbox and is sent back, or bounced back, tothe sender with an error message thatindicates to the sender that the e-mail wasnever successfully transmitted. But whathappens when someone sends an e-mail outinto cyberspace, and why do e-mails some-times bounce back?

When a user attempts to send an e-mail, he is telling his e-mail system to look forthe domain of the recipient (for example,rediffmail.com) and the domain’s mail server.Once the e-mail system makes contact withthe recipient’s mail server, the mail serverlooks at the message to determine if it will letthe message pass through the server. If therecipient’s server has predetermined that it isnot accepting e-mails from the sender’saddress (for example, if it has blocked theaddress for anti-spamming purposes), theserver will reject the message and it willsubsequently bounce back to the sender. Themessage will also bounce back to the server ifthe mail server on the recipient’s end is busyand cannot handle the request at that time.When an e-mail is returned to the senderwithout being accepted by the recipient’s mailserver, this is called a hard bounce.

Once the e-mail has been accepted bythe recipient’s mail server there are still waysfor the message to be rejected. The mailserver has to determine if the recipient (for

Why E-Mails BOUNCETake a behind-the-scene look to find out why all thosemails bounced just when it was most important

example, webmaster@rediffmail.com) actuallyexists within its system and if that recipient isallowed to accept e-mails. If the recipient’saddress does not exist on the mail server,then the message will be rejected becausethere is no one to deliver the message to. Ifthe sender misspells the recipient’s address(for example, qebmaster@rediffmail.com) thenthe system will recognize this as a nonexistentaddress and bounce the message back. If therecipient exists but does not have enough diskspace to accept the message (i.e. if his e-mailapplication is filled to storage capacity) thenthe message will bounce back to the sender.Some mail systems predetermine a maximummessage size that it will accept and willautomatically bounce the message if itexceeds that size and some mail systemspredetermine a maximum amount of diskspace the user is allowed to occupy on theserver. When an e-mail is returned to thesender after it has already been accepted bythe recipient’s mail server, this is called a softbounce. Some mail servers are programmedto accept incoming e-mails and store them forfurther analysis without initially checking todetermine if the recipient exists or is evencapable of receiving the message.

Occasionally, a network failure at thesender or recipient end will cause an e-mail tobounce back to the sender. Typically, abounced e-mail returns to the sender with anexplanation of why the message bounced.

A L G O R Y T H M S

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“It’s only fair for me to demand my share of education… but I am deprived of quality education in India today. Icannot wait for gearing up of Indian Education System to better standards”.

- Chant of students affected by their inability to get admissions into the IIT’s and IIM’s.

Need For Education in US

These are the students who are looking for studiesin US. In last four years number of students goingfor further studies to US has almost doubled (from37,482 in 1997-98 to 66,836 in 2001-02 as perreport by Institute of International Education inNew York). This leads the student to jump ontothe bandwagon for a US qualification and is justi-fied, by all means. This is where the choice of a‘right’ university is important. Education is open,transparent and Private Industry in USA. It has tobe borne in mind that if there are world class re-puted institutions in US, there are also absolutelyworthless and bad universities. There are also anumber of doubtful players in the industry run-ning colleges. As Education is Private Industry inUSA, there are no entry or exit barriers and any-one can start a college, there being no restrictions.While there are many excellent universities, thereare some with questionable credentials. The mar-ket forces decide whether an educational instituteexists thrives or closes down. If a college is bad,the market forces the closure of that college (andnot the government). It may invite trouble if webelieve every US institute is worth its salt.This calls for an exercise of utmost caution-de-tailed research of all the institutes available! Evennative students in USA engage the services of theeducational consultant/counselor for the right se-lection of University. There are a large number ofProfessional (Educational) Consultants in US of-fering specialized services for the selection ofUniversity. Given the choice of options available,if native American student thinks it necessary toengage the services of the counselor for selectionof University; it makes even more sense for In-dian Student to carry out detailed research on vari-ous US universities. Selection of the right univer-sity is one of the most important and crucial deci-sions. Right decision means a step in the right di-

rection; wrong decision-a regret for lifetime! Awell-informed decision is an imperative and ines-capable necessity.

Student Recruiter or Counselor?

There are about 3500 universities/colleges. Onlytop 100-200 are competitive. Rest of the universi-ties are broadly not competitive. They competewith each other to get more students. It is a well-accepted practice in US to appoint an EducationalConsultant (Referred to as a Student Recruiter) onCommission basis. In these universities you justhave to apply for admission (either directly or thruRecruiter/Agent) and they are more than eager togive you admission. Therefore, the Recruiter gen-erally doesn’t charge any fees from the student inreturn. On the other hand there are Professionaleducational counsellors who receive fees from stu-dent to counsel student on right selection of uni-versity. He does not receive any commission orfees from university nor does he have any tie upwith any university. He is expected to concentrateonly on the interest of student.

Prospect of job in US for Indian Students

In order to compete in US job market after com-pletion of education, Indian student must havemuch more (academic/professional) strength com-pared to his local counterpart in US in order tosecure a job. As a foreigner, an Indian student facesproblems in US job market. He needs that extraedge to out-compete locals to overcome the handi-cap. Only a good university can provide that ad-ditional edge and strength needed to compete &survive the fiercely competitive industry of U.S.Hence it makes sense for Indian student to con-centrate only on top ranked and good universities.

STUDIES IN USA & SELECTION OFRIGHT UNIVERSITY

-Article by R. Arjun - B.Tech (IIT-Delhi); MBA (IIM-Ahmedabad)Founder - Arjun Classes, Educational Counselor since 14 years - counseling students for various US

Universities. Contact: 26485500 / email: arjun_classes@yahoo.com

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Too Many Cooks?

Great For The BrothA S H A K R I S H N A N

THE NEED FOR HIGH SPEED NETWORKS combined with high performance

processors has paved way for highly efficient multi-processor architecture models. The two existing mod-els – shared memory model and distributed memorymodel have their own shortcomings. While in the firstcase the processors access the same address spacethrough shared variables there arises the problem ofshared data integrity. Also the problem of reduced scal-ability arises due to limited bandwidth of the shareddata bus. The distributed model ensures better scala-bility since in this case each component is connectedto a high speed network. However the programmingmodel is difficult because it involves splitting the taskinto smaller modules for each processor and then reas-sembling the results into a single solution. PISMA(Parallel vIrtually Shared Memory Architecture)combines the benefits of these two models and over-comes their respective shortcomings.

PISMAPISMAPISMAPISMAPISMA : Parallel vIrtuallyShared Memory Architecture -A design of brilliance enablingfaster, simpler parallelprocessing

S M R U T I P A T E L

P R I Y A S A W A N T

&&&&&&&&&&

Charles B

abbage - Father Of The C

omputer

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PISMA ArchitectureThe basic model of PISMA comprises of a grid-like structure of alternating processor and mem-ory modules. Each proc-essor module is connect-ed to 4 other memorymodules and again eachmemory module is con-nected to 4 other proc-essor modules. In thisway each processor isconnected to 8 otherprocessors through itsfour adjacent memorymodules. Now the gridso formed is first foldedalong one axis and thenalong the other to forma doughnut like struc-ture. Thus the model ofPISMA is a torus of al-ternating processor andmemory models. Building element of PISMA isa 4 processor - 4 memory board. The four proc-essor boards attach onto the memory board withthe 4 memory modules. The connectors that con-nect the block with adjacent blocks or to the op-posite connectors of the same block form thesmallest 4 processor – 4 memories PISMA. Thegaps on every other processor or memory bushelp forming the “checker” pattern of proces-sors and memories when many blocks are com-bined together.

PISMA Programming ModelThe programming model of PIS-MA consists of mapping the exe-cution tree onto the grid of proc-essors. The dynamic load balanc-ing algorithm which is the keyelement in this architecture, as-signs tasks to the processors withthe objective of attaining a bal-ance between the conflictinggoals of equal distribution oftasks and prevention of creationof long paths of communicationbetween a remote processor anda memory module. The code isloaded randomly into one mem-ory module and assigned dynam-ically at runtime to the proces-sors. The dynamic load balanc-ing algorithm divides the workinto granules each consisting of

a header – bearing information about the re-sources employed by the work granule and thebody – consisting of the code to be executed.

Features of PISMA• Intra-processor com-munication: Since proc-essors communicate be-tween each otherthrough neighbouringmemory modules thecommunication does notrequire any networkmedia. It is therefore in-tra-processor communi-cation.• High fault tolerance:In the PISMA model ifone processor or mem-ory module along a par-

ticular path of communication fails the work isimmediately and dynamically assigned to an-other processor or memory module. So themodel has high fault tolerance.• Virtual memory management: There are twoaddressing modes in PISMA – direct address-ing mode and mixed addressing mode. The firstmode of addressing is when the data is residingin a adjacent memory. However for remote dataaccess the second mode is used. The mixed ad-dressing mode comprises of direct accessing aswell as message passing. In PISMA the memo-ry management is virtual in the sense the selec-

Suppose that you have to paint a really long fence. Itwill take a lot of work for you to paint it completely, andyou really don’t want to burden yourself. So you say toyourself, “If I get five people to share the work, I’ll haveto do much less.” So you pat yourself on the back andget four other friends of yours.

Now you pick up the bucket of paint and startpainting. You think to yourself, “I’ll paint for ten minutesand then I’ll give the paint bucket to the next person andso on. What a brilliant management of available re-sources!” That’s sharing of resources.

Suddenly you realize, that instead of this method,if you divide the paint equally among the five of you,then each person could begin painting simultaneously.Not only would the work load continue to be less oneach person, but also the work would get done in one-fifth of the total time. That’s working in parallel. And thisis the essence of PISMA - sharing of resources andworking in parallel.

P I S M A F O R D U M M I E S

PISMA Model

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tion of the appropriate addressing mode is com-pletely dynamic and transparent to the applica-tion programmer.Here arises the question of dividing data into twokinds – private data and shared data. Private data

are variables residing in one adjacent memorymodule and accessing is therefore straightfor-ward.The processor presents the real address on its busand reads from the appropriate memory. No soft-ware translation mechanism is needed for this.On the other hand shared data needs indirectionpointers to be specified. In this case a softwaretranslation mechanism is used .When the appli-cation software executes the data maybe directlyaccessible and referenced through an offset oraccessed by message passing. When a sharedvariable is directly accessible by a processor, thecorresponding indirection pointer contains itsphysical address in one of the four adjacent mem-ories. If not, then the value contained in the in-direction pointer will be a special memory ad-dress designated to generate an OS trap. The in-direction pointer contains additional informationabout the shared data location in the system, suchas the physical memory module, the address andusage status of this particular shared resource.The generated OS trap service routine translatesthe request into a remote-data requesting mes-

In PISMA the memory management is virtual in thesense the selection of the appropriate addressingmode is completely dynamic and transparent to theapplication programmer.

sage, utilizing the resource’s location informa-tion from the indirection pointer.• Message passing mechanism: As is alreadymentioned communication beyond the 8 proc-essors to which a processor is connected to is

achieved by message passing.Message passing is achievedthrough packet switchingwherein messages are forward-ed from processor to processortill the destination is reached.Each message is equipped witha header describing its type, itsdestination processor’s loca-

tion on the grid, and its originator (if this is nec-essary). The message route through the proc-essor grid is not pre-established when the mes-sage is generated. Each processor, upon receiv-ing a message, decides to forward it to one ofits eight neighboring processors, or to consumeit itself. The forwarding direction is found bycomparing the destination processor’s location,from the message header; with the forwardingprocessor’s own location (it is assumed thateach processor has the knowledge of its ownlocation).

ApplicationsAnalyzing the features of this architecture it isright to infer that this model will have applica-tions in fields that require high speed networks.One such example is for video-on-demand serv-ice. Given the current scenario where speed andperformance are the top most on a list of bur-geoning demands of the consumers, models suchas these aren’t a far-fetched dream, but insteada distant reality.

Adapted from the paper titled ‘PISMA’ byAsha Krishnan, Smruti Patel, Priya Sawant

TE Computers

A common misconception when deleting files is that they are completely removed from the hard drive.However, even highly sensitive data can still be retrieved from a hard drive even after the files have beendeleted because the data is not really gone. Files that are moved to the recycle bin (on PCs) or the trashcan (on Macs) stay in those folders until the user empties the recycle bin or trash can. Once they havebeen deleted from those folders, they are still located in the hard drive and can be retrieved with the rightsoftware.

Any time that a file is deleted from a hard drive, it is not erased. What is erased is the bit ofinformation that points to the location of the file on the hard drive. The operating system uses thesepointers to build the directory tree structure (the file allocation table), which consists of the pointers forevery other file on the hard drive. When the pointer is erased, the file essentially becomes invisible to theoperating system. The file still exists; the operating system just doesn’t know how to find it. It is, however,relatively easy to retrieve deleted files with the right software.

The only way to completely erase a file with no trace is to overwrite the data. The operatingsystem will eventually overwrite files that have no pointers in the directory tree structure, so the longer anun-pointed file remains in the hard drive the greater the probability that it has been overwritten. There arealso many “file erasing” software products currently on the market that will automatically permanentlyerase files by overwriting them.

Deleted Files ARE THEY REALLY GONE?

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CONFESSIONSCONFESSIONSCONFESSIONSCONFESSIONSCONFESSIONSO F A D I G I T A L I Z I N G W O M A N

Friend: “Hey what’s your resolution, Aparna?”

Me: “Umm, well… good question, now that you’ve brought itup. Maybe I’ll try and learn how to play the violin… or how toride a dirt bike. Haven’t thought about it Actually…”Friend: ‘Huh?? Whatever!! Mine’s 1152 x 864 …”- Realisation Dawns -

And that’s just another regular day in the life of technol-ogy un-savvy mortals such as myself. Not everyone has the goodfortune of being born with a silver Pentium chip in their mouths.I find that it’s becoming exceedingly difficult for me - a villagebumpkin when it comes to technology - to keep up with the paceof today’s world of growing CDMA networks and shrinking

mobile phones.The other day, as I sat agape, keenly observing the intri-

cacies of my latest Pentium-3 computer unfold before my in-credulous eyes, a friend calls (on my sad ol’ 3310) to tell meabout his latest P-4! Technology is just so overwhelming! Blink,and your hard-earned, brand new Gizmo is plunged into the throesof dark obsolescence, before you can even say ‘Bill Gates’.

What has happened to the world in which it was morethan possible to live quite contentedly without the luxury of someconvoluted Toenail-Massaging Device that you absolutely mustcarry (along with your gleaming new WAP phone of course) touse on Frequent Flights between New York and Reykjavik?? Onecan’t help but wonder if this maddening rat race to acquire the‘lightest’ mobile phone is reflective of the consumer’s own blind-ing light-headedness.

Don’t get me wrong - I strongly do believe that if technol-ogy is at your disposal, you should go ahead and make the mostof it. But at what cost? Some of the latest contraptions that onegets to read about are positively ludicrous! Move over Adam andEve, your ‘Objects of Desire’ have now taken on a whole newmeaning - digi-cams, MMS phones, mp3 players and what-have-you are here to stay.

I haven’t completely given up hope, though. Every nowand then, I’m thrown sops such as - “You Have SUCCESSFULLYLogged In” - that help restore my shattered self-esteem back tonormalcy. I guess this is all just a bad bout of Future Shock, asAlvin Toffler would have put it, and it’ll take some time, forti-tude and a whole lot of Brilliant -Tutorials before I can finallybegin to savour the wonders of the Digital Revolution.

Aparna JayakumarS.Y.B.A.,St. Xavier’s College

Guest Article

H U M O U R & S A T I R E

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AN ON-CAMPUS INTERVIEW IS GENERALLY THE FIRST BRUSH with thecorporate world that you, as an engineering student will facein your student life. Everyone is anxious to get ‘that dreamjob’, and to be at their best during the interview. However, atthe other side of the table, there are several things that cam-pus recruiters look out for when they conduct your interview.And it is in convincing them that YOU are their ideal employ-ee that your success in landing a job lies! This writeup takesyou through the mind of the recruiters. What are they lookingfor? And do you have that in you?

It is essential to remember that in a interview, the re-cruiters are already aware that you have atleast the minimumrequired technical skills, based on the information you haveprovided them - through your screening tests, resume, grades,etc. During the interview, recruiters are interested in gather-ing as much information as they can to determine if you willbe a good employee for the company. Being a ‘good’ employ-ee means that you are capable of and likely to do good workfor the company, are most likely to work in the company forat least 2-3 years, and are going to contribute proactively tothe company. They are also interested in determining whetheryou would fit in (and enjoy) the company’s culture, while si-

S H W E T A V E N G S A R K A R

Facing a campus interview? Stuff that you should know BEFOREyou step into that Interview Room...

C A R E E R T A L K

JobsAhoAhoAhoAhoAhoy!y!y!y!y!

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multaneously testing your technical skills andpotential to grow - independently and as part ofa team.

At the time of your interview, there are afew pointers for you too. Remember to dresswell. It is essential that you show the recruiterthat you do care for the time he/she has dedicat-ed to you, and that you are serious about the job.Dressing well generally implies wearing formalclothes, even if the recruiters may themselvesbe dressed casually! Ensure that you have a

good-quality pen and maybe, a notepad whenyou go in for your interview. It doesn’t promoteyour job application, when you show signs ofinadequate preparation for your interview. Al-ways remember to look cheerful (even if youhave butterflies in your stomach) while greetingthe panelist(s) and wait for them to tell you to beseated. These things may appear trifle, but theyreflect on your professional courtesy.

Many recruiters tend to begin the inter-view with the question, “Tell me something aboutyourself”. Be prepared to talk about yourselffor atleast 2-3 minutes, while they peruse throughyour resume / screening test results etc. Avoidrepeating the points you have mentioned in yourresume, instead concentrate on some distinctions(academic or non-academic) that you may havereceived, your outlook towards life, maybesomething about your family / hobbies etc. Thisis generally a good starting point, as the inter-viewer may talk about your personal interests tomake you feel at ease. A few other casual ques-tions later, the real interview begins. Dependingon your field of engineering, you may be askedto talk about your favourite subjects, why youlike them etc. remember that the recruiters arenot there to prove to you that there are so manythings you do not know. Rather, they are thereto find out how strong your fundamentals in yourcore subjects are, whether you have the abilityto grasp things easily, whether you can ‘re-learn’,how quickly you can think on your feet.

An interview is not an examination whereyou have to get a perfect score to clear the test.There may be questions to which you don’t haveanswers, or you may have answered certain ques-tions incorrectly. It doesn’t matter so much, ifyou have been otherwise able to answer mostquestions correctly. What appears to be more

important during an interview, especially for atechnically inclined job, is that you are confi-dent about your answers, and that you candid-ly admit to not knowing some of the answers.

Behavioral questions, such as “Whatwould you do if..?” which involve your re-sponse in a given hypothetical question havebeen on the rise (especially for the non-techni-cal / marketing type of jobs) for the past fewyears. These questions should be answered inas honest a way as possible, without the typical

“I shall live and die formy company” answers.In today’s world, it iswell known that onlythe owner of the com-pany is most capable of

living upto such a claim. Also, avoid trying toinclude unwanted wisecracks during your in-terview. Humour is endearing, but not over-smartness!

Remember always to be polite, cheerful(don’t keep grinning throughout!) and lookcomfortable (don’t recline in your chairthough!) throughout your interview. Avoidcausal behavior, use of slang, drinking too muchwater, stammering too much, criticizing others,unnecessary hand movements, looking downor at the ceiling while talking to the recruiteretc. Generally, towards the end of the interview,most recruiters ask you if you have any ques-tions about the company. Make use of this op-portunity to clarify any doubts, and if you havenone, ask atleast something about your proba-ble placement, training programs for fresh grad-uates before joining the company etc. When youare told that the interview is over, don’t forgetto thank the interviewer(s) before leaving theroom.

Last but not the least, when you comeout of the room, don’t ever discuss your inter-view & interviewer loudly outside the room.Talk to your friends about it 2-3 rooms awayfrom where your interview took place! Afterseveral interviews without an offer, it is easy toget discouraged when your friends have alreadybeen placed. In times like these, try and figureout where you have lost out, and improve onyour weaknesses, and turn them into your as-sets.

The campus interview, albeit only a shortamount of time, is a crucial tool for your eval-uation and may be important in deciding wheth-er you shall be offered the job or not. Hence,take it seriously, but at the same time, don’twork yourself into knots over it. All the best!!

Shweta Vengsarkar

Interviewers don’t want to prove their superiority. Ratherthey want to know how strong your fundamentals are inthe subjects that you claim to have interest in.

“““““.....”””””

We hirepeople, not

on knowl-edge, but on‘learnability’

Narayan MurthyInfosys

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MANAGEMENTEXPRESS

THE the road well-travelled... getting into a b-school

Heller’s Law:The greatest myth about management is that it exists.

K U N A L M U N D R A

CATACLYSMIC DAY IN THE LIFE OF OVER ONE LAKH stu-

dents who appear for the CATastrophic Common Admission Test

conducted by the six IIMs! The mathematical probability of making

it to the IIMs is believed to be less than 1 per cent; for getting into

IIMA, it is less than 0.5 per cent. This article by Kunal Mundra

ventures into issues from as basics of why an MBA, to preparing

yourself for the final combat - the GD/PI! For those who believe

along with Elbert Ron Hubbard that “an ounce of performance is

worth more than a pound of preachment”- Kunal Mundra has him-

self received calls from all the six IIMs as well as NITIE and IIT

SoMs. Read on.

A

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Why an MBA?In today’s world, a Management degree is one ofthe basic stepping-stones to becoming a part ofthe industry. It catapults you directly into the ‘de-cision making’ league of an organization help-ing you bypass the several years you would havehad to put in as a simple engineering graduatetrainee. People often ask whether this degree isactually necessary and worthwhile since workexperience teaches you exactly the same funda-mentals at a more practical level. However theessential difference lies not only in the structuredall-round perspective and understanding of theIndustry we get to develop, but also in the highlycompetitive atmosphere which we currently workin.

Being a non management graduate sim-ply means that somewhere down the line, a glassceiling will prevent any further progress up thecorporate ladder and the only way to cross it willbe to do an MBA course thus bringing us back tosquare one. One can site examples of exemplarynon-MBAs who are success stories in the man-agement world-the likes of Bill Gates, J.R.D.Tata,and Dhirubhai Ambani. However the fact remainsthat MBA provides an added advantage of expe-diting the growth as a manager. MBA in itself isan excellent professional qualification that makesyou belong to a select fraternity.

Where do I do an MBA from?Various institutes, both Indian and internationaloffer various management courses with someeven offering hybrid courses for engineers where

you can actually evolve and adapt your engineer-ing background as a foundation for your man-agement career. These can be divided as below.International - Premier institutes such as thosein the Ivy League require at least 3-4 years workexperience in a quality company and cost around$100,000 for a 2 year course with no options forscholarships. This requires you to take the GMATand isn’t really a viable option for fresh gradu-ates.Indian - India has a large number of manage-ment institutes ranging from world class to de-pressing. Viable options are• IIMs (6) - CAT

• XLRI Jamshedpur - XAT• SP Jain Mumbai - CAT• Bajaj Mumbai - CET• MDI Gurgaon - CAT• NITIE - Mumbai• IITs (4) - JMET• FMS Delhi• NMIMS Mumbai• Symbiosis PuneThe rankings are quite subjective however thetop 4 by far are the IIMs at Ahmedabad,Bangalore, Calcutta and Lucknow. Others havecertain strong areas for example XLRI is com-parable with the IIMs for HR management whileNITIE and the IITs have a technology basedmanagement course. The final decisions takenby you on the universities you would like tostudy in should consider the fact that the 2 yearsyou spend here decide the direction your life willtake for the next 40 years. This fact combinedwith the advantage of the high caliber of facultyand colleagues you will find yourself amongstin the top colleges means that it is worthwhilewaiting for a year or two if needed so as to bepart of the best college you possibly can. Don’tforget that every year you wait gives you onemore valuable year of work experience (pro-vided of course that you take a job) which willfurther add value to your resume leaving you ina great win - win position.

An Executive MBA is offered by a few ofthe colleges such as SP Jain and is a 3 years

course for work-ing profession-als which allowsyou to finishyour MBA whileyou continue towork. Some ofthe companies

even sponsor these courses for their employees.The only drawback is that the premier institutessuch as the IIMs do not offer these courses.

How to take the CAT?The most important fact about the CAT is that itis first and foremost an aptitude test. This meansquite simply that it has to be approached verydifferently as compared to your conventionalexams. Once you have decided to take the CAT,you have to work slowly and steadily towardsit, developing your reading and comprehensionabilities besides building up your overall speedand then actually ‘studying’ in the last 4 months.

Managementmeans, in thelast analysis,the substitu-tion of thoughtfor brawn andmuscle, ofknowledge forfolkways andsuperstition,and of coop-eration forforce. It meansthe substitu-tion of respon-sibility forobedience torank, and ofauthority ofperformancefor the author-ity of rank.

Being a non management graduate simply means that some-where down the line, a glass ceiling will prevent any furtherprogress up the corporate ladder and the only way to cross itwill be to do an MBA course

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The preparation should be approached in 3clearly defined steps.1. Assuming that the CAT is in November, Janu-ary till June must be spent in reading novels, fic-tion and non-fiction , newspaper editorials andother reading material covering topics such aspolitics, philosophy, religion and technical. Thisis to build up on your comprehension skills andspeed since these need to be developed over time.Wordlists as those for the GRE are not of muchuse since the CAT focuses more on application;however doing ‘Word Power’ is a good idea.Engineers will be in touch with math so there isnot much work to be done here. This is the timeyou should identify your weak points and thenwork on them.2. In the second stage starting in June/July youwill actually start ‘studying’ the CAT materialwhich is available. Building a strong foundationin math is very important and individual tricksand shortcuts must be developed instead of try-ing to memorize the various readymade ‘tricks’you might read in books. Speed in math must bedeveloped and accuracy should be emphasizedon. Data interpretation is a new section for mostof us and since this is calculation extensive, ad-ditional time needs to be spent here to actuallyget comfortable. Critical reasoning (a part ofEnglish along with reading comprehension) andlogical reasoning can only be perfected throughpractice and analysis after which they become aquick source of marks.3. In the final step you start taking mock CATs.Here the most important thing is to analyze yourpapers, spending as much as 3 hours on eachpaper after solving and correcting. This is farmore important than simply solving tens of fulllength tests and is the key to increasing yourscores. You need to develop your own strategiesand shortcuts centered around your strengths.

Overall the main points to be rememberedare that firstly, you need to be flexible since theformat is not specified and hence keeps chang-ing. This coupled with the fact that CAT has sec-tional cutoffs means that you need to be equallycompetent across all sections. The last and mostimportant fact is that accuracy is important notonly because of the negative marking (this isagain not explicitly mentioned and thereforecould be 0.25, 0.333 or just about any othervalue) but also because the percentage accuracyis considered when giving calls.

After The Initial Hurdle…Having cleared the initial hurdle of the writtentest, and having received the calls from the pre-

mier institutes, the euphoria subsides whensomeone in his or her bid to be helpful says “Letme tell you what happened to my cousin at hisIIM interview last year...”. Proceeding to de-scribe the degeneration of an intelligent andpoised young man into a blubbering jellyfish.

Group DiscussionsFirst the GDs! All your college years, you par-ticipate in many inter and intra college groupdiscussions with a view to prepare yourself bet-ter for the ‘actual’ GDs .Well though the basicrules for these are the same as the GDs you haveknown, the course that your GD will take de-pends on many factors. First and foremost thetopic- you need to be a voracious reader to beable to tackle any topic given. Next yourgroupmates! The GD is by far a team effort andyou can just hope that to have a nice organizedGD your groupmates are also aware of the basicrules that you have known for so long. But beready for the worst: what this means is GDssometimes are misunderstood as throat-clean-ing exercise! But the important thing to remem-ber here is you should not shout as your decibellevels are not going to take you anywhere. Insuch a scenario, try to divert the group from thepoint of discussion which was the cause of chaosand start some new sub-topic. Or if u can, putsome new ideas so that the group jumps on to itand sanity is restored. A GD is all about remain-ing normal in an abnormal scenario. Some ofthe qualities that are judged in a GD areproactivity, team work, leadership, initiative,creativity, facilitation, clarity of thought andcommunication.

Interviews“Every breath you take, every move you make,every word you speak, every step you take, I’llbe watching you…” catchy lyrics from the mu-sic group, the Police. Well, this pretty much sumsup the mood of the interview panel. As you en-ter the room, with a folder in hand, anxiety inheart, waves of nervousness raging inside and abrave smile on your face, imprint the followingsuccess table in your mind:• Confidence• Motivation• Competitive instincts• Presence of mind• Controlled aggression• Withstanding stress• Self-awareness

The Terrible TruthAbout Organiza-

tions.

Marketing says Yes.Finance says No.

Legal will review it.Planning is frantic.

Engineering is aboveit all.

Manufacturing wantsmore floor place.Top Management

wants to holdsomeone responsi-

ble for the mess.

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• Ability to maintain one’s poise• LuckMost of these interviews are known to be ‘stressinterviews’. Many a times, you will be asked aquestion that you may not know the answer to.But the important point here is that the intervieweris not looking for answers, the questions aremeans to gauge your attitude and presence orabsence of the above mentioned qualities. Someinteresting anecdotes may prove instrumental inproviding a better idea as to what is it that theyreally expect.

First andforemost, Confi-dence! The fact thatyou have reachedthe interview levelitself proves thatyou are capable ofbeing there. So atno point of time inan interviewshould you feel thatyou are the wrongperson in the rightplace. You are therebecause you de-serve to be! Thequestions mostly

asked will be such that you may be tempted tocontradict yourself, Beware!…here lies the trap!Be confident of yourself and your answers.

Breaking norms - Heard of instances ofpeople walking into IIM interviews in casualattire and then walking straight into the IIMs?!How come? The desire to be unique, to make astatement leads to breaking norms, but you shouldbe confident enough to substantially support youract. That’s how come! For instance, every otherinterviewee happens to wear white shirt and blacktrousers - typical formal attire. Enters a guy, wear-ing blue shirt and grey trousers. In his interviewhe is asked as to whether he thinks the combina-tion looks good and when the reply is affirma-tive, the interviewer wants the candidate to sellthe product to him, thereby testing not only hisconfidence, his keen sense of observation but alsohis marketing skills.

Motivation and competitive instincts - Aprimary requirement for any manager and the im-portance of the same need not or cannot bestressed more. Questions such as “How loyal willyou be to your company?” are very common. Aninterviewee who vows to do anything for thecompany is asked to jump from the window forthe company. In such an eventuality the only sav-

ing grace would be your presence of mind. Theperson walks out and jumps into the roomFROM the window. This simple act says a lotabout the person - his motivation, determina-tion, presence of mind and sense of humor.Speaking of which, if you take pride in the factthat you are humorous then the most obviousdemand is a joke. Well under the pressure youblurt out the first stupidest joke that comes toyour mind. And if it happens to be targeting aparticular community then all seemingly (to you)unnecessary and cliché issues such as religioustolerance, protection of rights of minority com-munities etc. pop up veering the interview to aterritory where your knowledge of the currentissues becomes imperative.

Most innovative and interesting ways aredevised to test your presence of mind. When youenter the room to make you feel at ease you areoffered something to eat, say, a plate of fruit. Assoon as you accept the offer in your effort tonot seem rude, questions start popping fromevery possible direction and you are forced tojuggle between eating and speaking simultane-ously. The best way out of this would be po-litely refuse the food saying you just had a heavybreakfast or are looking forward to having lunchwith a friend.

One interesting story goes like this -when the candidate entered the room a phonewas placed in front of him. He was asked tofind out the score of a cricket match withoutleaving the room. The candidate made a fewphone calls and found the score which heproudly declared to the panel. The immediatequestion asked was why the candidate used thephone without permission! Obviously, here, alittle presence of mind would have promptedthe candidate to ask for permission to use thephone prior to its use. The most common ques-tion asked as soon as the candidate enters a roomis “What is the color of the wall behind you?”.The impulse is to turn around and look behind.However common sense says it’s same as thatof the other three walls which the candidate caneasily see!

Sometimes very obtrusive, blatant ques-tions can be put forth which may seem very in-sulting such as, “How would you react if youare told that your mother is a prostitute?” Thekey to answering such questions is ‘ControlledAggression’ - “I wouldn’t mind if my father isthe only client!” Quick, confident impregnatedwith the right dose of aggression, exhibiting theability to maintain one’s poise!

Picture this - As you enter, the room is

Read on about a few of the ‘freak’cases in the IIM interviews and how to

deal with them

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suddenly abuzz with discussions or heated ar-guments amongst the interviewers who do notacknowledge your presence. Finally when yousettle, you find it increasingly difficult to look ateach and every interviewer while answering thequestions especially when some of them seemvery hostile or totally disinterested. You still goon. In the middle of the interview you becomeconscious of the female interviewer in front ofyou who hasn’t spoken a word and is only star-ing at you or her feet. Having to face such animmobile figure that doesn’t seem to make senseout of any word that you utter could be very un-comfortable, weird, eerie, and worse-scary! Theonly thing that you can wish for in such a situa-tion is the mental strength to withstand this stressand continue answering the questions unper-turbed.

Self awareness is the most important vir-tue. Be truthful. Be sure of what you want. At nopoint of time should you be sitting on the fence.Also if you are from technical fields please do

not assume that your technical expertise will notbe questioned. It’s most likely that the mostgrueling questions of your interview are basedon your technical know-how, the belief being ifyou are good in your field then you will defi-nitely be adaptive to any situation.

Last but not the least is Luck! A very in-teresting anecdote to prove the same- A com-merce graduate proficient in book-keeping isasked if he knows what bee-keeping is. Whenhe replies in affirmative he is asked all possiblequestions on bee-keeping which he replies withthe confidence of an expert in the field. Coinci-dence? Luck? Call it that, because it is luck thatmade this commerce graduate read an article onbee-keeping in a magazine while waiting for hisinterview!

So gear up, get motivated, be self-as-sured, and most importantly keep your fingerscrossed!

Kunal MundraBE Teleommunications

Rajesh Dodeja

The

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