Sunday, December 10, 2006


Bluetooth is one of the most popular words in the mobile industry. It is basically a cable replacement technology. It is a substitute to the cables which have become a pain in many houses and offices. Technically, a Bluetooth is a protocol of short range frequency hopping radio link.

It was first developed by Sven Mattison and Jaap Haartsen who were working for Ericsson Mobile platforms. Bluetooth is formally known as IEEE 802.15.1.

The name Bluetooth is derived from a Danish Viking and King Harald Blatand (translated as Bluetooth in English) who lived in the latter part of the 10th century. He united and controlled Denmark and Norway. He got his name from his very dark hair which was uncommon for Vikings. Blatand means dark complexion. However a more popular reason is that he had a strong inclination for eating blueberries which made his teeth stained with the color. Its logo merges with the Nordic runes analogous to the modern Latin H and B.

Bluetooth is known for its low power consumption and a low production cost. But at the same time it has a short range. However as it uses a radio communications system, the devices which are undergoing a Bluetooth communication need be in line of sight, as long as the transmission is powerful enough.

One of the most important applications of this Bluetooth is in data transfer. It uses the SAFER+ algorithm for authentication and key generation for preventing eavesdropping. It has even replaced the traditionally used Infrared. This is because data transfer in Infrared takes place in the form of straight lines where as on the other hand, for Bluetooth it is concentric circles. This technology has even crept into the gaming industry in the form of wireless controls for game consoles like Nintendo Wii, Microsoft Xbox 360, Sony's PlayStation 3.

Along with Bluetooth, there is the WiFi (Wireless Fidelity) which is widely used in homes and offices. Even in the game consoles mentioned above. WiFi uses the same radio frequency as that of Bluetooth, but with higher power consumption resulting in a stronger connection. Spatial capacity is a method used to compare the efficiency of wireless transmission protocols.

The future versions of Bluetooth code named Libson and Seattle concentrate more on enabling faster data transfer with low power operations.

Wednesday, November 22, 2006


Thermistor is a portmanteau of the words thermal and resistor. A thermistor is a type of resistor used to measure temperature changes, relying on the change in its resistance with changing temperature. The temperature coefficient of a thermistor is defined as change in the resistance for 1 K change in temperature.

Semi conductors are classified as posistor and a thermistor based on their temperature coefficient of resistance. A posistor has a positive coefficient of temperature where as a thermistor has a negative coefficient of temperature. That is as the temperature increases the resistance decreases for a thermistor. Thermistors are semiconducting ceramics composed of mixtures of several metal oxides such as those of Cobalt, Magnesium, Manganese, Nickel, Tin, Titanium, Uranium, Zinc and Aluminum. Some NTC thermistors are crystallized from semiconducting material such as Silicon and Germanium.

Electrical circuitry is colder at start-up than after running for a length of time. NTC thermistors are used to take advantage of this to protect the circuitry from the surge in electrical flow that accompanies start-up. Because the resistance of NTC thermistors varies gradually with temperature, they are also used as temperature measuring devices.

The variation of resistance with temperature can be expressed linearly for a small change of temperature. However for higher temperatures, the resistance / temperature curve must be described in more detail. So, Steinhart Hart equation is widely used,

1/T = a + b ln(R) + c (ln(R))^3 where T is the temperature and R is the resistance. Further a, b, c are Steinhart-Hart parameters which change from device to device.

The above equation can be approximated for a temperature T as 1/T = a + b ln(R). When T = T0 then R = R0, we get

1/T - 1/T0 = B (ln(Rt) - ln(R0))

This equation on simplification gives Rt = R0 exp B (1/T - 1/T0) where,
R0 - Resistance at T0 K in ohms
Rt - Resistance at T K in ohms
B - a constant depending on the material of the device

The value of B is given by B = E/K where,

E - energy gap in eV
K - Boltzmans constant (8.625 x 10^(-5) eV/K)

If T tends to infinity then R tends to A which is the thermistors resistance as temperature approaches infinity. Therefore, the temperature resistance relations can be written as Rt = A exp B/T.

The temperature coefficient of resistance is usually expressed as

alpha = dR/dT (1/R)
= (A exp B/T) (-B/T^2) (1/A exp (B/T))
= -B/T^2

where T is the absolute temperature in Kelvin.

Saturday, November 11, 2006

Towers Of Hanoi

The Towers of Hanoi puzzle was published in 1883 by French mathematician Edouard Lucas, under the pen-name N. Lucas de Siam. The Towers of Hanoi puzzle basically consists of three towers. A specific number of discs are placed on one of the towers, such that the discs are placed in the ascending order of their size from top to bottom. The objective of the game is to move the discs to another tower such that they still follow the same order. Further only one disc can be moved at a time and a bigger disc cannot stand on a smaller disc.

Consider the following scenario. Here we have three towers. The first one will have three discs arranged in ascending order from top to bottom. The other two towers will be empty. The ending scenario could be - The towers 1 and 2 will be empty and the third one will have the three discs arranged in ascending order from top to bottom. The challenge of Tower of Hanoi is to achieve this with the constraint that only one disc can be moved at a time and a bigger disc cannot stand on a smaller disc. The choice of starting tower and destination tower is possible and also the number of discs can be chosen. The more the number of discs, the challenge becomes more difficult.


There is a legend related with the game which states that in Benares, during the reign of the Emperor Fo Hi, there was a temple with a dome which marked the center of the world. In this temple there contained a large room with three time-worn posts in it surrounded by 64 golden discs. The priests of Brahma, acting out the command of an ancient prophecy, have been moving these discs, in accordance with the rules of the puzzle. According to the legend, when the last move of the puzzle is completed the world will end. The puzzle is therefore also known as Tower of Brahma puzzle.

If the legend were true, and if the priests were able to move discs at a rate of 1 per second, using the smallest number of moves, it would take them 2^64 - 1 seconds or roughly 585 billion years.

There are many variations on this legend. For instance, in some stories the temple is a monastery and the priests are monks. The temple or monastery may be said to be in different parts of the world - including Hanoi, Vietnam and may be associated with any religion. In some versions, other elements are introduced, such as the fact that the tower was created at the beginning of the world, or that the priests or monks may make only one move per day.

Mathematical Significance

The problem of the Towers of Hanoi is isomorphic to finding a Hamiltonian path on a n-hypercube. The problem is solved by a remarkably simple recursive procedure. Further the terms of the sequence resembles the binary carry sequence. Amazingly, the number of discs moved after the kth step is the same as the element which needs to be added or deleted in the kth addend of the Ryser formula.

The number of steps required for n discs is 2^(n) - 1 which is the Mersenne numbers. Further this relates the Pascal's triangle to the Hanoi graph.

Significance in Computers

The problem of Towers of Hanoi is one the common methods of finding the speed of the computer. A code is written to solve the problem and the time taken for the computer to execute this code is used to determine the speed of the computer. You can try out the Towers of Hanoi here.

Wednesday, November 08, 2006

Vocabulary 03

  • Aggrandize - To extend or exaggerate
    The media always tries to aggrandize any news it gets.
  • Alienate - To isolate oneself from others or another person from oneself
    After finding that Ramu was a thief, he was alienated by all his friends.
  • Amalgamate - To merge or combine into a single thing
    The two companies were amalgamated as they were not functioning properly.
  • Ambiguous - Unclear or capable of having more than one meaning
    It was ambiguous what the lawyer was trying to prove in the court.
  • Ambivalent - Characterized by uncertainty; unable to decide between opposites
    The jury was ambivalent when it was asked to choose the winners.
  • Ameliorate - To enhance or improve something
    After the company had been taken over, it was ameliorated by the new CEO.
  • Amenable - Responsive to suggestion; willing
    My boss was amenable to the suggestion I made.
  • Amiable - Friendly and pleasant
    The students of my class were amiable to me when I first met them.
  • Amortize - To reduce gradually over a period of time
    The prices of Televisions have amortized from the past 10 to 15 years.
  • Anachronistic - Out of order; chronologically misplaced
    The death of the king was anachronistic in the textbook.

Sunday, October 29, 2006

Song For All Professionals - The 8 Stages

  1. When in College - Hum honge kaamiyaab, Hum honge kaamiyaab ek din...
  2. When giving an interview to a Multinational company - Tu hi re... Tu hi re... Tere binaaa main kaise jiyunn...
  3. Waiting for Interview Result - Intehaa ho gai intzaarki... Aayinaaa kuch khabar mere yaarki...
  4. Just joined - Too cheez badi hai mast mast...
  5. After some time - Ye kahaan aagaye hum?
  6. After some more time - Naa koyi umang hai, Naa koyi tarang hai, Mere jindagi kya ek kati pathang hai (booohoooo)
  7. Floating the Resume - Kabootar ja ja ja... Kabootar ja ja ja... Pehele pyar ki peheli chitti...
  8. Finally when you don't get a better offer - Jeena yehaan, Marna yehaan iske si wa jaana kahaan...

PlayStation Emulators

Do not have a PlayStation but interested in playing PlayStation games? Try a PlayStation software emulator.

A software emulator allows computer programs to run on platforms other than the one for which they were originally written for. There are several emulators for PlayStation. A few of them are ePSXe, pSX, Bleem!.

  • Bleem! was one of the commercial PlayStation emulators. It could execute a few games but however could not run all the commercial games available
  • pSX is a little different from the modern emulators since it does not use plugins for graphics, sound and controller. However it requires a BIOS (Basic Input/Output System) for it's execution
  • ePSXe is the best free PlayStation emulator available. It requires plugins for Graphics, Controller, Sound, CD-ROM. Further it requires a BIOS for it's execution. This emulator is worth the effort, it's plays almost every commercial game available in the market. Personally, I tried games like Tekken 3, Monkey Magic, Spider-Man 2 and they worked perfectly in this emulator

One of the hiccups of obtaining a working PlayStation emulator is finding a BIOS since the websites with these emulators do not provide it because of legal issues. So a little effort and search is to be put in for this.

Emulators for PlayStation and other consoles can be obtained in many sites. Emulator Zone is one of them. Download the requirements and configure your emulator properly to get things up and running.

Happy Gaming!!!

Vocabulary 02

  • Accretion - A gradual increase in the amount or size of something
    There was an accretion in the balloon when it was attached to the cylinder.
  • Acquisitive - Characterized by a strong desire to gain or retain information
    My friend was acquisitive about Greek mythology.
  • Acrid - Harsh or bitter taste or smell
    The cough syrup given to me had an acrid taste.
  • Acute - Sharp; quick and precise; intense
    A calculator is an acute device for calculations.
  • Adhere - To stick fast; to remain in support of
    The wood pieces started to adhere after applying glue.
  • Adjacent - In the nearest position; next to
    I was standing adjacent to my favorite actor in the audio release.
  • Adroit - Showing skill and experience
    The scientist is adroit in nuclear technology.
  • Aesthete - One with an excessive sensibility to beauty
    The painting was appreciated by a famous aesthete.
  • Aesthetic - Appeals to the senses because it is beautiful
    The Taj Mahal is very aesthetic.
  • Affinity - Natural attraction; inherent similarity
    Ants have a great affinity towards sugar.

Monday, October 23, 2006

Gaming Prerequisites

We all like to play games, but do we know how they are made? A game is basically created using a game engine. Game engines initially arose in 1990s in connection with the 3D games such as Unreal and Doom. A game engine was created for these games and on these game engines, other developers created their own games.

Eg. Half-Life and Counter-Strike have similarities since they were created by the same game engine. A game engine is a library of 3D graphics functions. It consists of multiple editors like -

  • A Level Editor is used to design the 2D/3D world for the game
  • A Model Editor is used to design the game characters
  • A Scripting Editor is used to write scripts(code) for the game
  • An AI Editor is used to create intelligent opponent characters

Professionals use several game engines like Blitz, Nabula, Crystal Space, Cipher, Torque, Jupiter, etc. Advanced game engines such Unreal Engine 3, Doom 3 Engine are used for creating First Person Shooters (FPS) and game engines like Gamebyro are used for Massive Multiplayer Online Games (MMOG).

For game designers the knowledge of C/C++ and DirectX is very important. Further they should be able to

  • Program using game engine scripting languages
  • Create polygonal modeling work with 3D Studio Max/Maya
  • Create artwork using Adobe Photoshop/CorelDRAW

Remember every game we play, has a lot of effort put into it.

Vocabulary 01

  • Abate - To reduce or lessen
    The government has decided to abate the taxes on the people.
  • Aberration - A deviation or departure from the norm
    Because of the aberration the reading of the microscope could not be taken properly.
  • Abeyance - A temporary inactivity or suspension
    My computer was in a state of abeyance when I overloaded it with programs.
  • Abjure - To forswear or abstain from; to give up
    The company abjured the effort to get the contract after it realized that it was not worth it.
  • Abrade - To wear down or erode
    The iron piece started to abrade as soon as it came in contact with the liquid.
  • Abrogate - To end or do away with something
    Because of health problems my friend abrogated non vegetarian food.
  • Abridge - To shorten or reduce
    The teacher gave an abridged version of the story when she felt that the students would not be able to read it entirely in time.
  • Abscond - To withdraw and hide, typically to avoid arrest
    The criminal absconded after he killed an old man.
  • Absurd - Extremely ridiculous or completely lacking reason
    The student gave an absurd reason, when the teacher asked him a reason why he didn’t come the previous day.
  • Abysmal - Very profound or deep; very bad
    My performance in the internals was abysmal.

Vocabulary - Introduction

This is the new section of my blog. Every week I will add a few words with their meanings and an example for their usage. They can be utilized for many of the competitive exams. Hope you all find it useful.

Saturday, October 21, 2006

30 Good Definitions

  1. Cigarette - A pinch of tobacco rolled in paper with fire at one end and a fool at the other
  2. Love Affairs - Something like cricket where one day internationals are more popular than a five day tests
  3. Marriage - It's an agreement in which a man loses his bachelor degree and a woman gains her master
  4. Divorce - Future tense of marriage
  5. Lecture - An art of transferring information from the notes of the lecturer to the notes of the students without passing through the minds of either
  6. Conference - The confusion of one man multiplied by the number present
  7. Compromise - The art of dividing a cake in such a way that everybody believes he got the biggest piece
  8. Tears - The hydraulic force by which masculine will power is defeated by feminine water power
  9. Dictionary - A place where divorce comes before marriage
  10. Conference Room - A place where everybody talks, nobody listens and everybody disagrees later on
  11. Ecstasy - A feeling when you feel you are going to feel a feeling you have never felt before
  12. Classics - Books which people praise, but do not read
  13. Smile - A curve that can set a lot of things straight
  14. Office - A place where you can relax after your strenuous home life
  15. Yawn - The only time some married men ever get to open their mouth
  16. Etc. - A sign to make others believe that you know more than you actually do
  17. Committee - Individuals who can do nothing individually and sit to decide that nothing can be done together
  18. Experience - The name men give to their mistakes
  19. Atom Bomb - An invention to end all inventions
  20. Philosopher - A fool who torments himself during life, to be spoken of when dead
  21. Diplomat - A person who tells you to go to hell in such a way that you actually look forward to the trip
  22. Opportunist - A person who starts taking bath if he accidentally falls into a river
  23. Optimist - A person who while falling from Eiffel Tower says in midway "See I am not injured yet"
  24. Pessimist - A person who says that O is the last letter in ZERO, instead of the first letter in word OPPORTUNITY
  25. Miser - A person who lives poor so that he can die rich
  26. Father - A banker provided by nature
  27. Criminal - A guy no different from the rest except that he got caught
  28. Boss - Someone who is early when you are late and late when you are early
  29. Politician - One who shakes your hand before elections and your Confidence after
  30. Doctor - A person who kills your ills by pills, and kills you with his bills

How The Lion Became The Boss Of The Jungle

It's a fine sunny day in the forest and a lion is sitting outside his cave lying lazily in the sun. Along comes a fox out on a walk.

Fox: "Do you know the time? Because my watch is broken"
Lion: "Oh, I can easily fix the watch for you"
Fox: "Hmm... But it's a very complicated mechanism and your big claws will only destroy it even more"
Lion: "Oh no, give it to me, and it will be fixed"
Fox: "That's ridiculous! Any fool knows that lazy lions with great claws cannot fix complicated watches"
Lion: "Sure they do, give it to me and it will be fixed"

The lion disappears into his cave, and after a while he comes back with the watch which is running perfectly. The fox is impressed, and the lion continues to lie lazily in the sun, looking very pleased with himself. Soon a wolf comes along and stops to watch the lazy lion in the sun.

Wolf: "Can I come and watch TV tonight with you because mine is broken"
Lion: "Oh, I can easily fix your TV for you"
Wolf: "You don't expect me to believe such rubbish, do you? There is no way that a lazy lion with big claws can fix a complicated TV"
Lion: "No problem. Do you want to try it?"

The lion goes into his cave, and after a while comes back with a perfectly fixed TV. The wolf goes away happily and amazed.

Scene: Inside the lion's cave. In one corner are half a dozen small and intelligent looking rabbits who are busily doing very complicated work with very detailed instruments. In the other corner lies a huge lion looking very pleased with himself.

Moral: If you want to know why a manager is famous; look at the work of his subordinates.

Thursday, October 05, 2006


This topic is related to one of the most important things of computers - Backups. It's always advisable to take backups of your important data as a computer is always at the risk of losing data because of viruses, crashes, etc. Further while upgrading between Operating Systems, it's important to take backup of our critical data.

There are several devices for taking backups such CD-ROM, DVD-ROM, USB Drives, etc. A typical USB drive of 1GB comes at around Rs.1500 which is a good investment for storing data. However this is generally used for a temporary backup.

For a permanent backup, we can use CDs and DVDs. Also Rewritable CDs and DVDs are available but they cost more than the Non-Rewritable ones. For larger backups, we can even store the entire hard disk. This is generally used in offices where such backups are required.

Before I conclude I would like to know how many of you take Backups. Please send in your comments.

Saturday, September 30, 2006

Numbering Systems

This article is based on the different numbering systems we have. Every number can be represented as the sum of increasing powers of another number. This is the basic principle of every numbering system. The numbering system we generally use is known as the Decimal System. In this system we use the base number as 10.

Eg. 379 can be represented as (3x100) + (7x10) + (9x1). In this example the increasing powers of 10 are used.

In the above example, if we use 2 instead of 10, it will constitute the Binary System.

Eg. 379 can be represented as (1x256) + (0x128) + (1x64) + (1x32) + (1x16) + (1x8) + (0x4) + (1x2) + (1x1). In this example the increasing powers of 2 are used.

In the above examples, if we use 8 or 16 as base numbers, it will form the Octal and Hexadecimal Systems respectively. It is mandatory to consider A, B, C and so on after 9 for higher systems. To convert a decimal number into another system divide it continuously with the base number and write the remainders from right to left.

Eg. 63 when divided with 16 gives a remainder 15(F) and a quotient 3. 3 cannot be divided by 16, so remainder is 3. Therefore the number in hexadecimal system is 3F.

To convert a number from any system into decimal, multiply it with powers of the base number starting from 1 from right to left.

Eg. 110001 in binary system is (1x1) + (0x2) + (0x4) + (0x8) + (1x16) + (1x32) which is 49 in decimal system.

Wednesday, September 27, 2006

C Programming

Hello Friends!

Didn't get a problem in C or Solved a difficult problem?
Have a great tip about C?
Share them with your friends.

Monday, September 25, 2006

Movie Reviews

Hi Friends!

Watched a new movie?
Share your ideas about it. Write a review on it.

Sunday, September 24, 2006

A Small Introduction

Hello Friends!

Welcome to my Blog.
Please give a small introduction about yourself using the comments section.

Thursday, September 21, 2006

My First Blog

Dear Friends!

Welcome to my Blog and Personal Website. Originally I wanted to create a Website but on second thoughts I felt a Blog is a cooler way to get my articles across.