Pranav's Brain

Blogging break

noreply@blogger.com (Pranav) — Fri, 09 Oct 2009 02:47:00 +0000

Have not written anything for quite a while now. My last post was a month ago! Have quite a few things to write about, but blogging has been moved on to the backburner for now. Hope to give it sometime coming weekend. Lets see...

Best (after) illusion I've ever seen!

noreply@blogger.com (Pranav) — Wed, 09 Sep 2009 03:30:00 +0000

Its worth the minute. Watch in full screen.

Twinks #2

noreply@blogger.com (Pranav) — Tue, 18 Aug 2009 02:22:00 +0000

Eight year old exploit uncovered in the Linux kernel http://bit.ly/qwT06

9 out of 10 Americans carry Cocaine with them, unknowingly! http://bit.ly/ojz6b

Female focused explanation of evolution of sexual behaviour - http://bit.ly/fYyhj A tall claim IMHO.

Brave (or oblivious ?) mouse - http://bit.ly/gAdMV Amazing photos

A Formally Correct Operating System Kernel http://bit.ly/4RwQP

How big a cluster can you build? With a little math and the speed of light you can find out http://bit.ly/IlGss

Interesting read - Lies, Damn Lies and File Systems Benchmarks - http://bit.ly/cZDF0 Paper - http://bit.ly/5hihv

Amazing acrobat!

noreply@blogger.com (Pranav) — Sat, 15 Aug 2009 10:35:00 +0000

This is the most amazing form of acrobatics I've ever seen. Hats off to this guy!!

Dramatic Acrobat - The most amazing bloopers are here

Biggest invention/discovery by man

noreply@blogger.com (Pranav) — Thu, 06 Aug 2009 03:09:00 +0000

     I was recently intrigued by the following question - what is the invention/discovery that has made the most direct practical difference to man since he appeared on the earth ? I'm not considering theoretical/philosophical discoveries (like cosmology or quantum physics or theory of mind or invention of zero). I'm talking about things which brought about phenomenal changes in man's life in addition to helping him survive.

     The first thing that came to mind was the wheel. The ubiquity and utility of the wheel are beyond question. What else ? Aha.. the lever. Another simple machine which must have helped man to move boulders, push heavy loads and eventually build homes (and pyramids too). Wooden and stone tools also deserve an honourable mention. Without them our ancestors would have been killed by wild animals and other men. Another significant one is of course fire (not referring to the Fully Integrated Robotised Engine from Fiat :D)! Fire kept away predators and allowed man to control temperature of his near surroundings to some extent. An important side-effect of having fires at hand was cooking. With cooking, man could condition food to suit his stomach and that probably widened the range of things he could eat thus, increasing his chance of survival. But, what could man cook ? Dead animals ? and easily available plants maybe. Man did not grow crops until about 10 thousand years ago. Around 9-10K years ago, man made the greatest invention of all time IMO - agriculture!

     In school, we studied a bit of history of agriculture but, I never appreciated it. Rather, I always thought that there is hardly any point in studying what crops man grew thousands of years ago, and how he settled near river beds and dug channels for water. Only now I realize that, the advent of agriculture/farming is an event of super importance in the history of mankind. Here is I imagine how -

     Before agriculture was invented, man was totally dependent on nature for his food, whether it be plants or hunted animals. That is why man must have been nomadic, because his stay at a particular place would have been dictated by the availability of food. Once he had harnessed completely whatever was there around his dwellings, it was simply impossible to stay at that same location. Artificially growing crops i.e farming must have given man the reason to stay at one place for many generations. Thus agriculture brought stability into man's life. Without stability man would have never gone into building permanent structures like houses, temples and townships eventually. With stability, there germinated a scope for long lasting art, music and endemic cultures. With stability, there developed kingdoms and there arose the politics of power.
     Before agriculture, the growth in population of man was directly limited by the naturally available resources around. Man could consume only what the forests produced at their natural rate. Acceleration in growth was not possible without extending boundaries i.e going to far-off places for hunting and gathering. Man had to search around for every bit of food that he must have ate. Agriculture solved that problem once and for all. Man could let his population grow by using more and more land for husbandry. Those that get rid of any kind of dependence are always great breakthroughs. For our forest scouring ancestors, this one must have been groundbreaking to say the least!

     Agriculture needs hard work. man learnt to offload the heavy duty work to animals. Thus the importance of maintaining cattle rose up and gave rise to animal husbandry.

     With agriculture came surplus produce, and what does one do with surplus grains ? Trade them of course!

     What does man do when it does not rain ? Pray to the rain God! And thus became important theology and religions...

     The amount of land and cattle controlled by men began to indicate their social status, thus a social hierarchy must have been created.

     In short, the coming of agriculture led to formation of civilizations(along with all its problems) which is the foundation of the kind of life we live today.

     Thus, agriculture is probably the biggest invention made by man so far. Many other inventions/discoveries improved man's life to a large extent, but none of them have transformed it to a degree that agriculture did then.

Twinks #1

noreply@blogger.com (Pranav) — Wed, 05 Aug 2009 17:48:00 +0000

Here is the first set of 'Twinks', read more about Twinks here

These are in no particular order -

RSS Subscribers or Twitter Followers: Which Are Worth More? http://bit.ly/QDbfu

Nikon's latest digicam has an unusual feature - a digital projector! (video) http://bit.ly/vVjGv

'Double check your damn pointers, okay ?' http://bit.ly/JnbyY

Preposterous and funny - http://pghcoder.posterous.com/

Have a look at Canon's amazing supertelephoto lens http://bit.ly/bVF6Q The huge 1Ds looks tiny relative to it.

Tweeted links to come on this blog.

noreply@blogger.com (Pranav) — Thu, 30 Jul 2009 03:15:00 +0000

      Twitter has become a massive phenomenon and, although skeptical about it in the beginning, now I too have become an active tweeter. Twitter is an excellent way to share knowledge and interesting links. Posting to twitter is much easy than posting on a blog. I can be found on twitter at http://twitter.com/pranavpeshwe
      Everyday I come across many interesting pages(via twitter and otherwise). I am planning to post some of the better links on his blog. The topics might range anywhere from technology to psychology not excluding webcomics ;) There is already a 'Link Of the Day' series on the blog. Now, in addition to that, I'm going to run a 'Twinks' (Tweeted Links) series of posts, which will contain no more than 10 links a post. As for the LOD posts, there will be no fixed frequency for Twinks.

      Lets see how it goes... :)

LOD 3E

noreply@blogger.com (Pranav) — Thu, 30 Jul 2009 02:44:00 +0000

Now you know where Apple gets their ideas from ;) http://www.geekculture.com/joyoftech/joyarchives/1270.html

MapReduce for the shell.

noreply@blogger.com (Pranav) — Wed, 08 Jul 2009 03:08:00 +0000

Google brought MapReduce into the world. At the core, it is essentially a divide-n-conquer with distributed processing support.
The guys at last.fm implemented a poor man's MapReduce in bash. It is definitely worth looking at.
Here is an article about it in linuxmag and here is BashReduce's page on github.

How much is a Terabyte ?

noreply@blogger.com (Pranav) — Mon, 06 Jul 2009 03:33:00 +0000

Recently, I heard that one of my movie collector friends was going to buy another 500GB disk drive. He already has a 1.5 terabyte store at his disposal which contains tens of hundreds of movies.
Thinking about that, lead me to think about how much a Terabyte of data actually is.

Here is one interesting compilation about units of data and their relativity -

Excluding additions done by myself, all the data is taken from here.

Bytes (8 bits)

0.1 bytes: A single yes/no decision (actually 0.125 bytes, but I rounded)
1 byte: One character
10 bytes: One word (a word of language, not a computer word)
100 bytes: Telegram; two punched computer (Hollerith) cards

Kilobyte
1,024 bytes; 2¹⁰;
approx. 1,000 or 10 ³

1 Kilobyte: Joke; (very) short story
2 Kilobytes: Typewritten page
10 Kilobytes: Page out of an encyclopedia
50 Kilobytes: Image of a document page, compressed
100 Kilobytes: Photograph, low-resolution
200 Kilobytes: Two boxes (4000) punched computer (Hollerith) cards
500 Kilobytes: Five boxes, one case (10,000 of punched computer (Hollerith) cards

Megabyte
1,048,576 bytes; 2²⁰;
approx 1,000,000 or 10 ⁶

1 Megabyte: Small novel; 3-1/2 inch diskette
2 Megabytes: Photograph, high resolution
5 Megabytes: Complete works of Shakespeare; 30 seconds of broadcast-quality video
10 Megabytes: Minute of high-fidelity sound; digital chest X-ray; Box of 3-1/2 inch diskettes
20 Megabytes: Two boxes of 3-1/2 inch diskettes
50 Megabytes: Digital mammogram
100 Megabytes: Yard of books on a shelf; two encyclopedia volumes
200 Megabytes: Reel of 9-track tape; IBM 3480 cartridge tape
500 Megabytes: Average data content of a CD-ROM

Gigabyte
1,073,741,824 bytes; 2³⁰;
approx 1,000,000,000 or 10 ⁹

1 Gigabyte: Paper in the bed of a pickup; symphony in high-fidelity sound; broadcast quality movie
2 Gigabytes: 20 yards of books on a shelf
5 Gigabytes: 8mm Exabyte tape
20 Gigabytes: Audio collection of the works of Beethoven
50 Gigabytes: Library floor of books on shelves
100 Gigabytes: Library floor of academic journals on shelves; large ID-1 digital tape
200 Gigabytes: 50 Exabyte tapes

Terabyte
1,099,511,627,776 or 2⁴⁰;
approx. 1,000,000,000,000 or 10 ¹²

1 Terabyte: Automated tape robot; all the X-ray films in a large technological hospital; 50,000 trees made into paper and printed; daily rate of EOS (Earth Orbiting System) data (1998)
2 Terabytes: Academic research ligrary
10 Terabytes: Printed collection of the U. S. Library of Congress
50 Terabytes: Contents of a large mass storage system
~70 Terabytes: Total space taken up by Google Earth imagery

Petabyte
1,125,899,906,842,624 bytes or 2⁵⁰
approx. 1,000,000,000,000,000 or 10 ¹⁵

1 Petabyte: 3 years of EOS data (2001)
2 Petabytes: All U. S. academic research libraries
5-8 Petabytes: Dec '08 estimate of monthly internet traffic of the entire world
20 Petabytes: 1995 production of hard-disk drives
200 Petabytes: All printed material; 1995 production of digital magnetic tape

Exabyte
1,152,921,504,606,846,976 bytes or 2⁶⁰
approx. 1,000,000,000,000,000,000 or 10 ¹⁸

1 Exabyte: 50,000 years of DVD quality video
5 Exabytes: All words ever spoken by human beings (in text)
988 Exabytes: Estimated size of total digital information created/duplicated in year 2010.

Zettabyte
1,180,591,620,717,411,303,424 bytes or 2⁷⁰
approx. 1,000,000,000,000,000,000,000 or 10 ²¹

~2.25 Zettabytes: Amount of information that can be stored in 1 gram of DNA
42 Zettabytes: Storage for all human speech if digitized as 16 kHz 16-bit audio

Yottabyte
1,208,925,819,614,629,174,706,176 bytes or 2⁸⁰
approx. 1,000,000,000,000,000,000,000,000 or 10 ²⁴

1 Yottabyte: Higher end estimate of the total number of grains of sand on earth

GPS based maps of the Sahyadris

noreply@blogger.com (Pranav) — Mon, 06 Jul 2009 03:17:00 +0000

Here are GPS based maps of most of the popular forts in the Sahyadri mountains -

http://www.geocities.com/DrChengalva/GPSMaps.html
and
more at http://ketan.khairnar.googlepages.com/map.html

Extremely useful for anyone trekking during the rainy season.

Hijacked brains.

noreply@blogger.com (Pranav) — Mon, 22 Jun 2009 01:20:00 +0000

      Another interesting incident happened to me recently. This one took place near our office. The story goes this way -

      It was around 11 in the morning, I was in the office and got a call from my friend. He said he was near my office and wanted me to come down quickly. I climbed down quickly and looked out on the road. At some distance I saw his car along with half a dozen people standing around it. I realized that, he was in trouble.
      Now, I am not particularly interested in roadside squabbles, but I am certainly interested in psychology. I believe, roadside tiffs lift the cover off of a usually unused facet of (modern) man. When I went near my friend's car, a guy supported by pals were arguing with him and asking him for compensation for some broken parts of their bike. What had happened was that - my friend, after putting the indicator on was taking a U-turn, just then, this guy tried to overtake him from the right and bumped straight into his cars rear door.

      Those guys were very aggressive and were determined to get the compensation. A few passers-by had gathered around and were suggesting the usual - 'भांङू नका, मिटवून टाका...' (don't fight, settle the matter). I tried to argue as logically as possible, fortunately, those guys were still in the realm of logic. It is extremely difficult to argue with someone who does not adhere to rationality, rather it is impossible to argue with such a person, especially if he is mad with anger. His argument was that, my friend must have seen him coming in the side view mirror, but he purposely did not stop. I told him that side-view mirrors are convex and, cannot display objects that are very close. I demoed that to him and he somewhat agreed.
      Then things become hot over his friend using foul language and my friend objecting that. This was probably a result of a commonly occurring misunderstanding. When people use F words(and equivalents), it is not necessary that they are directed towards any individual. In a situation like a roadside fight, when one party hears bad words, they are predisposed to assume that the words were directed at them. In fact, foul language is an excellent way to express one's frustration/disapproval/disappointment about the situation! For e.g Nasty language is regularly put to use when one's favorite sports team loses narrowly. Are we cursing the team ? Generally not, after all, they are a favorite and, one cannot win every match. Then, are we cursing the team who beat them ? Probably not, winning is no crime, they played well and so, won. Then, why the bad words ? What we are cursing is in fact the undesirable situation that we have been forced to experience!
     The most interesting part of episode is what happened next. The sun was almost overhead and it was not very comfortable to stand in the heat. So, i suggested in these very words- 'फारच ऊन आहे, वाद घालायचाच तर आपण तिथे सावलीत जावून घालू.' (Its too hot here, lets continue our conflict in the shadow over there') And my friend and myself moved towards the tree by the roadside.
Suddenly a surprising thing happened, the guy's friends(who were supporting him all this time) suddenly realized that they had other important stuff to do, the passers-by probably came to the same conclusion and everybody mysteriously left the scene! Ultimately, only the biker guy was left in the shade along with my friend and myself. He must have been disheartened by the reduced support, for, within a couple of minutes he almost agreed that it was his mistake. Even more, he said that the vehicle was not his and that, he had previously suffered two accidents which had damaged the bike! After all this, there was no question of giving him any compensation. The whole matter ended. We both gave him a friendly advice to drive carefully here onwards, and left for work.
     The turning point was when we decided to shift to under the tree. The change of subject, brought about change of thought in everybody's brains. The people who were least concerned suddenly realized that, they were investing in nothing useful.
      Taking the liberty to theorize, I would say that all the time during the dispute, the limbic system(the amgydala to blame in particular) had had hijacked the brains of everybody. After the limbic system takes over, the neo-cortex which is responsible for much of the rational/logical thinking by humans is sidelined. Evaluative beings turn totally emotion driven. The takeover of non-life-threatening situations by the amygdala more often than not creates trouble. The role of the amygdala is to make one act quickly in an emergency situation. When man lived in the jungles, the quick response initiated by the amygdala saved many a men. No wonder the amgydala made it through the evolutionary journey to homo sapiens sapiens.
      The good thing about amygdala activation is that, it lasts only for a very short amount of time (unless continuosly fuelled). To get the cortex back into control, a major change in topic or a sudden distraction is enough. In my case, the question whether we should shift to under the tree accidentally served this purpose and everyone was back to their rational, evaluative behaviour.
      I think a lot of fights and arguments would end better if we succeed in getting people to think using their cortexes rather than their excited amygdalas :)

Marriage age and economic progress.

noreply@blogger.com (Pranav) — Fri, 19 Jun 2009 01:13:00 +0000

Do single people take more economic risks than married ones ? And if that is the case, will countries with singles getting married late have more entrepreneurs ? And as a result, will a country with people marrying later progress faster ?

Here is what Scott Adams had written about it - http://dilbert.com/blog/entry/marriage_and_economies/

Here is a pdf supporting his theory - http://www.un.org/esa/population/publications/worldmarriage/worldmarriagepatterns2000.pdf Take a look at the bar graphs given at the end.

Of course, the data only suggests a correlation, there is no way to determine causality from it. Better economy might have in some way caused singles to marry late :-/

LOD 3D

noreply@blogger.com (Pranav) — Thu, 04 Jun 2009 03:07:00 +0000

A brief history of plastic money -
http://www.thebigmoney.com/slideshow/plastic-flashback

Vintage Bhimsen Joshi clip.

noreply@blogger.com (Pranav) — Sun, 31 May 2009 03:58:00 +0000

     Here is a vintage video clip of Pandit Bhimsen Joshi performing a Komal Rishab Asavari at the Sawai Gandharva of 1975. The performance, no need to mention, is impeccable!
     I am from the generation which was not here when maestros like Pandit Bhimsen Joshi, Pandit Jasraj and Gaansaraswati Kishori Amonkar were at their peak. A video clip like this one gives an idea of what it must have been to listen to them then. The energy and सहजता in the singing is simply awesome!

     When there will be invented a time machine, the first thing i will do is to go back and listen to all the Sawais I've missed...

Cars without onboard fuel ?

noreply@blogger.com (Pranav) — Thu, 28 May 2009 02:14:00 +0000

Electric cars are becoming popular, but folks at a South Korean university have gone even further. They have developed a system in which cars will be inductively powered by power lines beneath the road surface. Here are some more details.

LOD 3B

noreply@blogger.com (Pranav) — Sat, 23 May 2009 07:36:00 +0000

A useful online free OCR (optical character recognition) service: https://www.ocrterminal.com
Tried it with a sample and it worked very well.

Toying around with Wolfram Alpha

noreply@blogger.com (Pranav) — Wed, 20 May 2009 02:22:00 +0000

The makers of Mathematica recently released their much anticipated online tool - Wolfram Alpha.
For the uninitiated, Wolfram Alpha('WA' here onwards) is, as they call it a 'computational knowledge engine'. The primary interface - a single text box, looks similar to Google but WA is very different from Google. Google is like a peon at office who can search for the file you asked in the entire office and bring it to you diligently; WA is like an intelligent consultant who will try to understand what information you seek and will search for it in his own knowledgebase (rather than your office), find relevant data, correlate it if possible and present you with a succinct summary and a graphic visualization if feasible. WA does not depend on the Internet for information.

Here are some things I have tried out on WA -
Am not posting the screenshots, they would take too much of space and time.

First, I began with some silly 'Wh' questions - who are you ? where are you ? why are you ?
- WA failed on the why are you ? I was hoping to get something like 'I am because my creator created me.'
Then slightly different one - are you conscious ? and then, can you pass the turing test ?
- WA returned a satisfactory answer for the first, but failed the second

An inquiry about Pune gave some useful information but better is available on the wiki.Any two things can be compared by putting them next to one another like this.

Thus, contrary to the pithy phrase, one can very well 'compare apples and oranges' ;)

I asked WA about meclizine and then asked it to compare meclizine and meclozine
- WA correctly recognized it as a drug ingredient and gave very useful info about it. This is where having a reliable, structured knowlegebase of one's own makes a huge difference. WA need not spend time and power trying to classify the word(query) from scratch. It already has the classification ready, it just selects a category and uses it to fetch specific info. The Internet hosts a prodigious amount of information, but to extract, classify and interpret it is IMHO a herculean task. WA does not try to do that.
WA failed in the comparison. Meclizine and Meclozine are the same compound, WA interpreted Meclozine as Meclizine but could not infer that there is no point in giving a side-by-side comparison of two same things. Poor logic IMHO, but easily fixable.

Tried out a conversion I often need to do - miles per gallon into km per litre. Google Calculator cannot handle it, but I was sure WA (with Mathematica backing it) could do it easily.
- The answer came out well, WA also showed some relevant relative comparisons for the number I'd entered. US dollar to Indian rupee conversion worked fine too, it gave me a lot of additional info I'd not asked for :)

Tried to get a truth table printed for a simple expression
- Worked nicely. WA showed the minimum forms and even the logic circuit!
Then I tried to check equivalence of two expressions. I tried to use the same syntax used in Mathematica and it worked. Although WA showed the truth table with all 'T's, it did not give a verdict whether the expressions were equal or not, so my question remained unanswered. This also should be easily fixable.

Attempted to get some information about P & NP algorithms, sorting, Hamiltonian cycle, Huffman code but WA seemed to be oblivious about them :( Mathematica is aware of some of them though.

This comparison I tried out proved that WA has excellent resources when it comes to chemistry and materials.

WA also has a superb knowledgebase of genomic sequences, I'd expected to see hardly anything when I tried this. It was a cool surprise! WA not only knew the gene by name, it also knew a lot about it even including nucleotide polymorphism frequencies!! The data although not exhaustive, comes handy at times.

Next, I tried looking for a note - A natural
- WA gave useful info including freq, notation and key location on a keyboard. Then I tried to search for C#. WA was not aware about C# as a language, it interpreted it only as a musical note.

Tried to check out WA's fluid mechanics by searching for Reynolds number. WA brought up an interface which allowed one to calculate the RN by giving inputs. It had tabulated the inputs and laid out the equation well. With raised expectations then, searched for worm gear. Sadly, nothing relevant turned out. Instead, WA completely condoned the important word 'gear' and displayed information about worms(animals). Disregarding user input is the last thing to do!

Overall, WA is an interesting tool, but it is hardly as useful as Google. With the limited data that it currently has, many of our questions go unanswered. It is good for a quick overview and comparison of objectively quantifiable topics and for doing maths and statistical calulations that google calculator cannot yet handle. Google won't be left behind, the folks are already working on Google squared. With the vaaast amount of data already indexed by Google, IMO, Google will definitely have an edge over WA when it comes to coverage. WA on the other hand, will be better in data correlation and compute power requirements owing to the structured nature of its data sources.

Here is Wolfram Alpha for you to try out -

A superb video.

noreply@blogger.com (Pranav) — Tue, 19 May 2009 13:20:00 +0000

An amazing episode from the wild.
A longish one, but worth a watch. You can read about it here.

I'm glad that we(humans) are far from those days when we had to (literally) fight for our lives; animals in the wild have to. Nature has set up a set of unwritten rules for these creatures to live in. The one which treads least best is liable to physical harm. Neither brutal nor caring, nature is but perfectly apathetic!
The video reiterates the age old maxim - Unity is strength.

The useful vice.

noreply@blogger.com (Pranav) — Tue, 19 May 2009 03:56:00 +0000

    Whats the single most productive way of writing code ? The answer IMHO is - writing as less as possible i.e laziness.
     By 'laziness' I do not mean laziness in general, I just mean laziness towards writing code. I am extremely lazy when it comes to writing code. I have to get over a colossally stupendous amount of inertia to lift my hands and start coding! I try to find every other valid reason to avoid writing code, even if the problem I'm working on has a pretty obvious solution. I find thinking to be much more rewarding :)
     I think really hard on trying to avoid creation of new code. When given a task, I try to come up with various designs and prove it to the client/boss that the new creation might be optimized out or a previously created module could be employed again. But, is this not just the plain old funda of 'reuse' ? Yes, it is reuse, but not merely reuse. Laziness brings a very very strong urge to question every design decision taken(previously by ourselves or the boss or the client) and test (mentally) whether it really brings any good into the big picture (as far as we can see it). The urge is so strong that it never allows me to start coding until I'm totally convinced that every line of code that I'm going to write is indispensable and will never have to be changed(unless there is a major alteration in the design). While hunting for ways to avoid new code I often run into solutions that I could not think of earlier, ways that appreciably reduce the complexity and, arguments to prove to the client that a particular feature/facet is redundant or can be bettered if thought about in another manner. I often just sit still in my chair brainstorming about how I could get out of the situation without writing a single character of code.
     In this way I've saved myself hundreds of lines of code which effectively means I finished coding faster! Also, I am a strong believer in 'lesser code = lesser bugs', so, I've saved myself(and future maintainers of the code) a considerable amount of debugging time too. Another very useful attribute that automatically comes from laziness is - aversion towards complications. Will a truly lazy person ever write complicated code ? Never; unless it is absolutely unavoidable. With such lazily written code, during a code review the programmer is in a position to defend every single line of code he has written. In addition to that, the client/boss is never unhappy to see a programmer thinking rather than just programming.
     Thus it becomes a win-win situation for both of us - the client/boss is glad to know that I am trying my best not to write non-utile code and, I'm happy because I get more time to read my favorite blogs ;)

P.S: I couldn't find a way to write it with a lesser number of 'I's. It might seem that I'm all extolling myself here, but I humbly state that I'm not!

Time dilation experiment.

noreply@blogger.com (Pranav) — Wed, 13 May 2009 01:43:00 +0000

     Came across a really cool experiment on the web. The experiment was about experiencing time dilation. Thanks to general relativity, we know that time slows down with increase in speed and decrease in gravitational attraction(pardon the oversimplification).
      As a personal experiment, this guy takes 3 atomic clocks for a ride, to experience and measure time dilation. He expects to age 23 nanoseconds more than his wife who stayed at home :) His measurements at the end of the expt show that the dilation was between 20-30ns.
Here is the page with photos and details of his setup - http://www.leapsecond.com/great2005/tour/
Pretty kewl I think B-)
     Also, do take a look at the world's first atomic wristwatch ;)

LOD 3A

noreply@blogger.com (Pranav) — Mon, 11 May 2009 17:43:00 +0000

A very rare piece of history - http://paradoxoff.com/french-and-russian-bullets-collided-in-flight.html

Timeline of a vehicle crash.

noreply@blogger.com (Pranav) — Thu, 07 May 2009 14:08:00 +0000

      Here is an interesting write up about safety features in Ford's Falcon - http://www.drive.com.au/Editorial/ArticleDetail.aspx?ArticleID=56781&vf=26

Here is a video of the 50km/hr crash test - http://media.drive.com.au/?rid=40239

      The most interesting information is towards the end of the write up where they have given the timeline of the collision. The important part is at the end of that timeline - '150-300 ms - Occupant becomes aware of collision.' Thus, it can take up to one third of a second for us to just to become aware of the situation completely. Acting upon it will take at least another 200-300ms (brain will process the inputs, inject epinephrine into the nervous system, and will send signals to the heart and various muscles; after receiving the signals the muscles will begin their work). Completing the act (taking a solid hold of the handle/steering wheel, zeroing the throttle, depressing the brakes completely) will take at least another 500ms. The total comes to around 1100 ms which is a very optimistic estimate. Generally, 1.5 secs is the figure used. With rain or darkness the figure may double. It will take some more time for the vehicle to actually start braking after the brakes are pressed. Assuming that this whole episode takes an optimistic 1.5 secs, the car/bike (at 50 km/hr) will have travelled around 20 meters even before it starts to slow down! Age, vision acuteness and the surprise factor ('that puppy came out of nowhere!') are other important things to be considered.
      The reaction time can be decreased by driving practice, but only by a small amount. The only thing which can improve the situation is to have urgent & reliable brakes. The significance of good brakes can hardly be overstated. Losing a mere one tenth of second to your non-urgent(a better word welcome :)) means travelling four more feet without braking. I hope that my school pal, with whom I argue many times over the sloppy brakes on his bike reads this post.

Facebook's Haystack.

noreply@blogger.com (Pranav) — Sun, 03 May 2009 06:25:00 +0000

'Haystack' is the name of Facebook's photo storage and service infrastructure. Its an amazingly large and superbly scalable system which allows facebook to store and retrieve photos uploaded by millions of users. The system incorporates a distributed data storage which handles a whopping 25 terabytes of photo uploads every week!
Here is an interesting article about Haystack on facebook's engineering blog.

Funny comments in code.

noreply@blogger.com (Pranav) — Fri, 24 Apr 2009 15:53:00 +0000

Came across this thread at StackOverflow - http://stackoverflow.com/questions/184618?sort=votes
Some of them are really funny!
(Caution: Somewhat risque language on the page. You have been warned.)