Sunday, July 29, 2007

On Weddings

Yesterday, I went to the wedding of a friend and colleague. They had a cute little civic ceremony. The girl here is the theoretical physicist. The guy is a farmer. A real one, with his own orchard and fruit shop and tractor and everything. The ceremony was set in their orchard. The parents of the bride and groom spoke. Then the bride and the groom sang a song together. Then, they tossed a coin to decide who should say the wows first. The girl won the toss. They exchanged wows, a judge that was hanging around in the background in his robe, pronounced them husband and wife and said “You may now kiss the bride again” (for they had been hugging and kissing all through the ceremony so far, no pretence of virginal purity or any such hypocrisy any where in sight), and they got onto the tractor of the groom and drove away. Cool, huh?

And as always this got me thinking about Indian wedding ceremonies I have been to. I have only been to south Indian tam-bram weddings. And I haven’t been to one in a while as I had decided that I will not go to these “extended-family-no-alcohol-parties” unless I was friends with the bride or the groom and most of my friends got married at inconvenient times and in inconvenient places (in India when I was not able to travel for example). But of course I have distinct memories of the many weddings I went to before I left home for college. And I had an advantage, in that I sat through the ceremonial part of the wedding with my great-granddad, who explained to me the significance of the various aspects of the wedding. But again, his explanation always had a religious tilt to them and over the years I have come to associate social or sociological rationalizations to them as well.

As a consequence, I have categorized the bits and pieces of the ceremony into the adult and the child parts. For example, the “oonjal”, where the bride and groom sit on a swing and are rocked and fed sweet things and sung to, or when the they have the “nalangu”, which are essentially slapstick games of breaking stuff on each other and throwing things and being carried on the shoulder of relatives to see who can be lifted higher must all clearly belong to the “child” category, included to make 8 or 10 year old kids that used to be the bride and groom once upon a time comfortable with the whole process. Then there are the really cute things that broadly belong in the adult category, like the woman following the man when he takes her hand to signify her support for him, or the “ammi mithikkardhu” part, when the man takes the woman’s feet in his hands and puts on the “metti”, to say I am your slave as much as you are mine. If you are not able to see the cuteness, imagine it in the context of 16 year olds in love for the first time.

But in today’s day and age, when 30-somethings are the ones getting married, all of this takes a rather ridiculous bent, doesn’t it? I wonder if our ceremonial weddings have evolved to better fit the social context today. Do you know? And if they haven’t then here is to hoping that they will in very short order!

Sunday, July 22, 2007

Random stuff 2

I woke up early this morning to do some work. The work entailed going through the revised version of a paper I wrote that a collaborator sent back to me. And I got depressed. The paper is unrecognizable now as something I wrote and am not sure what to do about it. So I took the escapist route out, namely take a break and do other things. So I went to my feed reader to get caught up on my blog reading. On Born a Libran’s blog, in his response to a tag that is inspired by a sound of music song, I found the following cool videos. Could not resist embedding them here.

The first one is Toyota ad with the one and only Aamir.

The second one must qualify as the weirdest commercial I have seen in recent times.

And yesterday afternoon when I was similarly depressed about something else (another paper that I am writing and having the hardest time finding the right words) I decided to cook while watching some TV. So I made what must surely be the world’s best “Keeria Saambar” while watching Pulp Fiction on TV (with all the f*@#’s bleeped out of course). And so now I have a question for any fellow fans of the movie that stumble here. Do you remember the OD scene when they revive Mia? After the scene (which is in the video below), Mia tells Vincent the Ketchup Joke (not in the video). What is the point of the Joke here?

Hope you all had a better weekend than I did. More coherent posts later.

Friday, July 20, 2007

Biomechanics – Cool stuff!

The physics posts that have shown up until now on this blog have been on boring things (albeit, close to my heart boring things) such as the second law and equilibrium self assembly. So, I have been thinking for a while now that I should write something on a cooler topic, even though I might know a lot less about it. The topic kind of chose itself this last week when my idle reading on collective intelligence (more on that in a subsequent post) took an interesting tangent.

The tangent is Biomechanics. As a discipline, in the broadest terms, this is a quest to understand the locomotion of living things. Of course, this quest can be addressed at many levels. But for the purposes of this post, we are going to restrict ourselves to the following question. Clearly, living things have lots of stuff on their mind (read neural control circuit) apart from locomotion. So, they have evolved in such a way that they must have a minimal feedback-limited control circuit that governs locomotion. If we could figure out what this minimal model is, we could apply it to robotics and hence be able to design robots that walk easily and hence have room left in them to build in other functions. Why would we want to do that? A standing example could be what happened to the Mars Rover Opportunity. The video below is a time lapsed footage of the rover extricating itself from some loose sand. In real time, it was stuck for a month [1].

You see, the Mars rover belonged to the old robotics paradigm of control that was not feedback-limited and certainly not minimal. This idea of minimality is something we learnt from watching nature solve complicated problems with ease [2]. So, people started asking, how do living things walk/run? A successful minimal model that came out of this study is what I call the “foot-forward strategy”. This model essentially said that the organism put half its feet down and kept the other half in the air (3 feet if you are a hexapod and one if you are human). It measured the resistance that the surface gave each of its feet and decided how far ahead to land the feet that are in the air and then keep repeating the process [3,4]. This model, that has just two ingredients could successfully explain the locomotion of a wide range of living things in a wide range (not exhaustive as you will see below) of terrains.

This strategy was implemented with great success in a robot called the Rhex. See below a video of Rhex zipping through all kinds of terrain, in a direction given to it by a guy with a remote control [5].

This is all well and good and a success to the method of scientific enquiry. But this model works only when the terrain is solid. Consider for example the following video of a spider moving on some uneven substrate. This substrate has holes that are larger than the foot of the spider and deeper than the length of its leg, but it still manages to zip across it (the video is slowed down 20 times).

So the question now is how do we understand this kind of motion. In attempt to study this question systematically, researchers decided to take this motion into the lab. Find below a video of a cockroach running across a wide mesh. Again the video is slowed down 50 times. It is actually moving very fast [6].

Now, there are several possible explanations for how the cockroach manages this. One possible explanation could be that this is an emergent (euphemism for “pleasantly unforeseen”?) consequence of the foot-forward strategy itself. But this the researchers can test readily, for they had the Rhex and we know for a fact that Rhex does not know anything other than the foot-forward strategy. So they did that and let Rhex run on the mesh to see what happens.

Oops! Rhex does not like the mesh! This tells us that there are two possibilities. The messier of the two is the possibility that the Cockroach has more than the simple foot forward strategy built into its neural circuit and we need to figure out what that is. But there is a simpler possibility. May be there is a physiological feature of the leg of the insect that we are missing. And this latter turns out to be the answer. Look at the cartoon along side of a cockroach. Its legs have spines or hairs or whatever you want to call them. These hairs have the property that they give easily in one direction (when pushed towards the leg) and are very stiff in the other direction, requiring loads greater than the weight of the insect in question to make them give. What the insect does when its foot lands ina hole is to use one of these pikes for leverage. You can go back to the video of the cockroach to see that this is indeed the case. So the claim now is the foot-forward strategy together with spikes or hairs are sufficient to negotiate terrain with gaps. The researchers tested this as well. They took Rhex and put spikes on his legs with the same properties as those on the legs of insects and put him back on the mesh. See the outcome in the video below.

It works! Rhex manages to get across, even though less elegantly than his real insect counterparts. The researchers of course performed other tests to verify the hypohesis. They took a cockroach and removed the hair from its legs and watched it stumble on the mesh. They took one of the fastest running creature on earth, the ghost crab (Ocypode quadrata) and let it run on the mesh. It struggled of course, because it runs on sand and hence has no spikes on its legs. And then they put spikes on its legs and watched it make it across the mesh successfully [7]. And so the researchers have successfully demonstrated that the foot forward strategy is enough even with holes in the terrain! This whole thread is a cool illustration of scientific methodology in general and that is one of the reasons I decided to write about it. The other of course are the cool videos. Are you as impressed by the coolness of it all as I am?

Asides, References and Disclaimers:

[1] I had the unique opportunity of watching the rover stuck on Mars live! I was at a NASA meeting at the Kennedy Space Center at the time and they were supposed to show us the rover in action live. But as it turned out, the Rover was stuck for the duration of the meeting.

[2] I looked for a reference on the control strategy for the rover, but could not find one. So, what I am saying here is hearsay. It must be classified or something. And the hearsay comes from a friend of mine that is Robotics researcher at UPenn, subject to my understanding of what he said.

[3] Notice that individual sensing gives an advantage to the multilegged creature. If the resistance on the front most leg is smaller than the hind ones, you know you are probably going onto softer terrain and step accordingly and keep your eyes, if you have them, on your food or predator or ipod or whatever.

[4] This of course is my minimal interpretation of the model. Find more details on this and other models in this Science review paper and the references there in.

[5] All the references on the development and implementation of the Rhex can be found in the website liked above. As an aside note that this project is funded by DARPA. So, unless we have secretly discovered an alien inhabited planet that the U.S is planning to invade, Rhex is more likely to be used in Iraq or whatever the next location for the war on terror is!

[6] This and all of the following is work done by Daniel Goldman and his collaborators. You can find all relevant references at his website. The videos are all stolen from there as well.

[7] The crab videos are on youtube as well. If you want to watch them, they are here and here.

PS: Apologies if this post showed up multiple times in your feed reader. Blogger screwed me over.

Wednesday, July 18, 2007

An Onion Headline

Just in case you have n't already seen this...just could not resist embedding it!:)

Monday, July 16, 2007

Monies, memes and such

As (the mostly imaginary) readers of this blog would have realized, I am a person that is obsessed with understanding, and this obsession extends to understanding human psychology as well. And the way to go about this task is to take a lot of data from the world around me and build models that explain this data. As with all things, I share this obsession with some of my friends. So, a few years ago, a couple of my friends and I came up with a strategy for collecting such data. We decided we would come up with a few questions that we thought were “penetrating” in some sense. It was decided that we will ask these questions to all the people we met and we will catalogue and keep the answers for analysis after we had accumulated statistically significant amounts of data (or rather as many of the people we met as possible, I mean, if we really liked them we would not want to risk scaring them away for ever, would we?). This process will help help us get a statistical grasp of the human psyche (paah!! day dreams realizable only in utopia as you will see). I had forgotten all about this for a while now, but recently Bongo tagged me with a meme and this caused all our idealistic planning to come rushing back to my mind! Ok, you are allowed at this point to decide I am crazy, but read on anyway, it might amuse you.

Quite early on in this endeavor of gathering data, we realized of course that the problem was the absence of any “right” questions. For example, one of the questions a buddy came up with was some slight variation of “What would you do if you got a million dollars tomorrow”. We got answers that ranged from “Retire and move back to India” to “Oh! After capital gains and state taxes, that would let me clear may be 600000$, I guess I would pay off my house and three cars and add the rest to my portfolio in the form of some blue chip security or the other”. Clearly the only things that the above two answers told us was that the person with the first answer thought a million dollars was a lot of money and the second one must have a really large income and hence thought of a million dollars as an “everyday sum”. It later turned out that the second guy had a yearly income that was a little more than half the amount, vindicating my earlier statement. This was not useful. We could have found that out by just asking them how much they made every month.

We got some really “out there” answers as well such as : “I will buy a plane and live from October through March here (here being Gainesville Fl) and live March through October in a place of the same latitude in the southern hemisphere with all the same amenities, air conditioning, high speed internet and the VPN that will let me access all journals and such. This way I will have outdoor weather all year round”. May be you could infer from this that this geeky person is outdoorsy and is relatively happy with life as it is so that her biggest problem was the weather?

You see, the motivation behind asking the question was to see what people would change in their lives if money was not an object, but elicit the answer without explicitly stating the same. If you do explicitly state what you are asking, then their answer will be biased by what they think they can tell you about their pet peeves. You are more likely to see the truth if you can ask a clever indirect question from whose answer you could infer what you were looking for. And yes, you are right, what you infer will be biased by what you think about things and hence will not be a “one to one and onto map” that will be “invariant to changes in the reference frame” i.e., be the same irrespective of the mind of the person constructing it. So, after a very short while of trying to fine tune the questions we would ask and encountering the inevitable (in retrospect) frustration of not getting anything useful or trustworthy, we abandoned this scheme of ours.

Now what has this got to do with memes and tags and such? I have been away from the Blogsphere for a little more than a week, working too hard to have time left over to do anything other than check email. Then I try to reenter the world by reading the posts in my reader and find that there are such an overwhelming number of them that I was too lazy to even try. So, instead I clicked around to see the network created by the random facts meme. It lead me to the realization that this is such a rich hunting ground for psychological data! There are all manners of people being tagged, all manners of interpretations of any given tag and of course the value of the written word, where you can see what is being said without the burden of the real personality! So, now I have a new “holy grail” [1] goal for my blog life. After I become this famous blogger that everybody reads and people just love to get a link from me even if it is in the form of a tag because of the traffic I send their way, I will try and start memes with specific objectives and watch them propagate through the blogsphere and thereby acquire all the data I need!:))) . As the Thalaivar once said “How is it?”:))

[1] The “holy grail” idea comes from the lingo used in scientific proposals. You see, when you go asking for money for a project, you have three levels of possible results you predict will come out of it. The highest is the holy grail. This is a result you know you will not get, but if you do by some serendipity you will get the nobel prize as well. The second result, which is what you are really shooting for is called the “Nature” in that you would probably get a paper in that revered journal when you are done. And then there is the “fall back”, the minimum result that you are sure you will get irrespective of how badly things go.

Sunday, July 8, 2007

Janma Saabalyam adenchitein

Inikku Shivaji paathittein. Shivaji sumaara irundaalum MGR super aa irundaar. I had fun. Yaar enna sonnalum seri., aana vayasukku thalaivar super aa irukkar. Period. :))

Thursday, July 5, 2007

I’ve been tagged – random facts

Bongo, as of now being awarded the title of second gentleman of the blogsphere (the first gentleman of course is the ever polite Patrix) has tagged me with the random facts meme. And I award him this title in spite of the fact that he tagged me only because “those who I can force into responding to a tag have mostly been tagged already”, for as is true for most people in most social situations, even virtual ones, I feel insecure and invisible and being tagged helps, right?:))

And now on to the meme. There is no way for a person to write eight random facts about themselves as it is bound to be biased by what they want people to know. But, I am going to try by picking eight random aspects of a person and writing down one fact about that aspect.

1. Appearance: I wore my hair in a “boy cut” of some form for the first twenty years of my life. Then one fine day I stopped cutting it and by the time I was 24 I had hair that fell below my waist. So I guess the fact is that my body produces way too much keratin?

2. Food: I LOVE “thaiyir saadam” and “avakkaai oorugai”, even more so now that I am attempting to be a vegan and it is “forbidden”. So the fact is that I am a dyed in the wool tam-bram.

3. Drink: Good coffee in the morning and good alcohol in the evening (no girly martinis for me, whisky neat or brandy with water preferable :))) So the fact is I am not that much of a tam-bram after all.

4. Music: With apologies to all the erudite and esoteric folks out there, tamil film music in general and by ARR my man in particular.

5. School girlish wish : I want to have had the genes of my father and his sisters instead of what I have now, namely my mother and her sisters. They all became fat as they got older. I am not that fond of eating but I hate to have to exercise!

6. Ms Universe type wish : Everybody in the world should have enough to eat so that “where is my next meal coming from” is not a thought of significance in their minds.

7. Siddhartha/Vivekananda type wish : That I had more concentration, more presence of mind and more rational thinking capacity than I do.

8. WTF fact of the day: It is raining outside now.

Ok, that did not turn out to be that random after all. But am too lazy to go back and rethink it and I should be working and not blogging anyways. And finally, on the need to propagate the meme. I have so few readers I don’t want to risk scaring them away by tagging them. And what if I am imagining that they read me and they really don’t? Horror of all horrors! But, I don’t want to be a spoil sport either. So, I (with great trepidation and anxiety) tag vatsan and tangled.

Tuesday, July 3, 2007

Eating Animals

This is perhaps one more reason you would want to be a vegetarian like me!:))