Friday, February 22, 2008

Pareto Pessimum

A Pareto Optimum is a cute idea in optimization theory: In simple problems, you have one or more decision variables and one objective; your task is to find out the right values for the variables so that your objective is maximized (or minimized, depends on your way of looking at it).

Life gets interesting when you have many objectives all depending on the same one or more decision variables. The wiki page describes it rather neatly:

Given a set of alternative allocations of, say, income for a set of individuals, a movement from one allocation to another that can make at least one individual better off without making any other individual worse off is called a Pareto improvement. An allocation is Pareto efficient or Pareto optimal when no further Pareto improvements can be made. This is often called a Pareto optimum.

The old Guns-vs-Butter curve in economics is a standard example.

Life gets really interesting when you're in a situation where you can't make a move without making someone worse off, and by no means could you bear that state being called any kind of 'optimum'. A Pareto 'pessimum', then ? :-(

May you live in interesting times. - Spiteful old Chinese curse

[Now who could have guessed that that quote has a riveting wiki page of its own?]

Update: 23Feb: In the intoxicating spirit of 'Why put up a new post when you can make a tenuous 5-steps-removed-connection to something already up?', here's something!

I was speaking to Popup earlier today, and every time I speak to the man I learn something mindblowingly amazing; And so it happens that there's this song called the Sunscreen Song, which is, in essence, a page of (rather sound) advice on Life. Soundness of logic was never a sexy enough reason to read advice on living Life, but this one's different: first, it has a fascinating history. Second, it was originally most irresistibly titled "Advice, like youth, probably just wasted on the young". Third, the clincher: it's hilarious! Check this out:

Remember compliments you receive. Forget the insults. If you succeed in doing this, tell me how.

What are you still doing here?! Oh ok, here's a PhDComics parody. Now go read! :-)

And while we're still wallowing in this mood most sombre, here's the most sensible and sensitive one-line wish I've ever read:

May we have the grace to accept with serenity the things that cannot be changed, courage to change the things that should be changed, and the wisdom to distinguish the one from the other.

Strong O:-)

Monday, February 18, 2008

Hayflick limit, pooh!

[Ouch, this was languishing somewhere in my drafts, and I bumped into it only now. I wrote it a long time ago and it's a bit dated. In the meanwhile, I have realized that maybe Zen philosophy contributed more to the development of human knowledge than just inspiring exotic ice-cream koans (and plain vanilla Zen koans). Maintaining a distance is what takes you closest :-(  but c'est la vie.]

You know you're getting really old when you get a mail like this:

[Mech2k4] Sunday Declared Working and Instructional Day

bhoor Jan 17 2008 10:44 PM
how bout a mass bunk dudes??

On 1/17/08, Pasha wrote:
Are we looking forward to meeting some big shot that day?
Parliamentary Personality @ IIT M !!

On Jan 17, 2008 6:10 PM, Lace wrote:
Though i wonder how these *sarkari afsars * are working on a Sunday

On Jan 17, 2008 5:55 PM, Pota wrote:
shit. i have one slot :(
but it is sad that we are still living in a country where some vetti
politicians can cause things like the work week to be altered.

and all you can do is lament that you have no classes to bunk. Till 10th, it was only the school porkis and aspiring rowdies and KDs who would dare think of such gross sedition; Our fit and proper duty, Gentlemen, was to transcribe every cough that unbearable Civics teacher condescended to, cough, and make sure we kept our forearms and palms on rough sheets when drawing constructions in Geometry, lest the much-respected Geometry Classwork Neat Copy book gets a dusty smear somewhere and (the horror!) the teacher shakes her (nearly all my math teachers were kind old ladies) head in disapproval.

After that were the ol' JEE days where mere thought of bunking would greatly multiply your expected JEE rank; All we could do was go green (ooh I love that word!) with envy at the Commerce and Arts guys who'd call forth an act of social unity as sophisticated and involved as a mass bunk with just a scrawl on the blackboard, "Mas bunk 2day da! Njoi!". We were to silently bear the not-so-mild yoke of humiliation when all our behaviour-theoretic constructs and logic ("Macha, just wait and see da, everyone will say he (or she; the gentle reader will do well to note that we're talking about the blessed Arts and Commerce streams) will bunk, nobody actually will") failed miserably, and they actually ended up bunking en masse and going to the latest movie. Oh, Us ? You want to know what we did? We very dutifully found the effective resistance between two nodes in an infinite grid of resistors. ( That, by the way, is no trivial problem. Not at all trivial,

Then we came to IIT, and it felt like a gas expanding into vacuum. As in the latter case, no work was done, and 3.5 years went away before we knew it. And before you knew it, we have no more classes to bunk. Oh dang :-(

Customary decryption of title: The Hayflick limit is related to the number of times a cell can divide before it 'dies'. As you remember from school biology, when a cell divides, the daughter cells are as good as new, so theoretically, you wouldn't expect them to stop anytime. Neither did Alexis Carrel (the inventor of surgical stitches, by the way), but this other guy Leonard Hayflick proved him wrong. Apparently, an average human cell can divide only about 52 times before it can't divide anymore.

In short, the Hayflick limit is what kills us.

The idea is also fascinating because certain kinds of cells - stem cells and cancerous cells in particular - don't seem have this limit imposed on them, and they are, in a sense, immortal. There are lots of efforts to beat the limit, the nicest-named of which is the Methuselah Mouse prize (named after a patriarch in the Bible who is said to have reached 969 years of age). The prize is for researchers who extend the lifespan of a mouse to tremendous lengths. On a related note, do watch The Man from Earth; the movie is nice, but what makes it an especially compelling watch is this little matter of principle:

(From Wikipedia, the eternal fount of all knowledge:)

The Man from Earth is a 2007 independent film written by Jerome Bixby and directed by Richard Schenkman. In what may be an unprecedented move, the producer of this film, Eric D. Wilkinson, has publicly thanked users of BitTorrent who have distributed the movie without express permission, saying that it has lifted the profile of this product far beyond the financier's expectations.