Ascription is an Anathema to any Enthusiasm

Facinating article about a mast year in bamboo. Rat’s thrive and the following year people starve.

… Mizoram and Manipur … rats … army … teach … eradicate … flowering … bamboo … increase fertility rates … population explosion … crops … severe famines … the mautam in 1958-59 … triggered an insurgency … redrawing of boundaries…. Bamboo Flowering and Famine Control Schemes … rat tail … bounty … 200,000 rat tails… registering more tails… hunger currently prevail … grain production falling by 87% …collapse of the administrative machinery … refugee flows … worst is still to come….

Tip of the hat to Koranteng Ofosu-Amaah.

Search in a space requires poking around. In fact random search is the canonical strong method. Presuming you have time, can cover the search space, and recognize a solution it can solve any problem. Of course, drunken random walks are well known to result in repeatedly bumping into the same parking meter. So it is with some pleasure that I stumble upon a different kind of random walk. Better yet these walk’s principle feature is that their moves are power law distributed.

Levy walks are observed in nature. Searching animals have only a limited awareness of where food might be found. Outside that awareness they are reduced to random search. But they don’t move randomly in the sense of Browning motion, nor do they randomly select some destination and then move to it. Rather they appear to draw a random number from a highly skewed distribution and then make that move. If you browse the literature on Levy walks you can see that monkeys, humans, and many marine animals all use Levy walks to organize their search. Here’s a picture showing an example of those three kinds of walks.

I find this fascinating. As an engineer I’m surprised that I don’t think I’ve ever saw seen a search algorithm using this method. Looking down from above, this means you could observe the trajectory of any object and this simple statistic would tell you if it was alive. Looking out from within, since this is presumably a largely scale free phenomenon it’s quite suggestive about the trajectory of one’s life.

Another good posting on inequality.

Oh, yummy. Some data on the distribution of torrent traffic. Not what I expected. Curious!

That’s at Guillaume Besset’s blog, he’s also a collector of highly skewed distributions: More…

He’s also working on a p2p jabber based wiki, Bouillon.  I found this provocative: “… Everything you see in Bouillon is recommended by your friends … “  Of course given the way marketing people use the term relationship, Google, the Library, Wikipedia, and the Newspaper are my friends, aren’t they?

As requests go “How long will it take?” is one of the tough ones. Taleb’s book Black Swan makes an thought provoking point about it. Like most of that book the underlying question is what statistical distribution the data is drawn. Naturally, that should color our expectations.

Some project durations are reasonable, Gaussian. How long you will live, for example. As the project unfolds the expected end time draws progressively closer. Delay in these projects push out the end date; yes but, you do get always closer to the finish line. Such projects can be standardized.

But many projects are unreasonable, their duration is drawn from a highly skewed distribution. Choke-a-block with extreme cases and little black swans. In this case as the project unfolds it’s end date moves further out. Each delay increases the expected time to complete the project. Taleb’s example is the refugee who imagines that each passing day brings closer the day he will return home, but as that is likely the this second kind of project, these passing days infact push out that day.

You manage these two kinds of project in very different ways. Most projects are a hybrid. The nature of hope is very different for one v.s. the other.

See also: Time to Market