Tuesday, August 25, 2009

Business donuts are strictly ornamental

Last time I was down at U of T, their career center had a book posted in its window, entitled Don't take the last donut: New rules of business etiquette.

Let's take the title advice seriously: as a matter of business etiquette, don't take the last donut. Why? Obviously, because it's impolite to deprive someone else of the option to have a donut.

Now assume that everyone is polite, and suppose there are two donuts left. What if you take the second-to-last donut? It's impolite for anyone else to take the last donut, so since everyone is polite (by assumption), your action deprives everyone else of a donut. Thus, it must be as impolite to take the second-to-last donut as it is to take the last one. We can make a similar case for the third-to-last and fourth-to-last donut.

Indeed, by the same argument, we can construct an inductive case: assuming it is impolite to take the nth-to-last donut (for any n >= 1), and there are (n+1) donuts available, then it must be equally impolite to take the (n+1)th-to-last donut, because nobody can (politely) take a subsequent donut.

Thus, by induction, for any integer n > 0, it is impolite to take the nth-to-last donut. Thus, business donuts are strictly ornamental and it is impolite to ever eat them. QED.

Tuesday, August 11, 2009

PLoS One: Publish in good journals, reject more papers

A neat article in PLoS One about peer review: it turns out that your rejection rate as a reviewer is related more to where you publish than your experience as a researcher. And if you publish in higher-quality journals, you're likely to reject more papers.

There are lots of ways to analyze and criticize this result, but here's my take. If you generally publish in higher quality journals, you will be doing most of your reviewing for higher-quality journals, which are more selective.

As I mentioned, the authors didn't find a relationship between experience and rejection rate, but I thought this figure was interesting: early researchers are clustered around the same "rejection intensity", while later ones tend to be spread out between much more stringent and much easier.

Tuesday, August 4, 2009

Shameless self promotion: Transactions on Info Theory Edition

My recent paper in the Transactions:

A. W. Eckford, “Ordering finite-state Markov channels by mutual information,” IEEE Trans. Inform. Theory, vol. 55, no. 7, pp. 3081-3086, Jul. 2009. [PDF]

In a Markov channel, the channel parameter is selected by the state of a hidden Markov chain -- the most famous example is the Gilbert-Elliott channel, in which a channel use might see a "good" state with low crossover probability, or a "bad" state with high crossover probability.

In Gaussian noise, channels are ordered with respect to SNR -- we know that a channel with smaller SNR has smaller capacity. In this paper, I'm trying to find a similar ordering for Markov channels: the "degraded family" of a "parent" channel, where all channels in the family have smaller capacity than the parent.