Thursday, November 15, 2007

Reviewing Fun

One of the required courses for my Masters is a literature review on a topic which we can choose ourselves. So I've been reading lots and lots of papers (on Bayesian networks for modelling gene regulation, in case you want to know), and the more I read, the more I can see certain common themes emerge. Not common themes about the topic, mind you, but just about papers in general.

First of all, most papers can be summarised pretty easily. However, the summary I would come up with almost never matches with the abstract that the authors wrote. I realise that this is a function of their desire to show every aspect of the paper in their abstract, while I would summarise the most important ones (which might be subjective), but I'm still left with the feeling that most abstracts are not reflective of the gyst of the paper.

Secondly, too many papers overuse references. I've read papers where there's two pages of text and three pages of references. What especially ticks me off is when the mentions a topic and then gives five references for it. We don't need five references, we need one good reference. Maybe two if there are two particularly good papers and you can't decide. Five is just overkill.

Thirdly, and finally, I've noticed a distinct lack of detail in some explanations. Now this is something I can understand if you're trying to boil down a paper to two or three pages for publication. But if you're going to gloss over something, at least say that you're doing so. Also, since this is the 21st century, how about providing a link to your webpage where more detailed information can be found?

Monday, November 5, 2007

Undergrad Proves Important Theorem

I read on the Wired blog that a 20-year old engineering student from the University of Birmingham has formally proved that a certain Turing machine model invented by Stephen Wolfram* is the simplest possible model.

Turing machines, for those not up on their theoretical computer science, are simple computing machines that Alan Turing conjectured were capable of calculating any computable function (he didn't say anything about efficency).

The usual model is that of a machine with a ticker tape with a sequence of symbols and a number of states. The machine looks at the tape one symbol at a time, and, depending on the symbol and its current state, decides what to do: Go forward one character, go back one character, overwrite the current character, or change state.

What makes this minimal Turing machine special is that it only has two states and three different symbols (sometimes called colours). The student proved that if you take away a colour or a state, it wouldn't be a Turing machine anymore.

Meanwhile, what important result did I discover during my time as an undergraduate? Oh, that's right, I discovered that you can live on nothing but pizza for a week...

*Yes, the same one who created Mathematica.