Thursday, September 18, 2008

PPSN 2008, post 3

With some hindsight - that is, one day's worth of hindsight - I must say that PPSN 2008 was one of the best conferences I've ever attended. On my very personal ranking, it's up there in the top with CIG 2007 in Hawaii. The organisation of PPSN was top-notch, with nothing going wrong, the food good, the opportunities for socialising/networking plentiful and the schedule adhered to (this is Germany, after all).

It's striking how high the quality of the papers are in PPSN. In Gecco and CEC you know and then find papers you think should not have been accepted in a scientific conference, but never so in PPSN. There is also a difference in "scientificness". Many papers at the two other major conferences present yet another variation on a well-known algorithm, or yet another application, with little in the way of analysis and comparison to the state of the art. At PPSN, the norm seems to be to isolate a particular phenomenon, parameter or operator of known algorithms and benchmarks and study it further, making sure that even papers that are not groundbreaking (which is by necessity most papers) add to the body of human knowledge.

Of course, there are new algorithms and applications at PPSN as well. In particular, a number of variants of the CMA-ES were presented. CMA-ES seems to have become the standard algorithm to benchmark continuous optimization algorithms against, which makes sense, as it reaches good result very quickly on many problems.

Speaking of benchmarks, there seems to be a consensus that there is a lack of good reinforcement learning benchmark. A poster by Marc Schoenauer even went so far as to list "Stop balancing the double pole!" among it's conclusion. Of course, I tried to convince everybody who brought up the topic that they should use simplerace instead. A much better benchmark in many ways.

Now I'm going to prepare the talk I'll give tomorrow (with Marie Gustafsson) on "AI from Science to Fiction" at the Fantastic Film Festival in Lund, and the talk I will give on Monday on "Computational Intelligence and Game Design" at ITU Copenhagen.

Tuesday, September 16, 2008

PPSN 2008, post 2

We've now been to the conference dinner, in an old steel mill. Excellent food, and an excellent place to visit. I love lo-tech and especially huge, rusting metal structures.

Towards the end of the conference dinner, DJ JJ organized a singing competition between Spanish-speakers and a group of speakers of various other tongues(Swedish, English, Dutch, Hebrew etc.). Needless to say, we lost - we couldn't find any songs in English we all knew the lyrics to. After the dinner most of us went back to our respective hotels to recuperate. In my case, I'm recuperating from the excellent Dortmund nightlife. Clubbing until 4.30 on a packed dance floor, with the beers priced 50 cents each. On a Monday. Brilliant!

So you want to know about the scientific side of things? Well, PPSN is really a very good conference. It is hard to find a paper which is not good, though it is of course easy to find papers that don't interest me. I'm not interesting in everything. For example, a theoretical analysis of the behaviour of the 1+1 ES does not interest me very much, even if it is obvious that the research is sound and the paper good. Still, there are many papers here that I like.

Monday, September 15, 2008

PPSN 2008, post 1

I am at PPSN in Dortmund. I am listening to the talk on "Semidefinite Programming and Lift-and-Project Methods in Combinatorial Optimization" by Levent Tunçel. I do not understand anything at all of this talk. I am not the only one in the audience.

While I applaud the PPSN tradition of inviting people who are not evolutionary computation researchers to give keynotes, I don't think people outside our field understand how very little mathematics many (most?) people in this field know.

But the tutorials yesterday and the workshops on Saturday were really nice.