NIPS day 4

I went to (most of) the NIPS 2011 talks today (my first day at NIPS). Unlike the AAS meetings, the talks are very highly vetted (getting a talk at NIPS is harder—statistically speaking—than getting a prize fellowship in astronomy) and there are no parallel sessions, even though the meeting is almost as large as the AAS (NIPS is 1400; AAS winter is 2000-ish). One standout talk was by Laurent on the strange encoding of olfactory information in insects (and, apparently, humans, which are similar in this respect). There is a part of the olfactory system that looks like a sparse coding of the input, which looks (to my eyes) to be a very inefficient use of neurons. Another was by Feldman on coresets, which are data subsamples (imagine that you have way too many data points to fit in RAM) plus associated weights, chosen such that the weighted sum of log-likelihoods of the coreset points is an epsilon-close approximation to the full-data log-likelihood (or other additive objective function). This concept could be useful for astrophysics; it reminds me of my projects with Tsalmantza on archetypes.

On the bus to Sierra Nevada in the afternoon, Marshall and I tried to scope out our next paper. I put that in quotation marks because we don't have a very good track record of finishing projects! We are going to do something that involves image modeling and approximations thereto that can be performed on catalog (database) quantities.