Archive for Miami

moneyball

Posted in Books, pictures, Statistics, Travel, University life with tags , , , , , , , on January 17, 2012 by xi'an

When I received Significance today—this is the december 2011 issue,  I glimpsed it contained a coverage of the movie Moneyball my son watched a few days ago. Being completely blank about baseball (as well as cricket, but thanks to the Significance editors for their effort!),  I could not follow the argument in the movie (and in the review by Ray Stefani and Jim Albert) that made a statistician more efficient than a baseball scout, but it sounds like a very good argument for the profession! (Having Brad Pitt playing one of the statistically inclined, if not the statistician as mentioned in the review, cannot hurt with the students.)

Thankfully, there was nothing about the Russian election! And then an unexpected piece about a tunneller and the connections drilling tunnels has with statistics and Monte Carlo simulation. As it happened, the editor of Significance ran into the engineer who eventually wrote this paper in a pub in Miami Beach during JSM 11! This reminded me of a chance encounter I had with another tunnel driller in a plane to the US, who was sitting next to me and showed me a movie of his tunneller drilling under one of the major US airports. (This must have been in 2002 as I seem to remember travelling to Banff for an IMS meeting, along with Arnaud Guillin…)

In addition, I also enjoyed the simulation challenge of reproducing every bit of each of Shakespeare’s work by [virtual] monkeys typing at random. And a bit less the simulation of Chopin’s mazurkas as the notes were written in the letter code (instead of do, ré, mi, &tc.).

JSM 2011 [reflections]

Posted in pictures, Statistics, Travel, University life with tags , , , , , , on August 5, 2011 by xi'an

The meeting is now over and I should be busy packing rather than writing this post. This has been a highly busy week, with many meetings on the side, while working at night by refraining from fighting jetlag (as usual), so I should also let things rest rather than letting a sort of post-meeting melancholia express itself… As after last year JSM… Anyway, here are some of my raw reflections on JSM 2011.

On the positive side, I attended many exciting sessions, either because they were bringing new perspectives to me—maybe the keyword I will carry back from Miami Beach is pseudo-data— or because they exhibited a comprehensive and influential perspective on a domain (I am mostly thinking of David Cox’s and IMS medallion lectures). I met new people (including the editorial board of CHANCE!) and old friends (the Bayesian mixer was too short!),  delivered the rewards for the Mitchell Prize to a great paper on galaxy formation by Ian Vernon, Michael Goldstein, and Richard Bower, had several conclusive “business” meetings (and a few disappointing ones to keep the balance right!). I even managed to stick a working session into the tight program (although I wish it had been at another time in the day as I was partly dozing away…) I also enjoyed a terrific Cuban dinner in Versailles (!) and managed to take a few satisfactory pictures of sunrise (to be imposed on the readers in the coming days, I afraid!).

On the down side, I attended too many sessions with a very small audience, although the talks deserved better. Maybe due to the humongous size of the convention center, maybe due to the lesser attendance, maybe due to the strong attraction of the nearby beaches, I generally had a feeling of being in a small meeting. As noted by Julien, having so many parallel sessions is both an organisational nightmare and an academic absurdity. Besides forcing attendees to make choices between sessions (the worst case being the Savage award delivered during my Bayesian model assessment session!), it dulls the attractiveness of the meeting and the relevance of the talks. It is certainly not going to happen, but JSM should have a stronger filter for proposed talks in order to avoid contributed sessions where the only attendees are the five speakers plus the chair! It should also do something about the last day sessions: since canceling the last day of the conference is not possible (if only because there would be another last day!), inventing an attractive programme for the last sessions would anchor more attendees till the end. A national (and international) meeting of this size is an enormously expensive monster, in terms of costs both to the universities and companies (especially in Miami Beach!), and to the environment. The RSS went the major step of canceling the yearly meeting this year and, although the size of the meeting is not the same, the statistical societies involved in JSM could maybe consider alternatives. One way could be to encourage videotransmission of talks (of course, this would not reduce the number of talks, but impact the size of the audience. I tried to give a talk at MCQMC next year this way, as flying to Sydney for three days did not sound realistic, but this proposal was not received positively!) There is no obvious solution to this issue, otherwise it would have been found, but this feeling of somehow wasting enormous amounts of money in an uncertain economy contributes to my melancholia….

On a more personal [down]side, having to watch for Emily and planning for alternative vacation plans did not help with my stress level! (At this stage the hurricane warning is off. And so are we.) The constant heat and humidity did not either, even though I knew in advance it would be a problem and decided not to whine about it (at least on this blog…)  The cost of living in Miami Beach however came as a surprise, although it may explain for the lower attendance this year. (Having rented an apartment across the street from the convention center was a partial solution to both problems, though.)

JSM [4]

Posted in Books, pictures, Running, Statistics, Travel, University life with tags , , , , , , , on August 3, 2011 by xi'an

A new day at JSM 2011, admittedly not as tense as Monday, but still full. After a long run in the early hours when I took this picture, I started the day with the Controversies in the philosophy of Bayesian statistics with Jim Berger and Andrew Gelman, Rob Kass and Cosma Shalizi being unable to make it. From my point of view it was a fun session, even though I wish I had been more incisive! But I agreed with most of Jim said, so… It is too bad we could not cover his last point about the Bayesian procedures that were not Bayesianly justified (like posterior predictives) as I was quite interested in the potential discussion in this matter (incl. the position of the room on ABC!). Anyway, I am quite thankful to Andrew for setting up this session.As Jum said, we should have those more often, especially when the attendance was large enough to fill a double room at 8:30am.

Incidentally, I managed to have a glaring typo in my slides, pointed out by Susie Bayarri: Bayes theorem was written as

\pi(\theta) \propto \pi(\theta) f(x|\theta)

Aie, aie, aie! Short of better scapegoats, I will blame the AF plane for this… (This was a good way to start a controversy, however no one raised to the bait!) A more serious question reminded me of the debate surrounding A Search for Certainty: It was whether frequentist and subjective Bayes approaches had more justifications than the objective Bayes approach, in the light of von Mises‘ and personalistic (read, de Finetti) interpretations of probability.

While there were many possible alternatives for the next session, I went to attend Sylvia Richardson’s Medallion Lecture. This made sense on many levels, the primary one being that Sylvia and I worked and are working on rather close topics, from mixtures of distributions, to variable selection, to ABC. So I was looking forward the global picture she would provide on those topics. I particularly enjoyed the way she linked mixtures with more general modelling structures, through extensions in the distribution of the latent variables. (This is also why I am attending Chris Holmes’ Memorial Lecture tomorrow, with the exciting title of Loss, Actions, Decisions: Bayesian Analysis in High-Throughput Genomics.)

In the afternoon, I only attended one talk by David Nott, Efficient MCMC Schemes for Computationally Expensive Posterior Distribution, which involved hybrid Monte Carlo on complex likelihoods. This was quite interesting, as hybrid Monte Carlo is indeed the solution to diminish the number of likelihood evaluations, since it moves along iso-density slices… After this, we went working on ABC model choice with Jean-Michel Marin and Natesh Pillai. Before joining the fun at the Section for Bayesian statistical mixer, where the Savage and Mitchell and student awards were presented. This was the opportunity to see friends, meet new Bayesians, and congratulate the winners, including Julien Cornebise and Robin Ryder of course.

JSM 2011 [2]

Posted in Statistics, University life with tags , , , , on August 1, 2011 by xi'an

Yesterday at JSM 2011 was a slow start as I only attended the last session of the Sunday afternoon. (After completing recycling my class slides for the roundtable on Tuesday, exploring the Art Déco neighbourhood of the convention center, fighting the clamy heat by periodically dropping into AC stores, including the Apple store on Lincoln Mall, buying a much needed umbrella for my beach-deprived kids and finding a glasses store that kindly replaced a lost tiny screw on my daughter’s sunglasses, …) This was session 67, Bayesian methods in lifetime and longitudinal data. As is presumably the case for most late Sunday afternoon sessions in a massively parallel universe (89-44=45 sessions!), the room was filled by the speakers, the chairwoman and very few listeners…

The talks that had driven me to the far end of the convention centre, half a mile away from the registration desk!, were Sanjib Basu’s on Bayesian model comparison and Sanjay Chaudhuri’s on Bayesian empirical likelihood. Empirical likelihood remains for me a difficult concept in that it somehow clashes with the Bayesian paradigm: if there is no model and no likelihood, it seems delicate (a) to apply Bayes’ theorem and (b) to construct a prior distribution. I only have vague thoughts about the issue, but there should be a more Bayesian way of constructing the estimate of the likelihood function under the constraints, rather than using maximisation. (I think this is alluded to and somehow dismissed in Lazar’s 2005 Biometrika paper.) While mentioning some theoretical justifications for the approach, Sanjay’s talk also covered the more methodological issue of zero values in the empirical likelihood leading to a non-connected support. I do not know whether or not the classical theory brings a solution to this problem (again, having no connection at my rental does not help!), but I wonder if reparameterisation could help in this respect. The talk by Sanjib was about very familiar ground (see e.g. our San Antonio chapter), namely approximation methods for computing Bayes factors. He also ran a small experiment to compare Bayes factors with predictive pseudo-likelihood (i.e., Bayesian cross-validation) approximations and with DIC (discussed in the Bayesian Choice). I was a bit takecn aback when Sanjib suggested a return to the dreaded harmonic mean estimator as he had no guarantee his estimator was free from an infinite variance. When discussing with him later, I pointed out our alternative harmonic mean representation using HPD regions and he mentioned a 1997 paper by Tom DiCiccio doing something similar that I need to check.

JSM 2011

Posted in Statistics, Travel, University life with tags , , , , , , , on September 20, 2010 by xi'an

We are hardly back from JSM 2010 and we have to think forward to JSM 2011! On Saturday morning I got both news that the session I had proposed on behalf of ISBA was accepted by the ASA as an invited session on Bayesian Model Assessment (with Merlise Clyde, Andrew Gelman, Feng Liang and Jean-Michel Marin) and that the session on Controversies in the philosophy of Bayesian statistics proposed by Andrew Gelman, in which he had kindly invited me (along with Jim Berger, Rob Kass and Cosma Shalizi), was also accepted as an invited session. (I am not particularly attracted by the beaches of Miami!, but JSM is a good opportunity to interact with north America statisticians and to gather some of the on-going trends in the field…)

Follow

Get every new post delivered to your Inbox.

Join 701 other followers