Rennes street art [jatp]

self-portrait on a railway board [jatp]

MissData 2015 in Rennes [June 18-19]

This (early) summer, a conference on missing data will be organised in Rennes, Brittany, with the support of the French Statistical Society [SFDS]. (Check the website if interested, Rennes is a mere two hours from Paris by fast train.)

art brut

trip to Besançon (and the stars)

Today, I made a quick TGV trip to Besançon, in French Jura, to give a seminar to astronomers and physicists, in connection with the Gaia project I had mentioned earlier. I gave my talk straight out of the train and then we started discussing MCMC and ABC for the astronomy problems my guests face. To my surprise, I discovered that they do run some local form of ABC, using their own statistics and distances to validate simulation from the (uniform) prior on their parameter space. The discussion went far enough to take a peek under the hood, namely to look at some Fortran programs they are running (and make suggestions for acceleration and adaptation). It is quite interesting to see that ABC is actually a natural approach when people face complex likelihoods and that, while they construct appropriate tools, they feel somehow uncertain about the validation of those methods and are unaware of very similar tools in other fields. In addition to this great day of exchange, I had several hours of freedom in the train (and a plug) to work on the bayess package for Bayesian Essentials (not dead yet!). Here are my slides, pot-pourri of earlier talks. (Including the one on cosmology model choice in Vancouver.)