Archive for the Wines Category

Claire Voisin’s CNRS Gold Medal

Posted in pictures, University life, Wines with tags , , , , , , on December 27, 2016 by xi'an

voisatrLast week, I attended the award ceremony of the Gold Medal of the French Scientific Research Council, which may well be the most prestigious scientific award in the country. It was awarded this year to Claire Voisin who is a specialist in algebraic geometry.

While I ended up in the meeting by the chance occurrence of Jean-Michel Marin visiting me, it was an impressive event with great talks from Claire Voisin (with a poetic praise of the complex exponential) and the CRNS Head, Alain Fuchs, but also quite enjoyable and mostly a-political discourses from the two Ministers attending the ceremony, Najat Vallaud-Belkacem and Thierry Mandon, who both mixed quotes from classics with some appreciation of Claire Voisin’s work. Even if one may suspect that those discourses were not (completely) written by the speakers (even though Mandon went looking for a Zweig’s quote during the meeting and ended up reading it from his phone, which was clearly unrehearsed!), they were delivered with enough conviction to be, well, convincing!

voiseuxThe event took place in the Grand Amphithêatre de la Sorbonne, which looked much nicer in the evening than when I attended the IUF rentrée a few weeks ago. And the classic (19th) paintings on the walls of this part of La Sorbonne made the ensuing cocktail even more classy. (Not that we had any opportunity to mingle with the Ministers, who are most likely too risk-adverse to be drawn in potential debates on the status of [funding] French Academia and academics…)

An update: on the road to Normandy, to visit my mother, we listened to a one-hour interview of Claire Voisin on France Culture that was a very good layman introduction to the maths she works on. (In French only.)

Terres des Aînés

Posted in Mountains, Travel, Wines with tags , , , , on November 20, 2016 by xi'an

Terres des Aînés, a wine from Pic Saint Loup, near Montpelliers, rich and complex

travelling from pub to pub [in a straight line]

Posted in pictures, Wines with tags , , , , , , , , , , , on October 30, 2016 by xi'an

Above is the solution produced by a team at the University of Waterloo to the travelling salesman problem of linking all pubs in the UK (which includes pubs in Northern Ireland as well as some Scottish islands—even though I doubt there is no pub at all on the Island of Skye! They also missed a lot of pubs in Glasgow! And worst gaffe of all, they did not include the Clachaigh Inn, probably the best pub on Earth…). This path links over 24 thousand pubs, which is less than the largest travelling salesman problem solved at the current time, except that this case used the exact distances provided by Google maps. Of course, it would somehow make more sense to increase the distances by random amounts as the pub visits increase, unless the visitor sticks to tonic. Or tea.

eagle and child

a Venezia [ESOBE 2016]

Posted in pictures, Running, Statistics, Travel, University life, Wines with tags , , , , , , on October 26, 2016 by xi'an

Piazza Venezia, Roma, March 01, 2012Tomorrow I am off to Venezia for three days, attending the ESOBE 2016 workshop, where ESOBE stands for European Seminar on Bayesian Econometrics. This year it is indeed taking place in Venezia, Università Ca’ Foscari, in this beautiful building on the Gran Canale, and I have been invited to give a talk. Excited to get back to this unique place, hoping the high water will not be too high to prevent getting around (at random as usual).


Posted in Kids, Travel, Wines with tags , , , on October 20, 2016 by xi'an

Bayesian astrostats under Laplace’s gaze

Posted in Books, Kids, pictures, Statistics, Travel, University life, Wines with tags , , , , , , , , , , , on October 11, 2016 by xi'an

This afternoon, I was part of a jury of an astrostatistics thesis, where the astronomy part was about binary objects in the Solar System, and the statistics part about detecting patterns in those objects, unsurprisingly. The first part was highly classical using several non-parametric tests like Kolmogorov-Smirnov to test whether those binary objects were different from single objects. While the p-values were very tiny, I felt these values were over-interpreted in the thesis, because the sample size of N=30 leads to some scepticism about numerical quantities like 0.0008. While I do not want to sound pushing for Bayesian solutions in every setting, this case is a good illustration of the nefarious power of p-values, which are almost always taken at face value, i.e., where 0.008 is understood in terms of the null hypothesis and not in terms of the observed realisation of the p-value. Even within a frequentist framework, the distribution of this p-value should be evaluated or estimated one way or another, as there is no reason to believe it is anywhere near a Uniform(0,1) distribution.The second part of the thesis was about the estimation of some parameters of the laws of the orbits of those dual objects and the point of interest for me was the purely mechanical construction of a likelihood function that was an exponential transform of a sum of residuals, made of squared differences between the observations and their expectations. Or a power of such differences. This was called the “statistical model” in the thesis and I presume in part of the astrostats literature. This reminded me of the first meeting I had with my colleagues from Besançon, where they could not use such mechanical versions because of intractable expectations and used instead simulations from their physical model, literally reinventing ABC. This resolution had the same feeling, closer to indirect inference than regular inference, although it took me half the defence to realise it.

The defence actually took part in the beautiful historical Perrault’s building of Observatoire de Paris, in downtown Paris, where Cassini, Arago and Le Verrier once ruled!  In the council room under paintings of major French astronomers, including Laplace himself, looking quite smug in his academician costume. The building is built around the Paris Zero Meridian (which got dethroned in 1911 by the Greenwich Zero Meridian, which I contemplated as a kid since my childhood church had the Greenwich drawn on the nave stones). The customary “pot” after the thesis and its validation by the jury was in the less historical cafeteria of the Observatoire, but it included a jazz big band, which made this thesis defence quite unique in many ways!

A Milano [not jatp]

Posted in Kids, Mountains, pictures, Statistics, Travel, University life, Wines with tags , , , , , , , , on October 7, 2016 by xi'an

Today, I went to Milano for 13 hours to give a seminar at l’Università Bocconi. Where I thus gave a talk on Testing via mixtures (using the same slides as at ISBA last Spring). It was the first time I was in Milano (and thus at Bocconi) for more than a transfer to MCMski or to Pavia and it was great to walk through the city. And of course to meet and share with many friends there. While I glimpsed the end of the sunrise on the Italian Alps (near Monte Rosa?!), I was too late on my way back for the sunset.