Archive for Paris

postdoc on missing data at École Polytechnique

Posted in Kids, pictures, R, Statistics, Travel, University life with tags , , , , , , , , , , , on November 18, 2016 by xi'an

Julie Josse contacted me for advertising a postdoc position at École Polytechnique, in Palaiseau, south of Paris. “The fellowship is focusing on missing data. Interested graduates should apply as early as possible since the position will be filled when a suitable candidate is found. The Centre for Applied Mathematics (CMAP) is  looking for highly motivated individuals able to develop a general multiple imputation method for multivariate continuous and categorical variables and its implementation in the free R software. The successful candidate will be part of research group in the statistical team on missing values. The postdoc will also have excellent opportunities to collaborate with researcher in public health with partners on the analysis of a large register from the Paris Hospital (APHP) to model the decisions and events when severe trauma patients are handled by emergency doctors. Candidates should contact Julie Josse at polytechnique.edu.”

nuit de la philosophie

Posted in Books, Kids, pictures, University life with tags , , , , on November 15, 2016 by xi'an

nuitphilo

Paris, l’an dernier…

Posted in Kids, pictures with tags , , , on November 13, 2016 by xi'an

In memoriam of that deadly night of November 13, 2015. The sun might be shining strong but no one is forgiven, the sky might be unblemished blue but nothing is forgotten.

À la Sorbonne

Posted in pictures, University life with tags , , , , , , , on November 3, 2016 by xi'an

iuf16This morning, in Sorbonne,  I attended the opening ceremony for the 26th promotion of l’Institut Universitaire de France (IUF), as I had the incredible chance of being nominated a senior member of this French virtual institute this Spring and for the incoming five academic years. (I had been nominated once already, from 2010 to 2015.) This institute is virtual in that its members remain in their home university, with a comfortable grant that buys teaching off and provides research support. This morning ceremony was mostly attended by the new members and the main event was a talk by Jules Hoffmann, Medicine Nobel Prize in 2011, who gave a very engaging talk in immunity and his work on the characterisation of immunity, first on flies and then on humans. The setting was the Grand Ampithéâtre of the historical Sorbonne building, only used now for academic ceremonies such as this one. (And also rented for private events…)

post-doctoral position in Paris

Posted in Statistics, Travel, University life with tags , , , , on October 14, 2016 by xi'an

The Fondation Sciences Mathématiques de Paris (FSMP) is lauching a call for postdoctoral positions in mathematics (incl. statistics!) and in fundamental computer science in the main laboratories of Paris universities for the academic year 2017-2018. The call for applications is open until December 1st 2016, 11:59 (pm), Paris time.

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!

The Magicians [#2]

Posted in Books, Kids, pictures, Travel with tags , , , , , , , on October 1, 2016 by xi'an

magicienIn a minor key coincidence with my book review last week, I spotted this advertising board on my métro platform this morning. Announcing the diffusion of the first season of The Magicians on the French SyFy [sic] channel. (Next to this board, a more relevant one from Droit au Logement.)