Archive for Clermont-Ferrand

from here to infinity

Posted in Books, Statistics, Travel with tags , , , , , , , , , , , , , on September 30, 2019 by xi'an

“Introducing a sparsity prior avoids overfitting the number of clusters not only for finite mixtures, but also (somewhat unexpectedly) for Dirichlet process mixtures which are known to overfit the number of clusters.”

On my way back from Clermont-Ferrand, in an old train that reminded me of my previous ride on that line that took place in… 1975!, I read a fairly interesting paper published in Advances in Data Analysis and Classification by [my Viennese friends] Sylvia Früwirth-Schnatter and Gertrud Malsiner-Walli, where they describe how sparse finite mixtures and Dirichlet process mixtures can achieve similar results when clustering a given dataset. Provided the hyperparameters in both approaches are calibrated accordingly. In both cases these hyperparameters (scale of the Dirichlet process mixture versus scale of the Dirichlet prior on the weights) are endowed with Gamma priors, both depending on the number of components in the finite mixture. Another interesting feature of the paper is to witness how close the related MCMC algorithms are when exploiting the stick-breaking representation of the Dirichlet process mixture. With a resolution of the label switching difficulties via a point process representation and k-mean clustering in the parameter space. [The title of the paper is inspired from Ian Stewart’s book.]

ABC in Clermont-Ferrand

Posted in Mountains, pictures, Statistics, Travel, University life with tags , , , , , , , , , , , on September 20, 2019 by xi'an

Today I am taking part in a one-day workshop at the Université of Clermont Auvergne on ABC. With applications to cosmostatistics, along with Martin Kilbinger [with whom I worked on PMC schemes], Florent Leclerc and Grégoire Aufort. This should prove a most exciting day! (With not enough time to run up Puy de Dôme in the morning, though.)

tenure track position in Clermont, Auvergne

Posted in pictures, Travel, University life with tags , , , , , , , , , , on April 23, 2019 by xi'an

My friend Arnaud Guillin pointed out this opening of a tenure-track professor position at his University of Clermont Auvergne, in Central France. With specialty in statistics and machine-learning, especially deep learning. The deadline for applications is 12 May 2019. (Tenure-track positions are quite rare in French universities and this offer includes a limited teaching load over three years, potential tenure and titularisation at the end of a five year period, and is restricted to candidates who did their PhD or their postdoc abroad.)