Archive for slides

Bayesian Adversarial Privacy [v2]

Posted in Books, Statistics, University life with tags , , , , , , , , , , , , , , , , , , , , , , , , on September 11, 2026 by xi'an

We have just reposted our paper Bayesian Adversarial Privacy on arXiv to reflect the revision we wrote in the past months, to address the (quite sensible) comments from the reviewers. Interestingly the discussants of my Akaike lecture made similar points. The main changes are in explaining more clearly the nature of the combined loss, with Antoine coming up with the use of illuminating R-U map representations, in enlarging the references to other approaches, in stressing that Eve was an Alice’s construct rather than a genuine adversary, but still integrating the case of “multiple Eves”, in mellowing our criticisms of DP, and in expanding the conclusion with limitations and extensions subsections.

Bayesian Privacy [Akaike Lecture slides]

Posted in Books, pictures, Statistics, Travel, University life with tags , , , , , , , , , , , , , , , , , , , , on September 10, 2026 by xi'an

la vie (bayésienne), mode d’emploi

Posted in Books, pictures, Travel, University life with tags , , , , , , , , , , , on August 1, 2026 by xi'an

Bayesian privacies [slides]

Posted in Books, Statistics, Travel, University life with tags , , , , , , , , , , , , , on April 4, 2026 by xi'an

Bob’s talk at PariSanté

Posted in Books, Statistics, University life with tags , , , , , , , , , , , , , , , on March 25, 2026 by xi'an

We had a wonderful time (and an unusually large audience) at the mostly Monte Carlo seminar last week as Pierre del Moral and Bob Carpenter both presented on exciting recent developments of theirs! Pierre talked about Kantorovich contraction of Markov semigroups, which sounds rather daunting!, but actually covers fairly general and generic convergence results, using tools like potentials and Lyapunov contractions, reminding me of the early days of MCMC and the papers of Gareth Roberts (University of Warwick), Jeff Rosenthal, Richard Tweedie and others.

Bob then spoke about the latest version of NUTS, the within-orbit adaptive NUTS (WALNUTS) sampler, which adapts the step size at every leapfrog step in order to conserve the Hamiltonian and keep the path stable enough. The adaptation is facilitated by incorporating this step size as an extra parameter with an attached distribution, that the authors call Gibbs self tuning (GIST), for coupling tuning parameters and conditionally Gibbs-sampling them per iteration in Hamiltonian Monte Carlo. This has been done in the past, incl. in some of my papers (e.g., Andrieu & Robert, 2004), but I could not cite a particular reference during the seminar.

Further light reflections that came to mind during Bob’s talk:

  • with NUTS, if cycling is feasible in a finite time, we could wait for a second passage at the starting point and then get back halfway (with the difficulty of detecting this second passage)
  • changing the kinetic matrix at each leapfrog jump is actually Riemannian HMC (and with cubic cost!)
  • the doubling mechanism in both the original NUTS and in biased progressive NUTS is simulation wasting
  • but so is (surprise, surprise!) finding adaptive mass matrices for WALNUTS at reasonable costs