I was much saddened to hear yesterday that our friend and fellow Bayesian Hélène Massam passed away on August 22, 2020, following a cerebrovascular accident. She was professor of Statistics at York University, in Toronto, and, as her field of excellence covered [the geometry of] exponential families, Wishart distributions and graphical models, we met many times at both Bayesian and non-Bayesian conferences (the first time may have been an IMS in Banff, years before BIRS was created). And always had enjoyable conversations on these occasions (in French since she was born in Marseille and only moved to Canada for her graduate studies in optimisation). Beyond her fundamental contributions to exponential families, especially Wishart distributions under different constraints [including the still opened 2007 Letac-Massam conjecture], and graphical models, where she produced conjugate priors for DAGs of all sorts, she served the community in many respects, including in the initial editorial board of Bayesian Analysis. I can also personally testify of her dedication as a referee as she helped with many papers along the years. She was also a wonderful person, with a great sense of humor and a love for hiking and mountains. Her demise is a true loss for the entire community and I can only wish her to keep hiking on new planes and cones in a different dimension. [Last month, Christian Genest (McGill University) and Xin Gao (York University) wrote a moving obituary including a complete biography of Hélène for the Statistical Society of Canada.]
Archive for BIRS
Hélène Massam (1949-2020)
Posted in Statistics with tags 12w5105, Banff, Banff International Research Station for Mathematical Innovation, Bayesian Analysis, BIRS, Canada, DAG, Ecole Normal Supérieure, exponential families, Fontenay-aux-Roses, France, hyper-inverse Wishart distribution, ISBA, Marseiile, non-central Wishart distribution, obituary, Statistical Society of Canada, University of York, Wishart distribution, York on November 1, 2020 by xi'anthe year(s) with no conferences
Posted in Books, Mountains, pictures, Travel, University life with tags ABC in Grenoble, Banff, Banff International Research Station, BIRS, Brussels, Denver, Mount Rundle on March 21, 2020 by xi'anThis week, Nature has an article on “A year without conferences? How the coronavirus pandemic could change research”, where the journalist predicts a potential halt to scientific conferences. Taking as example the cancelled American Physical Society (APS) March Meeting, to quote
“many of them rapidly set up platforms to hold virtual sessions for the meeting, inviting their speakers to present by webcam or to upload their presentations to online repositories. Researchers who hadn’t been in a position to fly to Denver found themselves able to participate from afar in what became the Virtual APS March Meeting.”
On this same day I should have been traveling from Brussels to Grenoble for the ABC meeting there. Instead, I had a four day virtual panel meeting from home and there is no virtual version of the ABC in Gre[e]noble workshop. As no one seemed particularly eager to animate a few local talks with no guarantee of spectators. As things deteriorated to home confinement, it was actually better not to spend more efforts on the project. Since this confinement is bound to last much longer, it would however become more obvious that the community and the academic societies need plan virtual conference and invent different channels to gather members and disseminate innovation.
an oldie but a goldie [jatp]
Posted in Mountains, pictures, Travel, University life with tags Banff, Banff Mountain Festival, BIRS, Canada, Canadian Rockies, Cerro Torre, jatp, Patagonia, tee-shirt on March 19, 2020 by xi'ancomputational statistics and molecular simulation [18w5023]
Posted in pictures, Statistics, Travel, University life with tags 18w5023, Benzécri, BIRS, Casa Matemática Oaxaca, CMO, computational statistics, HMC, Jussieu, Mexico, molecular dynamics, Monte Carlos Statistical Methods, nested sampling, numerical integrator, path sampling, workshop on November 19, 2018 by xi'anThe last day of the X fertilisation workshop at the casa matematicà Oaxaca, there were only three talks and only half of the participants. I lost the subtleties of the first talk by Andrea Agazzi on large deviations for chemical reactions, due to an emergency at work (Warwick). The second talk by Igor Barahona was somewhat disconnected from the rest of the conference, working on document textual analysis by way of algebraic data analysis (analyse des données) methods à la Benzécri. (Who was my office neighbour at Jussieu in the early 1990s.) In the last and final talk, Eric Vanden-Eijden made a link between importance sampling and PDMP, as an integral can be expressed via a trajectory of a path. A generalisation of path sampling, for almost any ODE. But also a competitor to nested sampling, waiting for the path to reach an Hamiltonian level, without some of the difficulties plaguing nested sampling like resampling. And involving continuous time processes. (Is there a continuous time version of ABC as well?!) Returning unbiased estimators of mean (the original integral) and variance. Example of a mixture example in dimension d=10 with k=50 components using only 100 paths.