Archive for the Uncategorized Category

next OWABI webinar [27 Feb]

Posted in pictures, Statistics, Uncategorized with tags , , , , , , , , , , on February 21, 2025 by xi'an


The next One World Approximate Bayesian Inference (OWABI) Seminar is scheduled on Thursday, 27 February at 11am UK time, with the speaker being Ayush Bharti (Aalto University),

Cost-aware simulation-based inference

Abstract: Simulation-based inference (SBI) is the preferred framework for estimating parameters of intractable models in science and engineering. A significant challenge in this context is the large computational cost of simulating data from complex models, and the fact that this cost often depends on parameter values. We therefore propose cost-aware SBI methods which can significantly reduce the cost of existing sampling-based SBI methods, such as neural SBI and approximate Bayesian computation. This is achieved through a combination of rejection and self-normalised importance sampling, which significantly reduces the number of expensive simulations needed. Our approach is studied extensively on models from epidemiology to telecommunications engineering, where we obtain significant reductions in the overall cost of inference.

Keywords: simulation-based inference, approximate Bayesian computation, neural posterior estimation, neural likelihood estimation, importance sampling

next OWABI webinar [30 Jan]

Posted in pictures, Statistics, Uncategorized with tags , , , , , , , , , , , , on January 19, 2025 by xi'an


The next One World Approximate Bayesian Inference (OWABI) Seminar is scheduled on Thursday, the 30th January at 11am UK time, with the speaker being Paul Bürkner (TU Dortmund University),

Amortized Mixture and Multilevel Models

Abstract: Probabilistic mixture and multilevel models are central building blocks in Bayesian data analysis. However, they remain challenging to estimate and evaluate, especially when the involved likelihoods or priors are analytically intractable. Recent developments in generative deep learning and simulation-based inference have shown promising results in scaling up Bayesian inference through amortization. Against this background, we have developed specialized neural inference frameworks for estimating Bayesian mixture and multilevel models. The involved neural architectures are closely mirroring the probabilistic symmetries and conditional (in-)dependencies assumed by these models. This not only speeds up neural network training, but also enables amortized inference for new datasets of varying number of groups and sample sizes.

Keywords: Amortized Bayesian Inference; Neural Posterior Estimation; Probabilistic Factorization

even Bayesians may sink…

Posted in pictures, Uncategorized with tags , , , , , , , , , , , , , , on August 20, 2024 by xi'an

the story of Gertrud and Auguste Macé

Posted in Uncategorized with tags , , , , , , , , , , , , , , , , on August 6, 2020 by xi'an

The discussions about the links between early statistics and eugenism brought back to memory the tragic story of a German-Norman couple, friends of my grandparents, Gertrud(e) and Auguste Macé, whom I met in the mid 1980’s. Auguste Macé was a school friend of my grandmother, born near the harbour city of Granville, Manche and, like my grandparents,  a war orphan, son of a French conscript killed in combat during WW I. During WW II, when Nazi Germany promptly invaded France in the Spring of 1940, Auguste Macé was part of the millions of French conscripts captured by German troops and sent to a stalag, in North-Eastern Germany (Prussia), where he was made to work in farms missing their workforce conscripted to war. In one of these farms, he met Gertrud, daughter of the farm owners, they fell in love, and Gertrud eventually got pregnant. When her pregnancy was revealed, Auguste was sent to another POW camp. And, while Gertrud was able to give birth to a baby boy, she was dreadfully punished by the Nazis for it: as she had broken their racial purity laws, she was sterilised and prevented from having further children, presumably staying in her parents’ farm. At the end of WW II, Auguste was freed by Soviet troops and went searching for Gertrud. It took him around six months of traveling in the chaotic post-war Germany, but he eventually found both her and their son! They then went back to Auguste’s farm, in Normandy, where they spent the rest of their life, with further hardships like the neighbourhood hostility to a Franco-German couple, lost their young adult son in circumstances I cannot remember, and tragically ending their life together in a car accident in 1988, on a trip to Germany… [When remembering this couple, I have been searching on-line for more information about them but apart from finding the military card of Auguste’s father and Auguste’s 1988 death record by INSEE, I could not spot any link in birth or wedding certificates or in the 98 lists of WW II French POWs. Where I could not find my great-uncle, either.]

quote of the year

Posted in Uncategorized with tags , , , , , , , , , on October 19, 2019 by xi'an

“J’ai eu une vie assez droite, je ne me suis jamais conduit comme un salaud” [I have lived a rather righteous life, I never behaved like a bastard]

Jean-Marie le Pen [condemned for apology of war crimes (1969), contestation of crimes against humanity (2009), Holocaust denial (1988, 2006), antisemitism (1986), racial hatred (2005, 2008), provocation to discrimination against Muslims (2004, 2006) and Roma (2017), and insults (1993, 1998, 2018), demoted of his European parliamentary immunity (1997), suspended from the European parliament for assault (2000), suspected of misappropriation of public funds (2019) and of torture in Algeria, founder of the extreme-right Front National (1972), &tc., &tc., speaking on France Inter]