The traditional group picture at the end of Eric Moulines’ 60th anniversary celebration, at IHP, Paris. Some of the participants had already left (and I am carefully hidding in the background). Among the celebrating talks reflecting the huge thematic diversity of EM’s carreer, Patrick Flandrin gave a great historical account of a certain Édouard-Léon Scott de Martinville and his invention of a sound recording device that did not meet with the same success as the later phonograph by Edison. A song he had registered in 1860 was retrieved in 2008 by a team of the Lawrence Berkeley National Laboratory, making it the earliest known intelligible voice recording in existence! Jean-François Cardoso explained how the team at Institut d’Astrophysique de Paris produced a near optimal estimate of the Cosmic Microwave Background (CMB) by linear projections preserving normality. Sara Filippi exposed a variational Bayes approach to selecting groups of variables in a GLM. Gareth Roberts illustrated retrospective sampling with his recent foray with Jeff Rosenthal in the lack of uniformity in the FIFA World Cup draws. Anatoli Iouditski spoke about a recent work on polyhedral estimation in statistical linear inverse problems. And Elisabeth Gassiat strolled through recent works on inference for hidden Markov models, including one at NeurIPS 2021 with Aapo Hyvärinen and others on nonlinear ICA. This was quite a fun meeting, with plenty of anecdotes and a few older pictures (even though I could not find any prior to 2005, which may have been the year I bought my first digital camera!)
Archive for cosmic microwave background
sweet 60’s
Posted in Kids, pictures, Statistics, University life with tags Édouard-Léon Scott de Martinville, celebrations, CMB, cosmic microwave background, Eric Moulines, FIFA, football World Cup, group picture, IHP, Institut Henri Poincaré, Lawrence Berkeley National Laboratory, NeurIPS 2021, NYT, Paris, recording, The New York Times, Thomas Edison, Zeitschrift on October 9, 2023 by xi'anmelting hot!
Posted in Kids, pictures, Travel with tags coffee, cosmic microwave background, physics, Seattle, Starbucks on September 29, 2015 by xi'an
Despite majoring in her Physics class last year, my daughter forgot that microwaves are not very friendly to metal objects. Like this coffee tumbler I had brought back from Seattle, albeit not from Starbucks. The plastic part melted really well, even though the microwave oven resisted the experiment… And the coffee inside as well.
550 billion particles
Posted in Books, Kids, pictures, Statistics, Travel, University life with tags CMB, cosmic microwave background, cosmology, dark energy, DEUS, flops, Monte Carlo Statistical Methods, simulation, supercomputer, towel on April 22, 2012 by xi'an“Space,” it says, “is big. Really big. You just won’t believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space, listen…” The Hitchhiker’s Guide to the Galaxy, Douglas Adams
“There is a theory which states that if ever anyone discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened.” The Hitchhiker’s Guide to the Galaxy, Douglas Adams
Following a link on Science Daily when looking at this 64 kcal mystery, I found an interesting annoucement about the most complete simulation of the evolution of the Universe from the Big Bang till now. The cosmology research unit in charge of the project is furthermore called DEUS (for Dark Energy Universe Simulation!), mostly located at Université Paris-Diderot, and its “goal is to investigate the imprints of dark energy on cosmic structure formation through high-performance numerical simulations”. It just announced the “simulation of the full observable universe for the concordance ΛCDM model”, which allows for the comparison of several cosmological models. (Data is freely available.) Besides the sheer scientific appeal of the project, the simulation side is also fascinating, although quite remote from Monte Carlo principles, in that the approach relies on very few repetitions of the simulation. The statistics are based on a single simulation, for a completely observed (simulated) Universe.
“If life is going to exist in a Universe of this size, then the one thing it cannot afford to have is a sense of proportion…” The Hitchhiker’s Guide to the Galaxy, Douglas Adams
The amounts involved in this simulation are simply mindboggling: 92 000 CPUs, 150 PBytes of data, 2 (U.S.) quadrillion flops (2 PFlop/s), the equivalent of 30 million computing hours, each particle has the size of the Milky Way, and so on… Here is a videoed description of the project (make sure to turn the sounds off if, like me, you simply and definitely hate Strauss’ music, and even if you like it, since the pictures do not move at the same pace as the music!):
