Archive for surfing

Basque thesis defence [Bayes almost on the beach]

Posted in Books, Kids, pictures, Statistics, Travel, University life with tags , , , , , , , , , , , , , , , on October 21, 2021 by xi'an

Yesterday morning I took part in a thesis defence (as a jury member) in the coastal city of Anglet, in the (French part of the) Basque Country. The PhD candidate was Sébastien Coube-Sisqueille, whom I did not know directly (although we had crossed paths at CIRM years ago and he had attended my MCMC course at ENSAE even more years ago). As it happened all other members of the committee, apart from Sébastien’s advisor, Benoît Liquet, were on Teams, being unable to travel to the Basque Country. Sébastien’s thesis is about MCMC strategies to accelerate convergence in spatial models represented as nearest neighbor Gaussian processes (NNGP), which relates to the earlier works of (X)XL on interweaving. (Unsurprisingly, the defence was successful and the candidate awarded his PhD!) Icing on the cake, I managed to take a dip in the Atlantic Ocean, before flying back to Paris for dinner, on a very warm afternoon (and slightly cooler water), thanks to Sébastien driving me to a nearby beach!

atmospheric random generator?!

Posted in Books, Mountains, pictures, Statistics, Travel with tags , , , , , , , on April 10, 2012 by xi'an

As I was glancing through The Cleanest Line, (the outdoor clothing company) Patagonia‘s enjoyable—as long as one keeps in mind Patagonia is a company, although with commendable ethical and ecological goals—blog, I came upon this entry “And the Winner of “Chasing Waves” is …” where the name of the winner of the book Chasing Wave was revealed. (Not that I am particularly into surfing…!) The interesting point to which I am coming so circumlocutory (!) is that they use a random generator based on atmospheric noise to select the winner! I particularly like the sentence that the generator “for many purposes is better than the pseudo-random number algorithms typically used in computer programs”. For which purpose exactly?!

Now, to be (at least a wee) fair, the site of random.org contains an explanation about the quality of their generator. I am however surprised by the comparison they run with the rand() function from PHP on Microsoft Windows, since it produces a visible divergence from uniformity on a bitmap graph… Further investigation led to this explanation of the phenomenon, namely the inadequacy of the PHP language rather than of the underlying (pseudo-)random generator. (It had been a while since I had a go at this randomness controvery!)

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