Archive for Roissy

a journal of the plague year [long weekend reviews]

Posted in Books, Kids, pictures with tags , , , , , , , , , , , , , , , , , , , , , , , on August 15, 2020 by xi'an

Read Thinblade, ordered by mistake as I confused the author David Wells for another more famous one! An absolute disaster, from the poor quality of the printed-on-order self-published amazon-made copy to the abyssal style of the author (or of his dog). The story has no depth and no originality [a teenager discovers he must save the World against an evil entity released from captivity and gathers a team of un.be.lie.va.ble followers], the characters are uni-dimensional, either unbelievably good or complete evil and a colour comes with them to tell the hero which is which. The style (or lack thereof!) is massively indigest, with numerous repetitions about the feelings and questionings of the central characters, plus an hilarious focus on food, all menus being included in the text!, same endless drones about the incredible beauty of the visited castles a few days of ride from the hero’s farm. The plot is, again, laughably simplistic, making the Shannara books I read a few months ago sounding like an elaborate literary construct, and completely predictable. I cannot imagine myself or anyone else’s dog reading further books in the series

Watched The Old Guard after an exhausting day, including a (physical) trip to a dreaded DIY store!, after reading a somewhat lukewarm review in The New Yorker… I found out later that the film is based on a comics series with the same title. And it shows from the lack of real plot (need to get quickly to Afghanistan? just drop out from a freight train in the middle of Sudan…) to the predictability of the story (set-up heroes fight bad guys and at the end, guess what, …), to the massive amount of stale gun fights with the addition of archaic weapons (to make sure everyone understands the old guard is really old!). The funniest part is actually taking place in Goussainville, France, in the ghost section of this town located on the path of De Gaulle airport planes (and thus evacuated, but not demolished), and in its Roman church (listed, hence intact!). The lack of moral imperative or of higher being driving such immortal killers, who mostly seem tired of said immortality, and the absence of connection with the locals (as e.g. in the scenes taking place in Morocco) do not make this B movie any better. (And the French character definitely has an English accent!)

Had a chance lunch in a Michelin recommended restaurant, on the road to Chenonceau and a family vacation, as we were looking for an open restaurant. The haddock appetizer was fantastic (and enough!), while the trout was not so great, presumably frozen, even though the vegetables were original (incl. chayotte) and yummy.

Read Konungsbók (The King’s Book) by Arnaldur Indriðason, found on my mother’s bookshelves, which is a stand-alone book more of the “involuntary spy” type found in Eric Ambler‘s stories than the usual social theme detective story favoured by Indriðason. While the two involuntary spies in the story are indeed two archeolinguists blundering their way through implausible situations, against hidding Nazis and East German police, as Ambler’s The Dark Frontier, the appeal of the book is in the quest for the ultimate Icelandic saga that would close the nation’s history, The King’s Book, towards recovering other foundational and historical documents hoarded by Denmark. At some point, Halldór Guðjónsson Laxness gets the Nobel Prize in Literature, which first stuns the characters into stupefied pride and second helps them into making another unlikely escape. What I enjoyed in the novel is the feeling of ultimate importance attached to the sagas and their role in cementing Iceland as a genuine nation (again connecting with Laxness, whose books described the social desagregation produced by the American occupation).

ABC in Grenoble, 19-20 March 2020 [registration open]

Posted in Mountains, Statistics, Travel, University life with tags , , , , , , , , , , , , , , on January 7, 2020 by xi'an

Reminding readers that the next occurrence of the “ABC in…” workshops will very soon take place in Grenoble, France, on 19-20 March 2020. Confirmed speakers and sessions (with more to come) are

Misspecified models

Links with Machine Learning

  • Flora Jay (Université d’Orsay, France) TBA
  • Pierre-Alexandre Mattei (Inria Sophia Antipolis – Méditerranée, France) Partially Exchangeable Networks and Architectures for Learning Summary Statistics in Approximate Bayesian Computation
  • Dennis Prangle (Newcastle University, UK) Scalable approximate inference for state space models with normalising flows

As in most earlier versions of the “ABC in…”workshops (ABC in Paris, London, Roma, &tc.), we are aiming at a workshop atmosphere and, thanks to local sponsors, the registration fees are null, but registration is compulsory. And now open!

I also remind ‘Og’s readers that Grenoble can be easily reached by fast trains from Paris, Roissy, Geneva and Lyon. (There are also flights to Grenoble airport from Warwick, as well as Bristol, Edinburgh, London, Manchester, Rotterdam, Stockholm, Warsaw, but this is less convenient than flying to Lyon Saint-Exupery airport and then catching a direct train at the airport.) To add to the appeal of the place, the workshop occurs during the skiing season, with three mountain ranges in the close vicinity. Making ABski a genuine possibility for the weekend after!

ABC in Grenoble, 19-20 March 2020

Posted in Mountains, pictures, Running, Statistics, Travel, University life with tags , , , , , , , , , , , , on May 22, 2019 by xi'an

The next occurrence of the “ABC in…” workshops will take place in Grenoble, France, on 19-20 March 2020. Both local organising and international scientific committees have been constituted and the program should soon be constructed, along with calls to contributions launched at the same time. As in most earlier versions of the workshops (ABC in Paris, London, Roma, &tc.), we are aiming at a workshop atmosphere and, thanks to local sponsors, the registration fees if any will be low.

Grenoble can be easily reached by fast trains from Paris, Roissy, Geneva and Lyon. (There are also flights to Grenoble airport from Warwick, as well as Bristol, Edinburgh, London, Manchester, Rotterdam, Stockholm, Warsaw, but this is less convenient than flying to Lyon Saint-Exupery airport and catching a fast train at the airport.) To add to the appeal of the place, the workshop occurs during the skiing season, with three mountain ranges in the close vicinity. Making ABski a genuine possibility for the weekend after!

O’Bayes in action

Posted in Books, Kids, Statistics, University life with tags , , , , , , , , , , , , on November 7, 2017 by xi'an

My next-door colleague [at Dauphine] François Simenhaus shared a paradox [to be developed in an incoming test!] with Julien Stoehr and I last week, namely that, when selecting the largest number between a [observed] and b [unobserved], drawing a random boundary on a [meaning that a is chosen iff a is larger than this boundary] increases the probability to pick the largest number above ½2…

When thinking about it in the wretched RER train [train that got immobilised for at least two hours just a few minutes after I went through!, good luck to the passengers travelling to the airport…] to De Gaulle airport, I lost the argument: if a<b, the probability [for this random bound] to be larger than a and hence for selecting b is 1-Φ(a), while, if a>b, the probability [of winning] is Φ(a). Hence the only case when the probability is ½ is when a is the median of this random variable. But, when discussing the issue further with Julien, I exposed an interesting non-informative prior characterisation. Namely, if I assume a,b to be iid U(0,M) and set an improper prior 1/M on M, the conditional probability that b>a given a is ½. Furthermore, the posterior probability to pick the right [largest] number with François’s randomised rule is also ½, no matter what the distribution of the random boundary is. Now, the most surprising feature of this coffee room derivation is that these properties only hold for the prior 1/M. Any other power of M will induce an asymmetry between a and b. (The same properties hold when a,b are iid Exp(M).)  Of course, this is not absolutely unexpected since 1/M is the invariant prior and since the “intuitive” symmetry only holds under this prior. Power to O’Bayes!

When discussing again the matter with François yesterday, I realised I had changed his wording of the puzzle. The original setting is one with two cards hiding the unknown numbers a and b and of a player picking one of the cards. If the player picks a card at random, there is indeed a probability of ½ of picking the largest number. If the decision to switch or not depends on an independent random draw being larger or smaller than the number on the observed card, the probability to get max(a,b) in the end hits 1 when this random draw falls into (a,b) and remains ½ outside (a,b). Randomisation pays.

air static

Posted in Kids, Travel with tags , , , , , , , , on April 27, 2017 by xi'an

[On an Air France flight for Birmingham, two young French students apparently studying in Warwick kept blathering the entire time, with an utter lack of concern for their surroundings. Note: Les Marseillais is a particularly idiotic reality show on French TV.]

  •  …j’ai arrêté de regarder les Marseillais, c’est même pas conscient, tu vois…
  • …grave, c’est sûr, moi aussi j’ai arrêté, j’avais trop d’épisodes à rattraper…