Publications by xi'an
Le Monde puzzle [#847]
Another X’mas Le Monde mathematical puzzle: A regular dice takes the values 4, 8 and 2 on three adjacent faces. Summit values are defined by the product of the three connected faces, e.g., 64 for the above. What values do the three other faces take if the sum of the eight summit values is 1768? Here is the simple R code I used to find a so...
1062 sym R (322 sym/2 pcs) 8 img
MCMSki IV, Jan. 6-8, 2014, Chamonix (news #16)
I am now in Chamonix, a week before MCMSki IV. The town is packed with tourists from all over Europe, English being the dominant language. There is not much snow so far, even though some runs reach town. (I did ski in the nearby Les Houches today and the red runs were either icy or very thin, with stones and grass showing here and there…) Since...
1251 sym 6 img
MCMSki IV, Jan. 6-8, 2014, Chamonix (news #17)
We are a few days from the start, here are the latest items of information for the participants: The shuttle transfer on January 5th, from Geneva Airport to Chamonix lasts 1 hour 30 minutes. At your arrival in the airport , follow the “Swiss Exit”. After the customs, the bus driver (handling a sign “MCMC’Ski Chamonix”) will be waiting f...
2152 sym 6 img
MCMSki IV, Jan. 6-8, 2014, Chamonix (news #18)
MCMSki IV is about to start! While further participants may still register (registration is still open!), we are currently 223 registered participants, without accompanying people. I do hope most of these managed to reach the town of Chamonix-Mont-Blanc despite the foul weather on the East Coast. Unfortunately, three speakers (so far) cannot make...
1668 sym 6 img
MCMSki IV [day 1.5]
The afternoon sessions I attended were “Computational and Methodological Challenges in evidence synthesis and multi-step” organised by Nicky Best and Sylvia Richardson and “Approximate inference” put together by Dan Simpson. Since both Nicky and Sylvia were alas unable to attend MCMSki, I chaired their session, which I found most interest...
2716 sym 6 img
MCMSki IV [day #3]
Already on the final day..! And still this frustration in being unable to attend three sessions at once… Andrew Gelman started the day with a non-computational talk that broached on themes that are familiar to readers of his blog, on the misuse of significance tests and on recommendations for better practice. I then picked the Scaling and optim...
2058 sym 6 img
MCMSki IV [mistakes and regrets]
Now that the conference and the Bayesian non-parametric satellite workshop (thanks to Judith!) are over, with (almost) everyone back home, and that the post-partum conference blues settles in (!), I can reflect on how things ran for those meetings and what I could have done to improve them… (Not yet considering to propose a second edition of MC...
2400 sym 6 img
Le Monde puzzle [#849]
A straightforward Le Monde mathematical puzzle: Find a pair (a,b) of integers such that a has an odd number d of digits larger than 2 and ab is written as 10d+1+10a+1. Find the smallest possible values of a and of b. I ran the following R code d=3 for (a in 10^(d-1):(10^d-1)){ c=10^(d+1)+10*a+1 if (a*trunc(c/a)==c) print(c(a,c))} wh...
2088 sym R (363 sym/2 pcs) 6 img
Statistical modeling and computation [book review]
Dirk Kroese (from UQ, Brisbane) and Joshua Chen (from ANU, Canberra) just published a book entitled Statistical Modeling and Computation, distributed by Springer-Verlag (I cannot tell which series it is part of from the cover or frontpages…) The book is intended mostly for an undergrad audience (or for graduate students with no probability or s...
5965 sym 6 img
cut, baby, cut!
At MCMSki IV, I attended (and chaired) a session where Martyn Plummer presented some developments on cut models. As I was not sure I had gotten the idea [although this happened to be one of those few sessions where the flu had not yet completely taken over!] and as I wanted to check about a potential explanation for the lack of convergence discus...
3005 sym 10 img