Xian's Og

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Updated: 19 hours 8 min ago

snapshot from Vienna

Sun, 2014-09-21 08:18
Categories: Bayesian Bloggers

Le Monde puzzle [#879]

Sat, 2014-09-20 18:14

Here is the last week puzzle posted in Le Monde:

Given an alphabet with 26 symbols, is it possible to create 27 different three-symbol words such that

  1. all symbols within a word are different
  2. all triplets of symbols are different
  3. there is no pair of words with a single common symbol

Since there are


such three-symbol words, it could be feasible to write an R code that builds the 27-uplet, assuming it exists. However, by breaking those words into primary words [that share no common symbols] and secondary words [that share two symbols with one primary word], it seems to me that there can be a maximum of 26 words under those three rules…

Filed under: Books, Kids Tagged: combinatorics, Le Monde, mathematical puzzle
Categories: Bayesian Bloggers

Basil the chipmunk (#2)

Sat, 2014-09-20 08:18
Categories: Bayesian Bloggers

someone to watch over me [Horfðu á mig]

Fri, 2014-09-19 18:14

And yet another roman noir taking place in Iceland! My bedside read over the past two months was “Someone to watch over me” by Yrsa Sigurðardóttir. (It took that long because I was mostly away in July and August, not because the book was boring me to sleep every night!) It is a fairly unusual book in several respects: the setting is an institution for mentally handicapped patients that was set on fire, killing five of the patients as a result, the investigator is an Icelandic lawyer, Þóra Guðmundsdóttir, along with her German unemployed-banker boyfriend, the action takes place at the height [or bottom!] of the Icelandic [and beyond!] economic crisis, when most divorce settlements are about splitting the debts of the household, and when replacing a computer becomes an issue, some of the protagonists, including the main suspects, are mentally ill, and the police and justice are strangely absent from most of the story. The the book tells a lot about the Icelandic society, where a hit-and-run is so unheard of that the police is clueless. Or seems to be. And where people see ghosts. Or think they do, as the author plays (heavily?) on the uncertainty about those ghosts. (At least, there are no elves. Nor trolls.) Definitely more in tune with the “true” Iceland than Available dark. (Well, as far as I can tell!) The mystery itself is a wee bit stretched and the final resolution slightly disappointing, implying some unlikely behaviour from the major characters. In particular, I do not buy the explanation motivating the arson itself. Terrible cover too. And not a great title in English (Watch me or Look at me would have been better) given the many books, movies and songs with the same title. Nonetheless, I liked very much the overall atmosphere of the book, enough to recommend it.

Filed under: Books, Travel Tagged: autism, Þóra Guðmundsdóttir, financial crisis, Horfðu á mig, Iceland, Reykjavik, Yrsa Sigurðardóttir
Categories: Bayesian Bloggers

an ISBA tee-shirt?!

Fri, 2014-09-19 08:18

 Sonia Petrone announced today at BAYSM’14 that a competition was open for the design of an official ISBA tee-shirt! The deadline is October 15 and the designs are to be sent to Clara Grazian, currently at CEREMADE, Université Dauphine [that should be enough to guess her email!]. I will most certainly submit my mug design. And maybe find enough free time to design a fake eleven Paris with moustache tee-shirt. With Bayes’ [presumed] portrait of course…

Filed under: Kids, pictures, University life Tagged: BAYSM 2014, ISBA, Markov chain, mug, tee-shirt, werewolf
Categories: Bayesian Bloggers

Am Belvedere

Thu, 2014-09-18 18:14
Categories: Bayesian Bloggers

up [and down] Pöstlingberg

Thu, 2014-09-18 08:18

Early morning today, following my Linz guests’ advice, I went running towards the top of Pöstlingberg, a hill 250m over Linz and the Danube river. A perfect beacon that avoiding wrong turns and extra-mileage, but still a wee climb on a steep path for the last part. The reward of the view from the top was definitely worth the [mild] effort and I even had enough time to enjoy a good Austrian breakfast before my ABC talk

Filed under: Mountains, pictures, Running, Travel, University life Tagged: Austria, breakfast, Danube, Donau, IFAS, Linz, montain running, Pöstlingberg, seminar, sunrise
Categories: Bayesian Bloggers

my life as a mixture [slides]

Wed, 2014-09-17 18:14

Here are the slides of my talk today at the BAYSM’14 conference in Vienna. Mostly an overview of some of my papers on mixtures, with the most recent stuff…

Filed under: pictures, Statistics, Travel, University life Tagged: Austria, BAYSM 2014, church, mixtures, Neue Jesuitenkirche, slides, Universitätkirche, Vienna, Wien
Categories: Bayesian Bloggers

position at Warwick

Wed, 2014-09-17 08:18

A new position for the of Professor Of Statistics and Data Science / Director of the [newly created] Warwick Data Science Institute has been posted. To quote from the job description, “the position arises from the Department of Statistics’ commitment, in collaboration with the Warwick Mathematics Institute and the Department of Computer Science, to a coherent methodological approach to the fundamentals of Data Science and the challenges of complex data sets (for example big data).”  The interview date is November 27, 2014. All details available here.

Filed under: Statistics, University life Tagged: academic position, big data, data science, England, job opening, professor of statistics, University of Warwick, Warwick Data Science Institute
Categories: Bayesian Bloggers

arriving in Linz

Tue, 2014-09-16 18:14
Categories: Bayesian Bloggers

Le Monde [short] guide to Vienna

Tue, 2014-09-16 08:18

An interesting (?) coincidence: Le Monde weekend edition has its tourist page dedicated to Vienna! As usual, it is a list of places recommended by a local, Le Vienne de Robert Stadler, which includes

Maybe a wee bit limited a scope (albeit the house designed by Wittgenstein sounds definitely worth the trip!). For a wider range of Vienna highlights for BAYSM 2014 participants, The New York Times offers 36 hours in Vienna. With apparently no intersection with the above list. (But the same imbalance towards restaurants and bars!)

Filed under: Books, Travel Tagged: 36 hours in, Austria, Le Monde, Ludwig Wittgenstein, The New York Times, Vienna
Categories: Bayesian Bloggers

Statistics first slides

Mon, 2014-09-15 18:14

Today I started my new course of Statistics for our third year undergraduates. In English! A point that came as a surprise for the students but I got no complaint (so far) and they started asking questions in English during the class. The slides are “under construction” and this first chapter borrows a fair chunk from Andrew’s blog entries. Including the last slide on the six Kaiser Fung quotes, which was posted yesterday night. The next chapter is going to be more standard, with statistical models, limit theorems, and exponential families.

Filed under: Books, Kids, Statistics, University life
Categories: Bayesian Bloggers

Series B reaches 5.721 impact factor!

Sun, 2014-09-14 18:14

I received this email from Wiley with the great figure that JRSS Series B has now reached a 5.721 impact factor. Which makes it the first journal in Statistics from this perspective. Congrats to editors Gareth Roberts, Piotr Fryzlewicz and Ingrid Van Keilegom for this achievement! An amazing jump from the 2009 figure of 2.84…!

Filed under: Books, Statistics, University life Tagged: impact factor, John Wiley, JRSSB, Series B
Categories: Bayesian Bloggers

xkcd [interview & book]

Sat, 2014-09-13 18:14

Of interest for xkcd fans: What If?: Serious Scientific Answers to Absurd Hypothetical Questions is out! Actually, it is currently the #1 bestseller on amazon! (A physics book makes it to the top of the bestseller list, a few weeks after a theoretical economics book got there. Nice! Actually, a statistics book also made it to the top: Nate Silver’s The SIgnal and the Noise….) I did not read the book, but it is made of some of the questions answered by Randall Munroe (the father of xkcd) on his what if blog. In connection with this publication, Randall Munroe is interviewed on FiveThirtyEight (Nate Silver’s website), as kindly pointed out to me by Bill Jefferys. The main message is trying to give people a feeling about numbers, a rough sense of numeracy. Which was also the purpose of the guesstimation books.

Filed under: Books, Kids, Statistics Tagged: Amazon, bestseller, book review, FiveThirtyEight, Guesstimation, Nate Silver, what if?, xkcd
Categories: Bayesian Bloggers

available dark [book review]

Fri, 2014-09-12 18:14

“Paved roads had long ago surrended to gravel tracks that disappeared into a desert of snow covered lava. Black spires like a forest of charred trees blotted out the stars near the horizon.”

This is the last book I read from my Amazon package: Available Dark by Elizabeth Hand. I cannot remember how I came to order it… Maybe a confusion with another fantasy author like Elizabeth Moon? Or simply because the story was taking place between MaineFinland and Iceland?! Anyway, I read the book within two days during a short hiking trip to the volcano region of Central France. The plot has indeed a mesmerizing quality that made me keep reading further and further at ungodly hours. (With the help of an US jetlag.) It is original and intense enough to overcome the major difficulty that the central character, Cas, is far from sympathetic, from specialising in corpse photography to being almost constantly on drugs. But the construction of the plot and the introduction of the characters, always seen from Cas’ viewpoint, are well-done, even though the ending is both precipitated and unrealistic. Too many coincidences. The original setup of this novel is the Finnish black metal scene, with its undercurrents of satanism, ritual murders, and church burnings. Rather accurate judging from the wikipedia page on the topic! What I appreciated most was the description of the first impression of Iceland on Cas, when she landed from Helsinki. “The trip to Reykjavik [from the airport] was like a bus tour through Mordor. Black lava fields, an endless waste broken here and there by ruined machinery or a building of stained corrugated metal.” So I may consider reading another novel in the series in a near future…

Filed under: Books, Mountains, Travel Tagged: Available Dark, black metal, Elizabeth Hand, Finland, Helsinki, Iceland, Reykjavik
Categories: Bayesian Bloggers

3,000 posts and 1,000,000 views so far…

Fri, 2014-09-12 08:18

As the ‘Og went over its [first] million views and 3,000 posts since its first post in October 2008, the most popular entries (lots of book reviews, too many obituaries, and several guest posts):

In{s}a(ne)!! 9,330 “simply start over and build something better” 8,514 George Casella 6,712 About 4,853 Bayesian p-values 4,468 Sudoku via simulated annealing 4,150 Julien on R shortcomings 3,673 Solution manual to Bayesian Core on-line 3,040 Solution manual for Introducing Monte Carlo Methods with R 2,954 #2 blog for the statistics geek?! 2,706 Of black swans and bleak prospects 2,596 Gelman’s course in Paris, next term! 2,451 the Art of R Programming [guest post] 2,242 Parallel processing of independent Metropolis-Hastings algorithms 2,208 Bayes’ Theorem 1,925 Bayes on the Beach 2010 [2] 1,778 Do we need an integrated Bayesian/likelihood inference? 1,742 Théorème vivant 1,617 Dennis Lindley (1923-2013) 1,613 Coincidence in lotteries 1,543 The mistborn trilogy 1,532 Julian Besag 1945-2010 1,529 Frequency vs. probability 1,448 Bayes’ Theorem in the 21st Century, really?! 1,401 the cartoon introduction to statistics 1,398 understanding computational Bayesian statistics 1,369 The Search for Certainty 1,274 Bayesian modeling using WinBUGS 1,273 Particle MCMC discussion 1,256 Reference prior for logistic regression 1,215 Tornado in Central Park 1,142 Harmonic mean estimators 1,138 A ridiculous email 1,134 Andrew gone NUTS! 1,132 Top 15 all-timers? 1,130 Millenium 1 [movie] 1,121 Monte Carlo Statistical Methods third edition 1,102 Introducing Monte Carlo Methods with R: a first course 1,090

and the most frequent search terms (excluding those connected with my name), with again two beach towns at the top!

benidorm 1,804 surfers paradise 1,050 george casella 785 mont blanc 705 introducing monte carlo methods with r 587 marie curie 500 mistborn 480 millenium 413 i love r 411 andrew wyeth 398 abele blanc 385 bayesian p value 375 bayesian p-value 374 walter bonatti 351 nested sampling 333 particle mcmc 332 dumplings 298


Filed under: Books, Kids, Statistics Tagged: book reviews, guest post
Categories: Bayesian Bloggers

my life as a mixture [BAYSM 2014, Wien]

Thu, 2014-09-11 18:14

Next week I am giving a talk at BAYSM in Vienna. BAYSM is the Bayesian Young Statisticians meeting so one may wonder why, but with Chris Holmes and Mike West, we got invited as more… erm… senior speakers! So I decided to give a definitely senior talk on a thread pursued throughout my career so far, namely mixtures. Plus it also relates to works of the other senior speakers. Here is the abstract for the talk:

Mixtures of distributions are fascinating objects for statisticians in that they both constitute a straightforward extension of standard distributions and offer a complex benchmark for evaluating statistical procedures, with a likelihood both computable in a linear time and enjoying an exponential number of local models (and sometimes infinite modes). This fruitful playground appeals in particular to Bayesians as it constitutes an easily understood challenge to the use of improper priors and of objective Bayes solutions. This talk will review some ancient and some more recent works of mine on mixtures of distributions, from the 1990 Gibbs sampler to the 2000 label switching and to later studies of Bayes factor approximations, nested sampling performances, improper priors, improved importance samplers, ABC, and a inverse perspective on the Bayesian approach to testing of hypotheses.

I am very grateful to the scientific committee for this invitation, as it will give me the opportunity to meet the new generation, learn from them and in addition discover Vienna where I have never been, despite several visits to Austria. Including its top, the Großglockner. I will also give a seminar in Linz the day before. In the Institut für Angewandte Statistik.

Filed under: Books, Kids, Mountains, pictures, Statistics, Travel, University life Tagged: Austria, Bayes factor, Bayesian tests of hypotheses, BAYSM, Gibbs sampling, importance sampling, label switching, Linz, mixtures, Vienna, WU Wirtschaftsuniversität Wien
Categories: Bayesian Bloggers

O’Bayes 2015: back in València

Thu, 2014-09-11 08:18

The next O’Bayes meeting (more precisely the International Workshop on Objective Bayes Methodology, O-Bayes15), will take place in València, Spain, on June 1-4, 2015. This is the second time an O’Bayes conference takes place in València, after the one José Miguel Bernardo organised in 1998 there.  The principal objectives of O-Bayes15 will be to facilitate the exchange of recent research developments in objective Bayes theory, methodology and applications, and related topics (like limited information Bayesian statistics), to provide opportunities for new researchers, and to establish new collaborations and partnerships. Most importantly, O-Bayes15 will be dedicated to our friend Susie Bayarri, to celebrate her life and contributions to Bayesian Statistics. Check the webpage of O-Bayes15 for the program (under construction) and the practical details. Looking forward to the meeting and hopeful for a broadening of the basis of the O’Bayes community and of its scope!

Filed under: pictures, Statistics, Travel, University life Tagged: José Miguel Bernardo, O-Bayes 2015, objective Bayes, Spain, Susie Bayarri, Valencia conferences
Categories: Bayesian Bloggers