Archive for Christchurch

quantum forest

Posted in Books, R, Statistics, Travel, University life with tags , , , , , , , , on December 1, 2011 by xi'an

Thanks to a link on R-bloggers, I was introduced to Luis Apiolaza’s blog, Quantum Forest, which covers data analyses and R comments he encounters in his research as a quantitative forester/geneticist. And he works at the University of Canterbury, Christchurch, where I first taught from Bayesian Core in 2006. Which may be why he chose Bayesian Core as one of the three books he is currently reading to understand Bayesian statistics better. (The other two are Jim Albert’s Bayesian computation with R, and Bill Bolstad’s Introduction to Bayesian Statistics, which is not the one I reviewed recently.) Luis has just started the book but he mentions that “the book has managed to capture my interest”, which is real nice, and being annoyed by the self-contained label we put on the back cover. Which is a reaction I also got from some students when teaching the book for a week in Australia, as they thought they could take it without a probability background. Hopefully, we’ll manage to complete our revision before next summer!


Posted in pictures, Running with tags , , , , , , on March 12, 2011 by xi'an

Here are some images of “before” and “after” posted on the NASA website and reproduced by The Guardian. The magnitude of the thing is simply in-human… As in Christchurch three weeks ago and Haiti last year, my thoughts go to the survivors who have to comprehend the disaster before starting their long recovery work. I am sure many supportive initiatives like this one from a runner will show up in the coming days. In the meanwhile, only hope and thoughts…

Earthquake in Christchuch

Posted in Travel, University life with tags , , on September 4, 2010 by xi'an

There has been a major earthquake in Christchuch this morning. Support and best wishes to my friends and former colleagues at the University of Canterbury!

An update on the 5th: the damages are only material and no clear structural damage seems to have imperilled the buildings, but watching the million or so books off their shelves below means there is a substantial effort ahead! (Emails to are still bouncing back…)

València 9 snapshot [4]

Posted in Statistics, University life with tags , , , , , , , , on June 8, 2010 by xi'an

This one-before-last day at València 9 was fairly busy and I skipped the [tantalising] trip back to Sella to attend morning and afternoon talks. The first session involved Nicolas Chopin and Pierre Jacob’s free-energy paper whose earlier version I had heard at CREST, which builds on the earlier paper of Nicolas with Tony Lelièvre and Gabriel Stoltz to build a sequential Monte Carlo sampler that is biased along a preferential direction in order to fight multimodality and label switching in the case of mixtures. Peter Green rightly pointed out the difficulty in building this direction, which appears like a principal component to me, but this may open a new direction for research on a potentially adaptive direction updated with the SMC sampler… Although I always have trouble understanding the gist of causal models, Thomas Richardson’s talk about transparent parameterisation was quite interesting  in its links both with contingency tables and with identifiability issues (should Bayesians care about identifiability?! I did not really understand why the data could help in specifying the unidentified parameter in an empirical Bayes manner, though).

The morning talk by Darren Wilkinson was a particularly enticing talk in that Darren presented in a very articulate manner the specifics of analysing stochastic kinetic models for bacterial regulation and that he also introduced a likelihood-free MCMC that was not ABC-MCMC. (At first sight, it sounds like the auxiliary variable technique of Møller, Pettit, Reeves and Berthelsen, but I want to read the paper to understand better the differences.) Despite the appalling audio and video rendering in the conference room, the filmed discussion by Samuel Kou got into a comparison with ABC. The afternoon non-parametric session left me a bit confused as to the infinite regress on Dirichlet process expansions, but I enjoyed the next talk by Geoff Nicholls on partial ordering inference immensely, even though I missed the bishop example at the beginning because the talks got drifted due to the absence of the first speaker of the session. During the poster session (where again I only saw a fourth of the material!), I had the pleasant surprise to meet a student from the University of Canterbury, Christchurch, who took my Bayesian Core class when I visited in 2006.

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