Archive for England

redshirts

Posted in Books, pictures, Travel with tags , , , , , , on September 28, 2014 by xi'an

“For the first nine years of its existence, aside from being appointed the flagship, there was nothing particularly special about it, from a statistical point of view.”

A book I grabbed at the last minute in a bookstore, downtown Birmingham. Maybe I should have waited this extra minute… Or picked the other Scalzi’s on the shelf, Lock In that just came out! (I already ordered that one for my incomiing lecture in Gainesville. Along with the not final volume of Patrick Rothfuss’ masterpiece, The Slow Regard of Silent Things, which will just be out by then! It is only a side story within the same universe, as pointed out by Dan…)

“What you’re trying to do is impose causality on random events, just like everyone else here has been doing.”

What amazes most me is that Scalzi’s redshirts got the 2013 Hugo Award. I mean, The Hugo Award?! While I definitely liked the Old Man Wars saga, this novel is more like a light writing experiment and a byproduct of writing a TV series. Enjoyable at a higher conceptual level, but not as a story. Although this is somewhat of a spoiler (!), the title refers to the characters wearing red shirts in Star Trek, who have a statistically significant tendency to die on the next mission. [Not that I knew this when I bought the book! Maybe it would have warned me against the book.] And redshirts is about those characters reflecting about how unlikely their fate is (or rather the fate of the characters before them) and rebelling against the series writer. Ensues games with the paradoxes of space travel and doubles. Then games within games. The book is well-written and, once again, enjoyable at some level, with alternative writing styles used in different parts (or coda) of the novel. It still remains a purely intellectual perspective, with no psychological involvement towards those characters. I just cannot relate to the story. Maybe because of the pastiche aspect or of the mostly comic turn. redshirts certainly feels very different from those Philip K. Dick stories (e.g., Ubik) where virtual realities abounded without a definitive conclusion on which was which.

position at Warwick

Posted in Statistics, University life with tags , , , , , , , on September 17, 2014 by xi'an

the pond in front of the Zeeman building, University of Warwick, July 01, 2014the pond in front of the Zeeman building, University of Warwick, July 01, 2014the pond in front of the Zeeman building, University of Warwick, July 01, 2014

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.

Warwick campus

Posted in pictures, Travel, University life with tags , , , , , on September 3, 2014 by xi'an

quad

big data, big models, it is a big deal! [posters & talks]

Posted in Books, Kids, pictures, Statistics, Travel, University life with tags , , , , , , , , , , , , , , , on September 3, 2014 by xi'an

bdbmbdGreat poster session yesterday night and at lunch today. Saw an ABC poster (by Dennis Prangle, following our random forest paper) and several MCMC posters (by Marco Banterle, who actually won one of the speed-meeting mini-project awards!, Michael Betancourt, Anne-Marie Lyne, Murray Pollock), and then a rather different poster on Mondrian forests, that generalise random forests to sequential data (by Balaji Lakshminarayanan).  The talks all had interesting aspects or glimpses about big data and some of the unnecessary hype about it (them?!), along with exposing the nefarious views of Amazon to become the Earth only seller!, but I particularly enjoyed the astronomy afternoon and even more particularly Steve Roberts sweep through astronomy machine-learning. Steve characterised variational Bayes as picking your choice of sufficient statistics, which made me wonder why there were no stronger connections between variational Bayes and ABC. He also quoted the book The Fourth Paradigm: Data-Intensive Scientific Discovery by Tony Hey as putting forward interesting notions. (A book review for the next vacations?!) And also mentioned zooniverse, a citizens science website I was not aware of. With a Bayesian analysis of the learning curve of those annotating citizens (in the case of supernovae classification). Big deal, indeed!!!

big data, big models, it is a big deal!

Posted in pictures, Statistics, University life with tags , , , , , , on September 2, 2014 by xi'an

bdbmbd

a day of travel

Posted in pictures, Running, Travel with tags , , , , , , on September 1, 2014 by xi'an

Bham2I had quite a special day today as I travelled through Birmingham, made a twenty minutes stop in Coventry to drop my bag in my office, went down to London to collect a most kindly loaned city-bike and took the train back to Coventry with the said bike… On my way from Bristol to Warwick, I decided to spend the night in downtown Birmingham as it was both easier and cheaper than to find accommodation on Warwick campus. However, while the studio I rented was well-designed and brand-new, my next door neighbours were not so well-designed in that I could hear them and the TV through the wall, despite top-quality ear-plugs! After a request of mine, they took the TV off but kept to the same decibel level for their uninteresting exchanges. In the morning I tried to go running in the centre of Birmingham but, as I could not find the canals, I quickly got bored and gave up. As Mark had proposed to lend me a city bike for my commuting in [and not to] Warwick, I then decided to take the opportunity of a free Sunday to travel down to London to pick the bike, change the pedals in a nearby shop, add an anti-theft device, and head back to Coventry. Which gave me the opportunity to bike in London by Abbey Road, Regent Park, and Hampstead, before [easily] boarding a fast train back to Coventry and biking up to the University of Warwick campus. (Sadly to discover that all convenience stores had closed by then… )

high-dimensional stochastic simulation and optimisation in image processing [day #3]

Posted in pictures, Statistics, Travel, University life with tags , , , , , , , , , , , , on August 31, 2014 by xi'an

Last and maybe most exciting day of the “High-dimensional Stochastic Simulation and Optimisation in Image Processing” in Bristol as it was exclusively about simulation (MCMC) methods. Except my own talk on ABC. And Peter Green’s on consistency of Bayesian inference in non-regular models. The talks today were indeed about using convex optimisation devices to speed up MCMC algorithms with tools that were entirely new to me, like the Moreau transform discussed by Marcelo Pereyra. Or using auxiliary variables à la RJMCMC to bypass expensive Choleski decompositions. Or optimisation steps from one dual space to the original space for the same reason. Or using pseudo-gradients on partly differentiable functions in the talk by Sylvain Lecorff on a paper commented earlier in the ‘Og. I particularly liked the notion of Moreau regularisation that leads to more efficient Langevin algorithms when the target is not regular enough. Actually, the discretised diffusion itself may be geometrically ergodic without the corrective step of the Metropolis-Hastings acceptance. This obviously begs the question of an extension to Hamiltonian Monte Carlo. And to multimodal targets, possibly requiring as many normalisation factors as there are modes. So, in fine, a highly informative workshop, with the perfect size and the perfect crowd (which happened to be predominantly French, albeit from a community I did not have the opportunity to practice previously). Massive kudos to Marcello for putting this workshop together, esp. on a week where family major happy events should have kept him at home!

As the workshop ended up in mid-afternoon, I had plenty of time for a long run with Florence Forbes down to the Avon river and back up among the deers of Ashton Court, avoiding most of the rain, all of the mountain bikes on a bike trail that sounded like trail running practice, and building enough of an appetite for the South Indian cooking of the nearby Thali Café. Brilliant!

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