Here are the slides of the presentation I gave at the EPSRC Advanced Computational methods for complex models in Biology at University College London, last week. Introducing random forests as proper summaries for both model choice and parameter estimation (with considerable overlap with earlier slides, obviously!). The other talks of that highly interesting day on computational Biology were mostly about ancestral graphs, using Wright-Fisher diffusions for coalescents, plus a comparison of expectation-propagation and ABC on a genealogy model by Mark Beaumont and the decision theoretic approach to HMM order estimation by Chris Holmes. In addition, it gave me the opportunity to come back to the Department of Statistics at UCL more than twenty years after my previous visit, at a time when my friend Costas Goutis was still there. And to realise it had moved from its historical premises years ago. (I wonder what happened to the two staircases built to reduce frictions between Fisher and Pearson if I remember correctly…)
Archive for UCL
Last Sunday, I gave a talk on delayed acceptance at the 9th International Conference on Computational and Financial Econometrics (CFE 2015), joint with CMStatistics 2015, in London. This was a worthwhile session, with other talks by Matias Quiroz, on subsampling strategies for large data, David Frazier, on our joint paper about the consistency of ABC algorithms, and James Ridgway not on Pima Indians! And with a good-sized audience especially when considering the number of parallel sessions (36!). Earlier that day, I also attended an equally interesting session on the calibration of misspecified Bayesian models including talks by Peter Green [with a potential answer to the difficulty of parameters on the boundaries by adding orthogonal priors on those boundaries] and Julien Stoehr. calibrating composite likelihoods on Gaussian random fields. In the evening I went to a pub I had last visited when my late friend Costas Goutis was still at UCL and later enjoyed a fiery hot rogan josh.
While I could have attended two more sessions the next morning, I took advantage of the nice café in the Gower Street Waterstones to work a few hours with co-authors (and drink a few litres of tea from real teapots). Despite this quite nice overall experience, the 36 parallel session and the 1600 plus attendants at the conference still make wonder at the appeal of such a large conference and at the pertinence of giving a talk in parallel with so many other talks. And on about all aspects of statistics and econometrics. One JSM (or one NIPS) is more than enough! And given that many people only came for delivering their talk, there is very little networking between research teams or mentoring of younger colleagues, as far as I can tell. And no connection with a statistical society (it would be so nice if the RSS annual conference could only attract 1600 people!). Only a “CMStatistics working group” of which I discovered I was listed as a member [and asked for removal, so far with no answer]. Whose goals and actions are unclear, except to support Elsevier journals with special issues apparently constructed on the same pattern as this conference was organised, i.e., by asking people to take care [for free!] of gathering authors on a theme of their choice. And behind this “working group” an equally nebulous structure called ERCIM…
While the “robbed” in the title could be interpreted as wondering at the reason for paying such high registration fees (£250 for very early birds), I actually got robbed of my bicycle while away at the conference. Second bike stolen within a calendar year, quite an achievement! This was an old 1990 mountain bike I had bought in Cornell and carried back to France, in such a poor state that I could not imagine anyone stealing it. Wrong prior, obviously.
Apart from the minor initial inconvenience that I missed my train to Brussels thanks to the SNCF train company dysfunctional automata [but managed to switch to one half-an-hour later], my Belgian trip to Louvain-la-Neuve was quite enjoyable! I met with several local faculty [UCL] members I had not seen for several years, I gave my talk for the World Statistics Day in front of a large audience, maybe not the most appropriate talk for that day since it was somewhat skeptical about the nature of statistical tests, I got sharp questions, comments, and suggestions on the mixture approach to testing [incl. a challenging one about the Bernoulli B(p) case], I had a superb and animated and friendly dinner in a local restaurant—where everyone kindly spoke French although I was the only native French speaker—, I met the next morning with two PhD students from KU Leuven (the “other” part of the former Leuven university, albeit in the Flemmish side of the border) about functional ABC and generalised Jeffreys priors, I had a few more interesting discussions, and I managed to grab a few bags of Belgian waffles in Brussels before heading home! (In case you wonder from the above pixture, the crowds in the pedestrian streets of Louvain-la-Neuve were not connected to my visit!, but to a student festival centred at
beer a 24 hour bike relay that attracted around 50,000 students, for less than a hundred bikes!)
The University of Warwick is one of the five UK Universities (Cambridge, Edinburgh, Oxford, Warwick and UCL) to be part of the new Alan Turing Institute.To quote from the University press release, “The Institute will build on the UK’s existing academic strengths and help position the country as a world leader in the analysis and application of big data and algorithm research. Its headquarters will be based at the British Library at the centre of London’s Knowledge Quarter.” The Institute will gather researchers from mathematics, statistics, computer sciences, and connected fields towards collegial and focussed research , which means in particular that it will hire a fairly large number of researchers in stats and machine-learning in the coming months. The Department of Statistics at Warwick was strongly involved in answering the call for the Institute and my friend and colleague Mark Girolami will the University leading figure at the Institute, alas meaning that we will meet even less frequently! Note that the call for the Chair of the Alan Turing Institute is now open, with deadline on March 15. [As a personal aside, I find the recognition that
Alan Turing’s genius played a pivotal role in cracking the codes that helped us win the Second World War. It is therefore only right that our country’s top universities are chosen to lead this new institute named in his honour. by the Business Secretary does not absolve the legal system that drove Turing to suicide….]
The Journal of the Royal Statistical Society, Series B, has a new cover, a new colour and a new co-editor. As can be seen from the above shots, the colour is now a greenish ochre, with a picture of pedestrians on a brick plaza as a background, not much related to statistical methodology as far as I can tell. More importantly, the new co-editor for the coming four years is Piotr Fryzlewicz, professor at the London School of Economics, who will share the burden with Ingrid van Keilegom professor from UCL (Louvain-la-Neuve) who is now starting her third year… My friend, colleague and successor as Series B editor Gareth Roberts is now retiring after four years of hard work towards making Series B one of the top journals in Statistics. Thanks Gareth and best wishes to Ingrid and Piotr!
Today I took the Eurostar to London to give a seminar at the Gatsby Computational Neuroscience Unit, UCL. (Just a few blocks from the London School of Hygiene and Tropical Diseases, where I gave an ABC talk last year.) I had great fun, thanks to an uninterrupted sequence of meetings: I got a crash course on RKHS (reproducible kernel Hilbert spaces) by Arthur Gretton, discussed about estimating the number of species, dealing with unknown functions of the parameter in the likelihood, using tests as ABC statistics, and explained how to use empirical likelihoods in non-iid settings. After this full day, we had a superb dinner at St. John, a Michelin starred restaurant with highly enjoyable English cuisine, offering game and offal dishes that reminded me of Le Petit Marguery in Paris… (Not a place for vegetarians, obviously.)
Mark Girolami sent me this announcement for six PhD studentships in Statistical Methodology and Its Application at University College London (UCL) that are great opportunities for anyone interested in computational statistics!
The studentships are attached to the Department of Statistical Science at University College London, and a subset of them are UCL Impact awards. Impact awards support collaborative studentship projects with organisations such as charities, companies, government institutions and social enterprises. The impact awards are joint with Lloyds bank, Xerox Research Centre Europe, and NCR Labs, respectively. Continue reading