Archive for Europe

European statistics in Finland [EMS17]

Posted in Books, pictures, Running, Statistics, Travel, University life with tags , , , , , , , , , , , , , , on August 2, 2017 by xi'an

While this European meeting of statisticians had a wide range of talks and topics, I found it to be more low key than the previous one I attended in Budapest, maybe because there was hardly any talk there in applied probability. (But there were some sessions in mathematical statistics and Mark Girolami gave a great entry to differential geometry and MCMC, in the spirit of his 2010 discussion paper. Using our recent trip to Montréal as an example of geodesic!) In the Bayesian software session [organised by Aki Vetahri], Javier Gonzáles gave a very neat introduction to Bayesian optimisation: he showed how optimisation can be turned into Bayesian inference or more specifically as a Bayesian decision problem using a loss function related to the problem of interest. The point in following a Bayesian path [or probabilist numerics] is to reduce uncertainty by the medium of prior measures on functions, although resorting [as usual] to Gaussian processes whose arbitrariness I somehow dislike within the infinity of priors (aka stochastic processes) on functions! One of his strong arguments was that the approach includes the possibility for design in picking the next observation point (as done in some ABC papers of Michael Guttman and co-authors, incl. the following talk at EMS 2017) but again the devil may be in the implementation when looking at minimising an objective function… The notion of the myopia of optimisation techniques was another good point: only looking one step ahead in the future diminishes the returns of the optimisation and an alternative presented at AISTATS 2016 [that I do not remember seeing in Càdiz] goes against this myopia.

Umberto Piccini also gave a talk on exploiting synthetic likelihoods in a Bayesian fashion (in connection with the talk he gave last year at MCqMC 2016). I wondered at the use of INLA for this Gaussian representation, as well as at the impact of the parameterisation of the summary statistics. And the session organised by Jean-Michel involved Jimmy Olson, Murray Pollock (Warwick) and myself, with great talks from both other speakers, on PaRIS and PaRISian algorithms by Jimmy, and on a wide range of exact simulation methods of continuous time processes by Murray, both managing to convey the intuition behind their results and avoiding the massive mathematics at work there. By comparison, I must have been quite unclear during my talk since someone interrupted me about how Owen & Zhou (2000) justified their deterministic mixture importance sampling representation. And then left when I could not make sense of his questions [or because it was lunchtime already].

Takaisin helsinkiin

Posted in pictures, Statistics, Travel with tags , , , , , , , , , , on July 23, 2017 by xi'an

I am off tomorrow morning to Helsinki for the European Meeting of Statisticians (EMS 2017). Where I will talk on how to handle multiple estimators in Monte Carlo settings (although I have not made enough progress in this direction to include anything truly novel in the talk!) Here are the slides:

I look forward this meeting, as I remember quite fondly the previous one I attended in Budapest. Which was of the highest quality in terms of talks and interactions. (I also remember working hard with Randal Douc on a yet-unfinished project!)

Nobel Prizes against le Pen!

Posted in Statistics with tags , , , , , , , , , , , on April 19, 2017 by xi'an

“Certains d’entre nous, lauréats du prix Nobel d’économie, ont été cités par des candidats à l’élection présidentielle française, notamment par Marine Le Pen et ses équipes, pour ­justifier un programme politique sur la question de l’Europe. Les signataires de cette lettre ont des po­sitions différentes sur les sujets complexes que sont l’union monétaire et les politiques de ­relance. ­Cependant, nos opinions convergent pour condamner cette instrumentalisation de la pensée économique dans le cadre de la campagne électorale française.

– La construction européenne est capitale non seulement pour maintenir la paix sur le continent mais également pour le progrès économique des Etats membres et leur pouvoir politique dans le monde.

– Les évolutions proposées par les programmes antieuropéens déstabiliseraient la France et re­mettraient en cause la coopération entre pays européens, qui assure aujourd’hui une stabilité économique et politique en Europe.

– Les politiques isolationnistes et protectionnistes et les dévaluations compétitives, toutes menées au détriment des autres pays, sont de dangereux moyens d’essayer de générer de la croissance. Elles entraînent des mesures de représailles et des guerres commerciales. Au final, elles se révéleront préjudiciables à la France ainsi qu’à ses partenaires commerciaux.

– Quand ils sont bien intégrés au marché du travail, les migrants peuvent être une opportunité économique pour le pays d’accueil. Plusieurs des pays les plus prospères au monde ont su accueillir et intégrer les émigrés.

– Il y a une grande différence entre choisir de ne pas rejoindre l’euro en premier lieu et en sortir après l’avoir adopté.

– Il faut renouveler les engagements de justice sociale, et ainsi garantir et développer l’équité et la protection sociale, en accord avec les valeurs traditionnelles de la France, de liberté, d’égalité et de fraternité. Mais l’on peut et l’on doit parvenir à cette protection sociale sans protectionnisme économique.

– Alors que l’Europe et le monde font face à des épreuves sans précédent, il faut plus de solidarité, pas moins. Les problèmes sont trop sérieux pour être confiés à des politiciens clivants.”

Angus Deaton (Princeton, prix Nobel en 2015), Peter Diamond (MIT, 2010), Robert Engle (NYU, 2003), Eugene Fama (Chicago, 2013), Lars Hansen (Chicago, 2013), Oliver Hart (Harvard, 2016), Bengt Holmström (MIT, 2016), Daniel Kahneman (Princeton, 2002), Finn Kydland (CMU, 2004), Eric Maskin (Harvard, 2007), Daniel McFadden (Berkeley, 2000), James Mirrlees (Cambridge, 1996), Robert Mundell (Columbia, 1999), Roger Myerson (Chicago, 2007), Edmund Phelps (Columbia, 2005), Chris Pissarides (LSE, 2010), Alvin Roth (Stanford, 2012), Amartya Sen (Harvard, 1998), William Sharpe (Stanford, 1990), Robert Shiller (Yale, 2013), Christopher Sims (Princeton, 2011), Robert Solow (Columbia, 1987), Michael Spence (Stanford, 2001), Joseph Stiglitz (Columbia, 2001), Jean Tirole (Toulouse School of Economics, 2014)

Britain, please stay!

Posted in Books, Kids, pictures, Running, University life with tags , , , , , , , , , on June 7, 2016 by xi'an

A love letter from some Europeans against Brexit that appeared in the Times Literary Supplement a few days ago, and which message I definitely support:

All of us in Europe respect the right of the British people to decide whether they wish to remain with us in the European Union. It is your decision, and we will all accept it. Nevertheless, if it will help the undecided to make up their minds, we would like to express how very much we value having the United Kingdom in the European Union. It is not just treaties that join us to your country, but bonds of admiration and affection. All of us hope that you will vote to renew them. Britain, please stay.

‘gold’ open access & gold mine for publishers

Posted in Statistics, University life with tags , , , , , , on March 8, 2013 by xi'an

Following a discussion within the IMS publication committee and the coincidental publication of a central double page in Le Monde, weekend science&techno section [not that it was particularly informative!], here are some thoughts of mine on open access and publications:

First, the EU is philosophically inclined toward Open Access and has been putting some money into the game towards that goal:

As of 2014, all articles produced with funding from Horizon 2020 will have to be accessible: articles will

either immediately be made accessible online by the publisher (‘Gold’ open access) – up-front publication costs can be eligible for reimbursement by the European Commission;

or researchers will make their articles available through an open access repository no later than six months (12 months for articles in the fields of social sciences and humanities) after publication (‘Green’ open access).

This means that putting IMS publications on arXiv or on HAL (which is compulsory for CNRS and AERES evaluations, hence for most French public researchers, contrary to what Le Monde states) is fine and sufficient for EU funded research. It seems to be the same in other countries (ok, EU is not yet a country!) like Australia…

My personnal position on the issue is that I do not understand the ‘gold’ open access perspective. Since tax-payers are supporting public-funded research, why should they support the journals that publish this research if it is available on a public depository like arXiv for free? Simply because the publication in the journals gives a validation of the scientific contents? The argument was that it would save money on public libraries subscribing to expensive journals like Elsevier‘s, but paying the ‘gold’ open access is another way of redirecting tax-payers money towards publishers’ pockets, so this sounds like a loophole… I would thus be very much in favour of keeping the arXiv solution as is, since it is the greenest one, as long as we comply with local national regulations.