Archive for Texas

and it only gets worse…

Posted in Kids, pictures with tags , , , , , , , , , , , , , , , , , on June 3, 2018 by xi'an

“Donald Trump’s attacks on the press are “out of control” and damaging “the civic life and debate of the country”, the editor of the New York Times said on Sunday. Dean Baquet was responding to a tweet in which the president attacked his main rival. “The Washington Post is far more fiction than fact,” Trump wrote. `Story after story is made up garbage – more like a poorly written novel than good reporting. Always quoting sources (not names), many of which don’t exist.’ ” The Guardian, April 8

The Trump administration is expected to announce today a rule that would strip federal funding from clinics that provide abortions or refer patients to places that do. The rule, a return to a Reagan-era policy, is a victory for social conservatives. It’s also a jab at Planned Parenthood, which serves 41 percent of women who receive federally funded family planning services.2  NYT, May 18

“Donald Trump pulled the US out of the landmark nuclear deal with Tehran on Tuesday, moving to re-impose sanctions on Iran and defying pleas from close allies who had called for the agreement to be preserved. The decision marks a bitter defeat for America’s European allies, who have spent months beseeching Mr Trump to stay in a deal that he has denounced as “insane”. Critics warned it would further endanger stability in the Middle East. ” FT, May 8

“Donald Trump has slammed the gun laws of major US allies, claiming foreign countries could better protect their citizens – and possibly stop terrorist attacks – by loosening their gun control laws. In a speech to the NRA Leadership Forum, Mr Trump sought to reassure members of the US’s largest gun rights lobbying group of his support for the Second Amendment, after briefly expressing support for gun control measures in the wake of a school shooting in Florida.” The Independent, May 5

 

U of T sunset [jatp]

Posted in pictures, Running, Travel, University life with tags , , , , , on December 14, 2017 by xi'an

Au’Bayes 17

Posted in Statistics, Travel, University life with tags , , , , , , , , , , , , , , , , , on December 14, 2017 by xi'an

Some notes scribbled during the O’Bayes 17 conference in Austin, not reflecting on the highly diverse range of talks. And many new faces and topics, meaning O’Bayes is alive and evolving. With all possible objectivity, a fantastic conference! (Not even mentioning the bars where Peter Müller hosted the poster sessions, a feat I would have loved to see duplicated for the posters of ISBA 2018… Or the Ethiopian restaurant just around the corner with the right amount of fierce spices!)

The wiki on objective, reference, vague, neutral [or whichever label one favours] priors that was suggested at the previous O’Bayes meeting in Valencià, was introduced as Wikiprevia by Gonzalo Garcia-Donato. It aims at classifying recommended priors in most of the classical models, along with discussion panels, and it should soon get an official launch, when contributors will be welcome to include articles in a wiki principle. I wish the best to this venture which, I hope, will induce O’Bayesians to contribute actively.

In a brilliant talk that quickly reverted my jetlag doziness, Peter Grünwald returned to the topic he presented last year in Sardinia, namely safe Bayes or powered-down likelihoods to handle some degree of misspecification, with a further twist of introducing an impossible value `o’ that captures missing mass (to be called Peter’s demon?!), which absolute necessity I did not perceive. Food for thoughts, definitely. (But I feel that the only safe Bayes is the dead Bayes, as protecting against all kinds of mispecifications means no action is possible.)

I also appreciated Cristiano Villa’s approach to constructing prior weights in model comparison from a principled and decision-theoretic perspective even though I felt that the notion of ranking parameter importance required too much input to be practically feasible. (Unless I missed that point.)

Laura Ventura gave her talk on using for ABC various scores or estimating equations as summary statistics, rather than the corresponding M-estimators, which offers the appealing feature of reducing computation while being asymptotically equivalent. (A feature we also exploited for the regular score function in our ABC paper with Gael, David, Brendan, and Wonapree.) She mentioned the Hyvärinen score [of which I first heard in Padova!] as a way to bypass issues related to doubly intractable likelihoods. Which is a most interesting proposal that bypasses (ABC) simulations from such complex targets by exploiting a pseudo-posterior.

Veronika Rockova presented a recent work on concentration rates for regression tree methods that produce a rigorous analysis of these methods. Showing that the spike & slab priors plus BART [equals spike & tree] achieve sparsity and optimal concentration. In an oracle sense. With a side entry on assembling partition trees towards creating a new form of BART. Which made me wonder whether or not this was also applicable to random forests. Although they are not exactly Bayes. Demanding work in terms of the theory behind but with impressive consequences!

Just before I left O’Bayes 17 for Houston airport, Nick Polson, along with Peter McCullach, proposed an intriguing notion of sparse Bayes factors, which corresponds to the limit of a Bayes factor when the prior probability υ of the null goes to zero. When the limiting prior is replaced with an exceedance measure that can be normalised into a distribution, but does it make the limit a special prior? Linking  υ with the prior under the null is not an issue (this was the basis of my 1992 Lindley paradox paper) but the sequence of priors indexed by υ need be chosen. And reading from the paper at Houston airport, I could not spot a construction principle that would lead to a reference prior of sorts. One thing that Nick mentioned during his talk was that we observed directly realisations of the data marginal, but this is generally not the case as the observations are associated with a given value of the parameter, not one for each observation.The next edition of the O’Bayes conference will be in… Warwick on June 29-July 2, as I volunteered to organise this edition (16 years after O’Bayes 03 in Aussois!) just after the BNP meeting in Oxford on June 23-28, hopefully creating the environment for fruitful interactions between both communities! (And jumping from Au’Bayes to Wa’Bayes.)

O’Bayes 2017 group photograph

Posted in pictures, Statistics, Travel, University life with tags , , , , , , , , on December 13, 2017 by xi'an

red Capitol [jatp]

Posted in pictures, Running, Travel with tags , , , , , on December 12, 2017 by xi'an

sunrise over Colorado [jatp]

Posted in pictures, Running, Travel, University life with tags , , , , , , on December 11, 2017 by xi'an

off to Austin!

Posted in Books, Kids, Statistics, Travel, University life, Wines with tags , , , , , , , , , on December 9, 2017 by xi'an

Today I am flying to Austin, Texas, on the occasion of the O’Bayes 2017 conference, the 12th meeting in the series. In complete objectivity (I am a member of the scientific committee!), the scientific program looks quite exciting, with new themes and new faces. (And Peter Müller concocted a special social program as well!) As indicated above [with an innovative spelling of my first name!] I will give my “traditional” tutorial on O’Bayes testing and model choice tomorrow, flying back to Paris on Wednesday (and alas missing the final talks, including Better together by Pierre!). A nice pun is that the conference centre is located on Robert De[a]dman Drive, which I hope is not premonitory of a fatal ending to my talk there..!