Archive for New Brunswick

William (Bill) Strawderman (1941-2024)

Posted in pictures, Statistics, University life with tags , , , , , , , , , , , , , , , , on October 3, 2024 by xi'an

Earlier today, I was informed by several of our mutual friends that my long-time friend Bill Strawderman had sadly passed away yesterday, after fighting a cancer for the past months. I remember quite clearly meeting Bill in the Fall of 1988 in front of White Hall, which hosted the Cornell maths department at the time, as he was visiting George Casella from Rutgers where he spent most of his career. I was most eager to meet him as I had worked on several of his landmark papers during my PhD on shrinkage estimation, as well as a bit impressed. But his kindness, modesty, and congenial personality quickly put me at ease and we spent the rest of his visit discussing shrinkage but also literature and music. Especially Dickens! After that we met and collaborated quite regularly, to the point he started visiting France upon my return, at Paris 6 (Pierre & Marie Curie) University first, and then in Rouen, where he became a adjunct professor and launched a life-long collaboration and friendship with Dominique Fourdrinier. As my interest in shrinkage estimation dwindled along the years, we did not keep collaborating for the past two decades, but we remained in touch and I was very happy to participate in his 80th anniversary celebration in Rutgers two years ago. His contributions to the field are notable and several papers of his were part of the Bayesian classics I was giving my graduate class a few years ago. From the fabulous minimaxity paper of 1984, along with George Casella, to admissible estimators dominating the positive-part James-Stein estimator, to sufficient conditions of minimaxity for proper Bayes estimators, to decision theoretic properties of Bayesian credible interval estimators, to loss estimation, not to mention his more applied side… Besides his fabulous sense of humour, which made many evenings with him memorable, I will also cherish the memory of a bon vivant who liked good food and good wines, incl. the Calvados apple brandy I would bring him at each of my visits.

Bill’s 80th!!!

Posted in pictures, Statistics, Travel, University life with tags , , , , , , , , , , , , , , , , , , , , on April 17, 2022 by xi'an

“It was the best of times,
it was the worst of times”
[Dickens’ Tale of Two Cities (which plays a role in my friendship with Bill!)]

My flight to NYC last week was uneventful and rather fast and I worked rather well, even though the seat in front of me was inclined to the max for the entire flight! (Still got glimpses of Aline and of Deepwater Horizon from my neighbours.) Taking a very early flight from Paris was great making a full day once in NYC,  but “forcing” me to take a taxi, which almost ended up in disaster since the Über driver did not show up. At all. And never replied to my message. Fortunately trains were running, I was also running despite the broken rib, and I arrived at the airport some time before access was closed, grateful for the low activity that day. I also had another bit of a worrying moment at the US border control in JFK as I ended up in a back-office of the Border Police after the machine could not catch my fingerprints. And another stop at the luggage control as my lack of luggage sounded suspicious!The conference was delightful in celebrating Bill’s carreer and kindness (tinted with the most gentle irony!). Among stories told at the banquet, I was surprised to learn of Bill’s jazz career side, as I had never heard him play the piano or the clarinet! Even though we had chatted about music and literature on many occasions. Since our meeting in 1989… The (scientific side of the) conference included many talks around shrinkage, from loss estimation to predictive estimation, reminding me of the roaring 70’s and 80’s [James-Stein wise]. And demonstrating the impact of Bill’s wor throughout this era (incl. on my own PhD thesis). I started wondering at the (Bayesian) use of the loss estimate, though, as I set myself facing two point estimators attached with two estimators of their loss: it did not seem a particularly good idea to systematically pick the one with the smallest estimate (and Jim Berger confirmed this feeling on a later discussion). Among the talks on less familiar topics (of mine), I discovered work of Genevera Allen‘s on inferring massive network for neuron connections under sparse information. And of Emma Jingfei Zhang, equally centred on network inference, with applications to brain connectivity.

In a somewhat remote connection with Bill’s work (and our joint and hilarious assessment of Pitman closeness), I presented part of our joint and current work with Adrien Hairault and Judith Rousseau on inferring the number of components in a mixture by Bayes factors when the alternative is an infinite mixture (i.e., a Dirichlet process mixture). Of which Ruobin Gong gave a terrific discussion. (With a connection to her current work on Sense and Sensitivity.)

I was most sorry to miss Larry Wasserman’s and Rob Strawderman’s talk to rush back to the airport, the more because I am sure Larry’s talk would have brought a new light on causality (possibly equating it with tequila and mixtures!). The flight back was uneventfull, the plane rather empty and I slept most of the time. Overall,  it was most wonderful to re-connect with so many friends. Most of whom I had not seen for ages, even before the pandemic. And to meet new friends. (Nothing original in the reported feeling, just telling that the break in conferences and workshops was primarily a hatchet job on social relations and friendships.)

talks on the East Coast

Posted in Statistics, Travel, University life with tags , , , , , , , , on March 29, 2012 by xi'an

On Tuesday and Wednesday, next week, I will give seminars in Princeton University and Rutgers University, respectively. My talk at Princeton actually takes place in the Department of Economics, at the Oskar Morgenstern Memorial Seminar (Tuesday, April 3, 2:40 – 4:00pm 200 Fisher Hall). I must acknowledge that the prospect is a wee daunting. For addressing the manes of Morgenstern and for speaking in Nash‘s very own institution, if nothing else! And my talk at Rutgers is in the Department of Statistics and Bostatistics (Wedn, April 4, 3:20 – 4:20, Hill Center, Busch Campus), where I will meet with my friend of many years Bill Strawderman. And my former PhD student Aude Grelaud. Both talks will cover the same ground of ABC model choice and Bayesian consistency (surprise, surprise!). The format of the econometrics seminar at Princeton being a bit longer, I will give more background on ABC, mostly in connection with the econometric methods I mentioned in my ABC tutorial in Roma and at CREST. I presume I will skip this part in Rutgers as biologists and geneticists are more likely to attend than econometricians. In preparation, here is the current version of the talk, to be updated till Monday at the very least!