Archive for Canada

position at UBC

Posted in Statistics with tags , , , , , on November 22, 2021 by xi'an

The Department of Statistics at the University of British Columbia, Vancouver invites applications from outstanding new investigators for a tenure-track position at the rank of Assistant Professor in the area of statistical machine learning and artificial intelligence (AI), with an anticipated start date of July 1, 2022 or January 1, 2023.

This position is offered as part of a new, interdisciplinary research cluster, AI Methods for Scientific Impact (AIM-SI) within UBC’s Centre for AI Decision-making and Action (CAIDA). CAIDA consists of over 100 researchers whose research leverages AI; AIM-SI will hire 5 new faculty members across three departments: Computer Science, Mathematics, and Statistics. Those recruited will join over a dozen existing researchers who are highly active in the core AI Methods research community.

Candidates must have a Ph.D. in Statistics, Biostatistics, or a related field and must demonstrate evidence of research success and a high potential to be leaders in their research field. The successful candidate should have a strong record of research productivity commensurate with their experience and will be expected to develop an independent research program in an area that complements existing Department expertise and aligns with opportunities at UBC. The successful candidate will be expected to effectively supervise Statistics graduate students, collaborate with other faculty members, obtain external funding, teach undergraduate and graduate Statistics courses, and actively participate in departmental activities.

Equity and diversity are essential to academic excellence. An open and diverse community fosters the inclusion of voices that have been underrepresented or discouraged. We encourage applications from members of groups that have been marginalized on any grounds enumerated under the B.C. Human Rights Code, including sex, sexual orientation, gender identity or expression, racialization, disability, political belief, religion, marital or family status, age, and/or status as a First Nation, Métis, Inuit, or Indigenous person.

Applicants will be asked to complete an equity survey. The survey information will not be used to determine eligibility for employment, but will be collated to provide data that can assist us in understanding the diversity of our applicant pool and identifying potential barriers to the employment of designated equity group members. Applicants’ participation in the survey is voluntary and confidential and takes only a minute to complete. Applicants may self-identify in one or more of the designated equity groups, or may also decline to identify in any or all of the questions by choosing “not disclosed.”

All qualified candidates are encouraged to apply; however, Canadians and permanent residents will be given priority.

Deadline for application is December 15. More information is available at

intimate touch [wildlife photograph of the year]

Posted in Books, Kids, pictures, Travel with tags , , , , , , on October 20, 2021 by xi'an

journal of the [second] plague year [away]

Posted in Books, Kids, Mountains, pictures, Travel, University life, Wines with tags , , , , , , , , , , , , , , , on June 12, 2021 by xi'an

Read Fred Vargas’s Seeking Whom He May Devour (L’Homme à l’envers), which I found on a bookshelf of our vacation rental in Annecy. And got more quickly bored by the story as it is plagued with the same defects as the ones I read before, from a definitive issue with Canadians (!), to an attempt to bring supernatural causes in the story and reveal them as fake by the end of the book, to a collection of implausible and caricaturesque characters surrounded by the usual backcountry morons that would rather fit a Paasilinna novel, and to the incomprehensible intuitions of Inspector Adamsberg. I also went through the sequel to Infomocracy, Null states, albeit this was a real chore as it lacked substance and novelty (the title by itself should have been a warning!).

Watched Night in Paradise (낙원의 밤), another Korean gangster movie, which seems to repeat the trope of bad-guy-on-the-run-meets-lost-girl found in my previously watched Korean Jo-Phil: The Dawning Rage, where the main character, a crooked police officer is radically impacted after failing to save a lost teenager.  (And also in the fascinating The Wild Goose Lake.) The current film is stronger however in creating the bond between the few-words gangster on the run and the reluctant guest Jae-yeon who is on a run of a different magnitude. While the battle scenes are still grand-guignolesque (if very violent) in a Kill Bill spirit, and the gang leaders always caricaturesque, the interplay between the main characters makes Night in Paradise a pretty good film (and explains why it got selected for the Venice Film Festival of 2020). Also went through the appalling Yamakasi by Luc Besson, a macho, demagogical, sexist, simplist, non-story…

parallel tempering on optimised paths

Posted in Statistics with tags , , , , , , , , , , , , , , , on May 20, 2021 by xi'an

Saifuddin Syed, Vittorio Romaniello, Trevor Campbell, and Alexandre Bouchard-Côté, whom I met and discussed with on my “last” trip to UBC, on December 2019, just arXived a paper on parallel tempering (PT), making the choice of tempering path an optimisation problem. They address the touchy issue of designing a sequence of tempered targets when the starting distribution π⁰, eg the prior, and the final distribution π¹, eg the posterior, are hugely different, eg almost singular.

“…theoretical analysis of reversible variants of PT has shown that adding too many intermediate chains can actually deteriorate performance (…) [while] on non reversible regime adding more chains is guaranteed to improve performances.”

The above applies to geometric combinations of π⁰ and π¹. Which “suffers from an arbitrarily suboptimal global communication barrier“, according to the authors (although the counterexample is not completely convincing since π⁰ and π¹ share the same variance). They propose a more non-linear form of tempering with constraints on the dependence of the powers on the temperature t∈(0,1).  Defining the global communication barrier as an average over temperatures of the rejection rate, the path characteristics (e.g., the coefficients of a spline function) can then be optimised in terms of this objective. And the temperature schedule is derived from the fact that the non-asymptotic round trip rate is maximized when the rejection rates are all equal. (As a side item, the technique exposed in the earlier tempering paper by Syed et al. was recently exploited for a night high resolution imaging of a black hole from the M87 galaxy.)

Mission implausible

Posted in Books, Kids, pictures with tags , , , , , , , , , , , , , , , , on March 28, 2021 by xi'an

I watched two movies with the same starting point, namely an old man being forced to take care of an unknown girl, despite his lack of fatherhood experience and no initial inclination to do so, while later defying odds and surviving together… One is News of the World (absurdly translated as The Mission in French, hence my poor pun) with Tom Hanks and (fabulous!) Helena Zengel, the other is Midnight Sky, with the improved French title of Midnight in the Universe, with George Clooney and Caoilinn Springall. The first one is a (modern) Western, set in Texas right after the Civil War and sometimes presented as a modern (and over-washed) version of Ford’s The Searchers, while the second one is an ecological science-fiction film, set in 2049, as the Earth is collapsing under an unspecified but all encompassing disaster. The first is passable if implausible, the second one is a disaster at all levels.

In News of the World Tom Hanks is again doing his Jimmy Stewart impersonation, always doing the “right” thing even when this is rather implausible. The fact that no-one seems to care that a stranger goes away with a young girl may be plausible in the late 1800’s Texas, although I am surprised none of the very few women in the story, one of them the girl’s own aunt, does even object. On the other hand, the motive for the compulsory gun duel sounds very weak if darker than the rest of the story (and is there any chance a shotgun cartridge filled by coins (of the right diameter!) can fly true to its target?!) The choice of depicting Kiowa Indians as silent spectres walking away may be artistically motivated but it does not carry much weight, just like Hank in the movie is not making much progress in denunciation of slavery and genocide, besides keeping his own decency.

In Midnight Sky, George Clooney is a grumpy old scientist stuck in a Far North observatory, in terminal phase of a blood disease and who is gradually revealed as having always failed on the personal relation side. [Anyone wondering at the scientific pertinence of the presence of a most traditional observatory [incl. manual orienteering] at this latitude? Although I found that Canada has recently set an observatory on Ellesmere Island, Nunavut.] As Earth is collapsing under deadly radiation, Clooney finds himself alone until he discovers a little girl conveniently left behind during the evacuation of the station. As a space ship is returning to Earth, unaware of the disaster, the pair sets on an impossible mission to reach a better communication station. first on a snowmobile, then on foot!, with no goggles and a woolen hat in a snow storm!, just to make sure we can recognise Clooney!, while the disaster that see the pair stranded with only their clothes on a frozen tundra makes no sense. For instance, falling into Arctic water has a very low survival probability, esp. for a a sick and old man. And the part taking place on the very-low-tech space ship is light-years away from anything remotely realistic. Ending up (spoiler!) with the ship turning back to this habitable moon of Jupiter as if this would make any difference… Have a safe trip!

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