Archive for the Mountains Category

Alex Honnold free solos Freeride (5.13a/7c+)

Posted in Books, Kids, Mountains, pictures, Travel with tags , , , , , on June 11, 2017 by xi'an

fast ε-free ABC

Posted in Books, Mountains, pictures, Running, Statistics, Travel, University life with tags , , , , , , , , , on June 8, 2017 by xi'an

Last Fall, George Papamakarios and Iain Murray from Edinburgh arXived an ABC paper on fast ε-free inference on simulation models with Bayesian conditional density estimation, paper that I missed. The idea there is to approximate the posterior density by maximising the likelihood associated with a parameterised family of distributions on θ, conditional on the associated x. The data being then the ABC reference table. The family chosen there is a mixture of K Gaussian components, which parameters are then estimated by a (Bayesian) neural network using x as input and θ as output. The parameter values are simulated from an adaptive proposal that aims at approximating the posterior better and better. As in population Monte Carlo, actually. Except for the neural network part, which I fail to understand why it makes a significant improvement when compared with EM solutions. The overall difficulty with this approach is that I do not see a way out of the curse of dimensionality: when the dimension of θ increases, the approximation to the posterior distribution of θ does deteriorate, even in the best of cases, as any other non-parametric resolution. It would have been of (further) interest to see a comparison with a most rudimentary approach, namely the one we proposed based on empirical likelihoods.

Rundlestone Session

Posted in Mountains, pictures, Travel, Wines with tags , , , , , , , , , on May 20, 2017 by xi'an

art brut

Posted in Mountains, pictures, Running, Travel with tags , , , , , , , on May 20, 2017 by xi'an

Ueli Steck dies on Nupse [Ueli Steck tödlich verunglückt]

Posted in Books, Mountains, Running with tags , , , , , , , on April 30, 2017 by xi'an

Ueli Steck was a Swiss climber renowned for breaking speed records on the hardest routes of the Alps. Including the legendary Eigerwand. And having been evacuated under death threats from the Everest base camp two years ago. I have been following on Instagram his preparation for another speed attempt at Everest the past weeks and it is a hug shock to learn he fell to his death on Nupse yesterday. Total respect to this immense Extrembergsteiger, who has now joined the sad cenacle of top climbers who did not make it back…

morning run [jatp]

Posted in Kids, Mountains, pictures, Running, Travel, Wines with tags , , , , , , , , on April 30, 2017 by xi'an

Bayes Comp 2018

Posted in Mountains, pictures, Statistics, Travel, University life, Wines with tags , , , , , , , , , on April 28, 2017 by xi'an

After a rather extended wait, I learned today of the dates of the next MCMski conference, now called Bayes Comp, in Barcelona, Spain, March 26-29, next year (2018). With a cool webpage! (While the ski termination has been removed from the conference name, there are ski resorts located not too far from Barcelona, in the Pyrenees.) Just unfortunate that it happens at the same dates as the ENAR 2018 meeting. (And with the Gregynog Statistical Conference!)