Archive for motorbike

a journal of the constant chaos year

Posted in Books, Kids, Mountains, pictures, Travel, Wines with tags , , , , , , , , , , , , , , , , , , , , , , , , , , , on April 24, 2025 by xi'an

 Read (at last) The Cartographers, by Peng Shepherd, which I bought in Seattle last summer. And stated in India. A book that starts with the (fascinating) Fra Mauro map cannot be that terrible, but the story does not keep up with its promises, less for its core idea of taking the opposite of Korzybski’s “The map is not the territory” (since a special map is the territory!) than for its disappointing characters that prove more two-dimensional than the maps they profess to love. Dialogues are either lame or monologues. The central character, Nell, is mostly a pawn for the older characters. The constant unfolding of coïncidences is such that it makes the book sound even one-dimensional at times. The academia connections are ludicrous. The fire incident is beyond suspension of belief. And the ending is quite poor, maybe predictably since maps have no endpoints… I also started the Stormlight Archives, by (Mistborn author)  Brandon Sanderson, which may take a while to complete!

Made more roasted almond and black sesame butters, more whey buckwheat galettes, and various dahls. Visited a stupendous bagel store, Shelsky’s of Brooklyn, upon my (smooth) arrival in New York City, further tasting (and appreciating) smoked sturgeon for the first time. The bagels there definitely beat the famous Saint-Viateur bagels in Montréal! And a French bakery, Bread Story, in the East Village, which is run by a former apprentice of a cousin of mine’s and which sticks to traditional French breads, including buckwheat baguettes!

Watched Dhak Dhak in the plane to New York, an Hindi road movie about four women biking their way from Delhi to the 5,359m Khardung La pass, with plenty of great views. These women are riding on the iconic Royal Enfield Bullet bikes, found everywhere in India (and now spotted in Paris), and the story does not avoid a single pot-hole in the predictable route from the range of their backgrounds and motivations for the trip/pilgrimage/escape to their coming-of-age, along with 30mn of songs, up to the happy ending! In short, that’s a perfect plane movie.

accelerating MCMC

Posted in Statistics with tags , , , , , , , , , , , , on May 29, 2017 by xi'an

I have recently [well, not so recently!] been asked to write a review paper on ways of accelerating MCMC algorithms for the [review] journal WIREs Computational Statistics and would welcome all suggestions towards the goal of accelerating MCMC algorithms. Besides [and including more on]

  • coupling strategies using different kernels and switching between them;
  • tempering strategies using flatter or lower dimensional targets as intermediary steps, e.g., à la Neal;
  • sequential Monte Carlo with particle systems targeting again flatter or lower dimensional targets and adapting proposals to this effect;
  • Hamiltonian MCMC, again with connections to Radford (and more generally ways of avoiding rejections);
  • adaptive MCMC, obviously;
  • Rao-Blackwellisation, just as obviously (in the sense that increasing the precision in the resulting estimates means less simulations).

Les statistiques, évitons de rentrer dedans

Posted in pictures, Statistics with tags , , , , on December 24, 2010 by xi'an

A new campaign against urban road accidents caught my attention because of the above slogan… Playing on the double meaning of rentrer dans les statistiques (becoming part of the statistics) and of rentrer dans quelqu’un (hitting someone). The case for hitting motorbikes is particularly acute on the Paris beltway:  motorbikes are driving between lanes at speeds that are very different from those of the cars and when changing lanes in dense traffic (with a car) it is almost impossible to account for the possibility of a motorbike arriving at 100 km/h or above. There are around 800 accidents per year involving bikes on the beltway. Last time I went to the airport, my taxi got hit several times by a biker who was unhappy with the taxi changing lanes, despite him having signalled well in advance and all that… (Note the funny reflection of the pink tag on the car, also implemented in the other pictures. I am not sure what’s the point there.) Continue reading →