Archive for Elben

truncated t’s [typo]

Posted in pictures, Statistics with tags , , , , , on March 14, 2014 by xi'an

Last night, I received this email from Piero Foscari (im Hamburg) about my moment derivations for the absolute and the positive t distribution:

Elben, Hamburg, Feb. 21, 2013There might be two typos in the final second moment formula and its derivation (assuming no silly symmetric mistakes in my validation code): the first ν ought to be -ν, and there should be a corresponding scaling factor also for the boundary μ in Pμ,ν-2 since it arises from a change of variable. Btw in the text reference to Fig. 2 |X| wasn’t updated to X+. I hope that this is of some use.

and I checked that indeed I had forgotten the scale factor ν/(ν-2) in the t distribution with ν-2 degrees of freedom as well as the sign… So I modified the note and rearXived it. Sorry about this lack of attention to the derivation!

an hectic trip!

Posted in Running, Statistics, Travel, University life with tags , , , , , , , on February 22, 2013 by xi'an

Elben, Hamburg, Feb. 21, 2013The trip to Hamburg had started inauspiciously: a heart attack (someone else’s heart) in the métro (RER) has frozen the train traffic completely on Tuesday and I was lucky to find a taxi that managed to drive me to the airport in the nick of time. As there were warnings of strike in the Hamburg airport today, I decided to pack early and left DESY long enough in advance to reach the aiport by public transportation: it is only once I cleared security and sat at the gate that I realised I had forgotten my PC power box/cord in my room at DESY. What a drag! Anyway, I managed to buy a universal adapter in Paris on my way back from the airport and still to attend Adam Johansen’s seminar on Rao-Blackwellisation of particle filters at the Big’MC seminar. An interesting exploitation of missing variable structures within missing variables in a hidden Markov chain! (I missed the reason for the O(NM) computing time, though.) On the way home, I reflected on how little I had seen of Hamburg: a nice train system, a green and pleasant suburban area south of DESY towards the Elben (Groß Flottbeck), while running this morning, and…the airport! I wish I had had the opportunity and the time to get a glimpse of downtown Hamburg.

morning run

Posted in pictures, Running, Travel with tags , , on February 21, 2013 by xi'an

Elben, Hamburg, Feb. 21, 2013