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TZID:Europe/Paris
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BEGIN:VEVENT
UID:1-413@lptms.universite-paris-saclay.fr
DTSTART:20160419T110000Z
DTEND:20160419T120000Z
DTSTAMP:20160405T063044Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm
 s-marie-chupeau/
SUMMARY:Séminaire du LPTMS: Marie Chupeau - LPTMS\, salle 201\, 2ème éta
 ge\, Bât 100\, Campus d'Orsay - 19 Avr 16 11:00
DESCRIPTION:Random walks in confined geometry: convex hull and cover times\
 nMarie Chupeau (LPTMC\, UPMC\, Paris)\nWhat is the impact of a confinement
  on random walks? To answer this question\, I will first focus on a partia
 l confinement\, an infinite reflecting wall\, and study how the space take
 n by a planar random walk is affected by the presence of the wall. The spa
 ce explored by a random walk in the plane can be characterized by its conv
 ex hull\, defined as the minimum convex polygon enclosing the trajectory\,
  and in particular by its perimeter. After having studied a one-dimensiona
 l version of the problem\, I will show that the mean perimeter of the conv
 ex hull of a planar random walk exhibits a non-trivial dependance on the i
 nitial distance of the walker to the wall\, in sharp contrast with the res
 ults in one dimension.\nSecond\, I will consider a random walk in total co
 nfinement and study the time it takes to visit all sites of a given domain
 . This time\, known as the cover time\, is a key observable to quantify th
 e efficiency of exhaustive searches\, which require a complete exploration
  of an area and not only the  discovery of a single target. Despite its b
 road relevance\, in biology\, ecology\, or robotics\, the cover time has r
 emained elusive and so far\, explicit results have been scarce and mostly 
 limited to regular random walks. I will show how to determine the distribu
 tion of the cover time for a broad range of random search processes\, and 
 highlight its universal features. I will conclude with an application of t
 his result and discuss how the cover time can be optimized for some resear
 ch strategies.
CATEGORIES:seminars
LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 
 Rue Georges Clemenceau\, Orsay\, 91405\, France
GEO:48.698185;2.181768
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  Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è
 me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768
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