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Vivien Lecompte

Population dynamics and rare events
Lundi, 17 Juin, 2019 - 11:00 à 12:00
Résumé : 

Rare trajectories of stochastic systems are important to understand, because of their potential impact. However, their properties are by definition difficult to sample directly. Population dynamics provides a numerical tool allowing their study, by means of simulating a large number of copies of the system which are subjected to selection rules that favor the rare trajectories of interest.  

 
   This method exhibits systematic errors which can be large in some circumstances, particularly for systems with weak noise, with many degrees of freedom, or close to phase transitions. We show how these errors can be mitigated by introducing "control forces" within the algorithm. These forces are determined by an iteration-and-feedback scheme substantially improve the efficiency of algorithms, allowing to handle complex systems. They also provide, for actual biological systems with a population dynamics, an interesting picture of the effective forces generated by the selection-mutation process.
 
Joint work with: Esteban Guevara, Takahiro Nemoto, Freddy Bouchet, Rob Jack
Institution de l'orateur : 
LiPhy Grenoble
Thème de recherche : 
Probabilités
Salle : 
4
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