BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//wp-events-plugin.com//7.2.3.1//EN
TZID:Europe/Paris
X-WR-TIMEZONE:Europe/Paris
BEGIN:VEVENT
UID:8291@i2m.univ-amu.fr
DTSTART;TZID=Europe/Paris:20140930T110000
DTEND;TZID=Europe/Paris:20140930T120000
DTSTAMP:20241120T210325Z
URL:https://www.i2m.univ-amu.fr/evenements/scattering-in-locally-perturbed
 -periodic-waveguide-forward-and-inverse-problems/
SUMMARY: (...): Scattering in locally perturbed periodic waveguide : forwar
 d and inverse problems
DESCRIPTION:: This is a joint work with Patrick Joly (the forward problem) 
 and Laurent Bourgeois (the inverse problem). We are interested in propagat
 ion media which are a local perturbation of an infinite (or very large) pe
 riodic waveguide. We consider first the forward problem\, computing the so
 lution of the time harmonic wave equation in such media. We investigate th
 e question of finding artificial boundary conditions to reduce the actual 
 numerical computations to a neighborhood of the perturbation. More precise
 ly\, by revisiting the Floquet Bloch theory\, we propose a method for cons
 tructing Dirichlet-to-Neumann (DtN) operators. We will see in particular t
 hat the characterization of these DtN operators is linked to the definitio
 n of the physical or "outgoing" solution of the problem\, definition which
  is not obvious in periodic media. This difficulty will be treated using t
 he limiting absorption principle. We consider then the linear sampling met
 hod (LSM) to solve the inverse medium problem in a locally perturbed perio
 dic waveguide. The periodic waveguide is known and our aim is\, from scatt
 ering data\, to recover the defect within such periodic waveguide. This me
 thod is based on the far field of the Green function in a periodic wavegui
 de. Such analysis enables us to derive a modal formulation of the LSM in w
 hich the incident fields are formed by the Floquet modes.\n\nSonia Fliss\,
  ENSTA - UMA\, POems (UMR 7231 CNRS-INRIA-ENSTA)\, Palaiseau\n\n
CATEGORIES:Séminaire,Analyse Appliquée
END:VEVENT
BEGIN:VTIMEZONE
TZID:Europe/Paris
X-LIC-LOCATION:Europe/Paris
BEGIN:DAYLIGHT
DTSTART:20140330T030000
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
END:DAYLIGHT
END:VTIMEZONE
END:VCALENDAR