Learn More
The statistical properties of acoustic signals re ected by a randomly layered medium are analyzed when a pulsed spherical wave issuing from a point source is incident upon it. The asymptotic analysis of stochastic equations and geometrical acoustics is used to arrive at a set of transport equations that characterize multiply scattered signals observed at(More)
This essentially numerical study sets out to investigate vari ous geometrical properties of exact boundary controllability of the wave equation when the control is applied on a part of the boundary Re lationships between the geometry of the domain the geometry of the controlled boundary the time needed to control and the energy of the control are dealt with(More)
The present study is concerned with the properties of 2D shallow cavities having an irregular boundary. The eigenmodes are calculated numerically on various examples, and it is shown first that, whatever the shape and characteristic sizes of the boundary, irregularity always induces an increase of localized eigenmodes and a global decrease of the existence(More)
We consider for the wave equation the inverse problem of identifying locations of point sources and dipoles from limited-view data. Using as weights particular background solutions constructed by the geometrical control method, we recover Kirchhoff-, back-propagation-, MUSIC-, and arrival time-type algorithms by appropriately averaging limited-view data. We(More)
The numerical simulation of acoustic waves in complex three-dimensional (3D) media is a key topic in many branches of science, from exploration geophysics to non-destructive testing and medical imaging. With the drastic increase in computing capabilities this field has dramatically grown in the last 20 years. However many 3D computations, especially at high(More)
We are concerned in this work with simulations of the localization of a finite number of small electromagnetic inhomogeneities contained in a three-dimensional bounded domain. Typically, the underlying inverse problem considers the time-harmonic Maxwell equations formulated in electric field in this domain and attempts, from a finite number of boundary(More)