The state of the art to solve problems of active noise control and acoustic echo cancellation is to use adaptive control systems [1]. For acoustic echo cancellation, adaptive algorithms have to provide a correct estimate of the room impulse response of loudspeaker-enclosuremicrophone systems during operation. Test and evaluation of such algorithms requires either a real-time implementation or m...

Wave motion in acoustic and elastic media is highly influenced by the presence of outer boundaries and media interfaces. The solutions to the equations governing the wave motion at any point in the domain as a function of time can be sought either through analytical or numerical techniques. This thesis proposes provably stable finite difference schemes to accurately simulate wave interaction wi...

We propose two possible representative models for a 2D fracture in reservoirs. The first one simulates the fracture as a low-aspect ratio elliptical cylinder. The inner properties of this elliptical cylinder are assumed to be homogeneous and different from the surrounding medium that is also homogenous. This model can approximately describe the actual shape of fractures observed in the field, a...

We consider a time-harmonic acoustic wave propagation problem in a two dimensional water waveguide confined between a horizontal surface and a locally varying bottom. We formulate a model based on the Helmholtz equation coupled with nonlocal Dirichlet-to-Neumann boundary conditions imposed on two artificial boundaries. We establish the well-posedness of the associated variational problem, under...

In the present work the acoustic band structure of a two-dimensional (2D) phononic crystal (PC) containing an semiconducting ferroelectrics ABC (A=Sb, Bi; B=S, Se, Te; C=I, Br, and Cl) were investigated theoretically and numerically by the plane-waveexpansion (PWE) method. Two-dimensional PC with square lattices composed of semiconducting ferroelectric cylindrical rods embedded in the organic/i...