Justification of geometrical optics for non-convex obstacles

A High Frequency Bem for Scattering by Non-convex Obstacles

Traditional numerical methods for time-harmonic acoustic scattering problems become prohibitively expensive in the high-frequency regime where the scatterer is large compared to the wavelength of the incident wave. In this paper we propose and analyse a hybrid boundary element method (BEM) for a class of non-convex polygonal scatterers. In this method the approximation space is enriched with os...

Basic and legal analysis of the justification or non-justification of killing in defense of property

Justifying or not justifying killing in defense of property has always been a challenging issue for jurists Western jurists have studied such killing in the light of the principle of proportionalit. . That is,whether there is a balance and proportionality between defensive action - killing aggressor- and aggressive action - attacking property – or not. based on this principle, some believe that...

Geometrical Optics Formulaes for Helmholtz Equation

The present work deals with high frequency Helmholtz equation resolution using geometrical optics. We give formulaes in dimension 2 and 3 for mixed Dirichlet, Neumann and Robin boundaries conditions.

Matrix Methods in Geometrical Optics

As well as the geometrical methods used for solving lens problems, and locating the size and position of images in optical systems, there is an alternate, perhaps more versatile, method involving matrix manipulation. Many of you will be familiar with the use of simple 2x2 matrices. Firstly, however, before I consider the use of matrices in optics, I will review the matrix solution of two simult...

Electromagnetic Scintillation I. Geometrical Optics