We investigate the condition number of the matrices that appear in the boundary element method. In particular we consider the Laplace equation with mixed boundary conditions. For Dirichlet boundary conditions, the condition number of the system matrix increases linearly with the number of boundary elements. We extend the research and search for a relation between the condition number and the nu...

Several methods have been proposed to reduce boundary artifacts in image deblurring. Some of those methods impose certain assumptions on image pixels outside the field-of-view; the most important of these assume reflective or anti-reflective boundary conditions. Boundary condition methods, including reflective and anti-reflective ones, however, often fail to reduce boundary artifacts, and, in s...

The three–dimensional incompressible viscous Boussinesq equations, under the assumption of hydrostatic balance, govern the large scale dynamics of atmospheric and oceanic motion, and are commonly called the primitive equations. To overcome the turbulence mixing a partial vertical diffusion is usually added to the temperature advection (or density stratification) equation. In this paper we prove...

In quantum theory Hamilton operators with spininteractions have a long history [1 – 5]. Triple spin interaction have been studied by several authors [6 – 19]. Iglói [6] investigated an Ising model with three-spin interaction by finite-size scaling and applying free boundary conditions. Vanderzande and Iglói [7] studied the critical behaviour and logarithmic corrections of a quantum model with t...

This paper proves sharp inequalities for the frequencies of vibration of strings and cylindrical membranes, under either fixed or fixed-free boundary conditions. We establish such inequalities also on the "generalized" cylinder, which is the cross-product of an interval with a homogeneous Riemannian manifold. The goal is to better understand the effect that inhomogeneities in the mass distribut...

Controllability properties of a partial di erential equation (PDE) model describing a thermoelastic plate are studied. The PDE is comprised of a Kircho plate equation coupled to a heat equation on a bounded domain, with the coupling taking place on the interior and boundary of the domain. The coupling in this PDE is parameterized by > 0. Boundary control is exerted through the (two) free bounda...

this paper presents a new procedure for automatic extraction of the blood vessels and optic disk (od) in fundus fluorescein angiogram (ffa). in order to extract blood vessel centerlines, the algorithm of vessel extraction starts with the analysis of directional images resulting from sub‑bands of fast discrete curvelet transform (fdct) in the similar directions and different scales. for this pur...

the study of wave and its propagation on the water surface is among significant phenomena in designing quay, marine and water structures. therefore, in order to design structures which are exposed to direct wave forces, it is necessary to study and simulate water surface height and the wave forces on the structures body in different boundary conditions. in this study, the propagation of static ...