We consider a divergence-free non-dissipative fourth-order explicit staggered nite di erence scheme for the hyperbolic Maxwell's equations. Special one-sided di erence operators are derived in order to implement the scheme near metal boundaries and dielectric interfaces. Numerical results show the scheme is long-time stable, and is fourth-order convergent over complex domains that include diele...

Two approaches of multistage gradient robusti cation for image contour detection are presented in this paper: two stages of Di erence of Estimates and Di erence of Estimate followed by an optimal ltering. Watershed transformation is then applied to these robusti ed gradient images to e ectively detect image contours which are guaranteed to be in closed form. Multistage gradient robusti cation p...

A numerical method to simulate liquid-vapor phase change is presented. The method is based on the so-called single eld formulation where one set of equations for conservation of mass, momentum, and energy are written for the entire ow eld. Interfacial source terms for surface tension, interphase mass transfer and latent heat are added as delta functions that are non-zero only at the phase bound...

In recent years multigrid methods have been proven to be very e cient for solving large systems of linear equations resulting from the discretization of positive de nite di erential equations by either the nite di erence method or the h-version of the nite element method. In this paper an iterative method of the multiple level type is proposed for solving systems of algebraic equations which ar...

In this paper we will present a numerical method for computing incompressible free surface ows in irregular ge ometries in three dimensions The approach we are taking is based on three ideas The rst is the second order ac curate projection method of Bell Colella and Glaz Bell et al for computing nite di erence approximations to the incompressible ow equations on rectangular grids The second is ...

Multigrid has been a popular solver method for nite element and nite di erence problems with regular grids for over 20 years. The application of multigrid to unstructured problems is, however, not well understood and has been an active area of research in recent years. The two most promising categories of unstructured multigrid methods are 1) \geometric" methods that use standard nite element c...

A computer code has been developed that uses an implicit nitedi erence technique to solve nonsimilar, axisymmetric boundary layer equations for both laminar and turbulent ow. The code can treat ideal gases, air in chemical equilibrium, and carbon tetra uoride (CF4), which is a useful test gas for hypersonic blunt-body simulations. This is the only known boundary layer code that can treat CF4. C...

In this paper, I show how to use the generalized Schur form to solve a system of linear expectational di!erence equations (a multivariate linear rational expectations model). The method is simple to understand and to use, and is applicable to a large class of rational expectations models. The only hard part is taken care of by just two standard algorithms, both of which are available as freewar...

The purpose of this paper is to give a very short, \nuts and bolts", introduction to the lifting scheme and provide references for further reading. The lifting scheme is a new method for constructing biorthogonal wavelets. The main di erence with classical constructions [1-3] is that it does not rely on the Fourier transform. This way lifting can be used to construct second generation wavelets,...

This paper addresses the problem of the blind source separation which consists of recovering a set of signals of which only instantaneous linear mixtures are observed. A blind source separation approach exploiting the di erence in the time-frequency (t-f) signatures of the sources is considered. The approach is based on the diagonalization of a combined set of `spatial time-frequency distributi...