This article presents a staggered grid time-domain finite-difference (FD) program for the simulation of sH-wave propagation in a viscoelastic heterogeneous medium. The incorporation of realistic damping in FD program is based on a rheological model widely known as generalized maxwell body (gmB-EK). The accuracy of implementation of realistic damping is validated by comparing the numerically com...

To our knowledge, most numerical methods for solving discretizations of the Stokes equations depend on the Schur complement and thus the convergence rate depends on the aspect ratio of the domain. We present a preconditioner for a staggered grid discretization of the Stokes equations which is proven to be independent of the aspect ratio. Finally numerical experiments confirm the robustness of t...

In [5], we studied convergence and the structure of the error for several projection methods when the spatial variable was kept continuous . In this paper, we address similar problems for the fully discrete case when the spatial variable is discretized using the staggered grid. We prove that the numerical solution has full accuracy upto the boundary, despite the fact that there are numerical bo...

The subject of this paper is monadic second-order logic over two-dimensional grids. We give a game-theoretical proof for the strictness of the monadic second-order quan-tiier alternation hierarchy over grids. Additionally, we can show that monadic second-order logic over coloured grids is expressive enough to deene complete problems for each level of the polynomial time hierarchy.

T-spline surfaces are a powerful tool in geometric modelling. A T-spline surface is an approximation of a T-grid data structure. T-grids support adaption operations like local refinement or merging of existing NURBS grids. Digital terrain models based on T-spline surfaces benefit from non-regular control grids. We show some exemplary application cases for T-spline based terrain modelling.

In this paper a non-traditional approach to generation of orthogonal/Cartesian grids with local refinement tetra-hedrons near STL boundary on the basis of up-to-date CAD systems is considered. The features of the algorithm of constructing orthogonal grids are explained. Examples of constructed grids are presented.

Worldwide, electrical grids are developing into smart grids. To ensure reliability, robustness and optimized resource usage, these grids will need to rely heavily on modern information and communication technologies. To support the achievement of these goals in communication networks, we evaluated the possibility of using software-defined networking (SDN) infrastructure based on OpenFlow, to pr...