Homotopy perturbation method HPM and boundary element method BEM for calculating the exact and numerical solutions of Poisson equation with appropriate boundary and initial conditions are presented. Exact solutions of electrostatic potential problems defined by Poisson equation are found using HPM given boundary and initial conditions. The same problems are also solved using the BEM. The cell i...

This article is concerned with the formulation and implementation of a fast multipoleaccelerated BEM for 3-D elastodynamics in the frequency domain, based on the so-called diagonal form for the expansion of the elastodynamic fundamental solution, a multi-level strategy. As usual with the FM-BEM, the linear system of BEM equations is solved by GMRES, and the matrix is never explicitly formed. Th...

In this paper we describe a simple method to implement two block-coded modulation (BeM) families previously reported by the present authors. This method considerably simplifies the bit mapping procedure, and makes it possible to implement the two BeM families with long block lengths and large signal alphabets. Next, we address the problem of rotationally invariant code design that is necessary ...

Constant elements offer many advantages as compared with other higher-order elements in the boundary element method (BEM). With the use of constant elements, integrals in the BEM can be calculated accurately with analytical integrations and no corner problems need to be addressed. These features can make fast solution methods for the BEM (such as the fast multipole, adaptive cross approximation...

A SMALL PORTABLE ELECTRONIC DEVICE, named a blood electrometer (BEM), was developed to measure packed cell volume, which can be related to haematocrit (Hct). The electronic circuitry is simple and constructed from standard components. Being battery powered, the device is suitable for bedside or field use (‘point-of-care-testing’) without specialized training. The effects of temperature, anticoa...

A new adaptive fast multipole boundary element method (BEM) for solving 3-D half-space acoustic wave problems is presented in this paper. The half-space Green’s function is employed explicitly in the boundary integral equation (BIE) formulation so that a tree structure of the boundary elements only for the boundaries of the real domain need to be applied, instead of using a tree structure that ...

A fast multipole boundary element method (BEM) for solving large-scale thin plate bending problems is presented in this paper. The method is based on the Kirchhoff thin plate bending theory and the biharmonic equation governing the deflection of the plate. First, the direct boundary integral equations and the conventional BEM for thin plate bending problems are reviewed. Second, the complex not...

We analyze adaptive mesh-refining algorithms in the frame of boundary element methods (BEM) and the coupling of finite elements and boundary elements (FEM-BEM). Adaptivity is driven by the two-level error estimator proposed by Ernst P. Stephan, Norbert Heuer, and coworkers in the frame of BEM and FEM-BEM or by the residual error estimator introduced by Birgit Faermann for BEM for weakly-singula...

In this paper, a coupled numerical method of the edge-based smoothed finite element (ES-FEM) with the fast multipole BEM (FM-BEM) is proposed to analyze structural acoustic problems. The vibrating structure is modeled using the so-called ES-FEM-DSG3 method, where the 3-node linear triangle plate elements based on the Reissner–Mindlin plate theory with the discrete shear gap (DSG) technique for ...

The Boundary Element Method (BEM) is a powerful method for simulating scattering of acoustic waves which has many advantages, particularly when the problem concerns an object in an unbounded medium. Its applications are however limited in practice because standard schemes have a computational cost which grows extremely quickly as size and frequency is increased. Fundamentally this occurs becaus...