In order to reduce the computation time of a quasi-static problem solved by the finite element method, methods of model order reduction can be applied. In this context, two approaches, the Proper Orthogonal Decomposition and the Proper Generalized Decomposition, are applied to the vector potential formulation used to solve the quasi-static problem. The developped methods are compared on an acad...

In this paper we consider Runge-Kutta discontinuous Galerkin (RKDG) schemes for Vlasov-Poisson systems that model collisionless plasmas. One-dimensional systems are emphasized. The RKDG method, originally devised to solve conservation laws, is seen to have excellent conservation properties, be readily designed for arbitrary order of accuracy, and capable of being used with a positivity-preservi...

This paper develops a multilevel least-squares approach for the numerical solution of the complex scalar exterior Helmholtz equation. This second-order equation is first recast into an equivalent first-order system by introducing several “field” variables. A combination of scaled L and H norms is then applied to the residual of this system to create a least-squares functional. It is shown that,...

B-spline functions play important roles in both mathematics and engineering. To describe a numerical method for solving the boundary value problem of linear ODE with second-order by using B-spline. First, the cubic B-spline basis functions are introduced, then we use the linear combination of cubic B-spline basis to approximate the solution. Finally, we obtain the numerical solution by solving ...

In this paper, we develop a new stability and convergence theory for highly indefinite elliptic partial differential equations by considering the Helmholtz equation at high wave number as our model problem. The key element in this theory is a novel k-explicit regularity theory for Helmholtz boundary value problems that is based on decomposing the solution into in two parts: the first part has t...

A general probabilistic fatigue crack growth prediction methodology for accurate and efficient damage prognosis is proposed in this paper. This methodology consists two major parts. First, the realistic random loading is transformed to an equivalent constant amplitude loading process based on a recently developed mechanism model. This transformation avoids the cycle-by-cycle calculation of fati...

sufficient conditions are established under which the zero solution x = 0 of equation (2) isunstable.

A glycolytic model, which is an autocatalytic biochemical system, is solved numerically using two numerical methods based on finite-difference schemes. Method 1, the well known Euler method, is an explicit method, whereas method 2 is implicit. Although the implicit method, method 2, is first-order accurate in time it converges to the fixed point(s) for large time step, ‘. 2005 Elsevier Inc. All...

A novel Douglas alternating direction implicit (ADI) method is proposed in this work to solve a two-dimensional (2D) heat equation with interfaces. The ADI scheme is a powerful finite difference method for solving parabolic equations, due to its unconditional stability and high efficiency. However, it suffers from a serious accuracy reduction in space for interface problems with different mater...