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Abstract: This paper presents a generic high dimensional model representation (HDMR) method for approximating the system response in terms of functions of lower dimensions. The proposed approach, which has been previously applied for problems dealing only with random variables, is extended in this paper for problems in which physical properties exhibit spatial random variation and may be modelled as random fields. The formulation of the extended HDMR is similar to the spectral stochastic finite element method in the sense that both of them utilize Karhunen–Loève expansion to represent the input, and lower-order expansion to represent the output. The method involves lower dimensional HDMR approximation of the system response, response surface generation of HDMR component functions, and Monte Carlo simulation. Each of the low order terms in HDMR is sub-dimensional, but they are not necessarily translating to low degree polynomials. It is an efficient formulation of the system response, if higher-order variable correlations are weak, allowing the physical model to be captured by the first few lower-order terms. Once the approximate form of the system response is defined, the failure probability can be obtained by statistical simulation. The proposed approach decouples the finite element computations and stochastic computations, and consecutively the finite element code can be treated as a black box, as in the case of a commercial software. Numerical examples are used to illustrate the features of the extended HDMR and to compare its performance with full scale simulation. [Copyright &y& Elsevier]

Abstract: In this paper, we successfully use 1D model to approximate the 3D problems. Firstly the PDEs (Partial Differential Equations) forms of Koiter’s Model for 2D linear elastic shell is proposed on special curvature coordinate system, i.e., spherical-coordinate system. Then the ODEs (Ordinary Differential Equations) forms of Koiter’s Model for 2D linear elastic shell is proposed under the assumption that the shell is axis-symmetric. Finally, we do numerical experiments to verify validity and accuracy of 1D models. [Copyright &y& Elsevier]

Abstract: The Klein–Gordon–Schrödinger equations describe a classical model of the interaction between conservative complex neutron field and neutral meson Yukawa in quantum field theory. In this paper, we study the long-time behavior of solutions for the Klein–Gordon–Schrödinger equations. We propose the Chebyshev pseudospectral collocation method for the approximation in the spatial variable and the explicit Runge–Kutta method in time discretization. In comparison with the single domain, the domain decomposition methods have good spatial localization and generate a sparse space differentiation matrix with high accuracy. In this study, we choose an overlapping multidomain scheme. The obtained numerical results show the Pseudospectral multidomain method has excellent long-time numerical behavior and illustrate the effectiveness of the numerical scheme in controlling two particles. Some comparisons with single domain pseudospectral and finite difference methods will be also investigated to confirm the efficiency of the new procedure. [Copyright &y& Elsevier]

Abstract: In this paper, we discuss an -Galerkin mixed finite element method for a class of heat transport equations in the one-dimensional case. Optimal error estimates in -norm and -norm are obtained for both semi-discrete and fully discrete approximation scheme. Moreover, a numerical example is presented to illustrate the effectiveness of the method. [Copyright &y& Elsevier]

Abstract: This paper presents a simple model for the study of the dissolution of calcite and precipitation of gypsum in acidic solutions. The numerical predictions of calcium and hydroxyl ion concentration have been used to develop approximate analytical expressions for the growth rate of calcium in solution, and the hydroxyl ions concentration. These expressions have been used in turn to determine the evolution of the kinetic rate constants, and to make predictions that show good agreement with experimental data. [Copyright &y& Elsevier]