Home / Journals / CMES / Vol.22, No.2, 2007
Table of Content
  • Open Access

    ARTICLE

    A Comparative Study of Non-separable Wavelet and Tensor-product Wavelet in Image Compression

    Jun Zhang1
    CMES-Computer Modeling in Engineering & Sciences, Vol.22, No.2, pp. 91-96, 2007, DOI:10.3970/cmes.2007.022.091
    Abstract The most commonly used wavelets for image processing are the tensor-product of univariate wavelets, which have a disadvantage of giving a particular importance to the horizontal and vertical directions. In this paper, a new class of wavelet, non-separable wavelet, is investigated for image compression applications. The comparative results of image compression preprocessed with two different kinds of wavelet transform are presented: (1) non-separable wavelet transform; (2) tensor-product wavelet transform. The results of our experiments show that in the same vanishing moment, the non-separable wavelets perform better than the tensor-product wavelets in dealing with still images. More >

  • Open Access

    ARTICLE

    A New Uncertain Optimization Method Based on Intervals and An Approximation Management Model

    C. Jiang1, X. Han1,2
    CMES-Computer Modeling in Engineering & Sciences, Vol.22, No.2, pp. 97-118, 2007, DOI:10.3970/cmes.2007.022.097
    Abstract A new uncertain optimization method is developed based on intervals and an approximation management model. A general uncertain optimization problem is considered in which the objective function and constraints are both nonlinear and uncertain, and intervals are used to model the uncertainty existing in the system. Based on a possibility degree of interval,anonlinear interval number programming (NINP) method is proposed. A deterministic objective function is constructed to maximize the possibility degree of the uncertain objective function, and the uncertain constraints are changed into deterministic ones by introducing some possibility degree levels. If the optimal possibility degree of the objective function… More >

  • Open Access

    ARTICLE

    Investigation of the Effect of Frictional Contact in III-Mode Crack under Action of the SH-Wave Harmonic Load

    A.N. Guz1, V.V. Zozulya2
    CMES-Computer Modeling in Engineering & Sciences, Vol.22, No.2, pp. 119-128, 2007, DOI:10.3970/cmes.2007.022.119
    Abstract The frictional contact interaction of the edges of a finite plane crack is studied for the case of normal incidence of a harmonic SH-shear wave which produces antiplane deformation. The forces of contact interaction and displacement discontinuity are analyzed. Influence of the wave frequency on the stress intensity factor for different coefficients of friction is studied here. More >

  • Open Access

    ARTICLE

    Envelope frequency Response Function Analysis of Mechanical Structures with Uncertain Modal Damping Characteristics

    D. Moens1, M. De Munck, D. Vandepitte
    CMES-Computer Modeling in Engineering & Sciences, Vol.22, No.2, pp. 129-150, 2007, DOI:10.3970/cmes.2007.022.129
    Abstract Recently, an interval finite element methodology has been developed to calculate envelope frequency response functions of uncertain structures with interval parameters. The methodology is based on a hybrid interval implementation of the modal superposition principle. This hybrid procedure consists of a preliminary optimization step, followed by an interval arithmetic procedure. The final envelope frequency response functions have been proved to give a very good approximation of the actual response range of the interval problem. Initially, this method was developed for undamped structures. Based on the theoretical principles of this approach, this paper introduces a new method for the analysis of… More >

  • Open Access

    ARTICLE

    Boundary Element Analysis of Three-Dimensional Exponentially Graded Isotropic Elastic Solids

    R. Criado1, J.E. Ortiz1, V. Mantič1, L.J. Gray1,2, F. París1
    CMES-Computer Modeling in Engineering & Sciences, Vol.22, No.2, pp. 151-164, 2007, DOI:10.3970/cmes.2007.022.151
    Abstract A numerical implementation of the Somigliana identity in displacements for the solution of 3D elastic problems in exponentially graded isotropic solids is presented. An expression for the fundamental solution in displacements, Ujl, was deduced by Martin et al. (Proc. R. Soc. Lond. A, 458, pp. 1931--1947, 2002). This expression was recently corrected and implemented in a Galerkin indirect 3D BEM code by Criado et al. (Int. J. Numer. Meth. Engng., 2008). Starting from this expression of Ujl, a new expression for the fundamental solution in tractions Tjl has been deduced in the present work. These quite complex expressions of the… More >

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