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  • Open Access

    ARTICLE

    Self-Adaptive Differential Evolution Based on the Concept of Population Diversity Applied to Simultaneous Estimation of Anisotropic Scattering Phase Function, Albedo and Optical Thickness

    F. S. Lobato1, V. Steffen Jr2, A. J. Silva Neto3

    CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.1, pp. 1-18, 2010, DOI:10.3970/cmes.2010.069.001

    Abstract Differential Evolution Algorithm (DE) has shown to be a powerful evolutionary algorithm for global optimization in a variety of real world problems. DE differs from other evolutionary algorithms in the mutation and recombination phases. Unlike some other meta-heuristic techniques such as genetic algorithms and evolutionary strategies, where perturbation occurs in accordance with a random quantity, DE uses weighted differences between solution vectors to perturb the population. Although the efficiency of DE algorithm has been proven in the literature, studies indicate that the efficiency of the DE methods is sensitive to its control parameters (perturbation rate More >

  • Open Access

    ARTICLE

    The Concept of Best Vector Used to Solve Ill-Posed Linear Inverse Problems

    Chein-Shan Liu

    CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.5, pp. 499-526, 2012, DOI:10.3970/cmes.2012.083.499

    Abstract The iterative algorithms based on the concept of best vector are proposed to solve an ill-conditioned linear system: Bx-b=0, which might be a discretization of linear inverse problem. In terms of r:=Bx-b and a monotonically increasing positive function Q(t) of a time-like variable t, we define a future cone in the Minkowski space, wherein the discrete dynamics of the proposed algorithm is evolved. We propose two methods to approximate the best vector B-1r, and obtain three iterative algorithms for solving x, which we label them as the steepest-descent and optimal vectors iterative algorithm (SOVIA), the More >

  • Open Access

    ARTICLE

    Different concepts for the coupling of porous-media flow with lower-dimensional pipe flow

    M. O. Doğan1,2, H. Class2, R. Helmig2

    CMES-Computer Modeling in Engineering & Sciences, Vol.53, No.3, pp. 207-234, 2009, DOI:10.3970/cmes.2009.053.207

    Abstract Many flow problems in environmental, technical and biological systems are characterized by a distinct interaction between a flow region in porous-medium and a free-flow region in quasi-one-dimensional hollow structures. In this study, different model concepts, based on a dual-continuum strategy, for the simulation of coupled porous-media flow and (lower-dimensional) pipe flow are further developed and tested. The dual-continuum concept is extended for coupling multi-phase porous-media flow with lower-dimensional single-phase free flow. The complexity of the considered flow regimes is increased gradually. Examples are given for a coupled single-phase incompressible and compressible flow in both porous-media More >

  • Open Access

    ARTICLE

    Analysis of Shell Deformation Responses by the Meshless Local Petrov-Galerkin (MLPG) Approach

    T. Jarak1, J. Sorić1, J. Hoster1

    CMES-Computer Modeling in Engineering & Sciences, Vol.18, No.3, pp. 235-246, 2007, DOI:10.3970/cmes.2007.018.235

    Abstract A meshless computational method based on the local Petrov-Galerkin approach for the analysis of shell structures is presented. A concept of a three dimensional solid, allowing the use of completely 3-D constitutive models, is applied. Discretization is carried out by using both a moving least square approximation and polynomial functions. The exact shell geometry can be described. Thickness locking is eliminated by using a hierarchical quadratic approximation over the thickness. The shear locking phenomena in case of thin structures and the sensitivity to rigid body motions are minimized by applying interpolation functions of sufficiently high More >

  • Open Access

    ARTICLE

    Meshless Local Petrov-Galerkin (MLPG) Formulation for Analysis of Thick Plates

    J. Sorić1, Q. Li2, T. Jarak1, S.N. Atluri2

    CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.4, pp. 349-358, 2004, DOI:10.3970/cmes.2004.006.349

    Abstract An efficient meshless formulation based on the Local Petrov-Galerkin approach for the analysis of shear deformable thick plates is presented. Using the kinematics of a three-dimensional continuum, the local symmetric weak form of the equilibrium equations over the cylindrical shaped local sub-domain is derived. The linear test function in the plate thickness direction is assumed. Discretization in the in-plane directions is performed by means of the moving least squares approximation. The linear interpolation over the thickness is used for the in-plane displacements, while the hierarchical quadratic interpolation is adopted for the transversal displacement in order More >

  • Open Access

    ARTICLE

    Finite Rotations and large Strains in Finite Element Shell Analysis

    Y. Başar, O. Kintzel1

    CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.2, pp. 217-230, 2003, DOI:10.3970/cmes.2003.004.217

    Abstract The objective of this contribution is the development of a finite element model for finite rotation and large strain analysis of thin walled shells involving geometry intersections. The shell configuration is described by a linear polynomial in the thickness coordinate. The director of the shell is multiplicatively decomposed into a stretching parameter and an inextensible unit vector whose rotation is accomplished by an updated-rotation formulation. A rotation vector with three independent components is used throughout the shell which permits advantageously to consider smooth shells and compound shells by a unified procedure. This formulation is introduced More >

  • Open Access

    ARTICLE

    The Concept of a Vibrational Cell for Studying the Interface Chemical Kinetics. Vibrational Flow Structure

    A.A. Ivanova1, V.G. Kozlov1,2,3, D.A. Polezhaev1, D. Pareau3, M. Stambouli3

    FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.3, pp. 211-220, 2008, DOI:10.3970/fdmp.2008.004.211

    Abstract The problem for the optimization of mass-transfer on the interface of two immiscible liquids by means of vibrational hydromechanics is studied experimentally. A new vibrational cell of Lewis's type expressly conceived for such purposes is described. Flow is generated by activators in the form of disks inducing translational axial oscillations near the opposite end faces of the cavity. It is shown that such vibrating disks can lead to the onset of a large-scale toroidal whirlwind effectively mixing the liquid throughout the volume. According to the experiments, in particular, axisymmetrical radial flows are generated on both More >

  • Open Access

    ARTICLE

    YATA: Yet Another Proposal for Traffic Analysis and Anomaly Detection

    Yu Wang1,2,*, Yan Cao2, Liancheng Zhang2, Hongtao Zhang3, Roxana Ohriniuc4, Guodong Wang5, Ruosi Cheng6

    CMC-Computers, Materials & Continua, Vol.60, No.3, pp. 1171-1187, 2019, DOI:10.32604/cmc.2019.05575

    Abstract Network traffic anomaly detection has gained considerable attention over the years in many areas of great importance. Traditional methods used for detecting anomalies produce quantitative results derived from multi-source information. This makes it difficult for administrators to comprehend and deal with the underlying situations. This study proposes another method to yet determine traffic anomaly (YATA), based on the cloud model. YATA adopts forward and backward cloud transformation algorithms to fuse the quantitative value of acquisitions into the qualitative concept of anomaly degree. This method achieves rapid and direct perspective of network traffic. Experimental results with More >

  • Open Access

    ARTICLE

    Optimal Building Frame Column Design Based on the Genetic Algorithm

    Tao Shen1,*, Yukari Nagai1, Chan Gao2

    CMC-Computers, Materials & Continua, Vol.58, No.3, pp. 641-651, 2019, DOI:10.32604/cmc.2019.04885

    Abstract Building structure is like the skeleton of the building, it bears the effects of various forces and forms a supporting system, which is the material basis on which the building depends. Hence building structure design is a vital part in architecture design, architects often explore novel applications of their technologies for building structure innovation. However, such searches relied on experiences, expertise or gut feeling. In this paper, a new design method for the optimal building frame column design based on the genetic algorithm is proposed. First of all, in order to construct the optimal model More >

  • Open Access

    ARTICLE

    Thermal-Cyclic Fatigue Life Analysis and Reliability Estimation of a FCCSP based on Probabilistic Design Concept

    Yao Hsu1, Chih-Yen Su2, Wen-Fang Wu3,4

    CMC-Computers, Materials & Continua, Vol.36, No.2, pp. 155-176, 2013, DOI:10.3970/cmc.2013.036.155

    Abstract To study the fatigue reliability of a flip-chip chip scale package (FCCSP) subject to thermal cyclic loading, a Monte Carlo simulation-based parametric study is carried out in the present study. A refined procedure as compared with the recently released Probabilistic Design System (PDS) of ANSYS is proposed and employed in particular. The thermal-cyclic fatigue life of the package is discussed in detail since it is related directly to the reliability of the package. In consideration of the analytical procedure as well as real manufacturing processes, a few geometric dimensions and material properties of the package More >

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