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  • Open Access

    ARTICLE

    Convergence Properties of Genetic Algorithmsin a Wide Variety of Noisy Environments

    TakehikoNakama1

    CMC-Computers, Materials & Continua, Vol.14, No.1, pp. 35-60, 2009, DOI:10.3970/cmc.2009.014.035

    Abstract Random noise perturbs objective functions in practical optimization problems, and genetic algorithms (GAs) have been proposed as an effective optimization tool for dealing with noisy objective functions. In this paper, we investigate GAs in a variety of noisy environments where fitness perturbation can occur in any form-for example, fitness evaluations can be concurrently disturbed by additive and multiplicative noise. We reveal the convergence properties of GAs by constructing and analyzing a Markov chain that explicitly models the evolution of the algorithms in noisy environments. We compute the one-step transition probabilities of the Markov chain and… More >

  • Open Access

    ARTICLE

    Characterization of associated environments to natural populations of Pavonia cymbalaria (Malvaceae) in rangelands of Sierra de la Ventana (Buenos Aires)

    Torres1 YA, MA Long2, SM Zalba1

    Phyton-International Journal of Experimental Botany, Vol.77, pp. 225-240, 2008, DOI:10.32604/phyton.2008.77.225

    Abstract The objective of this work is to contribute to the biology of Pavonia cymbalaria A. St. Hil & Naudin (Malvaceae), a native species of the Southern mountains of Buenos Aires Province. This knowledge will contribute to (1) promote its use as an ornamental species, (2) its conservation and (3) stimulate the interest and public valuation of mountain systems biodiversity. Seven populations of P. cymbalaria were selected. Two of them were growing under Pinus halepensis forests to characterize different environments were the herbaceous species is growing in the wild. Environmental characteristics immediately associated to six individuals of the species More >

  • Open Access

    ABSTRACT

    Unsupervised Support Vector Machine Based Principal Component Analysis for Structural Health Monitoring

    Chang Kook Oh1, Hoon Sohn1

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.8, No.3, pp. 91-100, 2008, DOI:10.3970/icces.2008.008.091

    Abstract Structural Health Monitoring (SHM) is concerned with identifying damage based on measurements obtained from structures being monitored. For the civil structures exposed to time-varying environmental and operational conditions, it is inevitable that environmental and operational variability produces an adverse effect on the dynamic behaviors of the structures. Since the signals are measured under the influence of these varying conditions, normalizing the data to distinguish the effects of damage from those caused by the environmental and operational variations is important in order to achieve successful structural health monitoring goals. In this paper, kernel principal component analysis More >

  • Open Access

    ABSTRACT

    Computational Environment for the Multiscale, Multi-Physics Resin Transfer Molding Process

    B. J. Henz1, D. R. Shires2

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.7, No.1, pp. 13-18, 2008, DOI:10.3970/icces.2008.007.013

    Abstract The capability to predict the residual stresses induced during the manufacturing process in composite components is necessary for the timely fielding of new combat systems. At the U.S. Army Research Laboratory we have developed a computational environment to model the resin flow, heat transfer, curing, and residual stresses in composite components manufactured with the resin transfer molding (RTM) process. This computational environment uses object-oriented programming methods to provide model coupling capabilities and access to high performance computing assets. In this paper we will provide details of the physical models, software, and the validation/verification procedure used More >

  • Open Access

    ARTICLE

    Adhesive Models to Understand the Sensitivity of Bio-Molecules to Environmental Signals

    Shaohua Chen*

    Molecular & Cellular Biomechanics, Vol.5, No.2, pp. 97-106, 2008, DOI:10.3970/mcb.2008.005.097

    Abstract Recently, contact mechanics has been widely used to get some understanding of the biological adhesion mechanisms, such as cell-cell adhesion, insects' adhesion and locomotion. JKR theory is usually adopted as a basis, in which the interaction of molecules is considered in contrast to the classical Hertz solution. In this paper, two problems are summarized, which may give some insights to cells or bio-molecules sensitivity to environmental signals: (1) cell reorientation on a stretched substrate; (2) spontaneous detachment between cells or bio-molecules under the variation of environmental signals. The intention here is only to illustrate the… More >

  • Open Access

    ARTICLE

    Large-Scale Parallel Finite Element Analyses of High Frequency Electromagnetic Field in Commuter Trains

    A. Takei1, S. Yoshimura1, H. Kanayama2

    CMES-Computer Modeling in Engineering & Sciences, Vol.31, No.1, pp. 13-24, 2008, DOI:10.3970/cmes.2008.031.013

    Abstract This paper presents large-scale finite element analyses of high frequency electromagnetic fields in commuter trains. The ADVENTURE_Magnetic is one of the main modules of the ADVENTURE system, which is an open source parallel finite element analyses system, and is able to solve eddy current and magnetostatic problems using the hierarchical domain decomposition method (HDDM) with an iterative linear algebraic solver. In this paper, we improve the module so as to solve a high frequency electromagnetic field of 500-1000 M[Hz]. A stationary Helmholtz equation for electromagnetic wave problems is solved taking an electric field as an More >

  • Open Access

    ARTICLE

    Thermal Cycling Degradation of T650 Carbon Fiber/PT-30 Cyanate Ester Composite

    Huanchun Chen1, Kunigal Shivakumar1

    CMC-Computers, Materials & Continua, Vol.8, No.1, pp. 33-42, 2008, DOI:10.3970/cmc.2008.008.033

    Abstract Thermal cycling degradation effect on tensile and flexural properties of Cytec T650 carbon/Lonza Primaset PT-30 cyanate ester composite rods used for gas turbine engine brush seals was evaluated. The composite rods were thermal cycled in air from room temperature to 315°C for 100, 200, 400, 600 and 800 cycles. Each thermal cycle is a one hour period with 28 minutes hold at peak temperature and a high heating/cooling rate of 73°C/min. The composite withstood the first 100 thermal cycles with less than 10% property change. After that, tensile strength and fracture strain as well as More >

  • Open Access

    ABSTRACT

    PDSL and SDSL Parallel Visualization Algorithms for Large-scale Finite Element Analysis Data in Distributed Parallel Computing Environment

    Jin Yeon Cho1, Yun Hyuk Choi2, You Me Song3, Chang Sik Kim4

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.3, pp. 151-158, 2007, DOI:10.3970/icces.2007.004.151

    Abstract In this work, PDSL(pre-detection sort last) and SDSL(strip-wise decomposition sort last) parallel visualization algorithms are proposed for efficient visualization of massive data generated from large-scale parallel finite element analysis through investigating the characteristics of distributed parallel finite element analysis procedure. The proposed parallel visualization algorithms are based on the sort last approach, and designed to be highly compatible with the characteristics of domain-wise computation in parallel finite element analysis. To investigate the performances of proposed algorithms, in-house software is developed by applying the binary tree network communication pattern along with the proposed sorting algorithms, and More >

  • Open Access

    ARTICLE

    Buckling and Free Vibrations of Sandwich General shells of Revolution with Composite facings and Viscoelastic core under Thermal Environment using Semi-analytical Method

    Sharnappa1, N. Ganesan2, Raju Sethuraman3

    CMES-Computer Modeling in Engineering & Sciences, Vol.18, No.2, pp. 121-144, 2007, DOI:10.3970/cmes.2007.018.121

    Abstract This article presents the study on buckling and free vibration behavior of sandwich general shells of revolution under thermal environment using Wilkins theory. The temperature assumes to be uniform over the shell structure. The numerical analysis is based on the semi-analytical finite element method applicable to thick shells. The analysis is carried out for different geometry such as truncated conical and hemispherical shells with various facing and core materials under clamped-clamped boundary condition. The parametric study is carried out for different core to facing (tc / tf) thickness ratio by considering the temperature dependent and independent More >

  • Open Access

    ABSTRACT

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