The Experts below are selected from a list of 35664 Experts worldwide ranked by ideXlab platform
J L Batoz - One of the best experts on this subject based on the ideXlab platform.
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shape optimization of clinching tools using the response surface methodology with moving least Square Approximation
Journal of Materials Processing Technology, 2009Co-Authors: M Oudjene, L Benayed, A Delameziere, J L BatozAbstract:A response surface methodology (RSM), based on Moving Least-Square (MLS) Approximation and adaptive moving region of interest, is presented for shape optimization problem. To avoid a local optimum and to obtain an accurate solution at low cost, an efficient strategy which allows to improve the RSM accuracy in the vicinity of the global optimum is presented. During the progression of the optimization procedure, the region of interest is moving and the search space is reduced by half around each local optimum. The clinch forming process is considered as an application example using the ABAQUS finite element code. The geometries of both the punch and the die are optimized to improve the joints resistance to tensile loading.
Hao Helen Zhang - One of the best experts on this subject based on the ideXlab platform.
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short communication a new chi Square Approximation to the distribution of non negative definite quadratic forms in non central normal variables
Computational Statistics & Data Analysis, 2009Co-Authors: Yongqiang Tang, Hao Helen ZhangAbstract:This note proposes a new chi-Square Approximation to the distribution of non-negative definite quadratic forms in non-central normal variables. The unknown parameters are determined by the first four cumulants of the quadratic forms. The proposed method is compared with Pearson's three-moment central @g^2 Approximation approach, by means of numerical examples. Our method yields a better Approximation to the distribution of the non-central quadratic forms than Pearson's method, particularly in the upper tail of the quadratic form, the tail most often needed in practical work.
M Oudjene - One of the best experts on this subject based on the ideXlab platform.
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shape optimization of clinching tools using the response surface methodology with moving least Square Approximation
Journal of Materials Processing Technology, 2009Co-Authors: M Oudjene, L Benayed, A Delameziere, J L BatozAbstract:A response surface methodology (RSM), based on Moving Least-Square (MLS) Approximation and adaptive moving region of interest, is presented for shape optimization problem. To avoid a local optimum and to obtain an accurate solution at low cost, an efficient strategy which allows to improve the RSM accuracy in the vicinity of the global optimum is presented. During the progression of the optimization procedure, the region of interest is moving and the search space is reduced by half around each local optimum. The clinch forming process is considered as an application example using the ABAQUS finite element code. The geometries of both the punch and the die are optimized to improve the joints resistance to tensile loading.
Pierre Lafaye De Micheaux - One of the best experts on this subject based on the ideXlab platform.
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short communication computing the distribution of quadratic forms further comparisons between the liu tang zhang Approximation and exact methods
Computational Statistics & Data Analysis, 2010Co-Authors: Pierre Duchesne, Pierre Lafaye De MicheauxAbstract:Liu, Tang and Zhang [Liu, H. Tang, Y., Zhang H.H. 2009. A new chi-Square Approximation to the distribution of non-negative definite quadratic forms in non-central normal variables. Computational Statistics & Data Analysis 53, 853-856] proposed a chi-Square Approximation to the distribution of non-negative definite quadratic forms in non-central normal variables. To approximate the distribution of interest, they used a non-central chi-Square distribution, where the degrees of freedom and the non-centrality parameter were calculated using the first four cumulants of the quadratic form. Numerical examples were encouraging, suggesting that the Approximation was particularly accurate in the upper tail of the distribution. We present here additional empirical evidence, comparing Liu-Tang-Zhang's four-moment non-central chi-Square Approximation with exact methods. While the moment-based method is interesting because of its simplicity, we demonstrate that it should be used with care in practical work, since numerical examples suggest that significant differences may occur between that method and exact methods, even in the upper tail of the distribution.
L Benayed - One of the best experts on this subject based on the ideXlab platform.
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shape optimization of clinching tools using the response surface methodology with moving least Square Approximation
Journal of Materials Processing Technology, 2009Co-Authors: M Oudjene, L Benayed, A Delameziere, J L BatozAbstract:A response surface methodology (RSM), based on Moving Least-Square (MLS) Approximation and adaptive moving region of interest, is presented for shape optimization problem. To avoid a local optimum and to obtain an accurate solution at low cost, an efficient strategy which allows to improve the RSM accuracy in the vicinity of the global optimum is presented. During the progression of the optimization procedure, the region of interest is moving and the search space is reduced by half around each local optimum. The clinch forming process is considered as an application example using the ABAQUS finite element code. The geometries of both the punch and the die are optimized to improve the joints resistance to tensile loading.