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基于组合代理模型的箱形梁轻量化设计
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作者 陈杨 秦义校 杨俊乐 《起重运输机械》 2023年第14期21-27,共7页
文中针对常见的3种代理模型多项式响应面(RSM)、径向基(RBF)神经网络以及Kriging模型在结构优化中的代理效果进行对比研究。以桥式起重机箱形梁轻量化为例,分析了3种代理模型在确定系数下的代理效果,并以此为依据提出了1种适用于该优化... 文中针对常见的3种代理模型多项式响应面(RSM)、径向基(RBF)神经网络以及Kriging模型在结构优化中的代理效果进行对比研究。以桥式起重机箱形梁轻量化为例,分析了3种代理模型在确定系数下的代理效果,并以此为依据提出了1种适用于该优化案例的组合代理模型。最终,以智能算法与梯度算法的组合算法对得到的4种代理模型寻优,并将寻优结果通过有限元模型进行验证。实际工程案例表明,基于代理模型的结构优化算法,在保证优化效果的前提下,大幅度提高了优化效率。 展开更多
关键词 组合代理模型 确定系数 智能算法 箱形梁 布局优化
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A MRI quantitative study of corpus callosum in normal adults
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作者 yang junle Guo Youmin +3 位作者 Gao Yanjun Ma Mingyue Zhang Qiujuan Xu Min 《Journal of Medical Colleges of PLA(China)》 CAS 2008年第6期346-351,共6页
Objective: To investigate the possible age- and sex-related differences in the various dimensions of corpus callosum among Chinese normal adults. Methods: Magnetic resonance images of 286 healthy adults, including 1... Objective: To investigate the possible age- and sex-related differences in the various dimensions of corpus callosum among Chinese normal adults. Methods: Magnetic resonance images of 286 healthy adults, including 127 males and 159 females, and ranging in age from 20 to 81 years, were investigated. They were classified into 5 age groups ( 20-29, 30-39, 40-49, 50-59, and 60-81 years old). Corresponding to the age group sequence above, the male/female ratio of each group respectively was: 25/26, 26/33, 33/50, 32/36, and 11/14. The following dimensions of corpus callosum were systematically measured on the midsagittal Tl-weighted images: frontal to occipital pole (represented as line segment AB), total longitudinal dimension of the corpus callosum (CD), the maximum height (EF), the widths of the genu (CX), anterior one third (GH), central region (EZ), posterior one third (MN) and splenium (YD). After that, the obtained data was analyzed statistically. Results: (1) The total longitudinal dimension, maximum height, widths of the genu, central region and splenium were proved to be larger in females. But the widths of the anterior one third and posterior one third were similar in-between. In spite of that, a conspicuous sex-related difference was not found. (2) The total longitudinal dimension and the maximum height of the corpus callosum remained stable in all age subgroups. Yet the widths of the genu, anterior one third, central region, posterior one third and splenium had a tendency of decreasing gradually with aging. Statistical difference was seen in the anterior one third, central region, posterior one third (P〈0.05). Conclusion: There is no sex-related difference in all dimensions of corpus callosum. But, with aging, a significant difference is found in the widths of the anterior one third, central region and posterior one third. 展开更多
关键词 Normal adults Corpus callosum Magnetic resonance imaging
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