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杆系类天线结构的拓扑优化设计 被引量:3
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作者 段宝岩 徐国华 《电子学报》 EI CAS CSCD 北大核心 1992年第3期27-34,共8页
本文提出了一种适用于杆系类天线结构的拓扑优化设计方法。它可在满足电气性能所要求的主面形状的前提下获得最佳的拓扑结构形式(节点关联关系)。从一般杆系结构拓扑优化的角度看,该方法不仅可在拓扑优化过程中处理位移、应力等性态约束... 本文提出了一种适用于杆系类天线结构的拓扑优化设计方法。它可在满足电气性能所要求的主面形状的前提下获得最佳的拓扑结构形式(节点关联关系)。从一般杆系结构拓扑优化的角度看,该方法不仅可在拓扑优化过程中处理位移、应力等性态约束,而且不要求预给设计位移场。最后,将本方法应用于几个桁架结构与杆系类天线结构的拓扑优化设计中,取得了令人满意的结构。 展开更多
关键词 天线结构 设计 结构形式 杆系类
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Application of improved back-propagation algorithms in classification and detection of scars defects on rails surfaces
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作者 石甜 Kong Jianyi +1 位作者 Wang Xingdong Liu Zhao 《High Technology Letters》 EI CAS 2018年第3期249-256,共8页
An experimental platform with bracket structures,cables,parallel computer and imaging system is designed for defects detecting on steel rails. Meanwhile,an improved gradient descent algorithm based on a self-adaptive ... An experimental platform with bracket structures,cables,parallel computer and imaging system is designed for defects detecting on steel rails. Meanwhile,an improved gradient descent algorithm based on a self-adaptive learning rate and a fixed momentum factor is developed to train back-propagation neural network for accurate and efficient defects classifications. Detection results of rolling scar defects show that such detection system can achieve accurate positioning to defects edges for its improved noise suppression. More precise characteristic parameters of defects can also be extracted.Furthermore,defects classification is adopted to remedy the limitations of low convergence rate and local minimum. It can also attain the optimal training precision of 0. 00926 with the least 96 iterations. Finally,an enhanced identification rate of 95% has been confirmed for defects by using the detection system. It will also be positive in producing high-quality steel rails and guaranteeing the national transport safety. 展开更多
关键词 detection platform steel rail improved algorithm defect classification identification rate
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