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一种可靠信任推荐文本分类特征权重算法 被引量:6
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作者 焦庆争 蔚承建 《计算机应用研究》 CSCD 北大核心 2010年第2期472-474,共3页
从可信计算角度,提出一种可靠信任推荐文本分类特征权重算法,分析了特征在文档中的特性,基于Beta分布函数研究了特征与文档类之间的信任关系,建立特征权重计算模型,并实现简单高效的线性文本分类器。在比较实验中采用20newsgroup和复旦... 从可信计算角度,提出一种可靠信任推荐文本分类特征权重算法,分析了特征在文档中的特性,基于Beta分布函数研究了特征与文档类之间的信任关系,建立特征权重计算模型,并实现简单高效的线性文本分类器。在比较实验中采用20newsgroup和复旦中文语料集。与TFIDF算法进行性能比较,实验结果显示该算法性能较TFIDF显著提高,并对非平衡语料具有良好的适应性。 展开更多
关键词 文本分类 特征权重 可信计算 概率确定性密度 自然语言处理
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Probabilistic model and analysis of coupled train-ballasted track-subgrade system with uncertain structural parameters 被引量:7
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作者 MAO Jian-feng XIAO Yuan-jie +2 位作者 YU Zhi-wu Erol TUTUMLUER ZHU Zhi-hui 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第7期2238-2256,共19页
Random dynamic responses caused by the uncertainty of structural parameters of the coupled train-ballasted track-subgrade system under train loading can pose safety concerns to the train operation.This paper introduce... Random dynamic responses caused by the uncertainty of structural parameters of the coupled train-ballasted track-subgrade system under train loading can pose safety concerns to the train operation.This paper introduced a computational model for analyzing probabilistic dynamic responses of three-dimensional(3D)coupled train-ballasted track-subgrade system(TBTSS),where the coupling effects of uncertain rail irregularities,stiffness and damping properties of ballast and subgrade layers were simultaneously considered.The number theoretical method(NTM)was employed to design discrete points for the multi-dimensional stochastic parameters.The time-histories of stochastic dynamic vibrations of the TBSS with systematically uncertain structural parameters were calculated accurately and efficiently by employing the probability density evolution method(PDEM).The model-predicted results were consistent with those by the Monte Carlo simulation method.A sensitivity study was performed to assess the relative importance of those uncertain structural parameters,based on which a case study was presented to explore the stochastic probability evolution mechanism of such train-ballasted track-subgrade system. 展开更多
关键词 coupled train-ballast-subgrade system structural parameter uncertainty stochastic dynamic analysis probability density evolution method wheel-rail interaction
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