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拉格朗日早年对其变分方法的参数化与发展
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作者 贾小勇 邓明立 贾随军 《西北大学学报(自然科学版)》 CAS CSCD 北大核心 2017年第6期923-928,共6页
拉格朗日"变分方法"(亦称δ-算法)的引进,堪为变分法早期发展中的一次变革。然而在最初提出这一新方法时,拉格朗日却经历了由非参数向参数表示形式的转变,实现了该方法的参数化。依据原始文献,首先解析了拉格朗日δ-算法的非... 拉格朗日"变分方法"(亦称δ-算法)的引进,堪为变分法早期发展中的一次变革。然而在最初提出这一新方法时,拉格朗日却经历了由非参数向参数表示形式的转变,实现了该方法的参数化。依据原始文献,首先解析了拉格朗日δ-算法的非参数表示和参数表示,然后探讨了在参数化过程中他对变分法相关理论及应用所作的革新与发展。研究表明:通过参数化改造,拉格朗日对变分问题、变分方程、横截性条件以及变分法的力学应用——最小作用原理等均做出了拓广或发展。拉格朗日对其变分方法的参数化不仅开阔了变分法研究的范围,而且赋予了变分法在力学应用中的重大价值。 展开更多
关键词 拉格朗日(J.L.Lagrange 1736—1813) 变分方法 非参数表示 参数表示 参数
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Discriminant embedding by sparse representation and nonparametric discriminant analysis for face recognition
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作者 杜春 周石琳 +2 位作者 孙即祥 孙浩 王亮亮 《Journal of Central South University》 SCIE EI CAS 2013年第12期3564-3572,共9页
A novel supervised dimensionality reduction algorithm, named discriminant embedding by sparse representation and nonparametric discriminant analysis(DESN), was proposed for face recognition. Within the framework of DE... A novel supervised dimensionality reduction algorithm, named discriminant embedding by sparse representation and nonparametric discriminant analysis(DESN), was proposed for face recognition. Within the framework of DESN, the sparse local scatter and multi-class nonparametric between-class scatter were exploited for within-class compactness and between-class separability description, respectively. These descriptions, inspired by sparse representation theory and nonparametric technique, are more discriminative in dealing with complex-distributed data. Furthermore, DESN seeks for the optimal projection matrix by simultaneously maximizing the nonparametric between-class scatter and minimizing the sparse local scatter. The use of Fisher discriminant analysis further boosts the discriminating power of DESN. The proposed DESN was applied to data visualization and face recognition tasks, and was tested extensively on the Wine, ORL, Yale and Extended Yale B databases. Experimental results show that DESN is helpful to visualize the structure of high-dimensional data sets, and the average face recognition rate of DESN is about 9.4%, higher than that of other algorithms. 展开更多
关键词 dimensionality reduction sparse representation nonparametric discriminant analysis
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Nonparametric estimation of quantiles for a class of stationary processes
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作者 HUANG Chu WANG HanChao LIN ZhengYan 《Science China Mathematics》 SCIE CSCD 2015年第12期2621-2632,共12页
We study smoothed quantile estimator for a class of stationary processes. We obtain the convergency rates and the Bahadur representation, as well as the asymptotic normality for this estimator by the method of m-depen... We study smoothed quantile estimator for a class of stationary processes. We obtain the convergency rates and the Bahadur representation, as well as the asymptotic normality for this estimator by the method of m-dependent approximation. Our results can be used in the study of the estimation of value-at-risk(Va R) and applied to many time series which have important applications in econometrics. 展开更多
关键词 quantile estimator kernel method causal process m-dependent approximation asymptotic inference
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