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AN INEXACT SMOOTHING NEWTON METHOD FOR EUCLIDEAN DISTANCE MATRIX OPTIMIZATION UNDER ORDINAL CONSTRAINTS 被引量:1
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作者 qingna li Houduo Qi 《Journal of Computational Mathematics》 SCIE CSCD 2017年第4期469-485,共17页
When the coordinates of a set of points are known, the pairwise Euclidean distances among the points can be easily computed. Conversely, if the Euclidean distance matrix is given, a set of coordinates for those points... When the coordinates of a set of points are known, the pairwise Euclidean distances among the points can be easily computed. Conversely, if the Euclidean distance matrix is given, a set of coordinates for those points can be computed through the well known classical Multi-Dimensional Scaling (MDS). In this paper, we consider the case where some of the distances are far from being accurate (containing large noises or even missing). In such a situation, the order of the known distances (i.e., some distances are larger than others) is valuable information that often yields far more accurate construction of the points than just using the magnitude of the known distances. The methods making use of the order information is collectively known as nonmetric MDS. A challenging computational issue among all existing nonmetric MDS methods is that there are often a large number of ordinal constraints. In this paper, we cast this problem as a matrix optimization problem with ordinal constraints. We then adapt an existing smoothing Newton method to our matrix problem. Extensive numerical results demonstrate the efficiency of the algorithm, which can potentially handle a very large number of ordinal constraints. 展开更多
关键词 Nonmetric multidimensional scaling Euclidean distance embedding Ordinalconstraints Smoothing Newton method.
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中国乳腺癌自然史参数选择的优化方法
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作者 尹娟 王乐 +7 位作者 白晓宁 李燕婕 王鑫 张在坤 李炳照 李扬 石菊芳 李庆娜 《中国科学:数学》 CSCD 北大核心 2023年第6期895-913,共19页
乳腺癌是女性最常见的恶性肿瘤之一。为了提出有效的筛查策略并评估其效果,一个基本且重要的步骤是在中国乳腺癌自然史模型中选择合适的参数,即转移概率.选择合理的转移概率有两个挑战.首先,由于乳腺癌的流行病学特性,其他国家使用的转... 乳腺癌是女性最常见的恶性肿瘤之一。为了提出有效的筛查策略并评估其效果,一个基本且重要的步骤是在中国乳腺癌自然史模型中选择合适的参数,即转移概率.选择合理的转移概率有两个挑战.首先,由于乳腺癌的流行病学特性,其他国家使用的转移概率不一定适用于中国.其次,可用的筛查样本数据很少,这使得传统的基于统计的方法(如极大似然估计法)失效.本文从优化角度提出一种乳腺癌自然史参数选择的方法,基于公布的统计数据建立数学优化模型.该模型的挑战在于目标函数高度非线性且无显式表达式,本文提出一种坐标下降算法来处理这个挑战.最后,本文提出一种最佳匹配方法来估计每个转移概率的分布.本文所提出的方法为进一步提出合理的中国乳腺癌筛查策略和分析乳腺癌的经济负担提供了坚实的基础. 展开更多
关键词 乳腺癌 自然史 参数选择黄金分割法 无导数法 坐标下降法
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Robust PCA for Ground Moving Target Indication in Wide-Area Surveillance Radar System 被引量:1
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作者 qingna li He Yan +1 位作者 Leqin Wu Robert Wang 《Journal of the Operations Research Society of China》 EI 2013年第1期135-153,共19页
Robust PCA has found important applications in many areas,such as video surveillance,face recognition,latent semantic indexing and so on.In this paper,we study its application in ground moving target indication(GMTI)i... Robust PCA has found important applications in many areas,such as video surveillance,face recognition,latent semantic indexing and so on.In this paper,we study its application in ground moving target indication(GMTI)in wide-area surveillance radar system.MTI is the key task in wide-area surveillance radar system.Due to its great importance in future reconnaissance systems,it attracts great interest from scientists.In(Yan et al.in IEEE Geosci.Remote Sens.Lett.,10:617–621,2013),the authors first introduced robust PCA to model the GMTI problem,and demonstrate promising simulation results to verify the advantages over other models.However,the robust PCA model can not fully describe the problem.As pointed out in(Yan et al.in IEEE Geosci.Remote Sens.Lett.,10:617–621,2013),due to the special structure of the sparse matrix(which includes the moving target information),there will be difficulties for the exact extraction of moving targets.This motivates our work in this paper where we will detail the GMTI problem,explore the mathematical properties and discuss how to set up better models to solve the problem.We propose two models,the structured RPCA model and the row-modulus RPCA model,both of which will better fit the problem and take more use of the special structure of the sparse matrix.Simulation results confirm the improvement of the proposed models over the one in(Yan et al.in IEEE Geosci.Remote Sens.Lett.,10:617–621,2013). 展开更多
关键词 Ground moving target indication Alternating direction method Wide-area surveillance radar system Joint sparsity Matrix recovery
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