The clustering of objects(individuals or variables)is one of the most used approaches to exploring multivariate data.The two most common unsupervised clustering strategies are hierarchical ascending clustering(HAC)and...The clustering of objects(individuals or variables)is one of the most used approaches to exploring multivariate data.The two most common unsupervised clustering strategies are hierarchical ascending clustering(HAC)and k-means partitioning used to identify groups of similar objects in a dataset to divide it into homogeneous groups.The proposed topological clustering of variables,called TCV,studies an homogeneous set of variables defined on the same set of individuals,based on the notion of neighborhood graphs,some of these variables are more-or-less correlated or linked according to the type quantitative or qualitative of the variables.This topological data analysis approach can then be useful for dimension reduction and variable selection.It’s a topological hierarchical clustering analysis of a set of variables which can be quantitative,qualitative or a mixture of both.It arranges variables into homogeneous groups according to their correlations or associations studied in a topological context of principal component analysis(PCA)or multiple correspondence analysis(MCA).The proposed TCV is adapted to the type of data considered,its principle is presented and illustrated using simple real datasets with quantitative,qualitative and mixed variables.The results of these illustrative examples are compared to those of other variables clustering approaches.展开更多
针对导数更新(derivative based updating,DBU)方法计算量大的缺点,提出了一种可以直接对前视阵雷达接收的回波数据协方差矩阵进行修正的降维DBU方法。该方法利用矩阵分块求逆定理求出修正矩阵,然后利用已有的3DT降维空时自适应处理(spa...针对导数更新(derivative based updating,DBU)方法计算量大的缺点,提出了一种可以直接对前视阵雷达接收的回波数据协方差矩阵进行修正的降维DBU方法。该方法利用矩阵分块求逆定理求出修正矩阵,然后利用已有的3DT降维空时自适应处理(space-time adaptive processing,STAP)方法进行处理,不但减少了计算负担,而且降低了对独立同分布(independent identically distributed,IID)样本数目的要求,在性能上接近原来的DBU最优处理方法。实验结果表明,该方法在回波存在各种误差条件下仍然能达到与最优处理接近的性能。展开更多
针对高维小样本数据在核化图嵌入过程中出现的复杂度问题,引入基于核化图嵌入(kernel extension of graph embedding)的快速求解模型,提出了一种新的KGE/CCA算法(KGE/CCA-S_t)。首先将样本数据投影到维数远低于原样本空间维数的总体散...针对高维小样本数据在核化图嵌入过程中出现的复杂度问题,引入基于核化图嵌入(kernel extension of graph embedding)的快速求解模型,提出了一种新的KGE/CCA算法(KGE/CCA-S_t)。首先将样本数据投影到维数远低于原样本空间维数的总体散度矩阵对应的秩空间,然后采用核典型相关分析进行特征提取,整个过程减少了核矩阵的计算量。在Yale人脸库和JAFFE人脸库上进行仿真实验,结果表明这种KGE/CCA算法的识别率明显优于KFD、KLPP和KNPE算法的识别率;和传统的KGE/CCA算法相比,在不影响识别率的情况下,KGE/CCA-S_t算法有效减少了计算时间。展开更多
文摘The clustering of objects(individuals or variables)is one of the most used approaches to exploring multivariate data.The two most common unsupervised clustering strategies are hierarchical ascending clustering(HAC)and k-means partitioning used to identify groups of similar objects in a dataset to divide it into homogeneous groups.The proposed topological clustering of variables,called TCV,studies an homogeneous set of variables defined on the same set of individuals,based on the notion of neighborhood graphs,some of these variables are more-or-less correlated or linked according to the type quantitative or qualitative of the variables.This topological data analysis approach can then be useful for dimension reduction and variable selection.It’s a topological hierarchical clustering analysis of a set of variables which can be quantitative,qualitative or a mixture of both.It arranges variables into homogeneous groups according to their correlations or associations studied in a topological context of principal component analysis(PCA)or multiple correspondence analysis(MCA).The proposed TCV is adapted to the type of data considered,its principle is presented and illustrated using simple real datasets with quantitative,qualitative and mixed variables.The results of these illustrative examples are compared to those of other variables clustering approaches.
文摘针对高维小样本数据在核化图嵌入过程中出现的复杂度问题,引入基于核化图嵌入(kernel extension of graph embedding)的快速求解模型,提出了一种新的KGE/CCA算法(KGE/CCA-S_t)。首先将样本数据投影到维数远低于原样本空间维数的总体散度矩阵对应的秩空间,然后采用核典型相关分析进行特征提取,整个过程减少了核矩阵的计算量。在Yale人脸库和JAFFE人脸库上进行仿真实验,结果表明这种KGE/CCA算法的识别率明显优于KFD、KLPP和KNPE算法的识别率;和传统的KGE/CCA算法相比,在不影响识别率的情况下,KGE/CCA-S_t算法有效减少了计算时间。
