面向组件的软件测试技术

使用组件,特别是第三方商业组件集成开发而成的软件越来越多,面向组件的测试技术的需求越来越大。UML是目前软件开发业应用最广泛的可视化标准建模语言,它能应用于整个软件开发过程的各阶段。UML的许多特点与面向组件的软件测试需求相吻合。基于UML的软件测试技术在对面向组件的软件开发具有广阔的研究和应用前景。     

Canonical Analysis: Ranks,Ratios and Fits

Measurements of p variables for n samples are collected into a n×p matrix X, where the samples belong to one of k groups. The group means are separated by Mahalanobis distances. CVA optimally represents the group means of X in an r-dimensional space. This can be done by maximizing a ratio criterion (basically one- dimensional) or, more flexibly, by minimizing a rank-constrained least-squares fitting criterion (which is not confined to being one-dimensional but depends on defining an appropriate Mahalanobis metric). In modern n < p problems, where W is not of full rank, the ratio criterion is shown not to be coherent but the fit criterion, with an attention to associated metrics, readily generalizes. In this context we give a unified generalization of CVA, introducing two metrics, one in the range space of W and the other in the null space of W, that have links with Mahalanobis distance. This generalization is computationally efficient, since it requires only the spectral decomposition of a n×n matrix.