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arXiv 1902.03291math.STstat.MEstat.TH
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高维空间中基于距离和RKHS的依赖关系建模

Distance-based and RKHS-based Dependence Metrics in High Dimension

Changbo Zhu, Shun Yao, Xianyang Zhang, Xiaofeng Shao

摘要:

在本文中,我们研究了距离协方差,希尔伯特-施密特协方差(又名希尔伯特-施密特独立性标准[Gretton et al.(2008)])和相关的独立性测试在高维场景下。我们证明了两个随机向量之间的样本距离/Hilbert-Schmidt协方差可以近似为分量方向样本互协方差的平方和,直到一个渐近常数因子,这表明基于距离/Hilbert-Schmidt协方差的检验只能捕获高维线性相关。因此,当两个随机向量非线性相关但分量不相关时,Szekely和Rizzo(2013)开发的基于距离相关的独立性t检验具有平凡的限制能力。这种新的和令人惊讶的现象,这似乎是第一次发现,在我们的模拟研究中得到进一步证实。作为一种补救措施,我们提出了测试的基础上聚集的边际样本距离/希尔伯特-施密特协方差,并显示其优越的权力行为对他们的联合同行在模拟中。我们进一步将基于距离相关的t检验扩展到基于希尔伯特-施密特协方差和边缘距离/希尔伯特-施密特协方差的t检验。提出了一种新的统一的方法来分析零假设和备择假设下的学生化样本距离/Hilbert-Schmidt协方差以及学生化样本边缘距离协方差。我们的理论和模拟结果揭示了距离/希尔伯特-施密特协方差的限制时,联合使用的高维设置,并建议聚合的边缘距离/希尔伯特-施密特协方差作为一个有用的替代。

英文摘要:

In this paper, we study distance covariance, Hilbert-Schmidt covariance (aka Hilbert-Schmidt independence criterion [Gretton et al. (2008)]) and related independence tests under the high dimensional scenario. We show that the sample distance/Hilbert-Schmidt covariance between two random vectors can be approximated by the sum of squared componentwise sample cross-covariances up to an asymptotically constant factor, which indicates that the distance/Hilbert-Schmidt covariance based test can only capture linear dependence in high dimension. As a consequence, the distance correlation based t-test developed by Szekely and Rizzo (2013) for independence is shown to have trivial limiting power when the two random vectors are nonlinearly dependent but component-wisely uncorrelated. This new and surprising phenomenon, which seems to be discovered for the first time, is further confirmed in our simulation study. As a remedy, we propose tests based on an aggregation of marginal sample distance/Hilbert-Schmidt covariances and show their superior power behavior against their joint counterparts in simulations. We further extend the distance correlation based t-test to those based on Hilbert-Schmidt covariance and marginal distance/Hilbert-Schmidt covariance. A novel unified approach is developed to analyze the studentized sample distance/Hilbert-Schmidt covariance as well as the studentized sample marginal distance covariance under both null and alternative hypothesis. Our theoretical and simulation results shed light on the limitation of distance/Hilbert-Schmidt covariance when used jointly in the high dimensional setting and suggest the aggregation of marginal distance/Hilbert-Schmidt covariance as a useful alternative.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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