arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1104.4422stat.COmath.CA
收藏

多元Watson分布:极大似然估计及其它

The Multivariate Watson Distribution: Maximum-Likelihood Estimation and other Aspects

Suvrit Sra, Dmitrii Karp

摘要:

本文研究了使用多变量沃森分布建模数据的基本方面。虽然这些分布对于建模轴对称数据是自然的(即,单位向量,其中$\pm \x$是等价的),对于高维使用它们可能是困难的。为什么会这样呢?很大程度上是因为对于沃森分布,即使是最大似然等基本任务也具有数值挑战性。为了解决数值上的困难,一些近似已经得到-但这些要么是严重不准确的高维(\emph{Directional Statistics},Mardia & Pennerp。2000)或合理准确时(\emph{J. Machine Learning Research, W. & C.P., v2},Bijral \emph{et al.},2007,pp. #35742;,缺乏理论依据。我们推导出新的近似的最大似然估计,我们的近似理论上定义良好,数值上准确,易于计算。我们建立在我们的参数估计和讨论混合模型与沃森分布;在这里,我们发现了一个迄今未知的连接到“直径聚类”算法的Dhillon \emph{et al.}(\emph{Bioinformatics},19(13),2003年,第19页)。1612- 1619)。

英文摘要:

This paper studies fundamental aspects of modelling data using multivariate Watson distributions. Although these distributions are natural for modelling axially symmetric data (i.e., unit vectors where $\pm \x$ are equivalent), for high-dimensions using them can be difficult. Why so? Largely because for Watson distributions even basic tasks such as maximum-likelihood are numerically challenging. To tackle the numerical difficulties some approximations have been derived---but these are either grossly inaccurate in high-dimensions (\emph{Directional Statistics}, Mardia & Jupp. 2000) or when reasonably accurate (\emph{J. Machine Learning Research, W. & C.P., v2}, Bijral \emph{et al.}, 2007, pp. 35--42), they lack theoretical justification. We derive new approximations to the maximum-likelihood estimates; our approximations are theoretically well-defined, numerically accurate, and easy to compute. We build on our parameter estimation and discuss mixture-modelling with Watson distributions; here we uncover a hitherto unknown connection to the "diametrical clustering" algorithm of Dhillon \emph{et al.} (\emph{Bioinformatics}, 19(13), 2003, pp. 1612--1619).

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。

↑