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arXiv 1209.3056cs.LG
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参数局部度量学习的最近邻分类算法

Parametric Local Metric Learning for Nearest Neighbor Classification

University of Geneva(日内瓦大学)

Jun Wang, Adam Woznica, Alexandros Kalousis

摘要:

我们研究了最近邻分类的局部度量学习问题。大多数以前的作品在本地度量学习学习一些本地无关的指标。虽然这种“独立”方法提供了更大的灵活性,但其缺点是过度拟合的风险相当大。我们提出了一种新的参数局部度量学习方法,在该方法中,我们学习数据流形上的光滑度量矩阵函数。使用度量矩阵函数的近似误差界,我们学习局部度量作为实例空间不同区域上的锚点上定义的基本度量的线性组合。我们通过对线性组合流形进行正则化来约束度量矩阵函数,使学习到的度量矩阵函数沿着数据流形的测地线平滑地变化。我们的度量学习方法在预测能力和可扩展性方面都具有出色的性能。我们实验了几个大规模的分类问题,数万个实例,并将其与几种最先进的度量学习方法进行了比较,包括全局和局部,以及具有自动内核选择的SVM,所有这些都以显着的方式优于。

英文摘要:

We study the problem of learning local metrics for nearest neighbor classification. Most previous works on local metric learning learn a number of local unrelated metrics. While this "independence" approach delivers an increased flexibility its downside is the considerable risk of overfitting. We present a new parametric local metric learning method in which we learn a smooth metric matrix function over the data manifold. Using an approximation error bound of the metric matrix function we learn local metrics as linear combinations of basis metrics defined on anchor points over different regions of the instance space. We constrain the metric matrix function by imposing on the linear combinations manifold regularization which makes the learned metric matrix function vary smoothly along the geodesics of the data manifold. Our metric learning method has excellent performance both in terms of predictive power and scalability. We experimented with several large-scale classification problems, tens of thousands of instances, and compared it with several state of the art metric learning methods, both global and local, as well as to SVM with automatic kernel selection, all of which it outperforms in a significant manner.

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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