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arXiv 2209.06975stat.MLcs.LG
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Wasserstein $K$ -均值聚类概率分布

Wasserstein $K$-means for clustering probability distributions

University of Illinois at Urbana-Champaign(伊利诺伊大学厄巴纳-香槟分校)

Yubo Zhuang, Xiaohui Chen, Yun Yang

摘要:

聚类是一种重要的探索性数据分析技术,它根据对象的相似性对对象进行分组。广泛使用的$K$均值聚类方法依赖于距离的概念,将数据划分为较少数量的组。在欧几里得空间中,基于质心和基于距离的$K$均值公式是等价的。在现代机器学习应用中,数据通常以概率分布的形式出现,处理度量值数据的自然概括是使用最佳传输度量。由于Wasserstein空间的非负Alexandrov曲率,重心遭受正则性和非鲁棒性问题。Wasserstein重心的特殊行为可能使基于质心的公式无法表示聚类内的数据点,而更直接的基于距离的$K$ -均值方法及其半定规划(SDP)松弛能够恢复真实的聚类标签。在聚类高斯分布的特殊情况下,我们表明,SDP放松Wasserstein $K$ -手段,可以实现精确的恢复给定的集群下分离的$2$ -Wasserstein度量。我们的模拟和真实数据的例子也表明,基于距离的$K$ -手段,可以实现更好的分类性能比标准的基于质心的$K$ -手段聚类概率分布和图像。

英文摘要:

Clustering is an important exploratory data analysis technique to group objects based on their similarity. The widely used $K$-means clustering method relies on some notion of distance to partition data into a fewer number of groups. In the Euclidean space, centroid-based and distance-based formulations of the $K$-means are equivalent. In modern machine learning applications, data often arise as probability distributions and a natural generalization to handle measure-valued data is to use the optimal transport metric. Due to non-negative Alexandrov curvature of the Wasserstein space, barycenters suffer from regularity and non-robustness issues. The peculiar behaviors of Wasserstein barycenters may make the centroid-based formulation fail to represent the within-cluster data points, while the more direct distance-based $K$-means approach and its semidefinite program (SDP) relaxation are capable of recovering the true cluster labels. In the special case of clustering Gaussian distributions, we show that the SDP relaxed Wasserstein $K$-means can achieve exact recovery given the clusters are well-separated under the $2$-Wasserstein metric. Our simulation and real data examples also demonstrate that distance-based $K$-means can achieve better classification performance over the standard centroid-based $K$-means for clustering probability distributions and images.

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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