Title
Orthogonality-Promoting Distance Metric Learning: Convex Relaxation and Theoretical Analysis.
Abstract
Distance metric learning (DML), which learns a distance metric from labeled similar and dissimilar data pairs, is widely utilized. Recently, several works investigate orthogonality-promoting regularization (OPR), which encourages the projection vectors in DML to be close to being orthogonal, to achieve three effects: (1) high balancedness -- achieving comparable performance on both frequent and infrequent classes; (2) high compactness -- using a small number of projection vectors to achieve a metric; (3) good generalizability -- alleviating overfitting to training data. While showing promising results, these approaches suffer three problems. First, they involve solving non-convex optimization problems where achieving the global optimal is NP-hard. Second, it lacks a theoretical understanding why OPR can lead to balancedness. Third, the current generalization error analysis of OPR is not directly on the regularizer. In this paper, we address these three issues by (1) seeking convex relaxations of the original nonconvex problems so that the global optimal is guaranteed to be achievable; (2) providing a formal analysis on OPRu0027s capability of promoting balancedness; (3) providing a theoretical analysis that directly reveals the relationship between OPR and generalization performance. Experiments on various datasets demonstrate that our convex methods are more effective in promoting balancedness, compactness, and generalization, and are computationally more efficient, compared with the nonconvex methods.
Year
Venue
DocType
2018
ICML
Conference
Volume
Citations 
PageRank 
abs/1802.06014
1
0.35
References 
Authors
26
4
Name
Order
Citations
PageRank
Pengtao Xie133922.63
Wei Wu2868.96
Yichen Zhu310.69
Bo Xing47332471.43