Title
Proximal maximum margin matrix factorization for collaborative filtering.
Abstract
We propose an alternative and new MMMF scheme for discrete-valued rating matrix.Our work draws motivation of recent advent of proximal support vector machines.The propose method overcomes the problem of overtting.We validate our hypothesis by conducting experiments on real and synthetic datasets. Maximum Margin Matrix Factorization (MMMF) has been a successful learning method in collaborative filtering research. For a partially observed ordinal rating matrix, the focus is on determining low-norm latent factor matrices U (of users) and V (of items) so as to simultaneously approximate the observed entries under some loss measure and predict the unobserved entries. When the rating matrix contains only two levels (1), rows of V can be viewed as points in k-dimensional space and rows of U as decision hyperplanes in this space separating +1 entries from 1 entries. The concept of optimizing a loss function to determine the separating hyperplane is prevalent in support vector machines (SVM) research and when hinge/smooth hinge loss is used, the hyperplanes act as a maximum-margin separator. In MMMF, a rating matrix with multiple discrete values is treated by specially extending hinge loss function to suit multiple levels. MMMF is an efficient technique for collaborative filtering but it has several shortcomings. A prominent shortcoming is an overfitting problem wherein if learning iteration is prolonged to decrease the training error the generalization error grows. In this paper, we propose an alternative and new maximum margin factorization scheme for discrete-valued rating matrix to overcome the problem of overfitting. Our work draws motivation from a recent work on proximal support vector machines (PSVMs) wherein two parallel hyperplanes are used for binary classification and points are classified by assigning them to the class corresponding to the closest of two parallel hyperplanes. In other words, proximity to decision hyperplane is used as the classifying criterion. We show that a similar concept can be used to factorize the rating matrix if the loss function is suitably defined. The present scheme of matrix factorization has advantages over MMMF (similar to the advantages of PSVM over standard SVM). We validate our hypothesis by carrying out experiments on real and synthetic datasets.
Year
DOI
Venue
2017
10.1016/j.patrec.2016.12.016
Pattern Recognition Letters
Keywords
Field
DocType
Collaborative filtering,Matrix completion,Matrix factorization
Hinge loss,Matrix completion,Pattern recognition,Matrix (mathematics),Matrix decomposition,Support vector machine,Factorization,Artificial intelligence,Hyperplane,Overfitting,Mathematics
Journal
Volume
Issue
ISSN
86
C
0167-8655
Citations 
PageRank 
References 
3
0.40
18
Authors
5
Name
Order
Citations
PageRank
Vikas Kumar 00031254.76
Arun K. Pujari242048.20
Sandeep Kumar Sahu3192.63
Venkateswara Rao Kagita4598.13
Vineet Padmanabhan521625.90