SPCF: a stepwise partitioning for collaborative filtering to alleviate sparsity problems

  • Authors:
  • Elham Hoseini;Sattar Hashemi;Ali Hamzeh

  • Affiliations:
  • ;;

  • Venue:
  • Journal of Information Science
  • Year:
  • 2012

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Abstract

Collaborative filtering is a widely used approach in recommendation systems which predict user preferences by learning from user-item ratings. To extract either user relationship or item dependencies, there exist several well known approaches; among them clustering is of great importance. Traditional clustering methods in collaborative filtering usually suffer from two fundamental problems: sparsity and scalability. Sparsity refers to a situation where most users rate only a small number of items, while scalability denotes a huge number of both users and items. Inspired by these problems, this paper presents a novel stepwise paradigm, SPCF, which in the first step clusters users and items separately using their latent similarity. Once the primary clusters of the first level are formed, the second level simultaneously clusters the user and item clusters by means of co-clustering. The advantages of SPCF are threefold; first, it is able to alleviate the well known sparsity problem which intrinsically exists in collaborative filtering; second, the proposed method offers an elegant solution to the scalability problem based on dimensionality reduction which in turn leads to better performance of the model; third, experimental results on two versions of a Movielens dataset for prediction have demonstrated that the proposed method can reveal major interests of users or items in promising manner.