An iterative semi-explicit rating method for building collaborative recommender systems

  • Authors:
  • Buhwan Jeong;Jaewook Lee;Hyunbo Cho

  • Affiliations:
  • Data Mining Team, Daum Communications Corp, 1730-8 Odeung, Jeju 690-150, South Korea;Department of Industrial and Management Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja Pohang, Kyungbuk 790-784, South Korea;Department of Industrial and Management Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja Pohang, Kyungbuk 790-784, South Korea

  • Venue:
  • Expert Systems with Applications: An International Journal
  • Year:
  • 2009

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Abstract

Collaborative filtering plays the key role in recent recommender systems. It uses a user-item preference matrix rated either explicitly (i.e., explicit rating) or implicitly (i.e., implicit feedback). Despite the explicit rating captures the preferences better, it often results in a severely sparse matrix. The paper presents a novel iterative semi-explicit rating method that extrapolates unrated elements in a semi-supervised manner. Extrapolation is simply an aggregation of neighbor ratings, and iterative extrapolations result in a dense preference matrix. Preliminary simulation results show that the recommendation using the semi-explicit rating data outperforms that of using the pure explicit data only.