From neighbors to global neighbors in collaborative filtering: an evolutionary optimization approach

  • Authors:
  • Amine Boumaza;Armelle Brun

  • Affiliations:
  • University Lille Nord de France, Calais, France;Université de Lorraine, Nancy, France

  • Venue:
  • Proceedings of the 14th annual conference on Genetic and evolutionary computation
  • Year:
  • 2012

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Abstract

The accuracy of recommendations of collaborative filtering based recommender systems mainly depends on which users (the neighbors) are exploited to estimate a user's ratings. We propose a new approach of neighbor selection, which adopts a global point of view. This approach defines a unique set of possible neighbors, shared by all users, referred to as Global Neighbors (GN). We view the problem of defining GN as a combinatorial optimization problem and propose to use an evolutionary algorithm to tackle this search. Our aim is to find a relatively small GN as the size of the resulting model, as well as the complexity of the computation of recommendations highly depend on the size of GN. We present experiments and results on a standard benchmark data-set from the recommender system community that support our choice of the evolutionary approach and show that it leads to a high accuracy of recommendations and a high coverage, while dramatically reducing the size of the model (by 84%). We also show that the evolutionary approach produces results able to generate accurate recommendations to unseen users, while easily allowing the insertion of new users in the system with little overhead.