JCSE, vol. 7, no. 1, pp.21-29, March, 2013

DOI: http://dx.doi.org/10.5626/JCSE.2013.7.1.21

Using Experts Among Users for Novel Movie Recommendations

Kibeom Lee, Kyogu Lee
Department of Transdisciplinary Studies, Seoul National University, Seoul, Korea

Abstract: The introduction of recommender systems to existing online services is now practically inevitable, with the increasing number of items and users on online services. Popular recommender systems have successfully implemented satisfactory systems, which are usually based on collaborative filtering. However, collaborative filtering-based recommenders suffer from well-known problems, such as popularity bias, and the cold-start problem. In this paper, we propose an innovative collaborative-filtering based recommender system, which uses the concepts of Experts and Novices to create finegrained recommendations that focus on being novel, while being kept relevant. Experts and Novices are defined using pre-made clusters of similar items, and the distribution of users??ratings among these clusters. Thus, in order to generate recommendations, the experts are found dynamically depending on the seed items of the novice. The proposed recommender system was built using the MovieLens 1 M dataset, and evaluated with novelty metrics. Results show that the proposed system outperforms matrix factorization methods according to discovery-based novelty metrics, and can be a solution to popularity bias and the cold-start problem, while still re

Keyword: Recommender systems; Collaborative filtering; Experts

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