The TFC Model: Tensor Factorization and Tag Clustering for Item Recommendation in Social Tagging Systems
In this paper, a novel Tensor Factorization and tag Clustering (TFC) model is presented for item recommendation in social tagging systems. The TFC model consists of three distinctive steps, in each of which important innovative elements are proposed. More specifically, through its first step, the content information is exploited to propagate tags between conceptual similar items based on a relevance feedback mechanism, in order to solve sparsity and “cold start” problems. Through its second step, sparsity is further handled, by generating tag clusters and revealing topics, following an innovative tf idf weighting scheme. Furthermore, we experimentally prove that a few number of expert tags can improve the performance of quality recommendations, since they contribute to more coherent tag clusters. Through its third step, the latent associations among users, topics and items are revealed by exploiting the Tensor Factorization technique of High Order Singular Value Decomposition (HOSVD). This way the proposed TFC model tackles problems of real world applications, which produce noise and decrease the quality of recommendations. In our experiments with real world social data, we show that the proposed TFC model outperforms other state-of-the-art methods, which also exploit the Tensor Factorization technique of HOSVD.