Modeling Trust and Distrust Information in Recommender Systems via Joint Matrix Factorization with Signed Graphs

We propose an efficient recommendation algorithm, by incorporating the side information of users' trust and distrust social relationships into the learning process of a Joint Non-negative Matrix Factorization technique based on Signed Graphs, namely JNMF-SG. The key idea in this study is to generate clusters based on signed graphs, considering positive and negative weights for the trust and distrust relationships, respectively. Using a spectral clustering approach for signed graphs, the clusters are extracted on condition that users with positive connections should lie close, while users with negative ones should lie far. Then, we propose a Joint Non-negative Matrix factorization framework, by generating the final recommendations, using the user-item and user-cluster associations over the joint factorization. In our experiments with a dataset from a real-world social media platform, we show that we significantly increase the recommendation accuracy, compared to state-of-the-art methods that also consider the trust and distrust side information in matrix factorization.