HeteroGraphRec: A heterogeneous graph-based neural networks for social recommendations

Abstract Recommender systems in social networks are widely used for connecting users to their desired items from a vast catalog of available items. Learning the user’s preferences from all the possible sources of information in an extensive, multi- dimensional social network is one of the main challenges when building such recommenders. Graph Neural Networks have been gaining momentum in recent years and have been successful when dealing with large-scale graphs, and they can be applied to social networks with some modifications. In this research, we propose the HeteroGraphRec, which provides social recommendations by modeling the social network as a heterogeneous graph and utilizing GNNs with attention mechanisms to intelligently aggregate information from all sources when building the connections between user to user, item to item, and user to item. The HeteroGraphRec can gather information about the user’s connections (friendships, trust network), item interaction history, and item similarities to at- tain rich information about the preferences. To evaluate the HeteroGraphRec, we use three real-world benchmark datasets and demonstrate that the pro- posed HeteroGraphRec achieves superior performance compared to ten other state-of-the-art social recommender systems. We extensively analyze the HeteroGraphRec model to illustrate the effectiveness by changing the embedding dimensions of the users and items. We also show the interpretability of our model by examining each component of the model’s contribution. The results show that the HeteroGraphRec is robust and can consistently perform better than the baseline systems.