An Effective Two-way Metapath Encoder over Heterogeneous Information Network for Recommendation

Heterogeneous information networks (HINs) are widely used in recommender system research due to their ability to model complex auxiliary information beyond historical interactions to alleviate data sparsity problem. Existing HIN-based recommendation studies have achieved great success via performing graph convolution operators between pairs of nodes on predefined metapath induced graphs, but they have the following major limitations. First, existing heterogeneous network construction strategies tend to exploit item attributes while failing to effectively model user relations. In addition, previous HIN-based recommendation models mainly convert heterogeneous graph into homogeneous graphs by defining metapaths ignoring the complicated relation dependency involved on the metapath. To tackle these limitations, we propose a novel recommendation model with two-way metapath encoder for top-N recommendation, which models metapath similarity and sequence relation dependency in HIN to learn node representations. Specifically, our model first learns the initial node representation through a pre-training module, and then identifies potential friends and item relations based on their similarity to construct a unified HIN. We then develop the two-way encoder module with similarity encoder and instance encoder to capture the similarity collaborative signals and relational dependency on different metapaths. Finally, the representations on different meta-paths are aggregated through the attention fusion layer to yield rich representations. Extensive experiments on three real datasets demonstrate the effectiveness of our method.