Content-based Graph Reconstruction for Cold-start Item Recommendation

Graph convolutions have been successfully applied to recommendation systems, utilizing high-order collaborative signals present in the user-item interaction graph. This idea, however, has not been applicable to the cold-start items, since cold nodes are isolated in the graph and thus do not take advantage of information exchange from neighboring nodes. Recently, there have been a few attempts to utilize graph convolutions on item-item or user-user attribute graphs to capture high-order collaborative signals for cold-start cases, but these approaches are still limited in that the item-item or user-user graph falls short in capturing the dynamics of user-item interactions, as their edges are constructed based on arbitrary and heuristic attribute similarity. In this paper, we introduce Content-based Graph Reconstruction for Cold-start item recommendation (CGRC), employing a masked graph autoencoder structure and multimodal contents to directly incorporate interaction-based high-order connectivity, applicable even in cold-start scenarios. To address the cold-start items directly on the interaction graph, our approach trains the model to reconstruct plausible user-item interactions from masked edges of randomly chosen cold items, simulating fresh items without connection to users. This strategy enables the model to infer potential edges for unseen cold-start nodes. Extensive experiments on real-world datasets demonstrate the superiority of our model.