Curriculum Pre-Training Heterogeneous Subgraph Transformer for Top-$N$ Recommendation
This work addresses the problem of improving recommendation accuracy in systems with complex, heterogeneous data, representing an incremental advancement in HIN-based recommendation methods.
The paper tackles the challenge of effectively leveraging heterogeneous information networks (HINs) for top-N recommendation by proposing CHEST, a curriculum pre-training heterogeneous subgraph transformer, which achieves superior performance over competitive baselines, especially with limited training data.
Due to the flexibility in modelling data heterogeneity, heterogeneous information network (HIN) has been adopted to characterize complex and heterogeneous auxiliary data in top-$N$ recommender systems, called \emph{HIN-based recommendation}. HIN characterizes complex, heterogeneous data relations, containing a variety of information that may not be related to the recommendation task. Therefore, it is challenging to effectively leverage useful information from HINs for improving the recommendation performance. To address the above issue, we propose a Curriculum pre-training based HEterogeneous Subgraph Transformer (called \emph{CHEST}) with new \emph{data characterization}, \emph{representation model} and \emph{learning algorithm}. Specifically, we consider extracting useful information from HIN to compose the interaction-specific heterogeneous subgraph, containing both sufficient and relevant context information for recommendation. Then we capture the rich semantics (\eg graph structure and path semantics) within the subgraph via a heterogeneous subgraph Transformer, where we encode the subgraph with multi-slot sequence representations. Besides, we design a curriculum pre-training strategy to provide an elementary-to-advanced learning process, by which we smoothly transfer basic semantics in HIN for modeling user-item interaction relation. Extensive experiments conducted on three real-world datasets demonstrate the superiority of our proposed method over a number of competitive baselines, especially when only limited training data is available.