Hierarchical context enhancement for long-tail entity retrieval augmented generation

IntroductionRetrieval-Augmented Generation (RAG) in Domain-specific Question Answering (DSQA) often faces significant performance degradation due to semantic drift. Our analysis reveals that the main cause is the absence of a dedicated mechanism for handling low-frequency terms.MethodsMotivated by this observation, we propose a hierarchical context enhancement retrieval augmented generation (HCE-RAG). Specifically, in the indexing stage, we anchor low-frequency entities offline through entity-se