用关键概念筛选文档,大幅降低知识图谱构建成本。
Graph-Guided Concept Selection for Efficient Retrieval-Augmented Generation
- 基于重要概念筛选文档块,减少LLM调用次数
- 在降低90%以上构建成本下保持检索效果
- 适合需高效知识增强的医疗、法律等专业领域
基于图的检索增强生成(RAG)通过从文本块构建知识图谱(KG)来提升大语言模型(LLM)问答中的检索效果,尤其适用于生物医学、法律和政治科学等需多跳推理的领域。然而,此类方法需大量LLM调用从文本块中提取实体与关系,规模化时成本过高。通过细致的消融实验,我们发现某些词语(称为概念)及其关联文档更为关键。据此提出图引导的概念选择方法(G2ConS),核心包括:一种不依赖LLM的文档块选择机制,用于降低知识图谱构建成本;以及一个无需额外调用的独立概念图,用于填补因块筛选导致的知识空白。在多个真实数据集上的评估表明,G2ConS在构建成本、检索有效性和回答质量上均优于所有基线方法。
原文摘要 · Abstract (English)
Graph-based RAG constructs a knowledge graph (KG) from text chunks to enhance retrieval in Large Language Model (LLM)-based question answering. It is especially beneficial in domains such as biomedicine, law, and political science, where effective retrieval often involves multi-hop reasoning over proprietary documents. However, these methods demand numerous LLM calls to extract entities and relations from text chunks, incurring prohibitive costs at scale. Through a carefully designed ablation study, we observe that certain words (termed concepts) and their associated documents are more important. Based on this insight, we propose Graph-Guided Concept Selection (G2ConS). Its core comprises a chunk selection method and an LLM-independent concept graph. The former selects salient document chunks to reduce KG construction costs; the latter closes knowledge gaps introduced by chunk selection at zero cost. Evaluations on multiple real-world datasets show that G2ConS outperforms all baselines in construction cost, retrieval effectiveness, and answering quality.
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