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Improving retrieval augmented generation via denoising and reconstruction of knowledge graphs

Dan Yang

DR-NTU (Nanyang Technological University), 2026

Abstract

Retrieval-Augmented Generation (RAG) has greatly enhanced the performance of large language models (LLMs) in terms of knowledge intense area by retrieving relevant knowledge. Recent researches that combine RAG and knowledge graph (KG) is a new approach to utilize the advantages of both RAG and KG, providing structured facts with node descriptions and relationships, allowing LLM to generate more precise, various answers. However, during the extraction, KG may contain excessive nodes and edges, which will mislead the LLM to produce irrelevant answers. This structural noise and redundancy can inadvertently mislead the LLM, potentially degrading the relevance and accuracy of the generated response. To overcome these limitations, we introduce a new method called DenoiseKG, which denoises knowledge graph by post-processing similar nodes, together with relations between them, by refining retrieved KG subgraphs before they are utilized, DenoiseKG focuses specifically on reducing noise by identifying and deduplicating semantically similar nodes and consolidating their associated relations. This denoising process optimizes the overall performance of KG-augmented RAG systems. To address these limitations, we propose DenoiseKG, a post-processing method that denoises knowledge graphs by identifying and merging semantically similar nodes and consolidating their associated relations before use. By refining retrieved KG subgraphs, DenoiseKG effectively reduces noise in KG-augmented RAG…

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