KG-CQR: Leveraging Structured Relation Representations in Knowledge Graphs for Contextual Query Retrieval

Chi Minh Bui, Ngoc Mai Thieu, Vinh Van Nguyen, Jason J. Jung, Khac-Hoai Nam Bui


Abstract
The integration of knowledge graphs (KGs) with large language models (LLMs) offers significant potential to enhance the retrieval stage in retrieval-augmented generation (RAG) systems. In this study, we propose KG-CQR, a novel framework for Contextual Query Retrieval (CQR) that enhances the retrieval phase by enriching complex input queries with contextual representations derived from a corpus-centric KG. Unlike existing methods that primarily address corpus-level context loss, KG-CQR focuses on query enrichment through structured relation representations, extracting and completing relevant KG subgraphs to generate semantically rich query contexts. Comprising subgraph extraction, completion, and contextual generation modules, KG-CQR operates as a model-agnostic pipeline, ensuring scalability across LLMs of varying sizes without additional training. Experimental results on the RAGBench and MultiHop-RAG datasets demonstrate that KG-CQR outperforms strong baselines, achieving improvements of up to 4–6% in mAP and approximately 2–3% in Recall@25. Furthermore, evaluations on challenging RAG tasks such as multi-hop question answering show that, by incorporating KG-CQR, the performance outperforms the existing baseline in terms of retrieval effectiveness.
Anthology ID:
2025.emnlp-main.824
Volume:
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Christos Christodoulopoulos, Tanmoy Chakraborty, Carolyn Rose, Violet Peng
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EMNLP
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Publisher:
Association for Computational Linguistics
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Pages:
16292–16309
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https://preview.aclanthology.org/ingest-emnlp/2025.emnlp-main.824/
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Cite (ACL):
Chi Minh Bui, Ngoc Mai Thieu, Vinh Van Nguyen, Jason J. Jung, and Khac-Hoai Nam Bui. 2025. KG-CQR: Leveraging Structured Relation Representations in Knowledge Graphs for Contextual Query Retrieval. In Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing, pages 16292–16309, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
KG-CQR: Leveraging Structured Relation Representations in Knowledge Graphs for Contextual Query Retrieval (Bui et al., EMNLP 2025)
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