NUST Nova at RIRAG 2025: A Hybrid Framework for Regulatory Information Retrieval and Question Answering

Mariam Babar Khan, Huma Ameer, Seemab Latif, Mehwish Fatima


Abstract
NUST Nova participates in RIRAG Shared Task, addressing two critical challenges: Task 1 involves retrieving relevant subsections from regulatory documents based on user queries, while Task 2 focuses on generating concise, contextually accurate answers using the retrieved information. We propose a Hybrid Retrieval Framework that combines graph-based retrieval, vector-based methods, and keyword matching BM25 to enhance relevance and precision in regulatory QA. Using score-based fusion and iterative refinement, the framework retrieves the top 10 relevant passages, which are then used by an LLM to generate accurate, context-aware answers. After empirical evaluation, we also conduct an error analysis to identify our framework’s limitations.
Anthology ID:
2025.regnlp-1.11
Volume:
Proceedings of the 1st Regulatory NLP Workshop (RegNLP 2025)
Month:
January
Year:
2025
Address:
Abu Dhabi, UAE
Editors:
Tuba Gokhan, Kexin Wang, Iryna Gurevych, Ted Briscoe
Venues:
RegNLP | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
73–78
Language:
URL:
https://aclanthology.org/2025.regnlp-1.11/
DOI:
Bibkey:
Cite (ACL):
Mariam Babar Khan, Huma Ameer, Seemab Latif, and Mehwish Fatima. 2025. NUST Nova at RIRAG 2025: A Hybrid Framework for Regulatory Information Retrieval and Question Answering. In Proceedings of the 1st Regulatory NLP Workshop (RegNLP 2025), pages 73–78, Abu Dhabi, UAE. Association for Computational Linguistics.
Cite (Informal):
NUST Nova at RIRAG 2025: A Hybrid Framework for Regulatory Information Retrieval and Question Answering (Khan et al., RegNLP 2025)
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PDF:
https://aclanthology.org/2025.regnlp-1.11.pdf