Traceable Cross-Source RAG for Chinese Tibetan Medicine Question Answering
Fengxian Chen, Zhilong Tao, Jiaxuan Li, Yunlong Li, Qingguo Zhou
TL;DR
The paper tackles the challenge of grounded question answering for Chinese Tibetan medicine across partitioned, heterogeneous knowledge bases (encyclopedia, classics, clinical papers) where density bias and provenance are critical. It introduces two complementary components: DAKS routing with budgeted retrieval to balance source authority and reduce density-driven bias, and an alignment-graph guided fusion approach to improve cross-KB verification and evidence packing under a token budget. The authors formalize the problem, define metrics including CrossEv@5, and evaluate on a 500-query TM QA benchmark using a lightweight generator, reporting improvements in routing quality and cross-KB evidence coverage while maintaining faithfulness and citation correctness. The results demonstrate that the full system achieves the best end-to-end cross-KB evidence coverage, offering a practical path toward deployable, traceable TM QA systems.
Abstract
Retrieval-augmented generation (RAG) promises grounded question answering, yet domain settings with multiple heterogeneous knowledge bases (KBs) remain challenging. In Chinese Tibetan medicine, encyclopedia entries are often dense and easy to match, which can dominate retrieval even when classics or clinical papers provide more authoritative evidence. We study a practical setting with three KBs (encyclopedia, classics, and clinical papers) and a 500-query benchmark (cutoff $K{=}5$) covering both single-KB and cross-KB questions. We propose two complementary methods to improve traceability, reduce hallucinations, and enable cross-KB verification. First, DAKS performs KB routing and budgeted retrieval to mitigate density-driven bias and to prioritize authoritative sources when appropriate. Second, we use an alignment graph to guide evidence fusion and coverage-aware packing, improving cross-KB evidence coverage without relying on naive concatenation. All answers are generated by a lightweight generator, \textsc{openPangu-Embedded-7B}. Experiments show consistent gains in routing quality and cross-KB evidence coverage, with the full system achieving the best CrossEv@5 while maintaining strong faithfulness and citation correctness.
