arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2603.29232cs.CLcs.AIcs.LG
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长文档问答与结构化思维链及微调大语言模型

Long-Document QA with Chain-of-Structured-Thought and Fine-Tuned SLMs

The Hong Kong University of Science and Technology (Guangzhou)(香港科技大学(广州));EvenUp, USA(美国EvenUp公司)

Zhuowen Liang, Xiaotian Lin, Zhengxuan Zhang, Yuyu Luo, Haixun Wang, Nan Tang

AI总结:

本文提出LiteCoST框架,通过结构化思维链和微调小语言模型,实现高精度低延迟的长文档问答,采用双支柱方法提升准确性和效率。

摘要:

大型语言模型(LLMs)广泛应用于文档数据分析,但直接处理长且嘈杂的文档仍显得脆弱且易出错。因此,我们研究了文档问答(QA)问题,旨在将分散的证据整合为结构化输出(如表格、图表或片段)以支持可靠且可验证的问答。我们提出了一种双支柱框架LiteCoST,通过小语言模型(SLMs)实现高精度和低延迟。支柱1:结构化思维链(CoST)。我们引入了CoST模板,一种具有意识的指令,引导强LLM生成逐步的CoST轨迹和相应的结构化输出。该过程诱导了最小结构,规范化实体/单位,对齐记录,序列化输出,并验证/细化它,产生可审计的监督。支柱2:SLM微调。紧凑模型在LLM生成的CoST数据上进行两阶段训练:监督微调用于结构对齐,随后是组相对策略优化(GRPO),结合三重奖励用于答案/格式质量和过程一致性。通过将结构优先行为蒸馏到SLMs中,这种方法在多领域长文档问答中实现了与LLM相当的质量,使用3B/7B SLMs,同时比GPT-4o和DeepSeek-R1(671B)低2-4倍的延迟。代码可在https://github.com/HKUSTDial/LiteCoST上获得。

英文摘要:

Large language models (LLMs) are widely applied to data analytics over documents, yet direct reasoning over long, noisy documents remains brittle and error-prone. Hence, we study document question answering (QA) that consolidates dispersed evidence into a structured output (e.g., a table, graph, or chunks) to support reliable, verifiable QA. We propose a two-pillar framework, LiteCoST, to achieve both high accuracy and low latency with small language models (SLMs). Pillar 1: Chain-of-Structured-Thought (CoST). We introduce a CoST template, a schema-aware instruction that guides a strong LLM to produce both a step-wise CoST trace and the corresponding structured output. The process induces a minimal structure, normalizes entities/units, aligns records, serializes the output, and verifies/refines it, yielding auditable supervision. Pillar 2: SLM fine-tuning. The compact models are trained on LLM-generated CoST data in two stages: Supervised Fine-Tuning for structural alignment, followed by Group Relative Policy Optimization (GRPO) incorporating triple rewards for answer/format quality and process consistency. By distilling structure-first behavior into SLMs, this approach achieves LLM-comparable quality on multi-domain long-document QA using 3B/7B SLMs, while delivering 2-4x lower latency than GPT-4o and DeepSeek-R1 (671B). The code is available at https://github.com/HKUSTDial/LiteCoST.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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