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arXiv 2405.00611cs.CL
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解决大语言模型在主题建模中的主题粒度与幻觉问题

Addressing Topic Granularity and Hallucination in Large Language Models for Topic Modelling

The University of Sheffield(谢菲尔德大学)

Yida Mu, Peizhen Bai, Kalina Bontcheva, Xingyi Song

AI总结:

本文针对 LLM 主题建模中的主题粒度不一致和幻觉问题,提出利用直接偏好优化(DPO)结合重建流水线微调 Mistral-7B 等开源模型,在不依赖人工标注的情况下显著提升主题质量并减少幻觉主题。

摘要:

大语言模型(LLMs)凭借其强大的零样本主题提取能力,为概率主题建模和闭集主题分类方法提供了一种替代方案。作为零样本主题提取器,LLMs 被期望能够理解人类指令,并基于给定文档生成相关且无幻觉的主题。然而,基于 LLM 的主题建模方法在生成主题时往往难以遵循人类指令中指定的粒度要求,常常产生大量近似重复的主题。此外,针对 LLM 生成幻觉主题的处理方法尚未得到研究。在本文中,我们专注于解决主题粒度和幻觉问题,以实现更好的基于 LLM 的主题建模。为此,我们提出了一种新方法,利用直接偏好优化(DPO)对开源 LLM(如 Mistral-7B)进行微调。我们的方法不依赖传统的人工标注来排序偏好答案,而是采用一种重建流水线来修改 LLM 生成的原始主题,从而实现快速高效的训练和推理框架。对比实验表明,我们的微调方法不仅显著提高了 LLM 生成更连贯、更相关、更精确主题的能力,还减少了幻觉主题的数量。

英文摘要:

Large language models (LLMs) with their strong zero-shot topic extraction capabilities offer an alternative to probabilistic topic modelling and closed-set topic classification approaches. As zero-shot topic extractors, LLMs are expected to understand human instructions to generate relevant and non-hallucinated topics based on the given documents. However, LLM-based topic modelling approaches often face difficulties in generating topics with adherence to granularity as specified in human instructions, often resulting in many near-duplicate topics. Furthermore, methods for addressing hallucinated topics generated by LLMs have not yet been investigated. In this paper, we focus on addressing the issues of topic granularity and hallucinations for better LLM-based topic modelling. To this end, we introduce a novel approach that leverages Direct Preference Optimisation (DPO) to fine-tune open-source LLMs, such as Mistral-7B. Our approach does not rely on traditional human annotation to rank preferred answers but employs a reconstruction pipeline to modify raw topics generated by LLMs, thus enabling a fast and efficient training and inference framework. Comparative experiments show that our fine-tuning approach not only significantly improves the LLM's capability to produce more coherent, relevant, and precise topics, but also reduces the number of hallucinated topics.

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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