通过语义熵与上下文参数融合,提升RAG模型幻觉检测准确性
SEReDeEP: Hallucination Detection in Retrieval-Augmented Models via Semantic Entropy and Context-Parameter Fusion
- 利用语义熵与上下文参数融合,量化内外知识不平衡
- 在多个RAG数据集上实现比现有方法更高的幻觉检测准确率
- 适合关注大模型生成可信度、需改进幻觉检测的研究者
检索增强生成(RAG)模型在融合外部信息与内部参数化知识时常出现幻觉。实证研究表明,外部上下文信息与内部参数知识之间的失衡是幻觉产生的主要因素。现有检测方法多孤立关注外部或内部机制,忽视其协同效应。近期提出的ReDeEP框架将双重机制解耦,识别出两个关键诱因:前馈网络对参数知识的过度依赖,以及注意力机制(特别是复制头)对外部信息利用不足。ReDeEP通过定量评估这些因素来检测幻觉并动态调节其贡献。然而,多数方法仍基于词元级不确定性或语言级自洽性评估,未能充分捕捉响应的语义维度,导致在实际RAG应用中评估结果不一致。本文在ReDeEP基础上提出SEReDeEP,通过训练线性探针捕获语义熵,提升计算过程,使幻觉评估更贴近真实情况。
原文摘要 · Abstract (English)
Retrieval-Augmented Generation (RAG) models frequently encounter hallucination phenomena when integrating external information with internal parametric knowledge. Empirical studies demonstrate that the disequilibrium between external contextual information and internal parametric knowledge constitutes a primary factor in hallucination generation. Existing hallucination detection methodologies predominantly emphasize either the external or internal mechanism in isolation, thereby overlooking their synergistic effects. The recently proposed ReDeEP framework decouples these dual mechanisms, identifying two critical contributors to hallucinations: excessive reliance on parametric knowledge encoded in feed-forward networks (FFN) and insufficient utilization of external information by attention mechanisms (particularly copy heads). ReDeEP quantitatively assesses these factors to detect hallucinations and dynamically modulates the contributions of FFNs and copy heads to attenuate their occurrence. Nevertheless, ReDeEP and numerous other hallucination detection approaches have been employed at logit-level uncertainty estimation or language-level self-consistency evaluation, inadequately address the semantic dimensions of model responses, resulting in inconsistent hallucination assessments in RAG implementations. Building upon ReDeEP's foundation, this paper introduces SEReDeEP, which enhances computational processes through semantic entropy captured via trained linear probes, thereby achieving hallucination assessments that more accurately reflect ground truth evaluations.
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