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arXiv 2602.11641cs.LG
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拓扑与文本同样重要:重新审视基于LLM的文本属性图分布外检测

Both Topology and Text Matter: Revisiting LLM-guided Out-of-Distribution Detection on Text-attributed Graphs

Sun Yat-sen University(中山大学);Shandong University(山东大学)

Yinlin Zhu, Di Wu, Xu Wang, Guocong Quan, Miao Hu

AI总结:

针对文本属性图分布外检测中拓扑与文本信息利用不足的问题,提出LG-Plug框架,通过对齐拓扑与文本表示并利用聚类迭代LLM提示生成共识驱动的OOD样本,有效提升检测性能。

摘要:

文本属性图(TAGs)将节点与文本属性和图结构关联,使GNN能够联合建模语义和结构信息。尽管在分布内(ID)数据上有效,但GNN在面对具有未见文本或结构模式的分布外(OOD)节点时常常失败,产生过度自信的预测而缺乏可靠的OOD检测。现有的拓扑驱动方法通过邻域结构缓解节点级偏差,但通常将文本编码为浅层特征,未充分利用语义信息。最近的基于LLM的方法则从文本知识中合成伪OOD先验,但存在两个关键限制:(1)可靠性与信息性之间的权衡,生成的OOD暴露要么偏离真实的OOD语义,要么引入大量ID噪声;(2)依赖专用架构,限制了与先前工作中验证的拓扑级进展的兼容性。为解决这些问题,我们提出LG-Plug,一个用于TAG OOD检测的LLM引导的即插即用框架。LG-Plug对齐拓扑和文本表示以获得细粒度节点嵌入,然后通过聚类迭代LLM提示构建共识驱动的OOD暴露。为降低LLM查询成本,它进一步采用轻量级簇内码本和启发式采样。生成的OOD暴露作为正则化器,分离ID和OOD节点,实现与现有检测器的无缝集成。在六个TAG基准上的实验表明,LG-Plug持续改进拓扑驱动的OOD检测器(FPR95降低>7%),并超越先前基于LLM的方法(FPR95降低>5%)。

英文摘要:

Text-attributed graphs (TAGs) associate nodes with textual attributes and graph structure, enabling GNNs to jointly model semantic and structural information. Although effective on in-distribution (ID) data, GNNs often fail on out-of-distribution (OOD) nodes with unseen textual or structural patterns, producing overconfident predictions without reliable OOD detection. Existing topology-driven methods mitigate node-level bias through neighboring structures, but typically encode texts as shallow features, underutilizing semantic information. Recent LLM-based approaches instead synthesize pseudo OOD priors from textual knowledge, yet suffer from two key limitations: (1) a trade-off between reliability and informativeness, where generated OOD exposures either deviate from true OOD semantics or introduce substantial ID noise; and (2) dependence on specialized architectures, limiting compatibility with topology-level advances validated in prior work. To address these issues, we propose LG-Plug, an LLM-Guided Plug-and-play framework for TAG OOD detection. LG-Plug aligns topology and text representations to obtain fine-grained node embeddings, then constructs consensus-driven OOD exposure through clustered iterative LLM prompting. To reduce LLM query cost, it further adopts lightweight in-cluster codebooks and heuristic sampling. The generated OOD exposure acts as a regularizer that separates ID and OOD nodes, enabling seamless integration with existing detectors. Experiments on six TAG benchmarks demonstrate that LG-Plug consistently improves topology-driven OOD detectors (>7% FPR95 reduction) and surpasses prior LLM-based methods (>5% FPR95 reduction).

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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