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arXiv 2408.08754cs.LG
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面向链路符号预测的自解释图Transformer

Self-Explainable Graph Transformer for Link Sign Prediction

Huazhong Agricultural University(华中农业大学)

Lu Li, Jiale Liu, Xingyu Ji, Maojun Wang, Zeyu Zhang

AI总结:

针对符号图神经网络可解释性不足的问题,提出自解释符号图Transformer框架SE-SGformer,通过符号随机游走位置编码和K邻居解释机制,在提升预测精度的同时显著提高可解释性精度。

摘要:

符号图神经网络(SGNNs)已被证明能有效分析现实世界中正负链接共存场景下的复杂模式。然而,SGNN模型的可解释性较差,限制了其在需要理解预测背后推理逻辑的关键场景中的应用。据我们所知,目前尚无针对SGNN模型可解释性的研究工作。我们的目标是解决符号图神经网络特有的下游任务——链路符号预测的决策可解释性问题。由于事后解释并非直接从模型推导而来,可能存在偏差,无法真实反映实际的解释逻辑。因此,本文提出了自解释符号图Transformer(SE-SGformer)框架,该框架既能保证高预测精度,又能输出可解释信息。具体而言,我们提出了一种适用于符号图的新型Transformer架构,并从理论上证明,采用基于符号随机游走的位置编码,比现有SGNN方法及其他基于位置编码的图Transformer方法具有更强的表达能力。我们通过发现节点的K个最近(最远)正(负)邻居,替代基于神经网络的解码器来预测边的符号,构建了一种新颖的可解释决策流程。这些K个正(负)邻居代表了节点间正(负)边形成的关键信息,因此可作为决策过程中的重要解释信息。我们在多个真实世界数据集上开展实验验证SE-SGformer的有效性,在最优场景下,其预测精度比当前最优方法提升2.2%,可解释性精度提升73.1%。

英文摘要:

Signed Graph Neural Networks (SGNNs) have been shown to be effective in analyzing complex patterns in real-world situations where positive and negative links coexist. However, SGNN models suffer from poor explainability, which limit their adoptions in critical scenarios that require understanding the rationale behind predictions. To the best of our knowledge, there is currently no research work on the explainability of the SGNN models. Our goal is to address the explainability of decision-making for the downstream task of link sign prediction specific to signed graph neural networks. Since post-hoc explanations are not derived directly from the models, they may be biased and misrepresent the true explanations. Therefore, in this paper we introduce a Self-Explainable Signed Graph transformer (SE-SGformer) framework, which can not only outputs explainable information while ensuring high prediction accuracy. Specifically, We propose a new Transformer architecture for signed graphs and theoretically demonstrate that using positional encoding based on signed random walks has greater expressive power than current SGNN methods and other positional encoding graph Transformer-based approaches. We constructs a novel explainable decision process by discovering the $K$-nearest (farthest) positive (negative) neighbors of a node to replace the neural network-based decoder for predicting edge signs. These $K$ positive (negative) neighbors represent crucial information about the formation of positive (negative) edges between nodes and thus can serve as important explanatory information in the decision-making process. We conducted experiments on several real-world datasets to validate the effectiveness of SE-SGformer, which outperforms the state-of-the-art methods by improving 2.2\% prediction accuracy and 73.1\% explainablity accuracy in the best-case scenario.

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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