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arXiv 2409.03463cs.LGcs.AI

图神经网络中的大规模激活:解码注意力以实现领域相关的可解释性

Massive Activations in Graph Neural Networks: Decoding Attention for Domain-Dependent Interpretability

University of Geneva(日内瓦大学);Research Institute for Statistics and Information Science(统计与信息科学研究院)

Lorenzo Bini, Marco Sorbi, Stephane Marchand-Maillet

AI总结:

本研究揭示了边特征图神经网络注意力层中大规模激活(MAs)的出现,开发了MAs检测方法,并证明其编码领域信号、可作为归因指标,为连接GNN内部机制与领域知识提供关键见解。

摘要:

图神经网络(GNNs)在有效建模图结构数据方面日益普及,而注意力机制在使这些模型捕获复杂模式方面发挥了关键作用。在我们的研究中,我们揭示了将注意力整合到边特征GNNs中一个关键但尚未充分探索的后果:注意力层内大规模激活的出现。通过开发一种检测边特征上MAs的新方法,我们表明这些极端激活不仅是激活异常,而且编码了领域相关的信号。我们的事后可解释性分析表明,在分子图中,MAs主要聚集在常见键类型(例如单键和双键)上,而避开信息量更大的键(例如三键)。此外,我们的消融研究证实,MAs可以作为自然的归因指标,重新分配到信息量较小的边上。我们的研究使用基准数据集(包括ZINC、TOX21和PROTEINS)评估了各种基于边特征的注意力GNN模型。主要贡献包括:(1)建立了边特征GNNs中注意力机制与MAs生成之间的直接联系,(2)开发了MAs的稳健定义和检测方法,从而实现可靠的事后可解释性。总体而言,我们的研究揭示了注意力机制、边特征GNNs模型与MAs出现之间的复杂相互作用,为将GNNs内部机制与领域知识联系起来提供了关键见解。

英文摘要:

Graph Neural Networks (GNNs) have become increasingly popular for effectively modeling graph-structured data, and attention mechanisms have been pivotal in enabling these models to capture complex patterns. In our study, we reveal a critical yet underexplored consequence of integrating attention into edge-featured GNNs: the emergence of Massive Activations (MAs) within attention layers. By developing a novel method for detecting MAs on edge features, we show that these extreme activations are not only activation anomalies but encode domain-relevant signals. Our post-hoc interpretability analysis demonstrates that, in molecular graphs, MAs aggregate predominantly on common bond types (e.g., single and double bonds) while sparing more informative ones (e.g., triple bonds). Furthermore, our ablation studies confirm that MAs can serve as natural attribution indicators, reallocating to less informative edges. Our study assesses various edge-featured attention-based GNN models using benchmark datasets, including ZINC, TOX21, and PROTEINS. Key contributions include (1) establishing the direct link between attention mechanisms and MAs generation in edge-featured GNNs, (2) developing a robust definition and detection method for MAs enabling reliable post-hoc interpretability. Overall, our study reveals the complex interplay between attention mechanisms, edge-featured GNNs model, and MAs emergence, providing crucial insights for relating GNNs internals to domain knowledge.

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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