论文标题

具有元路径上下文和自适应加权的负样本的异质图对比度学习

Heterogeneous Graph Contrastive Learning with Meta-path Contexts and Adaptively Weighted Negative Samples

论文作者

Yu, Jianxiang, Ge, Qingqing, Li, Xiang, Zhou, Aoying

论文摘要

异质图对比度学习最近受到广泛关注。一些现有方法使用元路径,这些元素是捕获对象之间语义关系的对象类型的序列来构建对比视图。但是,他们中的大多数忽略了丰富的元路径上下文信息,该信息描述了如何通过元路径连接两个对象。此外,他们无法区分负面样本,这可能会对模型性能产生不利影响。为了解决这些问题,我们提出了Meow,它考虑了元路径上下文和加权负面样本。具体而言,Meow构建了一个粗糙的视图和对比度的细颗粒视图。前者反映了哪些对象是由元路径连接的,而后者则使用元路径上下文,并描述了对象如何连接的详细信息。然后,我们理论上分析了Infonce损失,并确定其计算负样本梯度的局限性。为了更好地区分阴性样本,我们根据节点聚类学习硬评价的权重,并使用典型的对比度学习将节点的紧密嵌入在同一群集中。此外,我们提出了一种变体模型,该模型可以自适应地学习负样本的软价值权重,以进一步改善节点表示。最后,我们进行了广泛的实验,以表明Meow和Adameow与其他最新方法的优越性。

Heterogeneous graph contrastive learning has received wide attention recently. Some existing methods use meta-paths, which are sequences of object types that capture semantic relationships between objects, to construct contrastive views. However, most of them ignore the rich meta-path context information that describes how two objects are connected by meta-paths. Further, they fail to distinguish negative samples, which could adversely affect the model performance. To address the problems, we propose MEOW, which considers both meta-path contexts and weighted negative samples. Specifically, MEOW constructs a coarse view and a fine-grained view for contrast. The former reflects which objects are connected by meta-paths, while the latter uses meta-path contexts and characterizes details on how the objects are connected. Then, we theoretically analyze the InfoNCE loss and recognize its limitations for computing gradients of negative samples. To better distinguish negative samples, we learn hard-valued weights for them based on node clustering and use prototypical contrastive learning to pull close embeddings of nodes in the same cluster. In addition, we propose a variant model AdaMEOW that adaptively learns soft-valued weights of negative samples to further improve node representation. Finally, we conduct extensive experiments to show the superiority of MEOW and AdaMEOW against other state-of-the-art methods.

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