针对带文本的超图,提出分阶段对比学习框架提升表示效果。
HiTeC: Hierarchical Contrastive Learning on Text-Attributed Hypergraph with Semantic-Aware Augmentation
- 分两阶段:先用结构感知目标预训练文本编码器,再引入语义增强生成多视图。
- 在6个真实数据集上优于基线方法,长程依赖捕捉能力显著提升。
- 适合处理含丰富文本信息的复杂关系数据,如社交网络、知识图谱。
对比学习已成为自监督超图学习的主流范式,可在无需昂贵标注的情况下有效训练。然而,现实世界超图中的节点常带有丰富的文本信息,现有方法对此关注不足。直接应用已有对比学习方法于文本属性超图(TAHG)存在三方面局限:(1) 普遍使用与图结构无关的文本编码器,无法捕捉文本语义与超图拓扑间的关联,导致表征表达力不足;(2) 依赖随机数据增强引入噪声,削弱对比信号;(3) 主要聚焦节点与超边层面的对比信号,难以捕捉长程依赖,影响表征学习效果。为此,我们提出HiTeC,一种面向文本属性超图的两级分层对比学习框架。第一阶段通过结构感知对比目标预训练文本编码器,克服传统方法的图无关性;第二阶段引入语义感知增强策略,包括结构上下文文本增强和语义感知超边丢弃,以生成更具信息量的视图。随后,提出基于s-walk的多尺度对比损失,实现子图级长程依赖建模。在六个真实数据集上的大量实验验证了所提方法的有效性。
原文摘要 · Abstract (English)
Contrastive learning (CL) has become a dominant paradigm for self-supervised hypergraph learning, enabling effective training without costly labels. However, node entities in real-world hypergraphs are often associated with rich textual information, which has been largely ignored in prior works. Directly applying existing CL-based methods to such text-attributed hypergraphs (TAHGs) leads to three key limitations: (1) The common use of graph-agnostic text encoders fails to capture the correlations between textual semantics and hypergraph topology, resulting in less expressive representations. (2) Their reliance on random data augmentations introduces noise and weakens the contrastive signals. (3) The primary focus on node- and hyperedge-level contrastive signals limits the ability to capture long-range dependencies, which is essential for effective representation learning. To address these challenges, we introduce HiTeC, a two-stage hierarchical contrastive learning framework for effective self-supervised learning on TAHGs. In the first stage, we pre-train the text encoder with a structure-aware contrastive objective to overcome the graph-agnostic nature of conventional methods. In the second stage, we begin by introducing semantic-aware augmentations, including structure-contextualized text augmentation and semantic-aware hyperedge dropping, to facilitate informative view generation. Subsequently, we propose a multi-scale contrastive loss with an $s$-walk-based subgraph-level objective to capture long-range dependencies. Extensive experiments on six real-world datasets validate the effectiveness of our proposed method.
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