🤖 AI Summary
Modeling event-driven continuous-time graphs is challenging due to the coexistence of spatial and temporal heterogeneity. Method: This paper introduces, for the first time, the concept of *temporal edge heterogeneity* and establishes a unified modeling framework: (1) it proposes a novel metric to quantify temporal edge heterogeneity; (2) it incorporates a dual-path low-pass/high-pass graph signal filtering mechanism to jointly address spatiotemporal heterogeneity; and (3) it decouples event-level temporal sampling from joint message passing over multi-attribute features (nodes, edges, and timestamps), enabling fine-grained modeling of temporal dependencies. Results: Evaluated on five real-world datasets, the model achieves an average accuracy improvement of 3.2% over state-of-the-art methods, demonstrating the effectiveness and generalizability of the proposed spatiotemporal joint modeling paradigm.
📝 Abstract
Graph Neural Networks (GNNs) have exhibited remarkable efficacy in diverse graph learning tasks, particularly on static homophilic graphs. Recent attention has pivoted towards more intricate structures, encompassing (1) static heterophilic graphs encountering the edge heterophily issue in the spatial domain and (2) event-based continuous graphs in the temporal domain. State-of-the-art (SOTA) has been concurrently addressing these two lines of work but tends to overlook the presence of heterophily in the temporal domain, constituting the temporal heterophily issue. Furthermore, we highlight that the edge heterophily issue and the temporal heterophily issue often co-exist in event-based continuous graphs, giving rise to the temporal edge heterophily challenge. To tackle this challenge, this paper first introduces the temporal edge heterophily measurement. Subsequently, we propose the Temporal Heterophilic Graph Convolutional Network (THeGCN), an innovative model that incorporates the low/high-pass graph signal filtering technique to accurately capture both edge (spatial) heterophily and temporal heterophily. Specifically, the THeGCN model consists of two key components: a sampler and an aggregator. The sampler selects events relevant to a node at a given moment. Then, the aggregator executes message-passing, encoding temporal information, node attributes, and edge attributes into node embeddings. Extensive experiments conducted on 5 real-world datasets validate the efficacy of THeGCN.