HGEN: Heterogeneous Graph Ensemble Networks
It addresses the challenge of heterogeneity in node types, features, and topology for ensemble learning in graph-based tasks, offering a novel method for researchers and practitioners in graph machine learning.
This paper tackles the problem of ensemble learning for heterogeneous graphs by proposing HGEN, a framework that uses meta-path and transformation-based optimization to improve classification accuracy, achieving consistent and substantial performance gains over state-of-the-art competitors on five heterogeneous networks.
This paper presents HGEN that pioneers ensemble learning for heterogeneous graphs. We argue that the heterogeneity in node types, nodal features, and local neighborhood topology poses significant challenges for ensemble learning, particularly in accommodating diverse graph learners. Our HGEN framework ensembles multiple learners through a meta-path and transformation-based optimization pipeline to uplift classification accuracy. Specifically, HGEN uses meta-path combined with random dropping to create Allele Graph Neural Networks (GNNs), whereby the base graph learners are trained and aligned for later ensembling. To ensure effective ensemble learning, HGEN presents two key components: 1) a residual-attention mechanism to calibrate allele GNNs of different meta-paths, thereby enforcing node embeddings to focus on more informative graphs to improve base learner accuracy, and 2) a correlation-regularization term to enlarge the disparity among embedding matrices generated from different meta-paths, thereby enriching base learner diversity. We analyze the convergence of HGEN and attest its higher regularization magnitude over simple voting. Experiments on five heterogeneous networks validate that HGEN consistently outperforms its state-of-the-art competitors by substantial margin.