GDM: Dual Mixup for Graph Classification with Limited Supervision

TL;DR

This paper introduces Graph Dual Mixup (GDM), a novel graph augmentation technique that combines structural and functional information to generate diverse labeled graph samples, significantly improving graph classification performance with limited supervision.

Contribution

GDM is the first method to jointly leverage structural auto-encoders and feature mixup for graph augmentation, enhancing performance in low-label scenarios.

Findings

GDM outperforms existing augmentation methods on benchmark datasets.

GDM effectively increases diversity and balance of generated graph samples.

GDM improves classification accuracy with scarce labeled data.

Abstract

Graph Neural Networks (GNNs) require a large number of labeled graph samples to obtain good performance on the graph classification task. The performance of GNNs degrades significantly as the number of labeled graph samples decreases. To reduce the annotation cost, it is therefore important to develop graph augmentation methods that can generate new graph instances to increase the size and diversity of the limited set of available labeled graph samples. In this work, we propose a novel mixup-based graph augmentation method, Graph Dual Mixup (GDM), that leverages both functional and structural information of the graph instances to generate new labeled graph samples. GDM employs a graph structural auto-encoder to learn structural embeddings of the graph samples, and then applies mixup to the structural information of the graphs in the learned structural embedding space and generates new graph structures from the mixup structural embeddings. As for the functional information, GDM applies mixup directly to the input node features of the graph samples to generate functional node feature information for new mixup graph instances. Jointly, the generated input node features and graph structures yield new graph samples which can supplement the set of original labeled graphs. Furthermore, we propose two novel Balanced Graph Sampling methods to enhance the balanced difficulty and diversity for the generated graph samples. Experimental results on the benchmark datasets demonstrate that our proposed method substantially outperforms the state-of-the-art graph augmentation methods when the labeled graphs are scarce.