Graph Data Augmentation for Node Classification

In recent years, Graph Neural Networks (GNNs) have emerged as powerful techniques for graph-structure data, which are essential for a wide range of graph-based tasks like link prediction and node classification. However, over-smoothing and over-fitting are two main challenges that impact negatively on model performance. Data augmentation is a good solution to these two problems, and it is also proven very effective in computer vision and nature language processing. But there is a relatively small body of literature when it comes to graph data augmentation. In this paper, we propose a Graph Data Augmentation (GDA) strategy to optimize the graph topology for node classification tasks. Our GDA approach consists of two operations: edge manipulation based on similarities of node pairs (GDA-E) and new nodes addition to under-informed old nodes (GDA-N). GDA-E is designed to add missing edges and remove noisy edges, while GDA-N is established to help nodes with low degree. Both operations can improve the information-to-noise ratio of the whole graph and lead to better performance of GNNs. The comparative results of experiments on three different datasets show that our GDA approach achieves considerable improvement (11.0% average) over origin graphs, and the ablation study verifies the effectiveness of both GDA-E and GDA-N.