Graph data augmentation proves to be an effective approach for enhancing the performance of graph classification. However, due to the complex structure of graphs, the semantic meanings of graphs are sensitive to minor modifications, while the labels of augmented graphs remain identical, thus limiting the potential benefits of graph data augmentation. To address this limitation, we propose Graph Soft Augmentation (GSA), a method to smooth the labels of augmented graphs. Instead of assigning hard and fixed labels to augmented graphs as traditional graph data augmentations, which do not consider the changed semantics, GSA smooths the labels of augmented graphs. GSA can be divided into two stages. In the first stage, a graph similarity network is trained with the original dataset until convergence. In the second stage, GSA adopts a general graph data augmentation to construct augmented graphs. The labels of augmented graphs are then smoothed based on the similarities computed by the similarity network. Finally, the resulting augmented graphs, along with their smoothed labels, are incorporated into the graph classification network as training samples. Experimental results on a variety of publicly available datasets reveal the effectiveness of our GSA.

Graph Neural Networks (GNNs) are widely used for node classification tasks but often fail to generalize when training and test nodes come from different distributions, limiting their practicality. To address this challenge, recent approaches have adopted invariant learning and sample reweighting techniques from the out-of-distribution (OOD) generalization field. However, invariant learning-based methods face difficulties when applied to graph data, as they rely on the impractical assumption of obtaining real environment labels and strict invariance, which may not hold in real-world graph structures. Moreover, current sample reweighting methods tend to overlook topological information, potentially leading to suboptimal results. In this work, we introduce the Topology-Aware Dynamic Reweighting (TAR) framework to address distribution shifts by leveraging the inherent graph structure. TAR dynamically adjusts sample weights through gradient flow on the graph edges during training. Instead of relying on strict invariance assumptions, we theoretically prove that our method is able to provide distributional robustness, thereby enhancing the out-of-distribution generalization performance on graph data. Our framework's superiority is demonstrated through standard testing on extensive node classification OOD datasets, exhibiting marked improvements over existing methods.

Graph Neural Network (GNN) is powerful in solving various graph-related tasks, while its message passing mechanism may lead to latency during inference time. Multi-Layer-Perceptron (MLP) can achieve fast inference speed but with limited performance. One solution to fill this gap is through Knowledge Distillation. However, current distillation methods follow a ''node-to-node'' paradigm, while considering the complex relationships between different node pairs, direct distillation fails to capture these multiple-granularity features in GNN. Furthermore, current methods which focuses on the alignment of logits in the final layer ignores further learning within layers inside student MLP. Therefore, in this paper, we introduce a multi-scale knowledge distillation method (MSN-GDM) aiming to capture multiple knowledge from GNN to MLP. We firstly propose a multi-scale node-pair grouping strategy to assign node pairs to different-scale groups according to node pair similarity metrics. The similarity metrics consider both node features and topological structures of the given node pair. Then based on the preprocessed node-set groups, we design a multi-scale distillation method that can capture comprehensive knowledge in the corresponding node-set groups. The hierarchical weighted sum of each layer is applied as the final output. Extensive experiments on eight real-world datasets demonstrate the effectiveness of our proposed method.