Mode connectivity provides novel geometric insights on analyzing loss landscapes and enables building high-accuracy pathways between well-trained neural networks. In this work, we propose to employ mode connectivity in loss landscapes to study the adversarial robustness of deep neural networks, and provide novel methods for improving this robustness. Our experiments cover various types of adversarial attacks applied to different network architectures and datasets. When network models are tampered with backdoor or error-injection attacks, our results demonstrate that the path connection learned using limited amount of bonafide data can effectively mitigate adversarial effects while maintaining the original accuracy on clean data. Therefore, mode connectivity provides users with the power to repair backdoored or error-injected models. We also use mode connectivity to investigate the loss landscapes of regular and robust models against evasion attacks. Experiments show that there exists a barrier in adversarial robustness loss on the path connecting regular and adversarially-trained models. A high correlation is observed between the adversarial robustness loss and the largest eigenvalue of the input Hessian matrix, for which theoretical justifications are provided. Our results suggest that mode connectivity offers a holistic tool and practical means for evaluating and improving adversarial robustness.

本文提出使用模态连通性来研究深度神经网络的对抗鲁棒性，并提供了提高对抗鲁棒性的新方法。实验结果表明，使用少量的真实数据学习到的路径连接可以有效地减轻对抗攻击的影响，同时在干净数据上保持原有的准确性。同时，该研究还使用模态连通性来对比分析正常模型和鲁棒模型的损失，在对抗鲁棒性损失的路径上存在壁垒，该损失与输入 Hessian 矩阵的最大特征值之间存在高度相关性。

丢失景观和对抗鲁棒性中的桥接模式连接