Mitigating the Structural Bias in Graph Adversarial Defenses

Fuente: arXiv
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Main Authors: Fang, Junyuan, Liu, Huimin, Yang, Han, Wu, Jiajing, Zheng, Zibin, Tse, Chi K.
Format: Preprint
Published: 2025
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_version_ 1866913812360200192
author Fang, Junyuan
Liu, Huimin
Yang, Han
Wu, Jiajing
Zheng, Zibin
Tse, Chi K.
author_facet Fang, Junyuan
Liu, Huimin
Yang, Han
Wu, Jiajing
Zheng, Zibin
Tse, Chi K.
contents In recent years, graph neural networks (GNNs) have shown great potential in addressing various graph structure-related downstream tasks. However, recent studies have found that current GNNs are susceptible to malicious adversarial attacks. Given the inevitable presence of adversarial attacks in the real world, a variety of defense methods have been proposed to counter these attacks and enhance the robustness of GNNs. Despite the commendable performance of these defense methods, we have observed that they tend to exhibit a structural bias in terms of their defense capability on nodes with low degree (i.e., tail nodes), which is similar to the structural bias of traditional GNNs on nodes with low degree in the clean graph. Therefore, in this work, we propose a defense strategy by including hetero-homo augmented graph construction, $k$NN augmented graph construction, and multi-view node-wise attention modules to mitigate the structural bias of GNNs against adversarial attacks. Notably, the hetero-homo augmented graph consists of removing heterophilic links (i.e., links connecting nodes with dissimilar features) globally and adding homophilic links (i.e., links connecting nodes with similar features) for nodes with low degree. To further enhance the defense capability, an attention mechanism is adopted to adaptively combine the representations from the above two kinds of graph views. We conduct extensive experiments to demonstrate the defense and debiasing effect of the proposed strategy on benchmark datasets.
format Preprint
id arxiv_https___arxiv_org_abs_2504_20848
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Mitigating the Structural Bias in Graph Adversarial Defenses
Fang, Junyuan
Liu, Huimin
Yang, Han
Wu, Jiajing
Zheng, Zibin
Tse, Chi K.
Machine Learning
Artificial Intelligence
Cryptography and Security
In recent years, graph neural networks (GNNs) have shown great potential in addressing various graph structure-related downstream tasks. However, recent studies have found that current GNNs are susceptible to malicious adversarial attacks. Given the inevitable presence of adversarial attacks in the real world, a variety of defense methods have been proposed to counter these attacks and enhance the robustness of GNNs. Despite the commendable performance of these defense methods, we have observed that they tend to exhibit a structural bias in terms of their defense capability on nodes with low degree (i.e., tail nodes), which is similar to the structural bias of traditional GNNs on nodes with low degree in the clean graph. Therefore, in this work, we propose a defense strategy by including hetero-homo augmented graph construction, $k$NN augmented graph construction, and multi-view node-wise attention modules to mitigate the structural bias of GNNs against adversarial attacks. Notably, the hetero-homo augmented graph consists of removing heterophilic links (i.e., links connecting nodes with dissimilar features) globally and adding homophilic links (i.e., links connecting nodes with similar features) for nodes with low degree. To further enhance the defense capability, an attention mechanism is adopted to adaptively combine the representations from the above two kinds of graph views. We conduct extensive experiments to demonstrate the defense and debiasing effect of the proposed strategy on benchmark datasets.
title Mitigating the Structural Bias in Graph Adversarial Defenses
topic Machine Learning
Artificial Intelligence
Cryptography and Security
url https://arxiv.org/abs/2504.20848