NeiGAD: Augmenting Graph Anomaly Detection via Spectral Neighbor Information

Fuente: arXiv
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Autores principales: Qing, Qing, Huang, Huafei, Hou, Mingliang, Luo, Renqiang, Guizani, Mohsen
Formato: Preprint
Publicado: 2026
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author Qing, Qing
Huang, Huafei
Hou, Mingliang
Luo, Renqiang
Guizani, Mohsen
author_facet Qing, Qing
Huang, Huafei
Hou, Mingliang
Luo, Renqiang
Guizani, Mohsen
contents Graph anomaly detection (GAD) aims to identify irregular nodes or structures in attributed graphs. Neighbor information, which reflects both structural connectivity and attribute consistency with surrounding nodes, is essential for distinguishing anomalies from normal patterns. Although recent graph neural network (GNN)-based methods incorporate such information through message passing, they often fail to explicitly model its effect or interaction with attributes, limiting detection performance. This work introduces NeiGAD, a novel plug-and-play module that captures neighbor information through spectral graph analysis. Theoretical insights demonstrate that eigenvectors of the adjacency matrix encode local neighbor interactions and progressively amplify anomaly signals. Based on this, NeiGAD selects a compact set of eigenvectors to construct efficient and discriminative representations. Experiments on eight real-world datasets show that NeiGAD consistently improves detection accuracy and outperforms state-of-the-art GAD methods. These results demonstrate the importance of explicit neighbor modeling and the effectiveness of spectral analysis in anomaly detection. Code is available at: https://github.com/huafeihuang/NeiGAD.
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id arxiv_https___arxiv_org_abs_2603_28300
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle NeiGAD: Augmenting Graph Anomaly Detection via Spectral Neighbor Information
Qing, Qing
Huang, Huafei
Hou, Mingliang
Luo, Renqiang
Guizani, Mohsen
Machine Learning
Artificial Intelligence
Graph anomaly detection (GAD) aims to identify irregular nodes or structures in attributed graphs. Neighbor information, which reflects both structural connectivity and attribute consistency with surrounding nodes, is essential for distinguishing anomalies from normal patterns. Although recent graph neural network (GNN)-based methods incorporate such information through message passing, they often fail to explicitly model its effect or interaction with attributes, limiting detection performance. This work introduces NeiGAD, a novel plug-and-play module that captures neighbor information through spectral graph analysis. Theoretical insights demonstrate that eigenvectors of the adjacency matrix encode local neighbor interactions and progressively amplify anomaly signals. Based on this, NeiGAD selects a compact set of eigenvectors to construct efficient and discriminative representations. Experiments on eight real-world datasets show that NeiGAD consistently improves detection accuracy and outperforms state-of-the-art GAD methods. These results demonstrate the importance of explicit neighbor modeling and the effectiveness of spectral analysis in anomaly detection. Code is available at: https://github.com/huafeihuang/NeiGAD.
title NeiGAD: Augmenting Graph Anomaly Detection via Spectral Neighbor Information
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2603.28300