GFM4GA: Graph Foundation Model for Group Anomaly Detection

Fuente: arXiv
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Main Authors: Chen, Jiujiu, Zeng, Weijun, Hu, Shaofeng, Xie, Sihong, Xiong, Hui
Format: Preprint
Published: 2026
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author Chen, Jiujiu
Zeng, Weijun
Hu, Shaofeng
Xie, Sihong
Xiong, Hui
author_facet Chen, Jiujiu
Zeng, Weijun
Hu, Shaofeng
Xie, Sihong
Xiong, Hui
contents Group anomaly detection is crucial in many network applications, but faces challenges due to diverse anomaly patterns. Motivated by the success of large language models (LLMs) in natural language processing, graph foundation models (GFMs) is proposed to handle few-shot learning task with fewer labeling efforts. GFMs have been successfully applied to detection of individual anomalies but cannot be generalized to group anomalies, as group anomaly patterns must be detected as a whole and individuals in an abnormal group can look rather normal. Therefore, we propose GFM4GA, a novel graph foundation model for group anomaly detection. The pipeline is pretrained via dual-level contrastive learning based on feature-based estimation and group extraction, to capture potential group anomaly structure and feature inconsistencies. In the downstream tasks, the pipeline is finetuned in parameter-constrained and group-anomaly-proportion weighted few-shot settings, and its adaptive ability to unseen group anomalies expanded via group contexts determined by labeled anomaly neighbors. Experiments show that GFM4GA surpasses group anomaly detectors and GFMs for individual anomalies, achieving average improvements of 2.85% in AUROC and 2.55% in AUPRC.
format Preprint
id arxiv_https___arxiv_org_abs_2601_10193
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle GFM4GA: Graph Foundation Model for Group Anomaly Detection
Chen, Jiujiu
Zeng, Weijun
Hu, Shaofeng
Xie, Sihong
Xiong, Hui
Artificial Intelligence
Group anomaly detection is crucial in many network applications, but faces challenges due to diverse anomaly patterns. Motivated by the success of large language models (LLMs) in natural language processing, graph foundation models (GFMs) is proposed to handle few-shot learning task with fewer labeling efforts. GFMs have been successfully applied to detection of individual anomalies but cannot be generalized to group anomalies, as group anomaly patterns must be detected as a whole and individuals in an abnormal group can look rather normal. Therefore, we propose GFM4GA, a novel graph foundation model for group anomaly detection. The pipeline is pretrained via dual-level contrastive learning based on feature-based estimation and group extraction, to capture potential group anomaly structure and feature inconsistencies. In the downstream tasks, the pipeline is finetuned in parameter-constrained and group-anomaly-proportion weighted few-shot settings, and its adaptive ability to unseen group anomalies expanded via group contexts determined by labeled anomaly neighbors. Experiments show that GFM4GA surpasses group anomaly detectors and GFMs for individual anomalies, achieving average improvements of 2.85% in AUROC and 2.55% in AUPRC.
title GFM4GA: Graph Foundation Model for Group Anomaly Detection
topic Artificial Intelligence
url https://arxiv.org/abs/2601.10193