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Related papers: Cluster Aware Graph Anomaly Detection

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In a variety of applications, one desires to detect groups of anomalous data samples, with a group potentially manifesting its atypicality (relative to a reference model) on a low-dimensional subset of the full measured set of features.…

Networking and Internet Architecture · Computer Science 2015-11-04 Zhicong Qiu , David J. Miller , George Kesidis

Hard negative mining has shown effective in enhancing self-supervised contrastive learning (CL) on diverse data types, including graph CL (GCL). The existing hardness-aware CL methods typically treat negative instances that are most similar…

Machine Learning · Computer Science 2024-01-09 Chaoxi Niu , Guansong Pang , Ling Chen

Within a large database G containing graphs with labeled nodes and directed, multi-edges; how can we detect the anomalous graphs? Most existing work are designed for plain (unlabeled) and/or simple (unweighted) graphs. We introduce…

Databases · Computer Science 2022-05-03 Hung T. Nguyen , Pierre J. Liang , Leman Akoglu

Graph-based clustering has shown promising performance in many tasks. A key step of graph-based approach is the similarity graph construction. In general, learning graph in kernel space can enhance clustering accuracy due to the…

Machine Learning · Computer Science 2019-05-22 Zhao Kang , Honghui Xu , Boyu Wang , Hongyuan Zhu , Zenglin Xu

In this work, we propose GLUE (Graph Deviation Network with Local Uncertainty Estimation), building on the recently proposed Graph Deviation Network (GDN). GLUE not only automatically learns complex dependencies between variables and uses…

Machine Learning · Computer Science 2021-12-08 Saswati Ray , Sana Lakdawala , Mononito Goswami , Chufan Gao

This work considers a practical semi-supervised graph anomaly detection (GAD) scenario, where part of the nodes in a graph are known to be normal, contrasting to the extensively explored unsupervised setting with a fully unlabeled graph. We…

Machine Learning · Computer Science 2024-12-20 Hezhe Qiao , Qingsong Wen , Xiaoli Li , Ee-Peng Lim , Guansong Pang

Learning to detect real-world anomalous events using video-level annotations is a difficult task mainly because of the noise present in labels. An anomalous labelled video may actually contain anomaly only in a short duration while the rest…

Computer Vision and Pattern Recognition · Computer Science 2021-05-03 Muhammad Zaigham Zaheer , Jin-ha Lee , Marcella Astrid , Arif Mahmood , Seung-Ik Lee

Graph-level anomaly detection (GLAD) aims to identify graphs that exhibit notable dissimilarity compared to the majority in a collection. However, current works primarily focus on evaluating graph-level abnormality while failing to provide…

Machine Learning · Computer Science 2023-10-26 Yixin Liu , Kaize Ding , Qinghua Lu , Fuyi Li , Leo Yu Zhang , Shirui Pan

A graph-based sampling and consensus (GraphSAC) approach is introduced to effectively detect anomalous nodes in large-scale graphs. Existing approaches rely on connectivity and attributes of all nodes to assign an anomaly score per node.…

Machine Learning · Computer Science 2019-10-23 Vassilis N. Ioannidis , Dimitris Berberidis , Georgios B. Giannakis

Fraud detection problems are usually formulated as a machine learning problem on a graph. Recently, Graph Neural Networks (GNNs) have shown solid performance on fraud detection. The successes of most previous methods heavily rely on rich…

Machine Learning · Computer Science 2021-10-05 Chen Wang , Yingtong Dou , Min Chen , Jia Chen , Zhiwei Liu , Philip S. Yu

In this paper, we propose a novel framework that combines ensemble learning with augmented graph structures to improve the performance and robustness of semi-supervised node classification in graphs. By creating multiple augmented views of…

Machine Learning · Computer Science 2025-03-25 Maryam Abdolali , Romina Zakerian , Behnam Roshanfekr , Fardin Ayar , Mohammad Rahmati

To detect anomalies in real-world graphs, such as social, email, and financial networks, various approaches have been developed. While they typically assume static input graphs, most real-world graphs grow over time, naturally represented…

Machine Learning · Computer Science 2024-07-26 Jongha Lee , Sunwoo Kim , Kijung Shin

Anomalies often occur in real-world information networks/graphs, such as malevolent users, malicious comments, banned users, and fake news in social graphs. The latest graph anomaly detection methods use a novel mechanism called truncated…

Social and Information Networks · Computer Science 2026-03-03 Xiong Zhang , Hong Peng , Zhenli He , Cheng Xie , Xin Jin , Hua Jiang

The superiority of graph contrastive learning (GCL) has prompted its application to anomaly detection tasks for more powerful risk warning systems. Unfortunately, existing GCL-based models tend to excessively prioritize overall detection…

Machine Learning · Computer Science 2025-07-22 Yiming Xu , Zhen Peng , Bin Shi , Xu Hua , Bo Dong , Song Wang , Chen Chen

Anomaly detection in dynamic graphs is essential for identifying malicious activities, fraud, and unexpected behaviors in real-world systems such as cybersecurity and power grids. However, existing approaches struggle with scalability,…

Machine Learning · Computer Science 2025-09-16 Ocheme Anthony Ekle , William Eberle

Anomaly detection is a crucial task in complex distributed systems. A thorough understanding of the requirements and challenges of anomaly detection is pivotal to the security of such systems, especially for real-world deployment. While…

Network Intrusion Detection Systems (NIDS) are essential tools for detecting network attacks and intrusions. While extensive research has explored the use of supervised Machine Learning for attack detection and characterisation, these…

Cryptography and Security · Computer Science 2026-04-23 Georgios Anyfantis , Pere Barlet-Ros

Graph anomaly detection has long been an important problem in various domains pertaining to information security such as financial fraud, social spam and network intrusion. The majority of existing methods are performed in an unsupervised…

Machine Learning · Computer Science 2024-08-27 Xiongxiao Xu , Kaize Ding , Canyu Chen , Kai Shu

Graph anomaly detection (GAD) is a vital task since even a few anomalies can pose huge threats to benign users. Recent semi-supervised GAD methods, which can effectively leverage the available labels as prior knowledge, have achieved…

Machine Learning · Computer Science 2023-06-21 Shuang Zhou , Xiao Huang , Ninghao Liu , Huachi Zhou , Fu-Lai Chung , Long-Kai Huang

Graph anomaly detection (GAD) is a vital task since even a few anomalies can pose huge threats to benign users. Recent semi-supervised GAD methods, which can effectively leverage the available labels as prior knowledge, have achieved…

Machine Learning · Computer Science 2023-07-25 Shuang Zhou , Xiao Huang , Ninghao Liu , Fu-Lai Chung , Long-Kai Huang