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Attributed graph clustering, which learns node representation from node attribute and topological graph for clustering, is a fundamental but challenging task for graph analysis. Recently, methods based on graph contrastive learning (GCL)…

Machine Learning · Computer Science 2023-05-15 Wei Xia , Quanxue Gao , Ming Yang , Xinbo Gao

This paper proposes a simple but effective graph-based agglomerative algorithm, for clustering high-dimensional data. We explore the different roles of two fundamental concepts in graph theory, indegree and outdegree, in the context of…

Computer Vision and Pattern Recognition · Computer Science 2015-03-20 Wei Zhang , Xiaogang Wang , Deli Zhao , Xiaoou Tang

The widespread application of graph data in various high-risk scenarios has increased attention to graph anomaly detection (GAD). Faced with real-world graphs that often carry node descriptions in the form of raw text sequences, termed…

Machine Learning · Computer Science 2025-08-04 Yiming Xu , Xu Hua , Zhen Peng , Bin Shi , Jiarun Chen , Xingbo Fu , Song Wang , Bo Dong

Adversarial attacks present a significant challenge to the dependable deployment of machine learning models, with patch-based attacks being particularly potent. These attacks introduce adversarial perturbations in localized regions of an…

Cryptography and Security · Computer Science 2024-08-28 Nandish Chattopadhyay , Amira Guesmi , Muhammad Abdullah Hanif , Bassem Ouni , Muhammad Shafique

Detecting anomalies in large complex systems is a critical and challenging task. The difficulties arise from several aspects. First, collecting ground truth labels or prior knowledge for anomalies is hard in real-world systems, which often…

Machine Learning · Computer Science 2021-06-01 Huiling Qin , Xianyuan Zhan , Yu Zheng

Anomaly detection is defined as discovering patterns that do not conform to the expected behavior. Previously, anomaly detection was mostly conducted using traditional shallow learning techniques, but with little improvement. As the…

Computer Vision and Pattern Recognition · Computer Science 2022-12-13 Zhiyuan Liu , Chunjie Cao , Jingzhang Sun

The problem of outlier detection is extremely challenging in many domains such as text, in which the attribute values are typically non-negative, and most values are zero. In such cases, it often becomes difficult to separate the outliers…

Information Retrieval · Computer Science 2017-01-06 Ramakrishnan Kannan , Hyenkyun Woo , Charu C. Aggarwal , Haesun Park

We develop a new density-based clustering algorithm named CRAD which is based on a new neighbor searching function with a robust data depth as the dissimilarity measure. Our experiments prove that the new CRAD is highly competitive at…

Computation · Statistics 2019-04-09 Xin Huang , Yulia R. Gel

Detecting outliers which are grossly different from or inconsistent with the remaining dataset is a major challenge in real-world KDD applications. Existing outlier detection methods are ineffective on scattered real-world datasets due to…

Machine Learning · Computer Science 2009-12-30 Ke Zhang , Marcus Hutter , Huidong Jin

Outlier detection tasks aim at discovering potential issues or opportunities and are widely used in cybersecurity, financial security, industrial inspection, etc. To date, thousands of outlier detection algorithms have been proposed.…

Machine Learning · Computer Science 2025-02-11 Qi Li

In today's data-driven digital era, the amount as well as complexity, such as multi-view, non-Euclidean, and multi-relational, of the collected data are growing exponentially or even faster. Clustering, which unsupervisely extracts valid…

Machine Learning · Computer Science 2025-01-10 Zhao Kang , Xuanting Xie , Bingheng Li , Erlin Pan

The minimum regularized covariance determinant method (MRCD) is a robust estimator for multivariate location and scatter, which detects outliers by fitting a robust covariance matrix to the data. Its regularization ensures that the…

Machine Learning · Statistics 2024-07-08 Joachim Schreurs , Iwein Vranckx , Mia Hubert , Johan A. K. Suykens , Peter J. Rousseeuw

We propose a new method to visualize and detect shape outliers in samples of curves. In functional data analysis we observe curves defined over a given real interval and shape outliers are those curves that exhibit a different shape from…

Computation · Statistics 2013-10-01 Ana Arribas-Gil , Juan Romo

Detecting out-of-distribution (OOD) data is critical for machine learning, be it for safety reasons or to enable open-ended learning. However, beyond mere detection, choosing an appropriate course of action typically hinges on the type of…

Machine Learning · Computer Science 2026-04-28 Achref Jaziri , Martin Rogmann , Martin Mundt , Visvanathan Ramesh

Detection of interesting (e.g., coherent or anomalous) clusters has been studied extensively on plain or univariate networks, with various applications. Recently, algorithms have been extended to networks with multiple attributes for each…

Machine Learning · Computer Science 2018-09-21 Feng Chen , Baojian Zhou , Adil Alim , Liang Zhao

This paper focuses on a significant yet challenging task: out-of-distribution detection (OOD detection), which aims to distinguish and reject test samples with semantic shifts, so as to prevent models trained on in-distribution (ID) data…

Computer Vision and Pattern Recognition · Computer Science 2026-05-26 Xiang Fang , Arvind Easwaran , Blaise Genest , Ponnuthurai Nagaratnam Suganthan

Community detection is a fundamental task in graph analysis, with methods often relying on fitting models like the Stochastic Block Model (SBM) to observed networks. While many algorithms can accurately estimate SBM parameters when the…

Machine Learning · Statistics 2025-06-05 Leonardo Martins Bianco , Christine Keribin , Zacharie Naulet

With the sweeping digitalization of societal, medical, industrial, and scientific processes, sensing technologies are being deployed that produce increasing volumes of time series data, thus fueling a plethora of new or improved…

Machine Learning · Computer Science 2024-04-23 David Campos , Tung Kieu , Chenjuan Guo , Feiteng Huang , Kai Zheng , Bin Yang , Christian S. Jensen

As language models become more general purpose, increased attention needs to be paid to detecting out-of-distribution (OOD) instances, i.e., those not belonging to any of the distributions seen during training. Existing methods for…

Machine Learning · Computer Science 2024-07-19 Aryan Gulati , Xingjian Dong , Carlos Hurtado , Sarath Shekkizhar , Swabha Swayamdipta , Antonio Ortega

Out-of-Distribution (OOD) detection is a crucial problem for the safe deployment of machine learning models identifying samples that fall outside of the training distribution, i.e. in-distribution data (ID). Most OOD works focus on the…

Machine Learning · Computer Science 2023-10-04 Soroush Seifi , Daniel Olmeda Reino , Nikolay Chumerin , Rahaf Aljundi