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We consider state estimation for networked systems where measurements from sensor nodes are contaminated by outliers. A new hierarchical measurement model is formulated for outlier detection by integrating the outlier-free measurement model…

Applications · Statistics 2022-11-08 Hongwei Wang , Hongbin Li , Wei Zhang , Junyi Zuo , Heping Wang , Jun Fang

In a network meta-analysis, some of the collected studies may deviate markedly from the others, for example having very unusual effect sizes. These deviating studies can be regarded as outlying with respect to the rest of the network and…

Methodology · Statistics 2023-01-11 Silvia Metelli , Dimitris Mavridis , Perrine Créquit , Anna Chaimani

The outlier detection problem in some cases is similar to the classification problem. For example, the main concern of clustering-based outlier detection algorithms is to find clusters and outliers, which are often regarded as noise that…

Machine Learning · Computer Science 2014-05-25 M. H. Marghny , Ahmed I. Taloba

Notwithstanding the popularity of conventional clustering algorithms such as K-means and probabilistic clustering, their clustering results are sensitive to the presence of outliers in the data. Even a few outliers can compromise the…

Machine Learning · Statistics 2015-05-27 Pedro A. Forero , Vassilis Kekatos , Georgios B. Giannakis

Selecting informative data points for expert feedback can significantly improve the performance of anomaly detection (AD) in various contexts, such as medical diagnostics or fraud detection. In this paper, we determine a set of theoretical…

Machine Learning · Computer Science 2023-07-06 Aodong Li , Chen Qiu , Marius Kloft , Padhraic Smyth , Stephan Mandt , Maja Rudolph

We study two problems in high-dimensional robust statistics: \emph{robust mean estimation} and \emph{outlier detection}. In robust mean estimation the goal is to estimate the mean $\mu$ of a distribution on $\mathbb{R}^d$ given $n$…

Data Structures and Algorithms · Computer Science 2019-06-28 Yihe Dong , Samuel B. Hopkins , Jerry Li

In this paper, we propose a novel approach for outlier detection, called local projections, which is based on concepts of Local Outlier Factor (LOF) (Breunig et al., 2000) and RobPCA (Hubert et al., 2005). By using aspects of both methods,…

Outlier detection (also known as anomaly detection or deviation detection) is a process of detecting data points in which their patterns deviate significantly from others. It is common to have outliers in industry applications, which could…

Machine Learning · Computer Science 2019-11-06 Kasra Babaei , ZhiYuan Chen , Tomas Maul

Given an unsupervised outlier detection (OD) algorithm, how can we optimize its hyperparameter(s) (HP) on a new dataset, without any labels? In this work, we address this challenging hyperparameter optimization for unsupervised OD problem,…

Machine Learning · Computer Science 2022-10-11 Yue Zhao , Leman Akoglu

Anomaly detection is a longstanding and active research area that has many applications in domains such as finance, security, and manufacturing. However, the efficiency and performance of anomaly detection algorithms are challenged by the…

Machine Learning · Computer Science 2025-04-16 Yang Cao , Haolong Xiang , Hang Zhang , Ye Zhu , Kai Ming Ting

Unsupervised anomaly detection (UAD) aims to identify image- and pixel-level anomalies using only normal training data, with wide applications such as industrial inspection and medical analysis, where anomalies are scarce due to privacy…

Computer Vision and Pattern Recognition · Computer Science 2025-10-09 Zhe Zhang , Mingxiu Cai , Gaochang Wu , Jing Zhang , Lingqiao Liu , Dacheng Tao , Tianyou Chai , Xiatian Zhu

Unsupervised outlier detection is attractive because it eliminates the need for labeled data. Moreover, forming multi-model ensembles can improve detection robustness. However, composing an ensemble without labeled data is challenging.…

Machine Learning · Computer Science 2026-05-19 Hong-Phuc Phan , Tuan-Anh Vu , Tung Kieu , Son Ha Xuan , Bin Yang , Christian S. Jensen

Outliers widely occur in big-data applications and may severely affect statistical estimation and inference. In this paper, a framework of outlier-resistant estimation is introduced to robustify an arbitrarily given loss function. It has a…

Methodology · Statistics 2023-04-20 Yiyuan She , Zhifeng Wang , Jiahui Shen

Machine learning offers potential solutions to current issues in industrial systems in areas such as quality control and predictive maintenance, but also faces unique barriers in industrial applications. An ongoing challenge is extreme…

Machine Learning · Computer Science 2026-01-15 Lesley Wheat , Martin v. Mohrenschildt , Saeid Habibi

We propose an anomaly detection method for multi-variate scientific data based on analysis of high-order joint moments. Using kurtosis as a reliable measure of outliers, we suggest that principal kurtosis vectors, by analogy to principal…

Computational Physics · Physics 2019-05-01 Konduri Aditya , Hemanth Kolla , W. Philip Kegelmeyer , Timothy M. Shead , Julia Ling , Warren L. Davis

The task of outlier detection is to find small groups of data objects that are exceptional when compared with rest large amount of data. Detection of such outliers is important for many applications such as fraud detection and customer…

Databases · Computer Science 2007-05-23 Zengyou He , Xiaofei Xu , Shengchun Deng

Irregularities in public health data streams (like COVID-19 Cases) hamper data-driven decision-making for public health stakeholders. A real-time, computer-generated list of the most important, outlying data points from thousands of…

Artificial Intelligence · Computer Science 2024-01-04 Ananya Joshi , Kathryn Mazaitis , Roni Rosenfeld , Bryan Wilder

Many computer vision tasks involve processing large amounts of data contaminated by outliers, which need to be detected and rejected. While outlier detection methods based on robust statistics have existed for decades, only recently have…

Computer Vision and Pattern Recognition · Computer Science 2017-04-14 Chong You , Daniel P. Robinson , René Vidal

Network meta-analysis has been gaining prominence as an evidence synthesis method that enables the comprehensive synthesis and simultaneous comparison of multiple treatments. In many network meta-analyses, some of the constituent studies…

Methodology · Statistics 2021-07-14 Hisashi Noma , Masahiko Gosho , Ryota Ishii , Koji Oba , Toshi A. Furukawa

It has become routine in neuroscience studies to measure brain networks for different individuals using neuroimaging. These networks are typically expressed as adjacency matrices, with each cell containing a summary of connectivity between…

Methodology · Statistics 2022-06-30 Pritam Dey , Zhengwu Zhang , David B. Dunson