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Related papers: Unsupervised Surrogate Anomaly Detection

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Unsupervised anomaly detection (AD) is critical for a wide range of practical applications, from network security to health and medical tools. Due to the diversity of problems, no single algorithm has been found to be superior for all AD…

Machine Learning · Computer Science 2023-05-18 Małgorzata Gutowska , Suzanne Little , Andrew McCarren

Anomaly detection is the process of identifying abnormal instances or events in data sets which deviate from the norm significantly. In this study, we propose a signatures based machine learning algorithm to detect rare or unexpected items…

Computational Finance · Quantitative Finance 2022-02-09 Erdinc Akyildirim , Matteo Gambara , Josef Teichmann , Syang Zhou

Anomaly detection on attributed networks aims at finding nodes whose patterns deviate significantly from the majority of reference nodes, which is pervasive in many applications such as network intrusion detection and social spammer…

Machine Learning · Computer Science 2020-02-13 Haoyi Fan , Fengbin Zhang , Zuoyong Li

This paper considers an important Graph Anomaly Detection (GAD) task, namely open-set GAD, which aims to train a detection model using a small number of normal and anomaly nodes (referred to as seen anomalies) to detect both seen anomalies…

Machine Learning · Computer Science 2025-06-23 Qizhou Wang , Guansong Pang , Mahsa Salehi , Xiaokun Xia , Christopher Leckie

Early detection of anomalies in medical images such as brain MRI is highly relevant for diagnosis and treatment of many conditions. Supervised machine learning methods are limited to a small number of pathologies where there is good…

Computer Vision and Pattern Recognition · Computer Science 2023-12-05 Alexander Frotscher , Jaivardhan Kapoor , Thomas Wolfers , Christian F. Baumgartner

Learning representations that clearly distinguish between normal and abnormal data is key to the success of anomaly detection. Most of existing anomaly detection algorithms use activation representations from forward propagation while not…

Computer Vision and Pattern Recognition · Computer Science 2020-07-21 Gukyeong Kwon , Mohit Prabhushankar , Dogancan Temel , Ghassan AlRegib

Many anomaly detection approaches, especially deep learning methods, have been recently developed to identify abnormal image morphology by only employing normal images during training. Unfortunately, many prior anomaly detection methods…

In this paper, we address the anomaly detection problem where the objective is to find the anomalous processes among a given set of processes. To this end, the decision-making agent probes a subset of processes at every time instant and…

Machine Learning · Computer Science 2021-05-14 Geethu Joseph , Chen Zhong , M. Cenk Gursoy , Senem Velipasalar , Pramod K. Varshney

Detecting novel anomalies in medical imaging is challenging due to the limited availability of labeled data for rare abnormalities, which often display high variability and subtlety. This challenge is further compounded when small abnormal…

Computer Vision and Pattern Recognition · Computer Science 2025-01-31 Jingkun Chen , Guang Yang , Xiao Zhang , Jingchao Peng , Tianlu Zhang , Jianguo Zhang , Jungong Han , Vicente Grau

The increasing complexity of medical imaging data underscores the need for advanced anomaly detection methods to automatically identify diverse pathologies. Current methods face challenges in capturing the broad spectrum of anomalies, often…

Image and Video Processing · Electrical Eng. & Systems 2024-01-22 Cosmin I. Bercea , Benedikt Wiestler , Daniel Rueckert , Julia A. Schnabel

Unsupervised anomaly detection is a daunting task, as it relies solely on normality patterns from the training data to identify unseen anomalies during testing. Recent approaches have focused on leveraging domain-specific transformations or…

Machine Learning · Computer Science 2024-09-17 Hyuntae Kim , Changhee Lee

Most classification algorithms used in high energy physics fall under the category of supervised machine learning. Such methods require a training set containing both signal and background events and are prone to classification errors…

Data Analysis, Statistics and Probability · Physics 2015-06-03 Mikael Kuusela , Tommi Vatanen , Eric Malmi , Tapani Raiko , Timo Aaltonen , Yoshikazu Nagai

The problem of anomaly detection has been studied for a long time. In short, anomalies are abnormal or unlikely things. In financial networks, thieves and illegal activities are often anomalous in nature. Members of a network want to detect…

Machine Learning · Computer Science 2017-02-28 Thai Pham , Steven Lee

Anomaly detection, a critical facet in data analysis, involves identifying patterns that deviate from expected behavior. This research addresses the complexities inherent in anomaly detection, exploring challenges and adapting to…

Machine Learning · Computer Science 2024-05-07 Aditya Singh , Pavan Reddy

Anomaly detection is defined as the problem of finding data points that do not follow the patterns of the majority. Among the various proposed methods for solving this problem, classification-based methods, including one-class Support…

Optimization and Control · Mathematics 2023-12-05 Amir Hossein Noormohammadia , Seyed Ali MirHassania , Farnaz Hooshmand Khaligh

Anomaly detection aims to find instances that are considered unusual and is a fundamental problem of data science. Recently, deep anomaly detection methods were shown to achieve superior results particularly in complex data such as images.…

Machine Learning · Computer Science 2021-01-01 Hongjing Zhang , Ian Davidson

Unsupervised anomaly detection (UAD) learns one-class classifiers exclusively with normal (i.e., healthy) images to detect any abnormal (i.e., unhealthy) samples that do not conform to the expected normal patterns. UAD has two main…

Computer Vision and Pattern Recognition · Computer Science 2021-07-01 Yu Tian , Guansong Pang , Fengbei Liu , Yuanhong chen , Seon Ho Shin , Johan W. Verjans , Rajvinder Singh , Gustavo Carneiro

This paper presents a novel density estimation method for anomaly detection using density matrices (a powerful mathematical formalism from quantum mechanics) and Fourier features. The method can be seen as an efficient approximation of…

Machine Learning · Computer Science 2022-10-27 Oscar Bustos-Brinez , Joseph Gallego-Mejia , Fabio A. González

In this paper, we propose and evaluate the application of unsupervised machine learning to anomaly detection for a Cyber-Physical System (CPS). We compare two methods: Deep Neural Networks (DNN) adapted to time series data generated by a…

Machine Learning · Computer Science 2017-12-25 Jun Inoue , Yoriyuki Yamagata , Yuqi Chen , Christopher M. Poskitt , Jun Sun

In this paper we address the abnormality detection problem in crowded scenes. We propose to use Generative Adversarial Nets (GANs), which are trained using normal frames and corresponding optical-flow images in order to learn an internal…

Computer Vision and Pattern Recognition · Computer Science 2017-09-01 Mahdyar Ravanbakhsh , Moin Nabi , Enver Sangineto , Lucio Marcenaro , Carlo Regazzoni , Nicu Sebe