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In this paper, a novel framework for anomaly estimation is proposed. The basic idea behind our method is to reduce the data into a two-dimensional space and then rank each data point in the reduced space. We attempt to estimate the degree…

Machine Learning · Computer Science 2021-05-12 Zhongping Ji

The problem of dimension reduction is of increasing importance in modern data analysis. In this paper, we consider modeling the collection of points in a high dimensional space as a union of low dimensional subspaces. In particular we…

Machine Learning · Statistics 2020-06-12 Weiwei Li , Jan Hannig , Sayan Mukherjee

Video anomaly detection aims to identify abnormal events that occurred in videos. Since anomalous events are relatively rare, it is not feasible to collect a balanced dataset and train a binary classifier to solve the task. Thus, most…

Computer Vision and Pattern Recognition · Computer Science 2022-11-24 Guangyu Sun , Zhang Liu , Lianggong Wen , Jing Shi , Chenliang Xu

This paper proposed a novel anomaly detection (AD) approach of High-speed Train images based on convolutional neural networks and the Vision Transformer. Different from previous AD works, in which anomalies are identified with a single…

Computer Vision and Pattern Recognition · Computer Science 2022-03-30 Zhixue Wang , Yu Zhang , Lin Luo , Nan Wang

Semi-supervised anomaly detection, which aims to improve the anomaly detection performance by using a small amount of labeled anomaly data in addition to unlabeled data, has attracted attention. Existing semi-supervised approaches assume…

Machine Learning · Statistics 2025-02-11 Hiroshi Takahashi , Tomoharu Iwata , Atsutoshi Kumagai , Yuuki Yamanaka

Data-driven anomaly detection methods typically build a model for the normal behavior of the target system, and score each data instance with respect to this model. A threshold is invariably needed to identify data instances with high (or…

Machine Learning · Statistics 2019-10-09 Sreelekha Guggilam , S. M. Arshad Zaidi , Varun Chandola , Abani Patra

One-class anomaly detection aims to detect objects that do not belong to a predefined normal class. In practice training data lack those anomalous samples; hence state-of-the-art methods are trained to discriminate between normal and…

Computer Vision and Pattern Recognition · Computer Science 2025-03-10 Romain Hermary , Vincent Gaudillière , Abd El Rahman Shabayek , Djamila Aouada

High-dimensional big data appears in many research fields such as image recognition, biology and collaborative filtering. Often, the exploration of such data by classic algorithms is encountered with difficulties due to `curse of…

Machine Learning · Computer Science 2016-07-13 Amit Bermanis , Aviv Rotbart , Moshe Salhov , Amir Averbuch

Deep learning approaches to anomaly detection have recently improved the state of the art in detection performance on complex datasets such as large collections of images or text. These results have sparked a renewed interest in the anomaly…

Due to the veracity and heterogeneity in network traffic, detecting anomalous events is challenging. The computational load on global servers is a significant challenge in terms of efficiency, accuracy, and scalability. Our primary…

Machine Learning · Computer Science 2023-03-15 William Marfo , Deepak K. Tosh , Shirley V. Moore

Visual anomaly detection aims to learn normality from normal images, but existing approaches are fragmented across various tasks: defect detection, semantic anomaly detection, multi-class anomaly detection, and anomaly clustering. This…

Computer Vision and Pattern Recognition · Computer Science 2023-11-15 Yujin Lee , Harin Lim , Seoyoon Jang , Hyunsoo Yoon

Several techniques for multivariate time series anomaly detection have been proposed recently, but a systematic comparison on a common set of datasets and metrics is lacking. This paper presents a systematic and comprehensive evaluation of…

Machine Learning · Computer Science 2021-09-24 Astha Garg , Wenyu Zhang , Jules Samaran , Savitha Ramasamy , Chuan-Sheng Foo

Synthetic data provides a promising approach to address data scarcity for training machine learning models; however, adoption without proper quality assessments may introduce artifacts, distortions, and unrealistic features that compromise…

Computer Vision and Pattern Recognition · Computer Science 2025-11-10 Rucha Deshpande , Tahsin Rahman , Miguel Lago , Adarsh Subbaswamy , Jana G. Delfino , Ghada Zamzmi , Elim Thompson , Aldo Badano , Seyed Kahaki

Monitoring network traffic data to detect any hidden patterns of anomalies is a challenging and time-consuming task that requires high computing resources. To this end, an appropriate summarization technique is of great importance, where it…

Machine Learning · Computer Science 2021-12-21 Samira Ghodratnama , Mehrdad Zakershahrak , Fariborz Sobhanmanesh

Anomaly detection is an important problem in computer vision; however, the scarcity of anomalous samples makes this task difficult. Thus, recent anomaly detection methods have used only normal images with no abnormal areas for training. In…

Computer Vision and Pattern Recognition · Computer Science 2022-10-17 Shinji Yamada , Satoshi Kamiya , Kazuhiro Hotta

Anomaly detection aims to distinguish abnormal instances that deviate significantly from the majority of benign ones. As instances that appear in the real world are naturally connected and can be represented with graphs, graph neural…

Machine Learning · Computer Science 2023-05-24 Sheng Tian , Jihai Dong , Jintang Li , Wenlong Zhao , Xiaolong Xu , Baokun wang , Bowen Song , Changhua Meng , Tianyi Zhang , Liang Chen

It is widely recognized that deep neural networks are sensitive to bias in the data. This means that during training these models are likely to learn spurious correlations between data and labels, resulting in limited generalization…

Machine Learning · Computer Science 2024-12-06 Vito Paolo Pastore , Massimiliano Ciranni , Davide Marinelli , Francesca Odone , Vittorio Murino

Video anomaly detection is a challenging task not only because it involves solving many sub-tasks such as motion representation, object localization and action recognition, but also because it is commonly considered as an unsupervised…

Computer Vision and Pattern Recognition · Computer Science 2020-12-04 Yuqi Ouyang , Victor Sanchez

While nowadays visual anomaly detection algorithms use deep neural networks to extract salient features from images, the high dimensionality of extracted features makes it difficult to apply those algorithms to large data with 1000s of…

Computer Vision and Pattern Recognition · Computer Science 2026-03-02 Teng-Yok Lee

Multivariate time series data come as a collection of time series describing different aspects of a certain temporal phenomenon. Anomaly detection in this type of data constitutes a challenging problem yet with numerous applications in…

Artificial Intelligence · Computer Science 2025-11-12 Jinbo Li , Hesam Izakian , Witold Pedrycz , Iqbal Jamal