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We propose a one-class neural network (OC-NN) model to detect anomalies in complex data sets. OC-NN combines the ability of deep networks to extract a progressively rich representation of data with the one-class objective of creating a…

Machine Learning · Computer Science 2019-01-14 Raghavendra Chalapathy , Aditya Krishna Menon , Sanjay Chawla

We study the densest subgraph problem and its NP-hard densest at-most-$k$ subgraph variant through the lens of learning-augmented algorithms. We show that, given a reasonably accurate predictor that estimates whether a node belongs to the…

Data Structures and Algorithms · Computer Science 2026-04-16 Thai Bui , Luan Nguyen , Hoa T. Vu

This paper introduces a novel anomaly detection framework that combines the robust statistical principles of density-estimation-based anomaly detection methods with the representation-learning capabilities of deep learning models. The…

Machine Learning · Computer Science 2024-08-15 Joseph Gallego-Mejia , Oscar Bustos-Brinez , Fabio A. González

The goal of anomaly detection is to identify examples that deviate from normal or expected behavior. We tackle this problem for images. We consider a two-phase approach. First, using normal examples, a convolutional autoencoder (CAE) is…

Computer Vision and Pattern Recognition · Computer Science 2020-03-20 Natasa Sarafijanovic-Djukic , Jesse Davis

In this study we evaluate 32 unsupervised anomaly detection algorithms on 52 real-world multivariate tabular datasets, performing the largest comparison of unsupervised anomaly detection algorithms to date. On this collection of datasets,…

Machine Learning · Computer Science 2024-05-28 Roel Bouman , Zaharah Bukhsh , Tom Heskes

Hypergraph is a data structure that enables us to model higher-order associations among data entities. Conventional graph-structured data can represent pairwise relationships only, whereas hypergraph enables us to associate any number of…

Machine Learning · Computer Science 2024-12-10 Md. Tanvir Alam , Chowdhury Farhan Ahmed , Carson K. Leung

Anomalies are samples that significantly deviate from the rest of the data and their detection plays a major role in building machine learning models that can be reliably used in applications such as data-driven design and novelty…

Machine Learning · Statistics 2023-06-19 Amin Yousefpour , Mehdi Shishehbor , Zahra Zanjani Foumani , Ramin Bostanabad

Inspired by recent advances in coverage-guided analysis of neural networks, we propose a novel anomaly detection method. We show that the hidden activation values contain information useful to distinguish between normal and anomalous…

Cryptography and Security · Computer Science 2021-02-25 Philip Sperl , Jan-Philipp Schulze , Konstantin Böttinger

There is a growing need for machine learning-based anomaly detection strategies to broaden the search for Beyond-the-Standard-Model (BSM) physics at the Large Hadron Collider (LHC) and elsewhere. The first step of any anomaly detection…

High Energy Physics - Phenomenology · Physics 2023-01-18 Gregor Kasieczka , Radha Mastandrea , Vinicius Mikuni , Benjamin Nachman , Mariel Pettee , David Shih

We study anomaly detection and introduce an algorithm that processes variable length, irregularly sampled sequences or sequences with missing values. Our algorithm is fully unsupervised, however, can be readily extended to supervised or…

Machine Learning · Statistics 2020-05-26 Oguzhan Karaahmetoglu , Fatih Ilhan , Ismail Balaban , Suleyman Serdar Kozat

Graph-level anomaly detection has become a critical topic in diverse areas, such as financial fraud detection and detecting anomalous activities in social networks. While most research has focused on anomaly detection for visual data such…

Machine Learning · Computer Science 2022-08-05 Chen Qiu , Marius Kloft , Stephan Mandt , Maja Rudolph

Deep neural networks (DNN) can achieve high performance when applied to In-Distribution (ID) data which come from the same distribution as the training set. When presented with anomaly inputs not from the ID, the outputs of a DNN should be…

Machine Learning · Computer Science 2021-10-08 Fangzhen Zhao , Chenyi Zhang , Naipeng Dong , Zefeng You , Zhenxin Wu

Anomaly detection is being regarded as an unsupervised learning task as anomalies stem from adversarial or unlikely events with unknown distributions. However, the predictive performance of purely unsupervised anomaly detection often fails…

Machine Learning · Computer Science 2014-01-27 Nico Goernitz , Marius Micha Kloft , Konrad Rieck , Ulf Brefeld

This paper proposes a low-power online anomaly detection framework based on neuromorphic wireless sensor networks, encompassing possible use cases such as brain-machine interfaces and remote environmental monitoring. In the considered…

Machine Learning · Computer Science 2025-10-17 Junya Shiraishi , Jiechen Chen , Osvaldo Simeone , Petar Popovski

In this paper we propose a novel machine-learning method for anomaly detection applicable to data with periodic characteristics where randomly varying period lengths are explicitly allowed. A multi-dimensional time series analysis is…

Signal Processing · Electrical Eng. & Systems 2019-05-22 Lia Ahrens , Julian Ahrens , Hans D. Schotten

Anomaly detection relies on designing a score to determine whether a particular event is uncharacteristic of a given background distribution. One way to define a score is to use autoencoders, which rely on the ability to reconstruct certain…

High Energy Physics - Phenomenology · Physics 2022-03-30 Katherine Fraser , Samuel Homiller , Rashmish K. Mishra , Bryan Ostdiek , Matthew D. Schwartz

Anomalies represent deviations from the intended system operation and can lead to decreased efficiency as well as partial or complete system failure. As the causes of anomalies are often unknown due to complex system dynamics, efficient…

Machine Learning · Computer Science 2021-08-31 Benjamin Lindemann , Benjamin Maschler , Nada Sahlab , Michael Weyrich

Neural network-based anomaly detection methods have shown to achieve high performance. However, they require a large amount of training data for each task. We propose a neural network-based meta-learning method for supervised anomaly…

Machine Learning · Statistics 2021-03-02 Tomoharu Iwata , Atsutoshi Kumagai

Anomaly detection or more generally outliers detection is one of the most popular and challenging subject in theoretical and applied machine learning. The main challenge is that in general we have access to very few labeled data or no…

Machine Learning · Computer Science 2023-05-31 Mansour Zoubeirou A Mayaki , Michel Riveill

We consider classification in the presence of class-dependent asymmetric label noise with unknown noise probabilities. In this setting, identifiability conditions are known, but additional assumptions were shown to be required for finite…

Machine Learning · Computer Science 2019-06-12 Henry W. J. Reeve , Ata Kaban