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High-dimensional data poses unique challenges in outlier detection process. Most of the existing algorithms fail to properly address the issues stemming from a large number of features. In particular, outlier detection algorithms perform…

Machine Learning · Computer Science 2020-09-22 Firuz Kamalov , Ho Hon Leung

Outlier detection refers to the identification of data points that deviate from a general data distribution. Existing unsupervised approaches often suffer from high computational cost, complex hyperparameter tuning, and limited…

Machine Learning · Computer Science 2022-08-26 Zheng Li , Yue Zhao , Xiyang Hu , Nicola Botta , Cezar Ionescu , George H. Chen

Mechanical defects in real situations affect observation values and cause abnormalities in multivariate time series, such as sensor values or network data. To perceive abnormalities in such data, it is crucial to understand the temporal…

Machine Learning · Computer Science 2023-05-09 Yungi Jeong , Eunseok Yang , Jung Hyun Ryu , Imseong Park , Myungjoo Kang

Machine learning-based Deepfake detection models have achieved impressive results on benchmark datasets, yet their performance often deteriorates significantly when evaluated on out-of-distribution data. In this work, we investigate an…

Computer Vision and Pattern Recognition · Computer Science 2025-07-09 Haroon Wahab , Hassan Ugail , Lujain Jaleel

Selecting and combining the outlier scores of different base detectors used within outlier ensembles can be quite challenging in the absence of ground truth. In this paper, an unsupervised outlier detector combination framework called DCSO…

Machine Learning · Computer Science 2019-11-26 Yue Zhao , Maciej K. Hryniewicki

Given an unsupervised outlier detection (OD) task on a new dataset, how can we automatically select a good outlier detection method and its hyperparameter(s) (collectively called a model)? Thus far, model selection for OD has been a "black…

Machine Learning · Computer Science 2021-03-18 Yue Zhao , Ryan A. Rossi , Leman Akoglu

An outlier is an observation or a data point that is far from rest of the data points in a given dataset or we can be said that an outlier is away from the center of mass of observations. Presence of outliers can skew statistical measures…

Machine Learning · Computer Science 2021-06-17 Amulya Agarwal , Nitin Gupta

Deep learning has become very popular for tasks such as predictive modeling and pattern recognition in handling big data. Deep learning is a powerful machine learning method that extracts lower level features and feeds them forward for the…

Machine Learning · Computer Science 2018-03-07 Steven Young , Tamer Abdou , Ayse Bener

Ensemble learning aims to improve generalization ability by using multiple base learners. It is well-known that to construct a good ensemble, the base learners should be accurate as well as diverse. In this paper, unlabeled data is…

Machine Learning · Computer Science 2010-09-28 Min-Ling Zhang , Zhi-Hua Zhou

The aim of surface defect detection is to identify and localise abnormal regions on the surfaces of captured objects, a task that's increasingly demanded across various industries. Current approaches frequently fail to fulfil the extensive…

Computer Vision and Pattern Recognition · Computer Science 2024-08-23 Blaž Rolih , Matic Fučka , Danijel Skočaj

Successful detection of Out-of-Distribution (OoD) data is becoming increasingly important to ensure safe deployment of neural networks. One of the main challenges in OoD detection is that neural networks output overconfident predictions on…

Computer Vision and Pattern Recognition · Computer Science 2023-10-26 Sangha Park , Jisoo Mok , Dahuin Jung , Saehyung Lee , Sungroh Yoon

Ensemble modeling has been widely used to solve complex problems as it helps to improve overall performance and generalization. In this paper, we propose a novel TemporalAugmenter approach based on ensemble modeling for augmenting the…

Machine Learning · Computer Science 2024-01-17 Nelly Elsayed , Constantinos L. Zekios , Navid Asadizanjani , Zag ElSayed

An ensemble method that fuses the output decision vectors of multiple feedforward-designed convolutional neural networks (FF-CNNs) to solve the image classification problem is proposed in this work. To enhance the performance of the…

Computer Vision and Pattern Recognition · Computer Science 2019-01-09 Yueru Chen , Yijing Yang , Wei Wang , C. -C. Jay Kuo

Recent state-of-the-art forecasting methods are trained on collections of time series. These methods, often referred to as global models, can capture common patterns in different time series to improve their generalization performance.…

Machine Learning · Computer Science 2024-04-30 Vitor Cerqueira , Nuno Moniz , Ricardo Inácio , Carlos Soares

Anomaly detection is a fundamental task for time series analytics with important implications for the downstream performance of many applications. Despite increasing academic interest and the large number of methods proposed in the…

Machine Learning · Computer Science 2025-12-03 Emmanouil Sylligardos , John Paparrizos , Themis Palpanas , Pierre Senellart , Paul Boniol

Outlier detection is an important task in data mining and many technologies have been explored in various applications. However, due to the default assumption that outliers are non-concentrated, unsupervised outlier detection may not…

Machine Learning · Computer Science 2020-03-10 Zhe Li , Chunhua Sun , Chunli Liu , Xiayu Chen , Meng Wang , Yezheng Liu

Anomaly detection has been a challenging task given high-dimensional multivariate time series data generated by networked sensors and actuators in Cyber-Physical Systems (CPS). Besides the highly nonlinear, complex, and dynamic natures of…

Machine Learning · Computer Science 2021-08-31 Kai Zhang , Yushan Jiang , Lee Seversky , Chengtao Xu , Dahai Liu , Houbing Song

Due to the dominant position of deep learning (mostly deep neural networks) in various artificial intelligence applications, recently, ensemble learning based on deep neural networks (ensemble deep learning) has shown significant…

Machine Learning · Computer Science 2022-11-07 Yongquan Yang , Haijun Lv , Ning Chen

In this paper, we aim to improve multivariate anomaly detection (AD) by modeling the \textit{time-varying non-linear spatio-temporal correlations} found in multivariate time series data . In multivariate time series data, an anomaly may be…

Machine Learning · Computer Science 2025-09-19 Padmaksha Roy , Almuatazbellah Boker , Lamine Mili

Detecting out-of-distribution (OOD) data is a fundamental challenge in the deployment of machine learning models. From a security standpoint, this is particularly important because OOD test data can result in misleadingly confident yet…

Machine Learning · Computer Science 2025-02-25 Onat Gungor , Amanda Sofie Rios , Nilesh Ahuja , Tajana Rosing