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We enlarge the number of available functional depths by introducing the kernelized functional spatial depth (KFSD). KFSD is a local-oriented and kernel-based version of the recently proposed functional spatial depth (FSD) that may be useful…

Methodology · Statistics 2015-01-09 Carlo Sguera , Pedro Galeano , Rosa Lillo

We propose two new outlier detection methods, for identifying and classifying different types of outliers in (big) functional data sets. The proposed methods are based on an existing method called Massive Unsupervised Outlier Detection…

Methodology · Statistics 2021-10-15 Oluwasegun Taiwo Ojo , Antonio Fernández Anta , Rosa E. Lillo , Carlo Sguera

We propose a new method to visualize and detect shape outliers in samples of curves. In functional data analysis we observe curves defined over a given real interval and shape outliers are those curves that exhibit a different shape from…

Computation · Statistics 2013-10-01 Ana Arribas-Gil , Juan Romo

We propose a novel procedure for outlier detection in functional data, in a semi-supervised framework. As the data is functional, we consider the coefficients obtained after projecting the observations onto orthonormal bases (wavelet, PCA).…

Machine Learning · Statistics 2017-12-14 Clémentine Barreyre , Béatrice Laurent , Jean-Michel Loubes , Bertrand Cabon , Loïc Boussouf

We consider functional outlier detection from a geometric perspective, specifically: for functional data sets drawn from a functional manifold which is defined by the data's modes of variation in amplitude and phase. Based on this manifold,…

Machine Learning · Statistics 2021-09-15 Moritz Herrmann , Fabian Scheipl

Outlier detection is a technique in data mining that aims to detect unusual or unexpected records in the dataset. Existing outlier detection algorithms have different pros and cons and exhibit different sensitivity to noisy data such as…

Machine Learning · Computer Science 2023-12-22 Yuanyuan Wei , Julian Jang-Jaccard , Fariza Sabrina , Timothy McIntosh

Functional data analysis can be seriously impaired by abnormal observations, which can be classified as either magnitude or shape outliers based on their way of deviating from the bulk of data. Identifying magnitude outliers is relatively…

Methodology · Statistics 2020-03-24 Wenlin Dai , Tomas Mrkvicka , Ying Sun , Marc G. Genton

Given a real-valued function $f$ defined over a manifold $M$ embedded in $\mathbb{R}^d$, we are interested in recovering structural information about $f$ from the sole information of its values on a finite sample $P$. Existing methods…

Computational Geometry · Computer Science 2015-04-08 Mickaël Buchet , Frédéric Chazal , Tamal K. Dey , Fengtao Fan , Steve Y. Oudot , Yusu Wang

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,…

A new anomaly detection method called kernel outlier detection (KOD) is proposed. It is designed to address challenges of outlier detection in high-dimensional settings. The aim is to overcome limitations of existing methods, such as…

Machine Learning · Computer Science 2025-07-01 Can Hakan Dağıdır , Mia Hubert , Peter J. Rousseeuw

Data depth is an efficient tool for robustly summarizing the distribution of functional data and detecting potential magnitude and shape outliers. Commonly used functional data depth notions, such as the modified band depth and extremal…

Methodology · Statistics 2023-11-07 Cristian F. Jimenez-Varon , Fouzi Harrou , Ying Sun

Surface, image and video data can be considered as functional data with a bivariate domain. To detect outlying surfaces or images, a new method is proposed based on the mean and the variability of the degree of outlyingness at each grid…

Methodology · Statistics 2016-02-01 Mia Hubert , Jakob Raymaekers , Peter J. Rousseeuw , Pieter Segaert

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 methods have become increasingly relevant in recent years due to increased security concerns and because of its vast application to different fields. Recently, Pauwels and Lasserre (2016) noticed that the sublevel sets of…

Machine Learning · Statistics 2018-06-19 Armin Askari , Forest Yang , Laurent El Ghaoui

We propose a new assumption in outlier detection: Normal data instances are commonly located in the area that there is hardly any fluctuation on data density, while outliers are often appeared in the area that there is violent fluctuation…

Machine Learning · Computer Science 2020-06-09 Ding Liu , Hui Li

In the present era of large scale surveys, big data presents new challenges to the discovery process for anomalous data. Such data can be indicative of systematic errors, extreme (or rare) forms of known phenomena, or most interestingly,…

Instrumentation and Methods for Astrophysics · Physics 2020-09-17 Daniel Giles , Lucianne Walkowicz

Detecting outliers which are grossly different from or inconsistent with the remaining dataset is a major challenge in real-world KDD applications. Existing outlier detection methods are ineffective on scattered real-world datasets due to…

Machine Learning · Computer Science 2009-12-30 Ke Zhang , Marcus Hutter , Huidong Jin

This paper considers the problem of outlier detection in functional data analysis focusing particularly on the more difficult case of shape outliers. We present an inductive conformal anomaly detection method based on elastic functional…

Methodology · Statistics 2025-04-11 Jason Adams , Brandon Berman , Joshua Michalenko , J. Derek Tucker

The minimum regularized covariance determinant method (MRCD) is a robust estimator for multivariate location and scatter, which detects outliers by fitting a robust covariance matrix to the data. Its regularization ensures that the…

Machine Learning · Statistics 2024-07-08 Joachim Schreurs , Iwein Vranckx , Mia Hubert , Johan A. K. Suykens , Peter J. Rousseeuw

Outlier detection in data streams has gained wide importance presently due to the increasing cases of fraud in various applications of data streams. The techniques for outlier detection have been divided into either statistics based,…

Distributed, Parallel, and Cluster Computing · Computer Science 2010-03-25 Parneeta Dhaliwal , M. P. S. Bhatia , Priti Bansal
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