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We propose a new class of robust and Fisher-consistent estimators for mixture models. These estimators can be used to construct robust model-based clustering procedures. We study in detail the case of multivariate normal mixtures and…

Methodology · Statistics 2021-06-09 Juan D. Gonzalez , Ricardo Maronna , Victor J. Yohai , Ruben H. Zamar

In this paper, a general class of regularized $M$-estimators of scatter matrix are proposed which are suitable also for low or insufficient sample support (small $n$ and large $p$) problems. The considered class constitutes a natural…

Applications · Statistics 2015-06-19 Esa Ollila , David E. Tyler

We introduce new estimators for robust machine learning based on median-of-means (MOM) estimators of the mean of real valued random variables. These estimators achieve optimal rates of convergence under minimal assumptions on the dataset.…

Statistics Theory · Mathematics 2017-12-04 Guillaume Lecué , Matthieu Lerasle

Robust estimators of large covariance matrices are considered, comprising regularized (linear shrinkage) modifications of Maronna's classical M-estimators. These estimators provide robustness to outliers, while simultaneously being…

Statistics Theory · Mathematics 2018-07-04 Nicolas Auguin , David Morales-Jimenez , Matthew R. McKay , Romain Couillet

A class of robust estimators of scatter applied to information-plus-impulsive noise samples is studied, where the sample information matrix is assumed of low rank; this generalizes the study of (Couillet et al., 2013b) to spiked random…

Probability · Mathematics 2014-05-01 Romain Couillet

In this paper, we introduce a class of improved estimators for the mean parameter matrix of a multivariate normal distribution with an unknown variance-covariance matrix. In particular, the main results of [D.Ch\'etelat and M. T.…

Statistics Theory · Mathematics 2024-06-25 Arash A. Foroushani , Severien Nkurunziza

In this note we introduce the M$S_n$ estimator (for Multivariate $S_n$) a new robust estimator of multivariate ranking. Like MVE and MCD it searches for an $h$-subset which minimizes a criterion. The difference is that the new criterion…

Methodology · Statistics 2014-06-24 Kaveh Vakili

A common assumption when sampling $p$-dimensional observations from $K$ distinct group is the equality of the covariance matrices. In this paper, we propose two penalized $M$-estimation approaches for the estimation of the covariance or…

Methodology · Statistics 2016-08-30 Esa Ollila , Ilya Soloveychik , David E. Tyler , Ami Wiesel

Markov chain Monte Carlo (MCMC) algorithms are used to estimate features of interest of a distribution. The Monte Carlo error in estimation has an asymptotic normal distribution whose multivariate nature has so far been ignored in the MCMC…

Statistics Theory · Mathematics 2016-07-05 Dootika Vats , James M. Flegal , Galin L. Jones

Covariance matrices play a major role in statistics, signal processing and machine learning applications. This paper focuses on the \textit{semiparametric} covariance/scatter matrix estimation problem in elliptical distributions. The class…

Signal Processing · Electrical Eng. & Systems 2020-10-28 Stefano Fortunati , Alexandre Renaux , Frédéric Pascal

This article studies two regularized robust estimators of scatter matrices proposed (and proved to be well defined) in parallel in (Chen et al., 2011) and (Pascal et al., 2013), based on Tyler's robust M-estimator (Tyler, 1987) and on…

Probability · Mathematics 2015-01-20 Romain Couillet , Matthew R. McKay

Let there be given a contaminated list of n R^d-valued observations coming from g different, normally distributed populations with a common covariance matrix. We compute the ML-estimator with respect to a certain statistical model with n-r…

Statistics Theory · Mathematics 2007-06-13 Maria Teresa Gallegos , Gunter Ritter

We propose a general framework for regularization in M-estimation problems under time dependent (absolutely regular-mixing) data which encompasses many of the existing estimators. We derive non-asymptotic concentration bounds for the…

Statistics Theory · Mathematics 2018-01-04 Demian Pouzo

Estimating a high-dimensional sparse covariance matrix from a limited number of samples is a fundamental problem in contemporary data analysis. Most proposals to date, however, are not robust to outliers or heavy tails. Towards bridging…

Statistics Theory · Mathematics 2020-08-04 John Goes , Gilad Lerman , Boaz Nadler

A new robust correlation estimator based on the spatial sign covariance matrix (SSCM) is proposed. We derive its asymptotic distribution and influence function at elliptical distributions. Finite sample and robustness properties are studied…

Methodology · Statistics 2022-04-12 Alexander Dürre , Daniel Vogel , Roland Fried

Estimation of covariance matrices or their inverses plays a central role in many statistical methods. For these methods to work reliably, estimated matrices must not only be invertible but also well-conditioned. In this paper we present an…

Methodology · Statistics 2014-08-06 Eric C. Chi , Kenneth Lange

We propose a class of robust estimates for multivariate linear models. Based on the approach of MM estimation (Yohai 1987), we estimate the regression coefficients and the covariance matrix of the errors simultaneously. These estimates have…

Statistics Theory · Mathematics 2025-12-03 Nadia L. Kudraszow , Ricardo A. Maronna

We present new algorithms for $M$-estimators of multivariate scatter and location and for symmetrized $M$-estimators of multivariate scatter. The new algorithms are considerably faster than currently used fixed-point and related algorithms.…

Computation · Statistics 2015-12-10 Lutz Duembgen , Klaus Nordhausen , Heike Schuhmacher

The support vector machine (SVM) is one of the most successful learning methods for solving classification problems. Despite its popularity, SVM has a serious drawback, that is sensitivity to outliers in training samples. The penalty on…

Machine Learning · Statistics 2014-09-04 Takafumi Kanamori , Shuhei Fujiwara , Akiko Takeda

We tackle covariance estimation in low-sample scenarios, employing a structured covariance matrix with shrinkage methods. These involve convexly combining a low-bias/high-variance empirical estimate with a biased regularization estimator,…

Instrumentation and Methods for Astrophysics · Physics 2024-06-28 Olivier Flasseur , Eric Thiébaut , Loïc Denis , Maud Langlois