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Classical semiparametric inference with missing outcome data is not robust to contamination of the observed data and a single observation can have arbitrarily large influence on estimation of a parameter of interest. This sensitivity is…

Methodology · Statistics 2021-03-02 Eva Cantoni , Xavier de Luna

In fitting a mixture of linear regression models, normal assumption is traditionally used to model the error and then regression parameters are estimated by the maximum likelihood estimators (MLE). This procedure is not valid if the normal…

Methodology · Statistics 2018-11-06 Yanyuan Ma , Shaoli Wang , Lin Xu , Weixin Yao

Mixtures of linear mixed models (MLMMs) are useful for clustering grouped data and can be estimated by likelihood maximization through the EM algorithm. The conventional approach to determining a suitable number of components is to compare…

Applications · Statistics 2014-05-26 Siew Li Tan , David J. Nott

Finite Gaussian mixture models are widely used for model-based clustering of continuous data. Nevertheless, since the number of model parameters scales quadratically with the number of variables, these models can be easily…

Methodology · Statistics 2018-09-25 Michael Fop , Thomas Brendan Murphy , Luca Scrucca

Expectation Maximization (EM) is among the most popular algorithms for maximum likelihood estimation, but it is generally only guaranteed to find its stationary points of the log-likelihood objective. The goal of this article is to present…

Machine Learning · Computer Science 2018-10-29 Ji Xu , Daniel Hsu , Arian Maleki

We give an efficient algorithm for robustly clustering of a mixture of two arbitrary Gaussians, a central open problem in the theory of computationally efficient robust estimation, assuming only that the the means of the component Gaussians…

Data Structures and Algorithms · Computer Science 2020-06-02 He Jia , Santosh Vempala

We systematically study various network Expectation-Maximization (EM) algorithms for the Gaussian mixture model within the framework of decentralized federated learning. Our theoretical investigation reveals that directly extending the…

Machine Learning · Statistics 2024-11-11 Shuyuan Wu , Bin Du , Xuetong Li , Hansheng Wang

We study Gaussian sparse estimation tasks in Huber's contamination model with a focus on mean estimation, PCA, and linear regression. For each of these tasks, we give the first sample and computationally efficient robust estimators with…

Machine Learning · Computer Science 2024-03-18 Ilias Diakonikolas , Daniel M. Kane , Sushrut Karmalkar , Ankit Pensia , Thanasis Pittas

Linear and Quadratic Discriminant Analysis are well-known classical methods but can heavily suffer from non-Gaussian distributions and/or contaminated datasets, mainly because of the underlying Gaussian assumption that is not robust. To…

Machine Learning · Statistics 2022-01-11 Pierre Houdouin , Frédéric Pascal , Matthieu Jonckheere , Andrew Wang

A weighted likelihood approach for robust fitting of a mixture of multivariate Gaussian components is developed in this work. Two approaches have been proposed that are driven by a suitable modification of the standard EM and CEM…

Methodology · Statistics 2018-11-19 Luca Greco , Claudio Agostinelli

Mixtures of Gaussian (or normal) distributions arise in a variety of application areas. Many heuristics have been proposed for the task of finding the component Gaussians given samples from the mixture, such as the EM algorithm, a…

Probability · Mathematics 2007-05-23 Sanjeev Arora , Ravi Kannan

Generalised linear models for multi-class classification problems are one of the fundamental building blocks of modern machine learning tasks. In this manuscript, we characterise the learning of a mixture of $K$ Gaussians with generic means…

We give a polynomial-time algorithm for the problem of robustly estimating a mixture of $k$ arbitrary Gaussians in $\mathbb{R}^d$, for any fixed $k$, in the presence of a constant fraction of arbitrary corruptions. This resolves the main…

Data Structures and Algorithms · Computer Science 2021-06-08 Ainesh Bakshi , Ilias Diakonikolas , He Jia , Daniel M. Kane , Pravesh K. Kothari , Santosh S. Vempala

Model-based clustering approaches concern the paradigm of exploratory data analysis relying on the finite mixture model to automatically find a latent structure governing observed data. They are one of the most popular and successful…

Methodology · Statistics 2014-04-29 Faicel Chamroukhi

We propose an Gaussian Mixture Model (GMM) learning algorithm, based on our previous work of GMM expansion idea. The new algorithm brings more robustness and simplicity than classic Expectation Maximization (EM) algorithm. It also improves…

Machine Learning · Computer Science 2023-09-07 Weiguo Lu , Xuan Wu , Deng Ding , Gangnan Yuan

This paper investigates Gaussian copula mixture models (GCMM), which are an extension of Gaussian mixture models (GMM) that incorporate copula concepts. The paper presents the mathematical definition of GCMM and explores the properties of…

Machine Learning · Computer Science 2023-05-25 Ke Wan , Alain Kornhauser

In this paper, we consider nonparametric multidimensional finite mixture models and we are interested in the semiparametric estimation of the population weights. Here, the i.i.d. observations are assumed to have at least three components…

Statistics Theory · Mathematics 2017-12-14 Elisabeth Gassiat , Judith Rousseau , Elodie Vernet

This paper proposes a flexible Bayesian approach to multiple imputation using conditional Gaussian mixtures. We introduce novel shrinkage priors for covariate-dependent mixing proportions in the mixture models to automatically select the…

Methodology · Statistics 2022-08-17 Shonosuke Sugasawa , Jae Kwang Kim , Kosuke Morikawa

Nonlinear mixed effects models have received a great deal of attention in the statistical literature in recent years because of their flexibility in handling longitudinal studies, including human immunodeficiency virus viral dynamics,…

Methodology · Statistics 2021-09-28 Fernanda L. Schumacher , Dipak K. Dey , Victor H. Lachos

The present study proposes incorporating non-parametric knowledge into the diffusion least-mean-squares algorithm in the framework of a maximum a posteriori (MAP) estimation. The proposed algorithm leads to a robust estimation of an unknown…

Machine Learning · Computer Science 2023-12-05 Soheil Ashkezari-Toussi , Hadi sadoghi-Yazdi