Robust semi-parametric mixtures of linear experts using the contaminated Gaussian distribution

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Autori principali: Mambondimumwe, Peterson, Skhosana, Sphiwe B., Rad, Najmeh Nakhaei
Natura: Preprint
Pubblicazione: 2026
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author Mambondimumwe, Peterson
Skhosana, Sphiwe B.
Rad, Najmeh Nakhaei
author_facet Mambondimumwe, Peterson
Skhosana, Sphiwe B.
Rad, Najmeh Nakhaei
contents Semi- and non-parametric mixture of regressions are a very useful flexible class of mixture of regressions in which some or all of the parameters are non-parametric functions of the covariates. These models are, however, based on the Gaussian assumption of the component error distributions. Thus, their estimation is sensitive to outliers and heavy-tailed error distributions. In this paper, we propose semi- and non-parametric contaminated Gaussian mixture of regressions to robustly estimate the parametric and/or non-parametric terms of the models in the presence of mild outliers. The virtue of using a contaminated Gaussian error distribution is that we can simultaneously perform model-based clustering of observations and model-based outlier detection. We propose two algorithms, an expectation-maximization (EM)-type algorithm and an expectation-conditional-maximization (ECM)-type algorithm, to perform maximum likelihood and local-likelihood kernel estimation of the parametric and non-parametric of the proposed models, respectively. The robustness of the proposed models is examined using an extensive simulation study. The practical utility of the proposed models is demonstrated using real data.
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id arxiv_https___arxiv_org_abs_2601_12425
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Robust semi-parametric mixtures of linear experts using the contaminated Gaussian distribution
Mambondimumwe, Peterson
Skhosana, Sphiwe B.
Rad, Najmeh Nakhaei
Methodology
Computation
Semi- and non-parametric mixture of regressions are a very useful flexible class of mixture of regressions in which some or all of the parameters are non-parametric functions of the covariates. These models are, however, based on the Gaussian assumption of the component error distributions. Thus, their estimation is sensitive to outliers and heavy-tailed error distributions. In this paper, we propose semi- and non-parametric contaminated Gaussian mixture of regressions to robustly estimate the parametric and/or non-parametric terms of the models in the presence of mild outliers. The virtue of using a contaminated Gaussian error distribution is that we can simultaneously perform model-based clustering of observations and model-based outlier detection. We propose two algorithms, an expectation-maximization (EM)-type algorithm and an expectation-conditional-maximization (ECM)-type algorithm, to perform maximum likelihood and local-likelihood kernel estimation of the parametric and non-parametric of the proposed models, respectively. The robustness of the proposed models is examined using an extensive simulation study. The practical utility of the proposed models is demonstrated using real data.
title Robust semi-parametric mixtures of linear experts using the contaminated Gaussian distribution
topic Methodology
Computation
url https://arxiv.org/abs/2601.12425