English
Related papers

Related papers: Finite Mixtures of Canonical Fundamental Skew t-Di…

200 papers

In this paper, we present an algorithm for the fitting of a location-scale variant of the canonical fundamental skew t (CFUST) distribution, a superclass of the restricted and unrestricted skew t-distributions. In recent years, a few…

Methodology · Statistics 2014-02-03 Sharon X. Lee , Geoffrey J. McLachlan

This paper presents an R package EMMIXcskew for the fitting of the canonical fundamental skew t-distribution (CFUST) and finite mixtures of this distribution (FM-CFUST) via maximum likelihood (ML). The CFUST distribution provides a flexible…

Computation · Statistics 2017-02-10 Sharon X. Lee , Geoffrey J. McLachlan

This paper describes an algorithm for fitting finite mixtures of unrestricted Multivariate Skew t (FM-uMST) distributions. The package EMMIX-uskew implements a closed-form expectation-maximization (EM) algorithm for computing the maximum…

Computation · Statistics 2013-03-29 Sharon X. Lee , Geoffrey J. McLachlan

In this paper, we comment on the recent comparison in Azzalini et al. (2014) of two different distributions proposed in the literature for the modelling of data that have asymmetric and possibly long-tailed clusters. They are referred to as…

Methodology · Statistics 2014-04-08 Geoffrey J. McLachlan , Sharon X. Lee

Analysis of matrix-variate data is becoming increasingly common in the literature, particularly in the field of clustering and classification. It is well-known that real data, including real matrix-variate data, often exhibit high levels of…

Methodology · Statistics 2024-07-30 Abbas Mahdavi , Narayanaswamy Balakrishnan , Ahad Jamalizadeh

We comment on the recent paper by Azzalini et al. (2015) on two different distributions proposed in the literature for the modelling of data that have asymmetric and possibly long-tailed clusters. They are referred to as the restricted and…

Statistics Theory · Mathematics 2016-01-06 Geoffrey J. McLachlan , Sharon X. Lee

We show how the expectation-maximization (EM) algorithm can be applied exactly for the fitting of mixtures of general multivariate skew t (MST) distributions, eliminating the need for computationally expensive Monte Carlo estimation. Finite…

Methodology · Statistics 2012-09-06 S. X. Lee , G. J. McLachlan

In clinical trials, studies often present longitudinal data or clustered data. These studies are commonly analyzed using linear mixed models (LMMs), usually considering Gaussian assumptions for random effect and error terms. Recently,…

Methodology · Statistics 2021-09-28 Fernanda L. Schumacher , Larissa A. Matos , Celso R. B. Cabral

Finite mixture of skew distributions have emerged as an effective tool in modelling heterogeneous data with asymmetric features. With various proposals appearing rapidly in the recent years, which are similar but not identical, the…

Methodology · Statistics 2013-05-29 Sharon X. Lee , Geoffrey J. McLachlan

Mixtures of factor analyzers (MFA) provide a powerful tool for modelling high-dimensional datasets. In recent years, several generalizations of MFA have been developed where the normality assumption of the factors and/or of the errors was…

Methodology · Statistics 2018-10-29 Sharon X. Lee , Tsung-I Lin , Geoffrey J. McLachlan

Handling missing data is a major challenge in model-based clustering, especially when the data exhibit skewness and heavy tails. We address this by extending the finite mixture of scale mixtures of multivariate skew-normal (FMSMSN) family…

Methodology · Statistics 2025-07-29 Jason Pillay , Cristina Tortora , Antonio Punzo , Andriette Bekker

Finite mixture models have been widely used for the modelling and analysis of data from heterogeneous populations. Maximum likelihood estimation of the parameters is typically carried out via the Expectation-Maximization (EM) algorithm. The…

Computation · Statistics 2016-06-08 Sharon X Lee , Kaleb L Lee , Geoffrey J McLachlan

Finite mixture models have been widely used to model and analyze data from a heterogeneous populations. Moreover, data of this kind can be missing or subject to some upper and/or lower detection limits because of the restriction of…

In this paper, we introduce a mixture of skew-t factor analyzers as well as a family of mixture models based thereon. The mixture of skew-t distributions model that we use arises as a limiting case of the mixture of generalized hyperbolic…

Methodology · Statistics 2014-05-05 Paula M. Murray , Ryan P. Browne , Paul D. McNicholas

Clustering is the process of finding underlying group structures in data. Although mixture model-based clustering is firmly established in the multivariate case, there is a relative paucity of work on matrix variate distributions and none…

Methodology · Statistics 2018-03-06 Michael P. B. Gallaugher , Paul D. McNicholas

Families of mixtures of multivariate power exponential (MPE) distributions have been previously introduced and shown to be competitive for cluster analysis in comparison to other elliptical mixtures including mixtures of Gaussian…

Computation · Statistics 2023-01-24 Utkarsh J. Dang , Michael P. B. Gallaugher , Ryan P. Browne , Paul D. McNicholas

Any clustering algorithm must synchronously learn to model the clusters and allocate data to those clusters in the absence of labels. Mixture model-based methods model clusters with pre-defined statistical distributions and allocate data to…

Machine Learning · Computer Science 2022-10-04 Dumindu Tissera , Kasun Vithanage , Rukshan Wijesinghe , Alex Xavier , Sanath Jayasena , Subha Fernando , Ranga Rodrigo

We propose a flexible formulation of the multivariate non-central skew t (NCST) distribution, defined by scaling skew-normal random vectors with independent chi-squared variables. This construction extends the classical multivariate t…

Methodology · Statistics 2025-07-15 Abeer M. Hasan , Ying-Ju Chen

A mixture of common skew-t factor analyzers model is introduced for model-based clustering of high-dimensional data. By assuming common component factor loadings, this model allows clustering to be performed in the presence of a large…

Methodology · Statistics 2014-05-05 Paula M. Murray , Paul D. McNicholas , Ryan P. Browne

Finite mixtures of skew distributions provide a flexible tool for modelling heterogeneous data with asymmetric distributional features. However, parameter estimation via the Expectation-Maximization (EM) algorithm can become very…

Computation · Statistics 2016-08-10 Sharon X Lee , Kaleb L Leemaqz , Geoffrey J McLachlan
‹ Prev 1 2 3 10 Next ›