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Autori principali: Tsagris, Michail, Alzeley, Omar
Natura: Preprint
Pubblicazione: 2023
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Accesso online:https://arxiv.org/abs/2302.02468
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author Tsagris, Michail
Alzeley, Omar
author_facet Tsagris, Michail
Alzeley, Omar
contents We introduce a novel family of projected distributions on the circle and the sphere, namely the circular and spherical projected Cauchy distributions, as promising alternatives for modelling circular and spherical data. The circular distribution encompasses the wrapped Cauchy distribution as a special case, while featuring a more convenient parameterisation. We also propose a generalised wrapped Cauchy distribution that includes an extra parameter, enhancing the fit of the distribution. In the spherical context, we impose two conditions on the scatter matrix of the Cauchy distribution, resulting in an elliptically symmetric distribution. Our projected distributions exhibit attractive properties, such as a closed-form normalising constant and straightforward random value generation. The distribution parameters can be estimated using maximum likelihood, and we assess their bias through numerical studies. Further, we compare our proposed distributions to existing models with real datasets, demonstrating equal or superior fitting both with and without covariates.
format Preprint
id arxiv_https___arxiv_org_abs_2302_02468
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Circular and Spherical Projected Cauchy Distributions: A Novel Framework for Circular and Directional Data Modeling
Tsagris, Michail
Alzeley, Omar
Methodology
62H11, 62H10
We introduce a novel family of projected distributions on the circle and the sphere, namely the circular and spherical projected Cauchy distributions, as promising alternatives for modelling circular and spherical data. The circular distribution encompasses the wrapped Cauchy distribution as a special case, while featuring a more convenient parameterisation. We also propose a generalised wrapped Cauchy distribution that includes an extra parameter, enhancing the fit of the distribution. In the spherical context, we impose two conditions on the scatter matrix of the Cauchy distribution, resulting in an elliptically symmetric distribution. Our projected distributions exhibit attractive properties, such as a closed-form normalising constant and straightforward random value generation. The distribution parameters can be estimated using maximum likelihood, and we assess their bias through numerical studies. Further, we compare our proposed distributions to existing models with real datasets, demonstrating equal or superior fitting both with and without covariates.
title Circular and Spherical Projected Cauchy Distributions: A Novel Framework for Circular and Directional Data Modeling
topic Methodology
62H11, 62H10
url https://arxiv.org/abs/2302.02468