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Modelling axial and circular data for vegetation stripes at Marion Island
Mini Dissertation (MSc (Advanced Data Analytics))--University of Pretoria, 2025.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2025
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| _version_ | 1867613660903374848 |
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| access_status_str | Open Access |
| author2 | Nagar, Priyanka |
| author_browse | Nagar, Priyanka |
| author_facet | Nagar, Priyanka |
| collection | Thesis |
| dc_rights_str_mv | © 2023 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Mini Dissertation (MSc (Advanced Data Analytics))--University of Pretoria, 2025. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/100650 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:39:41.079Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/100650 Modelling axial and circular data for vegetation stripes at Marion Island Nagar, Priyanka Bekker, Andriette, 1958- u18023691@tuks.co.za Von Holtzhausen, Francois Victor UCTD Sustainable Development Goals (SDGs) Copula Expectation-maximisation algorithm Mixture model Vegetation stripes Axial data Circular data Mini Dissertation (MSc (Advanced Data Analytics))--University of Pretoria, 2025. In this study, a bivariate model is proposed to analyse the joint distribution of Marion Island’s vegetation stripe and wind direction data. The objective is to investigate whether wind contributes to the formation of these irregular vegetation stripe patterns. Using a copula-based approach, the joint density function is modelled with a bivariate wrapped Cauchy circular component combined with various circular and axial distributions. Due to multimodality in the data, a finite mixture model is proposed to accurately model the overall density. This finite mixture model incorporates the slope angle and cone aspect as concomitant variables. The results indicate that a three latent component finite mixture model with von Mises and axial normal distributions as marginals provides the best fit. Using the proposed model it was determined that wind influences vegetation stripe orientation on the southern sides of cones, while no clear relationship is observed on the northern sides, likely due to harsher wind and sunlight exposure. These findings highlight the role of wind and other environmental factors, such as cone aspect and slope, in shaping vegetation patterns. Statistics MSc (Advanced Data Analytics) Unrestricted Faculty of Natural and Agricultural Sciences SDG-13: Climate action 2025-02-10T10:48:04Z 2025-02-10T10:48:04Z 2025-04 2025-02 Mini Dissertation * A2025 http://hdl.handle.net/2263/100650 https://doi.org/10.25403/UPresearchdata.28369058 en © 2023 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Sustainable Development Goals (SDGs) Copula Expectation-maximisation algorithm Mixture model Vegetation stripes Axial data Circular data Modelling axial and circular data for vegetation stripes at Marion Island |
| title | Modelling axial and circular data for vegetation stripes at Marion Island |
| title_full | Modelling axial and circular data for vegetation stripes at Marion Island |
| title_fullStr | Modelling axial and circular data for vegetation stripes at Marion Island |
| title_full_unstemmed | Modelling axial and circular data for vegetation stripes at Marion Island |
| title_short | Modelling axial and circular data for vegetation stripes at Marion Island |
| title_sort | modelling axial and circular data for vegetation stripes at marion island |
| topic | UCTD Sustainable Development Goals (SDGs) Copula Expectation-maximisation algorithm Mixture model Vegetation stripes Axial data Circular data |
| url | http://hdl.handle.net/2263/100650 https://doi.org/10.25403/UPresearchdata.28369058 |