{"id":3463,"date":"2019-05-22T13:09:34","date_gmt":"2019-05-22T11:09:34","guid":{"rendered":"https:\/\/test.viaboxx.de\/2019\/05\/22\/my-bachelor-thesis-at-viaboxx-2\/"},"modified":"2021-08-02T15:39:10","modified_gmt":"2021-08-02T15:39:10","slug":"my-bachelor-thesis-at-viaboxx-2","status":"publish","type":"post","link":"https:\/\/www.viaboxx.de\/en\/blog\/my-bachelor-thesis-at-viaboxx-2\/","title":{"rendered":"My Bachelor Thesis at Viaboxx"},"content":{"rendered":"\n<p>Between May and October 2018, I have been writing my bachelor thesis at Viaboxx GmbH as part of my study at the <a href=\"http:\/\/www.h-brs.de\">University of Applied Sciences Bonn-Rhein-Sieg<\/a>.  The topic was \u201cModeling of a planning problem to the optimal use of technicians\u201d, which is a variant of the vehicle routing problem with time windows.<\/p>\n\n\n\n<p><br>Therefore, the topic can be described in other words with: An optimal tour should be generated, where technicians are performing different kinds of orders with predetermined constraints (duration of a tour, number of technicians, time windows, etc.). My task was to transform the problem into a mathematical model, present algorithms for solving it and compare the different approaches. <\/p>\n\n\n\n<p><br>From the various available algorithms, I selected some which I then evaluated with the constraint solver <a href=\"http:\/\/www.optaplanner.org\">OptaPlanner<\/a> and a self-written tool. For the self-written tool, I chose Java as programming language, as on one hand, I used this language for most of the projects I had worked on before as student, and on the other hand, Viaboxx GmbH frequently uses it for their projects, too.<\/p>\n\n\n\n<p><br>A majority of the evaluated algorithms were in fact already implemented in <a href=\"http:\/\/www.optaplanner.org\">OptaPlanner<\/a>, but they had to be adapted to the data model. Since the integration of other algorithms (e.g. a new construction heuristic) in <a href=\"http:\/\/www.optaplanner.org\">OptaPlanner<\/a> could not be realized in time for the thesis, they were implemented separately in the self-written Java tool. With this tool, tours could be calculated, but not graphically represented. The calculated tours could, however, be graphically represented with <a href=\"http:\/\/www.optaplanner.org\">OptaPlanner<\/a>.<\/p>\n\n\n\n<p><br>To determine an optimal solution, a valid starting solution is required first, which is then improved with further algorithms.<\/p>\n\n\n\n<p><br>After the execution of multiple tests with different test instances, the best results could be achieved by the combination of the following two algorithms: <strong><a href=\"https:\/\/docs.optaplanner.org\/7.21.0.Final\/optaplanner-docs\/html_single\/index.html#allocateEntityFromQueue\">allocate entity from a queue <\/a><\/strong>as construction heuristic and <strong><a href=\"https:\/\/docs.optaplanner.org\/7.21.0.Final\/optaplanner-docs\/html_single\/index.html#lateAcceptance\">late acceptance<\/a><\/strong> as local search.  The first one was used to get a valid solution (all constraints were satisfied) and the second one to improve this solution.<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-medium is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.viaboxx.de\/wp-content\/uploads\/2021\/08\/image-300x251.png\" alt=\"\" class=\"wp-image-6635\" width=\"300\" height=\"251\" srcset=\"https:\/\/www.viaboxx.de\/wp-content\/uploads\/2021\/08\/image-300x251.png 300w, https:\/\/www.viaboxx.de\/wp-content\/uploads\/2021\/08\/image.png 376w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><figcaption>Visualization of a solution for technician tours with OptaPlanner<\/figcaption><\/figure><\/div>\n\n\n\n<p>The thesis showed, however, that by applying a new and not yet in <a href=\"http:\/\/www.optaplanner.org\/\">OptaPlanner<\/a> available construction heuristic, a good and valid initial solution could be quickly determined for the vehicle routing problem with timed windows. <br><br>Writing my Bachelor thesis at Viaboxx was the greatest experience so far for me. Encouraged and supported by a very good working atmosphere characterized by young, experienced colleagues, I could develop my skills in many fields like programming and complexity of algorithms.<br><br>Special thanks go to Jan Nonnen for his support and pieces of advice!<\/p>\n\n\n\n<p>by Emmanuel Andela<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Between May and October 2018, I have been writing my bachelor thesis at Viaboxx GmbH as part of my study at the University of Applied Sciences [&hellip;]<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"default","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"default","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[89,77,97],"tags":[102,103,104,105,106,107,108],"class_list":["post-3463","post","type-post","status-publish","format-standard","hentry","category-research","category-route-optimization","category-thesis","tag-bachelor","tag-optaplanner","tag-optimization","tag-technician","tag-thesis","tag-timed-windows","tag-vehicle-routing"],"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false},"uagb_author_info":{"display_name":"Jan Nonnen","author_link":"https:\/\/www.viaboxx.de\/en\/blog\/author\/jan-nonnenviaboxx-de\/"},"uagb_comment_info":0,"uagb_excerpt":"Between May and October 2018, I have been writing my bachelor thesis at Viaboxx GmbH as part of my study at the University of Applied Sciences [&hellip;]","_links":{"self":[{"href":"https:\/\/www.viaboxx.de\/en\/wp-json\/wp\/v2\/posts\/3463"}],"collection":[{"href":"https:\/\/www.viaboxx.de\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.viaboxx.de\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.viaboxx.de\/en\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.viaboxx.de\/en\/wp-json\/wp\/v2\/comments?post=3463"}],"version-history":[{"count":4,"href":"https:\/\/www.viaboxx.de\/en\/wp-json\/wp\/v2\/posts\/3463\/revisions"}],"predecessor-version":[{"id":6641,"href":"https:\/\/www.viaboxx.de\/en\/wp-json\/wp\/v2\/posts\/3463\/revisions\/6641"}],"wp:attachment":[{"href":"https:\/\/www.viaboxx.de\/en\/wp-json\/wp\/v2\/media?parent=3463"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.viaboxx.de\/en\/wp-json\/wp\/v2\/categories?post=3463"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.viaboxx.de\/en\/wp-json\/wp\/v2\/tags?post=3463"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}