{"id":10156,"date":"2022-02-14T17:13:24","date_gmt":"2022-02-14T17:13:24","guid":{"rendered":"http:\/\/141.23.68.248\/wp\/?page_id=10156"},"modified":"2022-02-15T18:08:23","modified_gmt":"2022-02-15T18:08:23","slug":"5-multi-objective-optimization","status":"publish","type":"page","link":"http:\/\/141.23.68.248\/wp\/?page_id=10156","title":{"rendered":"5.Multi-Objective Optimization"},"content":{"rendered":"<p class=\"p1\">As construction projects get larger and more complicated, it becomes more difficult to make the final decision because of several factors such as cost, time, environment. Multi-objective optimization model provides a solution to this problem by making use of the\u00a0Pareto front. This method can be used to assess multiple optimization objectives such as initial cost, maintenance cost, emission cost, etc.<\/p>\n<p>The Aim of a Multi-objective Optimization is to give the stakeholders an assist by the decision-making process. The method works by generating a high number of solutions over an interval and evaluate the results based on the objectives and the key results or key performance indicators.<br \/>\nThe Algorithm may take a high computational capacity. To overcome the problem, the models are usually reduced to the minimal needed complexity. The model of the integrated system has eight Parameters and nine outcomes. The algorithm will randomly generate, inside the given boundaries, a finite number of models and evaluate them based on the weighing of the criteria and choose the best models or solutions. Models, which have the best evaluation are called a Pareto Optimality and the whole group of best solutions is the Pareto frontier. Pareto optimality is defined as a state or an instant, which balances the results of the model in a way, that moving away on the Axis of any parameter will not result a bettering of the performance of a criterion without degrading another criterion.<\/p>\n<p>Due to the complexity of the models, the maintenance interventions for the subsystems examined in the second assignment\u00a0are used instead of the overall systems. The parameters of the model can be expanded here as required.<\/p>\n<p class=\"p1\">Subsequently, the most appropriate solution can be identified. It is implemented by following these steps [1]:identification of the problem<\/p>\n<ul>\n<li class=\"p1\">standardization of the objectives<\/li>\n<li class=\"p1\">establishment of the genetic algorithm.<\/li>\n<li class=\"p1\">identification of the optimization objectives<\/li>\n<li class=\"p1\">developing the data structure<\/li>\n<li class=\"p1\">definition of the fitness function<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-10776\" src=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2022\/02\/Concept-map-the-CBM-ontology-inspired-by-Bahill-et-al-2002_Q320.jpg\" alt=\"concept-map-the-cbm-ontology-inspired-by-bahill-et-al-2002_q320\" width=\"320\" height=\"320\" srcset=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2022\/02\/Concept-map-the-CBM-ontology-inspired-by-Bahill-et-al-2002_Q320.jpg 320w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2022\/02\/Concept-map-the-CBM-ontology-inspired-by-Bahill-et-al-2002_Q320-150x150.jpg 150w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2022\/02\/Concept-map-the-CBM-ontology-inspired-by-Bahill-et-al-2002_Q320-300x300.jpg 300w\" sizes=\"auto, (max-width: 320px) 100vw, 320px\" \/><\/p>\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"  wp-image-6695 aligncenter\" src=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/Screenshot-2021-02-24-at-18.36.04.png\" alt=\"screenshot-2021-02-24-at-18-36-04\" width=\"538\" height=\"527\" srcset=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/Screenshot-2021-02-24-at-18.36.04.png 1267w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/Screenshot-2021-02-24-at-18.36.04-300x294.png 300w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/Screenshot-2021-02-24-at-18.36.04-1024x1004.png 1024w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/Screenshot-2021-02-24-at-18.36.04-520x510.png 520w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/Screenshot-2021-02-24-at-18.36.04-740x725.png 740w\" sizes=\"auto, (max-width: 538px) 100vw, 538px\" \/>Figure 1. General optimization procedure for maintenance scheduling [2]<\/p>\n<p>\u00a0As for the total number of interruptions and the maximum distance between interventions, we have taken into account a large set of variables that play a role in our analysis. The mean value of the duration between interventions is calculated to give a rough estimate about the total duration. The aim is to maximize this as the systems should be able to operate without interventions as much as possible.<\/p>\n<div class=\"page\" title=\"Page 10\">\n<div class=\"layoutArea\">\n<div class=\"column\">\n<div class=\"page\" title=\"Page 9\">\n<div class=\"layoutArea\">\n<div class=\"column\">\n<p>The three\u00a0parameters that we follow in this integration are costs, total intervention time and the distance between the interventions. The best options would have a maximized distance between the interventions and minimized cost and distance. The pareto front described by the total duration of the interventions and the cost is shown below:<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<p><a href=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/paretofront2.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-large wp-image-7438\" src=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/paretofront2-1024x539.png\" alt=\"paretofront\" width=\"1024\" height=\"539\" srcset=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/paretofront2-1024x539.png 1024w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/paretofront2-300x158.png 300w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/paretofront2-520x274.png 520w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/paretofront2-740x390.png 740w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/paretofront2.png 1538w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><\/p>\n<p style=\"text-align: center;\">Fig 2. Pareto Frontier &#8211; Duration, Distance and Cost<\/p>\n<p>To see the accumulated impact of the input parameters on the performance criteria, duration\u00a0and time gap between the interventions are visualised below. The red lines represent the optimal solutions\u00a0while the blue lines represent the non-optimal solutions.<\/p>\n<p>&nbsp;<\/p>\n<p><a href=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2022\/02\/final1.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-large wp-image-10236\" src=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2022\/02\/final1-1024x581.jpg\" alt=\"final\" width=\"1024\" height=\"581\" srcset=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2022\/02\/final1-1024x581.jpg 1024w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2022\/02\/final1-300x170.jpg 300w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2022\/02\/final1-520x295.jpg 520w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2022\/02\/final1-740x420.jpg 740w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2022\/02\/final1.jpg 1450w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><a href=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2022\/02\/final.jpg\"><br \/>\n<\/a><\/p>\n<p style=\"text-align: center;\">Fig 3.\u00a0Accumulated Impact<\/p>\n<p>&nbsp;<\/p>\n<p><a href=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/Screenshot-2021-02-25-at-10.48.48.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone  wp-image-7739\" src=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/Screenshot-2021-02-25-at-10.48.48.png\" alt=\"screenshot-2021-02-25-at-10-48-48\" width=\"734\" height=\"459\" srcset=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/Screenshot-2021-02-25-at-10.48.48.png 2880w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/Screenshot-2021-02-25-at-10.48.48-300x188.png 300w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/Screenshot-2021-02-25-at-10.48.48-1024x640.png 1024w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/Screenshot-2021-02-25-at-10.48.48-520x325.png 520w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2021\/02\/Screenshot-2021-02-25-at-10.48.48-740x463.png 740w\" sizes=\"auto, (max-width: 734px) 100vw, 734px\" \/><\/a><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>REFERENCES<\/p>\n<p>[1] Q. Zhang, K. B, H. MacLean and J. Feng, &#8220;Life-cycle inventory of energy use and greenhouse gas emissions for two hydropower projects in China,&#8221; Journal of Infrastructure Systems, pp. 271-279, 2007.<br \/>\n[2] P. Meier, &#8220;Life-cycle assessment of electricity generation systems and climate applications,&#8221; University of Wisconsin-Madison, 2002.<br \/>\n[3] S. Kim and B. Dale, &#8220;Life cycle inventory information of the United States electricity system,&#8221; The International Journal of Life Cycle Assessment, no. 10, pp. 294-304, 2005.<br \/>\n[4] Guide To Concrete Repair, 2nd ed., U.S. Department of the Interior Bureau of Reclamation, 2015.<br \/>\n[5] Y. Lei, Q. Zhang, C. Nielsen and K. He, &#8220;An inventory of primary air pollutants and CO2 emissions from cement production in China, 1990-2020,&#8221; Atmospheric Environment, no. 45, pp. 147-154, 2011.<br \/>\n[6] &#8220;Emission Factor Documentation for AP-42:Iron and Steel Production,&#8221; U. S. Environmental Protection Agency, 2009.<br \/>\n[7] &#8220;Emission Factor Documentation for AP-42: Sand and Gravel Processing,&#8221; U. S. Environmental Protection Agency, 1995.<br \/>\n[8] J. de Brito and F. Agrela, &#8220;Life cycle assessment applied to recycled aggregate concrete,&#8221; in New Trends in Eco-efficient and Recycled Concrete, Woodhead Publishing, 2019.<\/p>\n<p>[9]Maintenance of Structures and Infrastructure Systems, Mohamed Soliman, A.M.ASCE* Dan M. Frangopol, Dist.M.ASCE\u2020<\/p>\n<p>[10]\u00a0Choongwan Koo, Taehoon Hong &amp; Sangbum Kim\u00a0(2015)\u00a0An integrated multi-objective optimization model for solving the construction time-cost trade-off problem,\u00a0Journal of Civil Engineering and Management,\u00a021:3,\u00a0323-333,\u00a0DOI:\u00a010.3846\/13923730.2013.802733<\/p>\n","protected":false},"excerpt":{"rendered":"<p>As construction projects get larger and more complicated, it becomes more difficult to make the final decision because of several factors such as cost, time, environment. Multi-objective optimization model provides a solution to this problem<a class=\"read-more\" href=\"http:\/\/141.23.68.248\/wp\/?page_id=10156\">Continue reading<\/a><\/p>\n","protected":false},"author":119,"featured_media":0,"parent":8853,"menu_order":0,"comment_status":"closed","ping_status":"open","template":"","meta":{"footnotes":""},"class_list":["post-10156","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/141.23.68.248\/wp\/index.php?rest_route=\/wp\/v2\/pages\/10156","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/141.23.68.248\/wp\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/141.23.68.248\/wp\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/141.23.68.248\/wp\/index.php?rest_route=\/wp\/v2\/users\/119"}],"replies":[{"embeddable":true,"href":"http:\/\/141.23.68.248\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=10156"}],"version-history":[{"count":7,"href":"http:\/\/141.23.68.248\/wp\/index.php?rest_route=\/wp\/v2\/pages\/10156\/revisions"}],"predecessor-version":[{"id":10780,"href":"http:\/\/141.23.68.248\/wp\/index.php?rest_route=\/wp\/v2\/pages\/10156\/revisions\/10780"}],"up":[{"embeddable":true,"href":"http:\/\/141.23.68.248\/wp\/index.php?rest_route=\/wp\/v2\/pages\/8853"}],"wp:attachment":[{"href":"http:\/\/141.23.68.248\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10156"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}