{"id":2751,"date":"2020-02-05T15:58:26","date_gmt":"2020-02-05T15:58:26","guid":{"rendered":"http:\/\/141.23.68.248\/wp\/?page_id=2751"},"modified":"2021-01-25T10:08:56","modified_gmt":"2021-01-25T10:08:56","slug":"multi-objective-optimization","status":"publish","type":"page","link":"http:\/\/141.23.68.248\/wp\/?page_id=2751","title":{"rendered":"4. Multi objective optimization"},"content":{"rendered":"<p style=\"text-align: justify;\">From the <a href=\"http:\/\/141.23.68.248\/wp\/?page_id=2743\">integrated maintenance strategies<\/a>\u00a0and <a href=\"http:\/\/141.23.68.248\/wp\/?page_id=2748\">life cycle analysis<\/a> it is clear that there are several parameters to consider, when finding the optimal solution for the maintenance of <a href=\"http:\/\/141.23.68.248\/wp\/?page_id=2732\">the system<\/a>. This can be done with multi objective optimization.<\/p>\n<p style=\"text-align: justify;\">For optimal solution we <strong>vary the maintenance strategy<\/strong> by <strong>duration time of each maintenance action<\/strong>. For example tunnel.IM = 3-5 days (range). As explained before, one design option and one maintenance strategy were chosen for each domain. Afterwards the <strong>life cycle for each subsystem<\/strong> were calculated and also <strong>the amount of emissions<\/strong>. Several assumptions were made:<\/p>\n<ul>\n<li>Function includes <strong><span style=\"text-decoration: underline;\">cost of construction<\/span><\/strong><\/li>\n<li><strong>Not<\/strong> included <strong><span style=\"text-decoration: underline;\">maintenance costs<\/span><\/strong><\/li>\n<li>Transform <strong>emission to cost value<\/strong><\/li>\n<li>It is prefered to have <strong>low duration time,<\/strong> <strong>low emission<\/strong> and in consequence <strong>low cost of emission<\/strong><\/li>\n<\/ul>\n<p style=\"text-align: justify;\">The following scatter plot (figure 1) shows the entire solution space. It&#8217;s clear from this that only the plots in the bottom left corner are interesting to study further, since linear relationships exists for emissions and cost values in the rest of the solution space.<\/p>\n<p style=\"text-align: justify;\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-3264\" src=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/all-scatter-plots-MOO.png\" alt=\"all-scatter-plots-moo\" width=\"1024\" height=\"958\" srcset=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/all-scatter-plots-MOO.png 1024w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/all-scatter-plots-MOO-300x281.png 300w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/all-scatter-plots-MOO-520x486.png 520w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/all-scatter-plots-MOO-740x692.png 740w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><br \/>\n<em>Figure 1: The entire solution space<\/em><\/p>\n<p style=\"text-align: justify;\">An optimal solution of duration time (days) based on the aspects above can lead to a maintenance strategy which provides a mercy way with respect to the environment and by this to the cost of company. Below the results are provided:<\/p>\n<p><a href=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-duration-intervention.distance.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-3275\" src=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-duration-intervention.distance.png\" alt=\"pareto-duration-intervention-distance\" width=\"698\" height=\"454\" srcset=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-duration-intervention.distance.png 698w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-duration-intervention.distance-300x195.png 300w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-duration-intervention.distance-520x338.png 520w\" sizes=\"auto, (max-width: 698px) 100vw, 698px\" \/><br \/>\n<\/a><em>Figure 2: Pareto front for minimizing total duration of interventions (days)<\/em><\/p>\n<p style=\"text-align: justify;\">When we have the <strong>minimal duration of intervention<\/strong> we save two times the interval of interventions (figure 2).<\/p>\n<p style=\"text-align: justify;\"><a href=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-duration-cost.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-3276\" src=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-duration-cost.png\" alt=\"pareto-duration-cost\" width=\"698\" height=\"454\" srcset=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-duration-cost.png 698w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-duration-cost-300x195.png 300w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-duration-cost-520x338.png 520w\" sizes=\"auto, (max-width: 698px) 100vw, 698px\" \/><\/a><br \/>\n<em>Figure 3: The price (\u20ac) for minimized duration of interventions (days)<\/em><\/p>\n<p style=\"text-align: justify;\">To <strong>minimize the duration of interventions<\/strong> will however <strong>costs more<\/strong> (figure 3).<\/p>\n<p><a href=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-co2-duration.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-3277\" src=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-co2-duration.png\" alt=\"pareto-co2-duration\" width=\"698\" height=\"454\" srcset=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-co2-duration.png 698w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-co2-duration-300x195.png 300w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-co2-duration-520x338.png 520w\" sizes=\"auto, (max-width: 698px) 100vw, 698px\" \/><\/a><br \/>\n<em>Figure 4: Pareto front for minimize emissions of CO2 (kg) and the duration of interventions (days)<\/em><\/p>\n<p style=\"text-align: justify;\"><strong>Lower duration<\/strong> leads to<strong> higher emissions of CO2<\/strong> (figure 4) and <strong>energy<\/strong> (figure 5). More time means you can choose more CO2 friendlier ways. It could also be because of the different systems. But there is not a big difference between the different options, since <strong>most of the emissions<\/strong> comes <strong>from construction<\/strong>.<\/p>\n<p><a href=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-energy-duration.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-3279\" src=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-energy-duration.png\" alt=\"pareto-energy-duration\" width=\"682\" height=\"499\" srcset=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-energy-duration.png 682w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-energy-duration-300x220.png 300w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/pareto-energy-duration-520x380.png 520w\" sizes=\"auto, (max-width: 682px) 100vw, 682px\" \/><\/a><br \/>\n<em>Figure 5: Pareto front for minimize energy consumption (MJ) and the duration of interventions (days)<\/em><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-3262\" src=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/optimal-solution.png\" alt=\"optimal-solution\" width=\"1078\" height=\"618\" srcset=\"http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/optimal-solution.png 1078w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/optimal-solution-300x172.png 300w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/optimal-solution-1024x587.png 1024w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/optimal-solution-520x298.png 520w, http:\/\/141.23.68.248\/wp\/wp-content\/uploads\/2020\/02\/optimal-solution-740x424.png 740w\" sizes=\"auto, (max-width: 1078px) 100vw, 1078px\" \/><\/p>\n<p style=\"text-align: justify;\"><em>Figure 6: The optimal solutions in red and the non-optimal solutions in blue<\/em><\/p>\n<p style=\"text-align: justify;\">For the optimal solution there are <strong>ranges for<\/strong> some of the <strong>interventions<\/strong>, whereas<strong> some are constant<\/strong>. For tunnel.MI the possible range is 3-5 days, but the optimal is always 4 days of intervention (figure 6). When it comes to tunnel.PR the optimal have a range, the duration should either be (about) 34 or 36 days. For the <strong>environmental costs<\/strong> they are almost <strong>constant for all solutions<\/strong>, which can be explained by the fact that most of the <strong>emissions are generated during<\/strong> <strong>construction<\/strong>.<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>From the integrated maintenance strategies\u00a0and life cycle analysis it is clear that there are several parameters to consider, when finding the optimal solution for the maintenance of the system. This can be done with multi<a class=\"read-more\" href=\"http:\/\/141.23.68.248\/wp\/?page_id=2751\">Continue reading<\/a><\/p>\n","protected":false},"author":49,"featured_media":0,"parent":2732,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-2751","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/141.23.68.248\/wp\/index.php?rest_route=\/wp\/v2\/pages\/2751","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\/49"}],"replies":[{"embeddable":true,"href":"http:\/\/141.23.68.248\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2751"}],"version-history":[{"count":14,"href":"http:\/\/141.23.68.248\/wp\/index.php?rest_route=\/wp\/v2\/pages\/2751\/revisions"}],"predecessor-version":[{"id":3505,"href":"http:\/\/141.23.68.248\/wp\/index.php?rest_route=\/wp\/v2\/pages\/2751\/revisions\/3505"}],"up":[{"embeddable":true,"href":"http:\/\/141.23.68.248\/wp\/index.php?rest_route=\/wp\/v2\/pages\/2732"}],"wp:attachment":[{"href":"http:\/\/141.23.68.248\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2751"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}