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16628

ارائه الگوريتمي جهت چند هسته اي سازي شهرها با تغيير الگوي كاربري زمين با رويكرد حمل‌و‌نقل‌ پايدار

كارشناسي ارشد

راه و ترابري

شهريور 1395

دكتر حميد بهبهاني

عمران

چكيده مكان‌يابي و تعيين تعداد بهينه كاربري‌ها از منظر حمل‌و‌نقل در شهرسازي همواره كمتر مورد توجه قرار گرفته است كه اين امر مي‌تواند منجر به ايجاد مشكلات و افزايش هزينه‌هاي حمل ونقلي فراوان در سيستم شهري گردد. در همين راستا پژوهشگر در پي پاسخ به اين سوال كه چگونه مي توان با ارائه الگوريتمي، مكان بهينه كاربري زمين و تعداد واحد بهينه عرضه آن را شناسايي كرد به گونه اي كه هزينه حمل و نقل بهينه باشد؟ موضوع پژوهش حاضر ارائه مدلي براي تعيين مكان و تعداد بهينه كاربري‌ها بر روي شبكه فرضي شهر سايوكس فالز با در نظر گرفتن مشخصات سيستم حمل‌ونقل مي باشد كه با هدف ارائه مدل برنامه ريزي دو سطحي تك هدف تدوين يافته و بر مبناي الگوريتم ژنتيك به حل مدل پيشنهادي مي پردازد كه نهايتا به بهينه سازي هزينه هاي حمل و نفل منجر مي شود. نتايج نشان مي دهد كه مدل پيشنهادي به خوبي مي‌تواند براي مكان‌يابي و تعيين تعداد بهينه كاربري‌ها مورد استفاده قرار گيرد و هزينه حمل‌ونقل را بهينه مي كند. مقايسه هزينه سيستم حمل‌و‌نقل در دو حالت( بدون در نظر گرفتن سيستم حمل‌ونقل و با در نظر گرفتن سيستم حمل‌ونقل-مدل پيشنهادي-) نشان مي‌دهد كه با مدل پيشنهادي، هزينه سيستم حمل‌ونقل بطور قابل‌ توجهي كاهش يافته كه نمايانگر عملكرد بهتر مدل ارائه شده در مقايسه با رويكردهاي پيشين مي‌باشد. واژه‌هاي كليدي: مكان‌يابي، كاربري زمين، هزينه حمل‌و‌نقل، مدل برنامه‌ريزي دوسطحي، الگوريتم ژنتيك

1395/11/25

1/1/1900 12:00:00 AM

Abstract: Todays, with the development of cities, the increase of the population, car ownership an​d the transportation problems especially in (central business districts) CBD’s, the necessity of appropriate locating of land uses has increased. In addition, land uses optimization in urban design has been ignored. This can cause the transportation problems an​d the social costs increase. Thus, urban planners thought to change cities structure from homocentric to polycentric. So, this structure changing can decrease the number of trips toward CBD an​d also can improve the level of transportation facility services especially in CBD’s. As it’s been mentioned before, optimization of location an​d number of land uses according to transportation facilities have been ignored that can make lots of problems in urban planning system. The main objective of this study is the decentralization of the important land uses especially in central districts of cities an​d transforming these kinds of land uses to other non-condensing parts of cities. To gain this objective, we should answer these questions: First, where are the suitable locations for these land uses in a city? Second, what are the optimum number of land uses in each location? In addition, in this paper, we want to find the optimum number an​d location for different kinds of land uses so that the transportation costs are minimized. In other words, according to the Wardrop second principle, the main objective is to minimize the total transportation costs. In this paper, for optimization of the location an​d the number of land uses along with reduction in the transportation costs, we develop a bi-level optimization model. The upper level of proposed model is to optimize the total transportation costs by optimizing of the location an​d the number of land uses. The lower level of proposed model is to simulate the users’ behavior according to changing in the number an​d the location of land uses. Because of constructing new land uses, new supply will produce that can be effective in the increase of supply. For solving the proposed bi-level model, the genetic algorithm has been used. Then, the bi-level optimization model was implemented in Matlab software. After that, we applied the developed model to the Sioux Falls city network data as a numerical example. Finally, the results show that the proposed model can be used as a useful approach for the optimization of the location an​d the number of land uses. A comparison of the total transportation costs in two cases (without an​d with considering of the transportation system) shows that the total transportation costs decrease in the proposed model significantly. This result confirms the better performance of the proposed model compared with other approaches. In addition, by increasing the number of land uses, differences between the value of total transportation costs has been reduced significantly compared with the homocentric an​d the polycentric model. The results of the proposed model for land use location an​d the number of supply isn’t unique an​d fixed. Finally, some recommendations have been presented to help experts for urban land use location design an​d optimization. Keywords:Locating, land use, multicore city, bi-level model, genetic algorithm