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Dynamic Vehicle Routing in Emergency EvacuationWen, Yi 14 August 2015 (has links)
Since Hurricane Katrina, extensive studies have been conducted aiming to optimize the transit vehicle routing in the event of an emergency evacuation. However, the vast majority of the studies focus on solving the deterministic vehicle routing problem that all the evacuation data are known in advance. These studies are generally not practical in dealing with real-world problems which involve considerable uncertainty in the evacuation data set. In this dissertation, a SmartEvac system is developed for dynamic vehicle routing optimization in emergency evacuation. The SmartEvac system is capable of processing dynamic evacuation data in real time, such as random pickup requests, travel time change, network interruptions. The objective is to minimize the total travel time for all transit vehicles. A column generation based online optimization model is integrated into the SmartEvac system. The optimization model is based on the following structure: a master problem model and a sub-problem model. The master problem model is used for routes selection from a restricted routes set while the sub-problem model is developed to progressively add new routes into the restricted routes set. The sub-problem is formulated as a shortest path problem with capacity constraint and is solved using a cycle elimination algorithm. When the evacuation data are updated, the SmartEvac system will reformulate the optimization model and generate a new routes set based on the existing routes set. The computational results on benchmark problems are compared to other studies in the literature. The SmartEvac system outperforms other approaches on most of the benchmark problems in terms of computation time and solution quality. CORSIM simulation is used as a test bed for the SmartEvac system. CORSIM Run-Time-Extension is developed for communications between the simulation and the SmartEvac system. A case study of the Hurricane Gustav emergency evacuation is conducted. Different scenarios corresponding to different situations that presented in the Hurricane Gustav emergency evacuation are proposed to evaluate the performance of the SmartEvac system in response to real-time data. The average processing time is 28.9 seconds and the maximum processing time is 171 seconds, which demonstrate the SmartEvac system’s capability of real-time vehicle routing optimization.
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An Assessment Of The Planning And Operational Performance Of The Bus Rapid Transit In IstanbulYuce, Elif Can 01 March 2013 (has links) (PDF)
In Turkey, the only city that currently operates BRT is Istanbul. There are researches that focus on different BRT systems in the world, yet there has not been a comprehensive, systematic and comparative evaluation of the BRT experience in Istanbul. There seems to be an urgent need to study this BRT investment, with a particular focus on planning, operation and ridership characteristics with a comparative approach.
This thesis analyses the BRT corridor in Istanbul and answers the question whether Metrobü / s in Istanbul is a success or not. In order to understand the criteria for defining success, planning, operation and ridership characteristics are identified based on the previous literature and particularly the analysis of three best practice cases that currently operate BRT / these are Curitiba, Bogota and Mexico City. The study sets the criteria in planning, operation and ridership of BRT systems drawn by previous studies and answers by people who were involved in these projects. It compares the best practice cases and the Istanbul Metrobü / s / focusing on planning and operation characteristics and using primary indicators of performance and ridership.
The study reveals strength and weaknesses of the Istanbul Metrobü / s in comparison to best practice BRT cases in the world. The findings provide lessons both for the future extensions of the BRT in Istanbul and for other cities that may consider implementing this transit technology.
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