FBE- İşletme Mühendisliği Lisansüstü Programı - Doktora
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Yazar "Al-Dalain, Reema Talab Hammad" ile FBE- İşletme Mühendisliği Lisansüstü Programı - Doktora'a göz atma
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ÖgeIntegrated management of mixed fleets of electric and conventional vehicles under routing considerations(Lisansüstü Eğitim Enstitüsü, 2021) Al-Dalain, Reema Talab Hammad ; Gonidis, Dilay Çelebi ; 709868 ; İşletme MühendisliğiPlanning and managing a set of freight delivery vehicles to minimize the total costs have always been a pressing issue in the transportation industry. However, recently and due to the environmental challenges, minimizing the greenhouse gas emissions in freight transport has become just as important as minimizing costs. In the race of dominance, the conventional vehicles used to overtake the electric vehicles in many aspects such as acquisition cost and refueling-recharging time, however effective management of electric vehicles in freight operations along with efficient cost planning throughout their lifecycle is expected to increase their adoption rate in urban freight. For heavy and medium duty vehicles there is uncertainty attached to the adoption rate due to limited driving range and charging battery, where companies might face losses of profit if vehicles needed to stop many times and for long periods during the day. Therefore, merging the electric vehicles with conventional vehicles in urban freight fleets can help to overcome the additional constraints induced by the specific characteristics of electric vehicles. A common practice for fleet mixed decisions is to use techniques that have been developed for managing conventional vehicles. These techniques may fall short in managing fleets with electric vehicles effectively. In this thesis, an attempt has been made to present a new perspective to the problem of managing a mixed fleet of electric and conventional vehicles in urban freight by integrating two models; fleet size and mixed vehicle routing problem with time window and replacement model. Our study was motivated by the recent practice of involving alternative vehicles in existing fleets as a response to the recent global advocates of minimizing the greenhouse gas emissions generated from using conventional vehicles in the transportation sector. We first consider a fleet size and mixed vehicle routing problem with time window to minimize the operational cost for different fleet compositions of electric and conventional vehicles, in which many constraints such as time window, limited distance range, and capacity are considered. Then we feed the results into a replacement model to find the best fleet mix policy. The replacement model is used to decide the optimal time periods to replace the used vehicles with a new one, taking into consideration different economic costs such as: annual discount rate, and energy prices for both fuel and electricity, along with the initial fleet compositions, and the planning time horizon. The methodology is implemented on generated and real life problems. Results from the computational experiments show that efficient planning of electric vehicles in urban operations can increase their presence compared to conventional vehicles. This is an important insight, since it shows that the adoption rate of electric vehicles in urban freight fleets may increase with better planning techniques, related to electric vehicles or with the increased experience of operational managers with electric vehicles.