Transportation
Azra Ghobadi; Reza Tavakkoli Moghadam; Mohammad Fallah; Hamed Kazemipoor
Abstract
The use of an Electric Vehicle (EV), particularly in different operations of goods distribution is a solution for salvaging the crowded cities of the world from air and noise pollutions as well as Green House Gas (GHG) emission. This paper presents a Multi-Depot Electric Vehicle Routing Problem (MD-EVRP) ...
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The use of an Electric Vehicle (EV), particularly in different operations of goods distribution is a solution for salvaging the crowded cities of the world from air and noise pollutions as well as Green House Gas (GHG) emission. This paper presents a Multi-Depot Electric Vehicle Routing Problem (MD-EVRP) with recharging stations by considering the expected penalty of fuzzy time windows in pickup/delivery. Since the MD-EVRP with Fuzzy Time Windows and Pickup/Delivery (MD-EVRP-FTW-PD) constraints is an NP-hard problem, three meta-heuristics (i.e., Simulated Annealing (SA), Variable Neighborhood Search (VNS) and a hybrid of SA and VNS (VNS-SA)) are used to solve such a hard problem. The parameters of these algorithms are measured by the Taguchi experimental design method. The proposed hybrid VNS-SA algorithm is more efficient in comparison with other algorithms.
Project Management
Nima Moradi; Shahram Shadrokh
Abstract
One of the classes of the project schedule is the Material Procurement Scheduling (MPS) problem, which is considered besides the material allocation to warehouse (MAW) problem recently. In the literature, the Simultaneous Solution of MPS-MAW is investigated by considering one warehouse and unlimited ...
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One of the classes of the project schedule is the Material Procurement Scheduling (MPS) problem, which is considered besides the material allocation to warehouse (MAW) problem recently. In the literature, the Simultaneous Solution of MPS-MAW is investigated by considering one warehouse and unlimited capacity of the warehouses most of the times. In this paper, we propose the propositional and mathematical model of the simultaneous MPS-MAW with multiple warehouses and the limited capacity at the whole of the horizon planning for each warehouse. The proposed model aims to obtain the best ordering point, selection of the best suppliers, the best activity start, and the fair material distribution to the warehouses as possible by the given objective function. The proposed model is NP-hard, so a metaheuristic namely simulated annealing is proposed to reach the acceptable but not optimal solutions in a short time. Also, to overcome the complexity of the model, the encoding of the decision variables have been done by adding the auxiliary variable. Comparing the solutions of the small problems with the exact methods shows the validation of the proposed SA. Also, the design of experiments shows the significance of the model and each SA parameters. Finally, by the optimum values of the SA parameters, the large problems have been solved at acceptable times.
