Navegando por Autor "Cruz, Raphael Carlos"
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Item An ILS-based algorithm to solve a large-scale real heterogeneous fleet VRP with multi-trips and docking constraints.(2016) Coelho, Vitor Nazário; Grasas, A.; Ramalinho, H.; Coelho, Igor Machado; Souza, Marcone Jamilson Freitas; Cruz, Raphael CarlosDistribution planning is crucial for most companies since goods are rarely produced and consumed at the same place. Distribution costs, inaddition, can be an important component of the final cost of the products. In this paper, westudya VRP variant inspired on a real case of a large distribution company. In particular, we consider a VRP with a heterogeneous fleet of vehicles that a real lowed to perform multipletrips. The problem also includes docking constraints in which some vehicles are unable to serve some particular customers, and a realistic objective function with vehicles’ fixed and distance- based costs and a costper customer visited. We design a trajectory search heuristic called GILS-VND that combines Iterated Local Search (ILS), Greedy Randomized Adaptive Search Procedure (GRASP) and Variable Neighborhood Descent (VND) procedures. This method obtains competitive solutions and improves the company solutions leading to significant savings in transportation costs.Item Genils-TS-CL-PR : um algoritmo heurístico para resolução do problema de roteamento de veículos com coleta e entrega simultânea.(2012) Silva, Thaís Cotta Barbosa da; Cruz, Raphael Carlos; Souza, Marcone Jamilson Freitas; Martins, Alexandre Xavier; Coelho, Vitor Nazário; Mine, Marcio TadayukiThis work addresses the Vehicle Routing Problem with Simultaneous Pickup and Delivery (VRPSPD). We propose the algorithm GENILS-TS-CL-PR for solving it. This algorithm combines the heuristic procedures Cheapest In- sertion, Cheapest Insertion with multiple routes, GENIUS, Iterated Local Search (ILS), Variable Neighborhood Descent (VND), Tabu Search (TS) and Path Relin king (PR). The first three procedures aim to obtain a good initial solution, and the VND and TS are used as local search methods for ILS. TS is applied after some iterations without any improvement through of the VND. The PR procedure is performed for each ILS iteration and it connects a local optimum with an elite solution generated during the search. The algorithm also uses a strategy to re- duce the number of solutions evaluated in the solution space. It was tested on benchmark instances taken from the literature and it was able to generate high quality solutions.Item GENVNS-TS-CL-PR: a heuristic approach for solving the vehicle routing problem with simultaneous pickup and delivery.(2012) Cruz, Raphael Carlos; Silva, Thaís Cotta Barbosa da; Souza, Marcone Jamilson Freitas; Coelho, Vitor Nazário; Mine, Marcio Tadayuki; Martins, Alexandre XavierThis work addresses the Vehicle Routing Problem with Simultaneous Pickup and Delivery (VRPSPD). Due to its complexity, we propose a heuristic algorithm for solving it, so-called GENVNS-TS-CL-PR. This algorithm combines the heuristic procedures Cheapest Insertion, Cheapest Insertion with multiple routes, GENIUS, Variable Neighborhood Search (VNS), Variable Neighborhood Descent (VND), Tabu Search (TS) and Path Relinking (PR). The first three procedures aim to obtain an good initial solution, and the VND and TS are used as local search methods for VNS. TS is called after some iterations without any improvement through of the VND. The PR procedure is called after each VNS iteration and it connects a local optimum with an elite solution generated during the search. The algorithm uses an strategy based on Candidate List to reduce the number of solutions evaluated in the solution space. The algorithm was tested on benchmark instances taken from the literature and it was able to generate high quality solutions.Item Multi-objective approaches for the open-pit mining operational planning problem.(2012) Coelho, Vitor Nazário; Souza, Marcone Jamilson Freitas; Coelho, Igor Machado; Guimarães, Frederico Gadelha; Lust, Thibaut; Cruz, Raphael CarlosThis work presents three multi-objective heuristic algorithms based on Two-phase Pareto Local Search with VNS (2PPLS-VNS), Multi-objective Variable Neighborhood Search (MOVNS) and Non-dominated Sorting Genetic Algorithm II (NSGA-II). The algorithms were applied to the open-pit-mining operational planning problem with dynamic truck allocation (OPMOP). Approximations to Pareto sets generated by the developed algorithms were compared considering the hypervolume and spacing metrics. Computational experiments have shown the superiority of the algorithms based on VNS methods, which were able to find better sets of non-dominated solutions, more diversified and with an improved convergence.