A matheuristic algorithm for the threedimensional loading capacitated vehicle routing problem (3L-CVRP) | Author : Luis Miguel Escobar Falcón, David Álvarez Martínez, Mauricio Granada Echeverri , John Willmer Escobar , Rubén Augusto Romero Lázaro | Abstract | Full Text | Abstract :This paper presents a hybrid algorithm for solving the Capacitated Vehicle Routing Problem with practical three-dimensional loading constraint. This problem is known as 3L-CVRP (Three-dimensional Loading Capacitated Vehicle Routing Problem). The proposed methodology consists of two phases. The first phase uses an optimization procedure based on cuts to obtain solutions for the well-known Capacitated Vehicle Routing Problem (CVRP). The second phase validates the results of the first phase of a GRASP algorithm (Greedy Randomized Adaptive Search Procedure). In particular, the GRASP approach evaluates the packing constraints for each performed route of the CVRP. The proposed hybrid algorithm uses a relaxation of the classical model of two sub-indices for the vehicle routing problem. Specifically different types of cuts are added: subtour elimination, capacity-cut constraints, and packing-cut constrains. The proposed algorithm is compared with the most efficient approaches for the 3L-CVRP on the set of benchmark instances considered in the literature. The computational results indicate that the proposed approach is able to obtain good solutions, improving some of the best-known solutions from the literatura |
| Assessment of postures and manual handling of loads at Southern Brazilian Foundries | Author : Eduardo Concepción Batiz, Antonio José dos Santos, Ana Lúcia Berretta Hurtado, Marcelo Macedo, Eliane Terezinha Schmitz Mafra | Abstract | Full Text | Abstract :Foundry workers are exposed to health risks arising from several factors, especially weight handling, adopted postures, and taken routes. This paper aims to evaluate the postures and cargo handling in foundry areas of industries at the south region of Brazil. Data was collected from a population of 35 workers that volunteered to take part in the research. The techniques used include an organizational questionnaire, interviewing, the Nordic musculoskeletal questionnaire, and the REBA and NIOSH methods. It was found that 74.3% of the sample reported symptoms of discomfort and pain in different parts of the body. The lumbar region appeared as the most affected part, as well as wrists, hands and fingers. The REBA method results indicated that 78.9% of analyzed postures are between medium and very high risk levels. Likewise, 100% of shipments surveyed carried risks of injury in the spine and musculoskeletal ligament system. |
| A matheuristic algorithm for the threedimensional loading capacitated vehicle routing problem (3L-CVRP) | Author : Luis Miguel Escobar Falcón, David Álvarez Martínez, Mauricio Granada Echeverri , John Willmer Escobar , Rubén Augusto Romero Lázaro | Abstract | Full Text | Abstract :This paper presents a hybrid algorithm for solving the Capacitated Vehicle Routing Problem with practical three-dimensional loading constraint. This problem is known as 3L-CVRP (Three-dimensional Loading Capacitated Vehicle Routing Problem). The proposed methodology consists of two phases. The first phase uses an optimization procedure based on cuts to obtain solutions for the well-known Capacitated Vehicle Routing Problem (CVRP). The second phase validates the results of the first phase of a GRASP algorithm (Greedy Randomized Adaptive Search Procedure). In particular, the GRASP approach evaluates the packing constraints for each performed route of the CVRP. The proposed hybrid algorithm uses a relaxation of the classical model of two sub-indices for the vehicle routing problem. Specifically different types of cuts are added: subtour elimination, capacity-cut constraints, and packing-cut constrains. The proposed algorithm is compared with the most efficient approaches for the 3L-CVRP on the set of benchmark instances considered in the literature. The computational results indicate that the proposed approach is able to obtain good solutions, improving some of the best-known solutions from the literature. |
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