Modelagem para localização de hubs no transporte de encomendas expressas
Modelling for location hubs in the express cargo transport
Alamo, Javier Antonio T.; Brinati, Marco Antonio
http://dx.doi.org/10.1590/S0103-65132006000300009
Prod, vol.16, n3, p.470-480, 2006
Resumo
Na presente pesquisa se propõe um modelo matemático de programação linear com variáveis binárias 0/1, para projetar a configuração de uma rede de distribuição de encomendas expressas, visando minimizar os custos e garantindo um bom nível de serviço. O modelo, que é uma modificação da formulação proposta por OKelly, define as posições dos hubs, a alocação deles às demais instalações físicas e a construção de roteiros com apenas uma parada intermediária, o que confere mais agilidade ao atendimento da demanda de transporte de carga. Considera-se a instalação de um único hub maior (Hub Principal), que serve como ponto de transbordo para os fluxos de carga entre as distintas regiões de um território, e um conjunto de terminais regionais (mini-hubs), servindo como ponto de conexão, unicamente, para os fluxos de carga existentes em um determinado raio de cobertura. Foram propostas extensões que incluem uma restrição da capacidade operacional do Hub Principal, para evitar seu congestionamento, e duas diferentes estratégias de induzir o aumento de fluxo de carga manipulado pelos mini-hubs. O modelo proposto e suas extensões foram aplicados ao estudo de um caso real, obtendo-se resultados consistentes e uma redução significativa no custo total da rede de distribuição da empresa analisada.
Palavras-chave
Localização industrial, pesquisa operacional, terminais de carga, transporte de carga
Abstract
This study proposes a mathematical model of linear programming with binary variables 0/1 to project the configuration of a distribution network for express cargo which aims to minimize costs and guarantee a high level of service. The model, which is a modification of the formulation proposed by OKelly, defines the position of the hubs, their allocation regarding the other physical installations, and the building of itineraries with only one intermediate stop, which increases agility in meeting the demand of cargo transport. It assumes the installation of a single, major hub (Main Hub), which serves as the transfer point for the flow of cargo between distinct regions of a territory and a set of regional terminals (mini hubs) serving as connection points solely for the flow of cargos existing within a determined area of coverage. Extensions were proposed with capacity constrains for the Main Hub, thereby avoiding congestion, and two different strategies to induce an increase of the flow of cargo manipulated by the mini-hubs. The proposed model and its extensions were applied to an actual case study, obtaining consistent results and a significant reduction in the total cost for the distribution network of the company studied.
Keywords
Industrial localization, operational research, cargo terminals, cargo transport
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