Abstract
This paper presents a new concept for a hub-and-spoke network structure, called “sub-hub”, applied to global operations of liner shipping. Hub-and-spoke networks are widely used in transportation due to the economy of scale offered to the demands between hubs. However, efficient network structures require more than an economy of scale with regard to transport costs. This study therefore, aims to demonstrate that lower transport costs are achievable by a hub-and-spoke with sub-hub structure because the economy of scale this model provides is combined with shorter alternative paths. A short sea operation in liner shipping is a circular route at cluster level (the hub and its allocated spokes). A deep sea operation functions as a direct connection between hubs. A sub-hub is an intersection point between two regional (cluster) routes, thereby allowing the transshipment of goods, for certain demands, without using hub nodes. Hubs and sub-hubs are selected between the existing ports (nodes), and installation costs are not included for these models. A cutting plane approach was implemented. Although the computation results of the models, which are classified as hub location-routing problems, were compared on small instances, a Variable Neighbourhood Decomposition Search (VNDS) was implemented to test large instances.
Acknowledgments
The authors would like to express their thanks to the Coordenação de Aperfeiçoamento de Pessoal de Nivel Superior (CAPES), a foundation within the Brazilian Ministry of Education, which funded a PhD scholarship in order to develop these studies.
Disclosure statement
No potential conflict of interest was reported by the authors.
ORCID
Fábio Francisco da Costa Fontes http://orcid.org/0000-0002-5070-3578
Gilles Goncalves http://orcid.org/0000-0001-5564-9673