We consider the hub location problem, where p hubs are chosen from a given set of nodes, each nonhub node is connected to exactly one hub and each hub is connected to a central hub. Links are installed on the arcs of the resulting network to route the traffic. The aim is to find the hub locations and the connections to minimize the link installation cost. We propose two formulations and a heuri...

This paper deals with hub-and-spoke network design in the liner shipping sector. It introduces a capacitated directed cycle hub location and cargo routing problem under congestion. The involves four decisions: of ports; allocation non-hub ports to construction cyclic route at port level; between all origin-destination demand pairs network. objective is minimize cost which includes fixed opening...

in this study, a hierarchical hub location problem by considering different modes of transportation and maximum allowed delay is investigated. this study is done on iran’s express postal service with 2 days maximum delay in delivery considering ground and airport hubs. the problem is of the type of location and single allocation for collection, transfer and distribution of the shipments. all th...

in this paper, we develop a capacitated location-covering model considering interval values for demand and service parameters. we also consider flexibility on distance standard for covering demand nodes by the servers. we use the satisfaction degree to represent the constraint of service capacity. the proposed model belongs to the class of mixed integer programming models. our model can be redu...

This paper presents a multiobjective continuous covering location problem in fuzzy environment. Because of uncertain covering radius, possibility of covering concept is introduced.Since, the uncertainty may cause risk of uncovering customers; the problemis formulated as a risk management model. The presented model is an extension of the discrete covering location models tocontinuous space. Two ...

Design of network, through which data, packages or even people can be transported, is an important issue for achieving a desired level of service quality at an acceptable cost. For this purpose, it is possible to design a network comprised of nodes that are connected to each other with dedicated lines. However, this kind of solution will not be cost effective. In order to decrease the total tra...