We offer a formulation that locates hubs on a network in a competitive environment; that is, customer capture is sought, which happens whenever the location of a new hub results in a reduction of the current cost (time, distance) needed by the traffic that goes from the specified origin to the...

Models are presented for the optimal location of hubs in airline networks, that take into consideration the congestion effects. Hubs, which are the most congested airports, are modeled as M/D/c queuing systems, that is, Poisson arrivals, deterministic service time, and {\em c} servers. A formula...

In this paper we address the issue of locating hierarchical facilities in the presence of congestion. Two hierarchical models are presented, where requests are attended first by lower level servers, and then some of the served customers are referred to higher level servers. In the first model,...