Integer programming formulations of discrete hub location problems

Hubs are facilities that serve as transshipment and switching points for transportation and telecommunication systems with many origins and destinations. This paper presents integer programming formulations for four types of discrete hub location problems: the p-hub median problem, the uncapacitated hub location problem, p-hub center problems and hub covering problems. Hub median and uncapacitated hub location problems have received limited attention from researchers. This paper introduces discrete hub center and hub covering problems. Basic formulations and formulations with flow thresholds for spokes are presented.