Facility location when demand is time dependent

In this article the authors investigate the problem of locating a facility among a given set of demand points when the weights associated with each demand point change in time in a known way. It is assumed that the location of the facility can be changed one or more times during the time horizon. There is a need to find the time ‘breaks’ when the location of the facility is to be changed, and the location of the facility during each time segment between breaks. The authors investigate the minisum Weber problem and also minimax facility location. For the former they show how to calculate the objective function for given time breaks and optimally solve the rectilinear distance problem with one time break and linear change of weights over time. Location of multiple time breaks is also discussed. For minimax location problems the authors devise two algorithms that solve the problem optimally for any number of time breaks and any distance metric. These algorithms are also applicable to network location problems.