Iterative approaches to design of robust emergency system

A robust structure of an emergency service system is usually designed so that the deployment of given number of service centers complies with specified scenarios by minimizing the maximal value of objective functions corresponding with the particular scenarios. If the problem is modelled by means of mathematical programming and solved by a general IP solver, than the min-max link-up constraints represent an undesirable burden in any integer programming design problems due to bad convergence of embedded branch-and-bound method. Within this paper, we try to overcome the drawback following from the link-up constraints by usage of several techniques based on iterative processing. We provide the reader with a comparison of the original min-max approach to the suggested approach based on the Lagrangean relaxation of the troublesome constraints and subsequent usage of sub-gradient method for Lagrangean multiplier adjustment.