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,...

Part I: Sources of uncertainty, risk, and imprecision -- Sources of Uncertainty in Location Analysis -- Risk, hazard and exposure time in Hazmat Location and Routing -- Customer related uncertainties in Facility Location Problems -- Part II: Models that protect against acts of nature, attackers,...