Editors' introduction: special issue on homeland security

Abstract

The events of September 11, 2001 will forever affect the lives of all those who observed their consequences. These events have changed the way in which people live and carry on their everyday affairs. These events also ignited the engineering community in general, and the industrial engineering community in particular, to refocus their energy to address problems that impact our nation’s safety, security, and well-being. This focused issue on homeland security reports several examples of how industrial engineering and operations research modeling and analysis techniques are being used to secure our nation’s borders, our transportation airspace system, our nation’s nuclear materials stockpiles, and the many critical infrastructures that support our social and economic foundations, and hence, impact the well-being of our citizens. Eight papers are included in this special issue, which span these vital and important areas of concern. Two papers consider issues surrounding interdiction. In the paper “Models for Nuclear Smuggling Interdiction,” Morton, Pan and Saeger introduce two stochastic network interdiction models for thwarting nuclear smuggling. In their first model, the smuggler travels through a transportation network on a path that maximizes the probability of evading detection, and the interdictor installs radiation sensors to minimize that evasion probability. In their second model, the interdictor and smuggler can have differing perceptions of these network parameters. Both models also consider the important special case in which the sensors can only be installed at border crossings of a single country. In a more general setting, the paper “Algorithms for Discrete and Continuous Multicommodity Flow Network Interdiction Problems,” by Lim and Smith, considers a network interdiction problem on a multicommodity flow network, where an attacker disables a set of network arcs so as to minimize the maximum profit that can be obtained from shipping commodities through the network. They examine problems in which interdiction must be discrete and in which interdiction can be continuous. They illustrate their models on a set of randomly generated test data. Several papers address the area of critical infrastructure support. In the paper “Allocation and Reallocation of Ambulances to Casualty Clusters in a Disaster Relief Operation,” Gong and Batta study ambulance allocation and reallocation models for a post-disaster relief operation. They consider allocating the correct number of ambulances to each cluster at the beginning of the rescue process, and formulate a method to determine the completion time for each cluster. They also analyze the ambulance reallocation problem on the basis of a discrete time policy. Jia, Ordonez and Dessouky study the problem of locating emergency medical service facilities to cope with large-scale emergencies. Their paper, “A Modeling Framework for Facility Location of Medical Services for Large-Scale Emergencies,” considers several strategies for deploying medical supplies to respond to low frequency, high impact events. The framework this research presents accounts for uncertainty in demand and geographical effects. Small examples based on the Los Angeles area are presented. In the paper, “Toward Modeling and Simulation of Critical National Infrastructure Interdependencies,” Min, Beyler, Brown, Son and Jones propose a modeling and analysis framework that considers the interdependencies between an integrated system of economic and physical infrastructures. They integrate individual infrastructure models together using system dynamics, functional models, and nonlinear optimization algorithms. An illustrative example is provided that demonstrates the technique using realistic models of the individual component infrastructures currently under development by government agencies, private industry, and academia. In the paper, “Integer Programming Models and Analysis for a Multilevel Passenger Screening Problem,” McLay, Jacobson and Kobza introduce the Multilevel Passenger