Solving a (0, 1) hyperbolic program by branch and bound

A problem in (0, 1) hyperbolic programming is formulated and solved by the use of branch and bound methods. Computational results are presented including a comparison among several branching rules. Heuristic methods for quickly finding relatively good feasible solutions are presented and tested. The problem finds application in the scheduling of common carriers. In the solution of the main problem, a subproblem is identified and solved. A geometric analogue is presented, which allows an interesting interpretation of the subproblem. The subproblem itself finds application in the design of gambles.     

INCAPACITATING BIOCHEMICAL WEAPONS

Military interest in incapacitating biochemical weapons has grown in recent years as advances in science and technology have appeared to offer the promise of new “non-lethal” weapons useful for a variety of politically and militarily challenging situations. There is, in fact, a long and unfulfilled history of attempts to develop such weapons. It is clear that advances are opening up a range of possibilities for future biological and chemical weapons more generally. The treaties prohibiting biological and chemical weapons make no distinction between lethal and “non-lethal” weapons—all are equally prohibited. Indeed, a sharp and technically meaningful distinction between lethal and “non-lethal” biological and chemical weapons is beyond the capability of science to make. Thus, interest in incapacitating biochemical weapons, and efforts on the part of various states to develop them, pose a significant challenge to the treaty regimes, to the norms against biological and chemical warfare that they embody, and, ultimately, to the essential protections that they provide. Preventing a new generation of biological and chemical weapons from emerging will take concerted efforts and action at the local, national, and international levels.     

Service design at diagnostic service centers

We study a service design problem in diagnostic service centers, call centers that provide medical advice to patients over the phone about what the appropriate course of action is, based on the caller's symptoms. Due to the tension between increased diagnostic accuracy and the increase in waiting times more in‐depth service requires, managers face a difficult decision in determining the optimal service depth to guide the diagnostic process. The specific problem we consider models the situation when the capacity (staffing level) at the center is fixed, and when the callers have both congestion‐ and noncongestion‐related costs relating to their call. We develop a queueing model incorporating these features and find that the optimal service depth can take one of two different structures, depending on factors such as the nurses' skill level and the maximum potential demand. Sensitivity analyses of the two optimal structures show that they are quite different. In some situations, it may (or may not) be optimal for the manager to try to expand the demand at the center, and increasing skill level may (or may not) increase congestion. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

A new kind of fictitious play

Gass, Zafra, and Qiu (1996) introduce a modified version of fictitious play for matrix games where only the more successful player's strategy is retained. This paper introduces additional modifications that appear to converge faster. © 2001 John Wiley & Sons, Inc.* Naval Research Logistics 48: 270–280, 2001     

Sensitivity curves for effective project management

A key problem in project management is to decide which activities are the most important to manage and how best to manage them. A considerable amount of literature has been devoted to assigning “importance” measures to activities to help with this important task. When activity times are modeled as random variables, these activity importance measures are more complex and difficult to use. A key problem with all existing measures is that they summarize the importance in a single number. The result is that it is difficult for managers to determine a range of times for an activity that might be acceptable or unacceptable. In this paper, we develop sensitivity curves that display the most useful measures of project performance (in terms of schedule) as a function of an activity's time. The structure of the networks allows us to efficiently estimate these curves for all desired activities, all desired time ranges, and all desired measures in a single set of simulation runs. The resulting curves provide insights that are not available when considering summarized measures alone. Chief among these insights is the ability to identify an acceptable range of times for an activity that will not lead to negative scheduling consequences. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 481–497, 2003     

An exact method for finding shortest routes on a sphere,avoiding obstacles

On the surface of a sphere, we take as inputs two points, neither of them contained in any of a number of spherical polygon obstacles, and quickly find the shortest route connecting these two points while avoiding any obstacle. The WetRoute method presented here has been adopted by the US Navy for several applications. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 374–385, 2016     

Country survey XVII: New zealand's defence policy

New Zealand's current defence strategy, first expressed in NZ Government (1991), is one of "self-reliance in partnership". We outline the country's defence policy in historical context, examine its current defence expenditure and capabilities, and document the genesis of recent major changes in security policy. We pay particular attention to the role of explicit economic analysis and advice in the formation of these policy changes.