Note: Facility location with closest rectangular distances

This paper considers the problem of locating one or more new facilities on a continuous plane, where the destinations or customers, and even the facilities, may be represented by areas and not points. The objective is to locate the facilities in order to minimize a sum of transportation costs. What is new in this study is that the relevant distances are the distances from the closest point in the facility to the closest point in the demand areas. © 2000 John Wiley & Sons, Inc. Naval Research Logistics 47: 77–84, 2000     

Localization of optimal strategies in certain games

Assume the payoffs of a matrix game are concave in the index of the maximizing player. That player is shown to have an optimal strategy which uses at most two consecutive pure strategies, identifiable through approximate solution of a related continuous game. Generalizations are given, and the results are applied to a motivating hidden-target model due to Shapley. © 1994 John Wiley & Sons, Inc.     

Two‐machine flow shop scheduling with common due window to minimize weighted number of early and tardy jobs

This article studies two due window scheduling problems to minimize the weighted number of early and tardy jobs in a two‐machine flow shop, where the window size is externally determined. These new scheduling models have many practical applications in real life. However, results on these problems have rarely appeared in the literature because of a lack of structural and optimality properties for solving them. In this article, we derive several dominance properties and theorems, including elimination rules and sequencing rules based on Johnsos order, lower bounds on the penalty, and upper bounds on the window location, which help to significantly trim the search space for the problems. We further show that the problems are NP‐hard in the ordinary sense only. We finally develop efficient pseudopolynomial dynamic programming algorithms for solving the problems. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009     

Do Democracies Support Violent Non-governmental Organizations Less Than Autocracies Do?

This study draws attention to the question: Do democracies fight indirectly through material support to violent non-governmental organizations (VNGOs) which wage intrastate war against other states in general and against democracies in particular, or are democracies less warlike by proxy? The main conclusions are: democracies are less warlike by proxy than non-democratic states, and the more democratic the regime the lower the probability that it will support VNGOs waging war against other states, both in general and against other democracies in particular. The results do not unequivocally support both the monadic or dyadic argument of democratic peaceful behaviour     

Democracy for the rescue—of dictators? The role of regime type in civil war interventions

Intrastate conflicts, long eclipsing interstate conflicts, are often internationalized. This paper examines internationalized intrastate conflicts through the types of both the intervening and the embattled regimes. Do democracies, more or less than autocracies, support autocratic governments in their fights against rebels? This paper tests three hypotheses: (1) democracies support autocrats fighting rebels less than autocracies do. (2) Democracies support democratic governments fighting against rebels more than autocracies do. (3) The more democratic two states are, the higher the probability one would support the other’s fight against rebels. Covering all documented external support in intrastate wars (1975–2000), our findings support hypothesis one and two only partly and confirm hypothesis three. However, comparing the two major accounts of the Democratic Peace theory (DPT)—the normative and the structural—our findings corroborate only the former robustly. The paper thus helps enriching the insights of the DPT beyond interstate conflicts.     

Route optimization for multiple searchers

We consider a discrete time‐and‐space route‐optimization problem across a finite time horizon in which multiple searchers seek to detect one or more probabilistically moving targets. This article formulates a novel convex mixed‐integer nonlinear program for this problem that generalizes earlier models to situations with multiple targets, searcher deconfliction, and target‐ and location‐dependent search effectiveness. We present two solution approaches, one based on the cutting‐plane method and the other on linearization. These approaches result in the first practical exact algorithms for solving this important problem, which arises broadly in military, rescue, law enforcement, and border patrol operations. The cutting‐plane approach solves many realistically sized problem instances in a few minutes, while existing branch‐and‐bound algorithms fail. A specialized cut improves solution time by 50[percnt] in difficult problem instances. The approach based on linearization, which is applicable in important special cases, may further reduce solution time with one or two orders of magnitude. The solution time for the cutting‐plane approach tends to remain constant as the number of searchers grows. In part, then, we overcome the difficulty that earlier solution methods have with many searchers. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

Determining restrictive goals in linear goal programs

Goal programming is a method for solving problems having multiple, conflicting objectives. Information on the characteristics of the goals can help in setting goal weights and levels, determining priority levels, and in conducting postoptimality analysis. One characteristic affecting the outcome of a goal program is the restrictiveness of a goal. A restrictive goal is one whose inclusion in the goal set most degrades the value of the total objective function, or the attainment of the remaining goals. An algorithm is presented that determines restrictive goals.     

A realist before ‘realism’: Quincy Wright and the study of international politics between two World Wars

Contrary to conventional belief, IR theorist Quincy Wright and his cohort before World War II were neither idealists, legalists, nor moralists. Deeply grounded in the realism and pragmatism that marked the University of Chicago's interwar climate, Wright applied an ethically neutral and empirical approach to understanding international relations. Unlike the stereotypical interwar theorist, Wright eschewed legalism. He recognized that a struggle for power drove international politics and would continue to do so for the forseeable future. Above all, Wright embraced the complexities of international politics, rejecting monocausal explanations for war or simplistic frameworks for understanding international relations.     

Bounded flexibility in days‐on and days‐off scheduling

This article presents a flexible days‐on and days‐off scheduling problem and develops an exact branch and price (B&P) algorithm to find solutions. The main objective is to minimize the size of the total workforce required to cover time‐varying demand over a planning horizon that may extend up to 12 weeks. A new aspect of the problem is the general restriction that the number of consecutive days on and the number of consecutive days off must each fall within a predefined range. Moreover, the total assignment of working days in the planning horizon cannot exceed some maximum value. In the B&P framework, the master problem is stated as a set covering‐type problem whose columns are generated iteratively by solving one of three different subproblems. The first is an implicit model, the second is a resource constrained shortest path problem, and the third is a dynamic program. Computational experiments using both real‐word and randomly generated data show that workforce reductions up to 66% are possible with highly flexible days‐on and days‐off patterns. When evaluating the performance of the three subproblems, it was found that each yielded equivalent solutions but the dynamic program proved to be significantly more efficient. © 2013 Wiley Periodicals, Inc. Naval Research Logistics 60: 678–701, 2013     

The Management of Pakistan's Nuclear Arsenal

Pakistan, the fastest growing nuclear weapon state in the world, has established over the last decade a nuclear management system it holds to be “foolproof.” Despite the explosion of radical groups challenging the writ of the state, it dismisses concerns by critics that its nuclear weapons are not safe and secure as “preposterous” and an attempt to “malign” the state. This article examines Pakistan's nuclear management system in four functional areas: command-and-control, physical security, nuclear surety, and doctrine. It describes what is publicly known in each area, identifies areas of omission and inadequacy in each one, and examines several premises of the nuclear program the author considers to be unfounded. Comparing these deficiencies in Pakistan's nuclear management system to the current problems plaguing the US nuclear management system, the author concludes that complacency and unfounded confidence in the efficacy of such programs, if not addressed and corrected, could lead to a future nuclear catastrophe in South Asia.