A robust sensor covering and communication problem

We consider the problem of placing sensors across some area of interest. The sensors must be placed so that they cover a fixed set of targets in the region, and should be deployed in a manner that allows sensors to communicate with one another. In particular, there exists a measure of communication effectiveness for each sensor pair, which is determined by a concave function of distance between the sensors. Complicating the sensor location problem are uncertainties related to sensor placement, for example, as caused by drifting due to air or water currents to which the sensors may be subjected. Our problem thus seeks to maximize a metric regarding intrasensor communication effectiveness, subject to the condition that all targets must be covered by some sensor, where sensor drift occurs according to a robust (worst‐case) mechanism. We formulate an approximation approach and develop a cutting‐plane algorithm to solve this problem, comparing the effectiveness of two different classes of inequalities. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 582–594, 2015     

Between Man and Nature: The Enduring Wisdom of Sir Halford J. Mackinder

This article argues for the continued relevance of the work and theories of the British Geostrategist Sir Halford J. Mackinder (1861-1947). It asserts that commentators and scholars who seek to marginalise Mackinder have too often dismissed his theories without setting them in the context of their continued endorsement in crucial areas of the globe. After 1945, despite his theories being tainted by association with Nazi Germany and Imperial Japan, both Moscow and Washington recognised the utility of Mackinder’s work and tailored policy accordingly. The end of Cold War saw Mackinder fall out of favour as his model was deemed unsuitable for policy analysis by a number of influential thinkers. It is argued here that, in recent years, the arena of international politics has seen a rehabilitation of Mackinder, accompanied by a resurgence of interest in Geopolitics. Finally, the piece examines those areas of the contemporary globe where Mackinder’s influence is greatest.     

Strategic “defensivism” and post-reset blues: US–Russian nuclear arms reductions,missile defenses and minimum deterrence

US nuclear deterrence and arms control policy may be moving, by design and by inadvertence, toward a posture of strategic “defensivism”. Strategic “defensivism” emphasizes the overlapping and reinforcing impact of: (1) reductions in US, Russian and possibly other strategic nuclear forces, possibly down to the level of “minimum deterrence,” (2) deployment of improved strategic and/or theater antimissile defenses for the US, NATO allies and other partners; and (3) additional reliance on conventional military forces for some missions hitherto preferentially assigned to nuclear weapons. This article deals with the first two of these aspects only: the interaction between missile defenses and offensive force reductions in US–Russian strategy and policy. The findings are that stable deterrence as between the USA and Russia is possible at lower than New Strategic Arms Reduction Treaty levels, but reductions below 1000 deployed long-range weapons for each state, toward a true minimum deterrent posture, will require multilateral as opposed to bilateral coordination of arms limitations. Missile defenses might provide some denial capability against light attacks by states with small arsenals, but they still fall short of meaningful damage limitation as between powers capable of massive nuclear strikes.     

Strategic obfuscation of production capacities

Recent supply‐chain models that study competition among capacity‐constrained producers omit the possibility of producers strategically setting wholesale prices to create uncertainty with regards to (i.e., to obfuscate) their production capacities. To shed some light on this possibility, we study strategic obfuscation in a supply‐chain model comprised of two competing producers and a retailer, where one of the producers faces a privately‐known capacity constraint. We show that capacity obfuscation can strictly increase the obfuscating producer's profit, therefore, presenting a clear incentive for such practices. Moreover, we identify conditions under which both producers' profits increase. In effect, obfuscation enables producers to tacitly collude and charge higher wholesale prices by moderating competition between producers. The retailer, in contrast, suffers a loss in profit, raises retail prices, while overall channel profits decrease. We show that the extent of capacity obfuscation is limited by its cost and by a strategic retailer's incentive to facilitate a deterrence. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 244–267, 2014     

Asymmetric information and third-party intervention in civil wars

I study a two-period model of conflict with two combatants and a third party who is an ally of one of the combatants. The third party is fully informed about the type of her ally but not about the type of her ally’s enemy. In a signaling game, I find that if the third party is unable to give a sufficiently high assistance to her ally, then there exists a unique separating equilibrium in which the third party’s expected intervention causes her ally’s enemy to exert more effort than in the absence of third-party intervention; this worsens the conflict.     

Tests for transient means in simulated time series

We present a family of tests to detect the presence of a transient mean in a simulation process. These tests compare variance estimators from different parts of a simulation run, and are based on the methods of batch means and standardized time series. Our tests can be viewed as natural generalizations of some previously published work. We also include a power analysis of the new tests, as well as some illustrative examples. © 1994 John Wiley & Sons, Inc.     

Radar pulse interleaving for multi‐target tracking

In a multifunction radar, the maximum number of targets that can be managed or tracked is an important performance measure. Interleaving algorithms developed to operate radars exploit the dead‐times between the transmitted and the received pulses to allocate new tracking tasks that might involve transmitting or receiving pulses, thus increasing the capacity of the system. The problem of interleaving N targets involves a search among N! possibilities, and suboptimal solutions are usually employed to satisfy the real‐time constraints of the radar system. In this paper, we present new tight 0–1 integer programming models for the radar pulse interleaving problem and develop effective solution methods based on Lagrangian relaxation techniques. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004.     

Dynamic proximity calculations for situation awareness

We apply dynamic proximity calculations (density and clustering) from dynamic computational geometry to a military application. The derived proximity information serves as an abstract view of a current situation in the battlefield that can help a military commander achieve situation awareness. We employ Delaunay triangulation as a computational tool in our framework, and study its dynamic update in depth. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004.     

Preservation of stochastic orders for random minima and maxima,with applications

It is shown, in this note, that the right spread order and the increasing convex order are both preserved under the taking of random maxima, and the total time on test transform order and the increasing concave order are preserved under the taking of random minima. Some inequalities and preservation properties in reliability and economics are given as applications. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004.