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.     

Shock wave mitigation using zig-zag structures and cylindrical obstructions

The present study focuses on the mitigation of shock wave using novel geometric passages in the flow field. The strategy is to produce multiple shock reflections and diffractions in the passage with minimum flow obstruction, which in turn is expected to reduce the shock wave strength at the target location. In the present study the interaction of a plane shock front (generated from a shock tube) with various geometric designs such as, 1) zig-zag geometric passage, 2) staggered cylindrical obstructions and 3) zig-zag passage with cylindrical obstructions have been investigated using computational technique. It is seen from the numerical simulation that, among the various designs, the maximum shock attenuation is produced by the zig-zag passage with cylindrical obstructions which is then followed by zig-zag passage and staggered cylindrical obstructions. A comprehensive investigation on the shock wave reflection and diffraction phenomena happening in the proposed complex passages have also been carried out. In the new zig-zag design, the initial shock wave undergoes shock wave reflection and diffraction process which swaps alternatively as the shock front moves from one turn to the other turn. This cyclic shock reflection and diffraction process helps in diffusing the shock wave energy with practically no obstruction to the flow field. It is found that by combining the shock attenuation ability of zig-zag passage (using shock reflection and diffraction) with the shock attenuation ability of cylindrical blocks (by flow obstruction), a drastic attenuation in shock strength can be achieved with moderate level of flow blocking.     

An historical review of US defense strategy from Vietnam to operation Iraqi freedom

Facing nearly half a billion dollars in spending cuts over the next five years, US defense planners and strategists must simultaneously rebuild a war-weary Army weakened from over a decade of war, build new sea and air capabilities for the Pacific theater, and reduce manpower, procurement, and contractor budgets while promoting innovation. The US defense department is embarking on what may be the most sweeping period of defense transformation in recent memory. This article reviews the history of American defense transformation, focusing on an important but largely overlooked period of military innovation that began in the shadow of Vietnam and ended with troops fighting through blinding sandstorms at night on the road to Baghdad. The multifaceted transformation strategy conceived in the 1970s paved the way for a military revolution in the 1990s and enabled unprecedented battlefield adaptation in the 2000s. After reviewing the revolutionary changes that led to American dominance in conventional warfare in the 1990s, the article examines US transformation policies in the 2000s to inform defense strategy and planning efforts in the 2010s.     

Scheduling with parallel processors and linear delay costs

This paper deals with the sequencing problem of minimizing linear delay costs with parallel identical processors. The theoretical properties of this m-machine problem are explored, and the problem of determining an optimum scheduling procedure is examined. Properties of the optimum schedule are given as well as the corresponding reductions in the number of schedules that must be evaluated in the search for an optimum. An experimental comparison of scheduling rules is reported; this indicates that although a class of effective heuristics can be identified, their relative behavior is difficult to characterize.     

Reinventing the Revolution: Technological Visions,Counterinsurgent Criticism,and the Rise of Special Operations

Two big ideas have shaped recent debate about military doctrine: the Revolution in Military Affairs (RMA) and Counterinsurgency (COIN). These ‘network centric’ and ‘population centric’ worldviews appear contradictory, but this is a false dichotomy. American forces have actively developed RMA concepts in COIN environments during recent wars in Iraq and Afghanistan; the exemplar par excellence is innovation by US Special Operations Command (SOCOM) in doctrine, technology, and organization for counterterrorism. Ironically, SOCOM's reimagining of the RMA managed to both improve the strengths and underscore the weaknesses of the American military's technological prowess.     

Decommissioning and paramilitary strategy in Northern Ireland: A problem compared

This study examines the problems of paramilitary decommissioning in Northern Ireland. It analyses why decommissioning has become so contentious in the Northern Ireland peace process. Decommissioning, though, is not a unique or intrinsically insurmountable problem. This is demonstrated by highlighting the issue in international context. Three examples of decommissioning in conflict resolution processes are assessed: the Lebanon, El Salvador and Mozambique. These varied examples do supply some limited lessons for Northern Ireland. This study argues that the explanation for the intractability of decommissioning in Northern Ireland resides, to a greater extent, in the tactical and strategic reasoning of the main paramilitary groupings in Northern Ireland. The factors that condition their thinking, however, can be found in the nature of the peace process itself which provides the paramilitiaries with every incentive to retain possession of their weapons.     

Whose Hearts and Whose Minds? The Curious Case of Global Counter-Insurgency

Traditionally regarded as a secondary activity in military thinking and practice, the notion of counter-insurgency (COIN) has undergone a remarkable renaissance. This analysis traces the origins of this renaissance to two distinctive schools: a neo-classical school and a global insurgency school. The global insurgency school critiques neo-classical thought and presents itself as a more sophisticated appreciation of current security problems. An examination of the evolution of these two schools of counter-insurgency reveals how the interplay between them ultimately leaves us with a confused and contradictory understanding of the phenomenon of insurgency and the policies and strategies necessary to combat it.     

Reviews

Ian Castle and Ian Knight, Fearful Hard Times: The Siege and Relief of Eshowe, 1879. Greenhill Books, London 1994, Pp.256, 85 illus, 6 maps, index. £17.95. ISBN 1–85367–180–0.

Michael E. Brown (ed.), Ethnic Conflict and International Security. Princeton: Princeton University Press, 1993, Pp.263, selected biblio, index. $45/£30 (cloth); $14.95/£12.95 (paper). ISBN 0–691–03368 and 00068–9.

Deborah Poole and Gerardo Renique, Peru: Time of Fear. London: Latin American Bureau (Research and Action) Ltd., 1992. Pp.212, 7 maps, photographs, glossary, sources/further reading, index. £17.99 ISBN 0–906156–70‐X and ‐71–8.

David A. Charters (ed.), Peacekeeping and the Challenge of Civil Conflict Resolution. Center for Conflict Studies, University of New Brunswick, 1994. Pp.viii+220. NP.

Joachim Remak, A Very Civil War: The Swiss Sonderbund War of 1847. Boulder, Colorado: Westview Press, 1993. Pp.xvi+221, 6 map's, 68 illus, biblio, index. $24.95/£16.95.     

Statistical equivalency and optimality of simple step‐stress accelerated test plans for the exponential distribution

Accelerated life testing (ALT) is commonly used to obtain reliability information about a product in a timely manner. Several stress loading designs have been proposed and recent research interests have emerged concerning the development of equivalent ALT plans. Step‐stress ALT (SSALT) is one of the most commonly used stress loadings because it usually shortens the test duration and reduces the number of required test units. This article considers two fundamental questions when designing a SSALT and provides formal proofs in answer to each. Namely: (1) can a simple SSALT be designed so that it is equivalent to other stress loading designs? (2) when optimizing a multilevel SSALT, does it degenerate to a simple SSALT plan? The answers to both queries, under certain reasonable model assumptions, are shown to be a qualified YES. In addition, we provide an argument to support the rationale of a common practice in designing a SSALT, that is, setting the higher stress level as high as possible in a SSALT plan. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2013