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Tactical learning is critical to battlefield success, especially in a counterinsurgency. This article tests the existing model of military adaption against a ‘most-likely’ case: the British Army’s counterinsurgency in the Southern Cameroons (1960–61). Despite meeting all preconditions thought to enable adaptation – decentralization, leadership turnover, supportive leadership, poor organizational memory, feedback loops, and a clear threat – the British still failed to adapt. Archival evidence suggests politicians subverted bottom-up adaptation, because winning came at too high a price in terms of Britain’s broader strategic imperatives. Our finding identifies an important gap in the extant adaptation literature: it ignores politics. 相似文献
316.
The anthrax attacks of 2001 energized research directed toward reducing health consequences from airborne contaminants by augmenting current heating ventilation and air-conditioning (HVAC) systems. Even during peacetime, interest will continue in improving HVAC components to reduce biocontaminants associated with sick building syndrome. Current HVAC design uses numerical simulation methods of ordinary differential equations to predict approximate performance. The authors show that state-space Laplace Transform calculations actually solve the underlying differential equations and yield algebraic expressions that provide new insight. To sharpen the arguments in favor of this methodology, attention is restricted to improving existing HVAC systems to increase protection from an external release of hazardous particulates. By nearly eliminating the need for dynamical simulation, the resulting methods can be applied to far more complex HVAC designs with little additional computational effort. The new methods reduce the time required for computation by three orders of magnitude. These algebraic methods also can be extended to disparate technical problems including internal particulate release, gas masks, and designing new protective buildings. 相似文献
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Nikolay I. Geraskin Andrey A. Krasnoborodko Taisia A. Piskureva 《Defense & Security Analysis》2015,31(4):330-345
In 2002, a Nuclear Security Culture (NSC) Enhancement Program with the mission to raise the level of the NSC at sites and facilities in Russia's nuclear complex was launched under the guidance of the Russian State Corporation “ROSATOM” and with support from the US Department of Energy. A Joint Working Group for NSC with both Russian Federation and US members was formed and charged with the design and implementation of the program. The program was implemented at sites and facilities on a pilot basis. Nine sites participated in the Pilot Project. The key program component was an establishment of Culture Coordinators (CCs) with the authority to coordinate and implement NSC enhancement activities at sites and facilities. The CCs have served as the force that has maintained the momentum of the Pilot Project and continuously steered the site NSC enhancement efforts. The contribution of the CCs in achieving the positive outcomes of the program cannot be overstated. 相似文献
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Motivated by wind energy applications, we consider the problem of optimally replacing a stochastically degrading component that resides and operates in a partially observable environment. The component's rate of degradation is modulated by the stochastic environment process, and the component fails when it is accumulated degradation first reaches a fixed threshold. Assuming periodic inspection of the component, the objective is to minimize the long‐run average cost per unit time of performing preventive and reactive replacements for two distinct cases. The first case examines instantaneous replacements and fixed costs, while the second considers time‐consuming replacements and revenue losses accrued during periods of unavailability. Formulated and solved are mixed state space, partially observable Markov decision process models, both of which reveal the optimality of environment‐dependent threshold policies with respect to the component's cumulative degradation level. Additionally, it is shown that for each degradation value, a threshold policy with respect to the environment belief state is optimal if the environment alternates between two states. The threshold policies are illustrated by way of numerical examples using both synthetic and real wind turbine data. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 395–415, 2015 相似文献
319.
A. Gmez‐Corral 《海军后勤学研究》2004,51(8):1068-1089
The model considered in this paper involves a tandem queue consisting of a sequence of two waiting lines. The main feature of our model is blocking, i.e., as soon as the second waiting line reaches a certain upper limit, the first line is blocked. The input of units to the tandem queue is the MAP (Markovian arrival process), and service requirements are of phase type. Our objective is to study the sojourn time distribution under the first‐come‐first‐serve discipline by analyzing the sojourn time through times until absorption in appropriately defined quasi‐birth‐and‐death processes and continuous‐time Markov chains. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004 相似文献
320.
We study a two‐machine flow shop scheduling problem with no‐wait in process, in which one of the machines is not available during a specified time interval. We consider three scenarios of handing the operation affected by the nonavailability interval. Its processing may (i) start from scratch after the interval, or (ii) be resumed from the point of interruption, or (iii) be partially restarted after the interval. The objective is to minimize the makespan. We present an approximation algorithm that for all these scenarios delivers a worst‐case ratio of 3/2. For the second scenario, we offer a 4/3‐approximation algorithm. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004 相似文献