基于随机漫游模型的协同搜索力最优分配方法

针对多平台协同搜索的最优搜索问题,以多无人机区域搜索任务为背景,将搜索论和随机规划引入到编队协同搜索中,建立了环境模型、无人机模型、传感器模型;为了解决目标丢失后的“应召”搜索问题,建立了目标的随机漫游模型;通过对搜索力最优分配问题的分析,认为其实质为一类线性规划问题,提出了一种基于递归原理的解算方法;最后,通过仿真计算,证明了该随机漫游模型的合理性,并验证了所提算法的有效性。     

Enmeshed in insurgency: Britain's protracted retreats from Iraq and Afghanistan

Ten years of counterinsurgency in Iraq and Afghanistan have produced little in Britain's national interest. This article examines the political objectives set in these wars and the reasons why they have proved elusive. The core foreign policy aim was to sustain Britain's position as a great power by assuming responsibility for global order. Alliances with the United States and NATO would be the diplomatic tool for pursuing this aim. These alliances brought obligations, in the shape of agreed common threats. Rogue regimes with weapons of mass destruction and international terrorists harboured in failed states were deemed the primary threats to British security. Military means were therefore used in Iraq and Afghanistan to attack them. Whether Tony Blair's vision of global order ever made sense is debatable, and it attracted scepticism from the outset. The article argues experience in Iraq and Afghanistan showed that a strategy to eliminate terrorism (the WMD threat turned out never to have existed) by expeditionary counterinsurgency could only fail. Therefore the attention lavished on operational-level performance by most studies is misplaced, because no amount of warfighting excellence could make up for strategic incoherence. Finally, the article proposes the more important question arising from the last ten years is why the UK pursued a futile strategy for so long. The difficulties associated with interpreting events, a malfunctioning strategic apparatus, weak political oversight, and bureaucratic self-interest are posited as the most significant explanations.     

Operations sequencing for a multi‐stage production inventory system

This article studies operations sequencing for a multi‐stage production inventory system with lead times under predictable (deterministic) yield losses and random demand. We consider various cases with either full or partial release of work‐in‐process inventories, for either pre‐operation or post‐operation cost structures, and under either the total discounted or average cost criteria. We derive necessary and sufficient criteria for the optimal sequence of operations in all cases. While the criteria differ in their specific forms, they all lead to the same principal: those operations with (1) lower yields, (2) lower processing costs, (3) longer lead times, and (4) lower inventory holding costs should be placed higher upstream in the system.Copyright © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 144–154, 2014     

Colombia: Changing strategy amidst the struggle

From 1965 to the present, Colombia has been confronted by the insurgency of the Revolutionary Armed Forces of Colombia (FARC). The threat reached a new level in 1996 with the advent of mobile warfare, whereby large units sought to neutralize the military in an effort to seize power and institute a Marxist-Leninist regime. Unlike Vietnam, what followed was a regaining of the strategic initiative by the government and a decimation of the insurgent threat. This was accomplished with US assistance but from first to last was driven by Colombian leadership and strategy. The strategy which led to this signal change, ‘Democratic Security’, unfolded under the leadership of President Álvaro Uribe. It was a civil–military partnership, which sought to expand the writ of Colombian democracy to all elements of society. Securing the population provided the shield behind which economic, social, and political life could occur as driven by the will of the people. It was the agreement upon legitimacy as the strategic goal and reform as the route to that goal which allowed the Colombians and the Americans to work so well together.     

A best practice for assessment in counterinsurgency

In September 2011, the Commander of the International Security Assistance Force (ISAF) in Afghanistan directed the Afghan Assessment Group to redesign the way in which ISAF was assessing the status of the war, and to be ‘revolutionary’ in so doing. The resulting assessment paradigm was novel, non-doctrinal, and effectively addressed the unique complexities of the counterinsurgency in Afghanistan and the needs of the ISAF Commander. It had a two-tier structure consisting of both strategic and campaign assessments. The former focused on answering a set of strategic questions in narrative, analytic form to address the strategic environment, while the latter used a set of standards and accompanying narrative responses to gauge accomplishment of campaign tasks. Both tiers captured the current state of the war while maintaining an eye on future challenges and opportunities. The two assessments and their associated processes were designed to stimulate discussions leading directly to decisions by senior leaders on actions they could take, direct, or request. While any assessment paradigm will have advantages and disadvantages, an examination of the pros and cons of this assessment paradigm makes clear that it should be considered a ‘best practice’ in the field of counterinsurgency assessment.     

Improved bounds for batch scheduling with nonidentical job sizes

Here, we revisit the bounded batch scheduling problem with nonidentical job sizes on single and parallel identical machines, with the objective of minimizing the makespan. For the single machine case, we present an algorithm which calls an online algorithm (chosen arbitrarily) for the one‐dimensional bin‐packing problem as a sub‐procedure, and prove that its worst‐case ratio is the same as the absolute performance ratio of . Hence, there exists an algorithm with worst‐case ratio , which is better than any known upper bound on this problem. For the parallel machines case, we prove that there does not exist any polynomial‐time algorithm with worst‐case ratio smaller than 2 unless P = NP, even if all jobs have unit processing time. Then we present an algorithm with worst‐case ratio arbitrarily close to 2. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 351–358, 2014     

基于遗传算法的吊放声纳搜潜策略优化

针对吊放声纳搜潜策略问题,在平均分配每点的搜索时间的典型搜潜策略的基础上,采用遗传算法优化搜潜策略中的吊点选择,进而给出合理的吊放声纳搜潜路径。算法中,利用实数编码优化初始种群,采用轮盘赌和期望值相结合的混合选择策略优化种群的进化。仿真运算表明:采用遗传算法优化吊放声纳搜潜路径是一种具有研究价值的方法,但算法复杂,计算量大,工程实现还需要进一步研究简化。     

基于“招标—投标”策略的舰艇编队协同反导优化

针对舰艇编队协同防空反导的作战过程,以缩短舰艇编队协同反导的整体拦截时间、降低反导资源的消耗为目标,构建了一种"招标—投标"策略的舰艇编队协同反导优化模型。该模型利用模糊数学和动态规划相结合的优化技术,在单个作战单元需要编队内其他作战单元协同反导的情况下,运用"招标—投标"策略建立满足反导策略的决策方案,能实时、动态的调整舰艇编队整体协同反导策略。     

基于搜索论的反舰导弹机动搜捕策略建模方法

针对概略射击条件下反舰导弹机动搜索目标策略优化选择的需求,采用搜索论的基本理论对反舰导弹机动搜捕策略问题进行了研究,建立了反舰导弹随机搜索策略、平行搜索策略和螺旋搜索策略搜捕概率计算模型,并进行了仿真计算。仿真结果表明:在已知目标概略位置的条件下,反舰导弹假若采取螺旋式搜索策略,能以较高的概率快速捕捉目标。     

US strategic preferences in the early twenty-first century

This article investigates how US national security planners have envisioned the emerging strategic environment during the early twenty-first century and evaluates how their perceptions of this strategic environment have changed during these years. This conceptual evolution can be seen in how defense planners define threats, identify defense priorities, and design security strategies. Five key strategic planning documents serve as the basis for this analysis and illustrate significant shifts in how the US government has envisioned its own security requirements as well as the context within which its strategic vision will need to be realized. These planning documents are: (1) Joint Vision 2020, (2) the Bush Administration's 2002 National Security Strategy of the United States, (3) the Obama Administration's 2010 National Security Strategy, (4) US Strategic Defense Guidance entitled Sustaining US Global Leadership: Priorities for 21^st Century Defense, and (5) the US Chairman of the Joint Chiefs of Staff's Capstone Concept for Joint Operations: Joint Force 2020.