双基地中两坐标收站的三维定位跟踪算法

文中讨论了Ｔ／Ｒ—Ｒ型双基地系统中无俯仰信息收站对运动目标的三维定位跟踪能力;通过若干观测点上测量数据的组合,较好地实现厂对运动目标的三维定位跟踪,从而可以将目标的高度信息从变化的距离和之差的测最值中提取出来。文中以仿真手段证明了这种方法的可行性。     

高空滑移条件对化学非平衡粘性流动的影响

本文用数值方法计算了不同高度滑移边界条件对钝体绕流流场特性的影响。采用化学非平衡粘性激波层控制方程,边界条件含壁面滑移、激波滑移和无滑移条件。计算结果表明,考虑滑移条件后,激波层较厚,激波处的电子数密度为一有限值。文中给出了计算结果,并与其它文献的结果作了比较。     

旋转稳定塑料弹体工程设计计算研究

本文以实验结果为依据,首先分析了塑料弹体影响弹丸膛内运动的物理性能,然后结合旋转弹丸的膛内运动特征,经过模拟试验,采用数学拟合法,初步建立旋转稳定弹塑料弹体工程设计计算的数学模型(包括结构尺寸设计计算、强度计算和内弹道计算)。     

挠度对钢丝绳弹性模量的影响

钢丝绳被广泛地应用在油气储运工程中。弹性模量是钢丝绳的一个重要物性参数,欧洲和前苏联对该问题研究较多,他们用实验的方法得到钢丝绳弹性模量的经验计算公式。笔者引用等效弹性模量的概念,根据悬索的斜抛物线长度计算公式,从理论上推导了挠度对钢丝绳弹性模量影响的计算公式。该公式推导过程简单,且可以定量地计算挠度对钢丝绳弹性模量的影响。     

Bureaucracy Does Its Thing: US Performance and the Institutional Dimension of Strategy in Afghanistan

It is not too soon to draw cautionary lessons from the inconclusive results of US performance during more than 11 years of Operation ‘Enduring Freedom’ in Afghanistan. As in Vietnam, fundamental difficulties persist in adapting enduring institutions to the requirements of strategy. At the heart of the matter is tension between the assumptions that underlie counterinsurgency as practiced in Afghanistan and organization of the US Armed Forces, State Department, and Agency for International Development. Knowledge of basic principles and necessary changes is available to answer the question, could the US have done better?     

Global counterinsurgency and US army expansion: the case for recruiting foreign troops

Given the nature of global counterinsurgency operations, the demands of military expansion, and the need for cultural, linguistic, and regional expertise, the United States Army should evaluate the establishment of US-led foreign troop units for its evolving force structure. This article proposes the creation of an American foreign legion based upon the recruitment of US-led, ethnically homogeneous tribal force units to meet the grist mill of counterinsurgency operations. This structured approach would be more beneficial than the current reliance on a de facto American Foreign Legion, represented by private military contractors (PMCs), many of them comprised of foreigners. These PMCs carry a number of oversight, accountability, and legal risks not found in a fully integrated, and US-officered foreign legion. The British Brigade of Gurkhas, the South-West African Police Counter-Insurgency Unit (Koevoet), and the Kit Carson Scouts serve as relevant historical examples where foreign troops were used to supplement national manpower resources.     

Counterinsurgency force ratio: strategic utility or nominal necessity

As a consequence of intervention in Iraq and Afghanistan, force ratio for counterinsurgency (COIN) has come under increased scrutiny. Reduced to its essence, the issue is simply, ‘How many troops does it take to get the job done?’ This answer has been sought by the US military, academia, and think tanks. There have been numerous responses, culminating in several ‘plug-and-play’ equations for minimum force ratios in COIN operations. Due to the impossibility of determining precisely how many insurgent forces there are, it has become common to base force ratios on the population of the country. In the realm of policy, the question above is posed as, ‘How many of our troops does it take to get the job done?’     

基于插件技术的人工免疫智能空间优化平台研究

采用人工智能方法求解空间优化问题已成为当前地理学研究领域的热点之一。研究目的在于通过设计一个开放的、可扩展的人工免疫空间优化模型框架,开发基于插件技术的优化工具软件,丰富空间优化决策支持的方法和技术体系。研究从空间优化问题的基本特点和计算需求出发,定义了面向空间优化问题求解的克隆选择优化模型框架。在此基础上,采用"插件-宿主平台"结构设计了人工免疫智能空间优化平台的总体架构,定义免疫算子插件与空间优化问题应用插件开发机制。实验结果表明,平台的架构和功能设计充分考虑了计算平台的开放性和扩展性,通过平台标准接口的功能扩展可实现对不同类型空间优化问题的求解。空间优化问题研究者或政府决策部门无需关系人工免疫优化方法的具体内涵即可基于本平台完成其具体空间优化决策支持任务。     

自补偿液体静压精密转台轴承设计与实验

设计了一种用于精密转台的新型自补偿圆锥形液体静压轴承,并完成了轴承的制造与性能测试。采用流量平衡原理推导了轴承设计公式,得到了轴向和径向的最优刚度及其优化条件,计入制造误差对轴承承载性能进行了仿真,并测试了轴承的刚度和回转精度。结果表明:轴承刚度受到节流间隙与承载间隙的流阻比以及油腔间内流系数影响,流阻比存在最优值,而内流系数越小,对刚度越有利;计入制造误差的仿真模型能够有效预测轴承刚度范围。     

Warning whom,for which response?

In June 2000, the Conference of Heads of State and Government of the Economic Community of Central African States (ECCAS) adopted the Protocol on the establishment of the Peace and Security Council for Central Africa (COPAX), with its two technical structures, namely the Central African Multinational Force (FOMAC) and the Central African Early Warning Mechanism (MARAC). MARAC is tasked with collecting and analysing data for the early detection and prevention of conflicts and crises. It currently consists of the Central Structure located at the ECCAS Executive Secretariat in Libreville (Gabon) and 31 Decentralised Correspondents spread throughout the ten member states of ECCAS. This article assesses the performance of MARAC in the light of its assigned objectives. Bearing in mind the peace and security challenges facing the central African sub-region, the central argument of this article is that while the establishment of MARAC is commendable, it flowed more from the logic and context of the establishment of similar mechanisms on the African continent during the same period than from any displayed capacity and/or readiness on the part of ECCAS to implement the recommendations due to emanate from such a structure.