Can NATO survive an accident prone Euro?

The European Monetary Union (EMU) is inherently unstable, and will be prone to repeated financial and fiscal crises. These crises pose a clear threat to NATO security and the political institutions of Alliance member states. There is no definitive way to eliminate the risks posed by monetary union, but straightforward reforms in EMU sovereign debt management represent a low-cost near-term means of mitigating these risks. With EMU nations facing a seeming leadership vacuum, it is well within NATO purview to press for adoption of such reforms.     

Service design at diagnostic service centers

We study a service design problem in diagnostic service centers, call centers that provide medical advice to patients over the phone about what the appropriate course of action is, based on the caller's symptoms. Due to the tension between increased diagnostic accuracy and the increase in waiting times more in‐depth service requires, managers face a difficult decision in determining the optimal service depth to guide the diagnostic process. The specific problem we consider models the situation when the capacity (staffing level) at the center is fixed, and when the callers have both congestion‐ and noncongestion‐related costs relating to their call. We develop a queueing model incorporating these features and find that the optimal service depth can take one of two different structures, depending on factors such as the nurses' skill level and the maximum potential demand. Sensitivity analyses of the two optimal structures show that they are quite different. In some situations, it may (or may not) be optimal for the manager to try to expand the demand at the center, and increasing skill level may (or may not) increase congestion. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

Double Mover–Stayer model on customer switching in telecommunications industry

Customer acquisition and customer retention are the most important challenges in the increasingly competitive telecommunications industry. Traditional studies of customer switching always assume that customers are homogeneous, and thus that model customer switching behavior follows a Markov formulation. However, this postulation is obviously inappropriate in most instances. Blumen et al. (Cornell Studies of Industrial and Labor Relations, Cornell University Press, Ithaca, NY, 1955) developed the Mover–Stayer (MS) model, a generalization of the Markov chain model, to relax the requirement of homogeneity and allow the presence of heterogeneity with two different types of individuals—“stayers,” who purchase the same kinds of products or services throughout the entire observation period; and “movers,” who look for variety in products or services over time. There are two purpose of this article. First, we extend the MS model to a Double Mover‐Stayer (DMS) model by assuming the existence of three types of individuals in the market: (1) stable and loyal customers, who have stable usage within the same company; (2) instable but loyal customers, whose usage varies within the same company over time; and (3) disloyal customers, who switch from one company to another to seek for new experiences or/and benefits. We also propose an estimation method for the DMS model. Second, we apply the DMS model to telecommunications data and demonstrate how it can be used for pattern identification, hidden knowledge discovery, and decision making. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

质量块控制自旋导弹的Lyapunov稳定性分析

给出了质量矩控制导弹的动力学模型及在一定条件下的简化动力学模型;用Lyapunov分析方法给出了动稳定性条件。结果说明,推力和静稳定度越大,越有利于动态稳定;阻力越大越不利于动态稳定。     

舰船稳性计算中附体影响的一种处理方法

提出在静水力曲线、邦戎曲线以及船形稳度力臂插值曲线计算中对附体处理的一种新方法,即建立在三次样条插值函数积分基础上的附体体积分布法.该方法将附体按体积与体积中心等效的条件分布到船体型值点上,其中船体体积与体积中心采用三次样条插值函数积分法进行计算,以此来修正其对船舶静力计算结果的影响.按该方法对某船带附体的静水力曲线、船形稳度力臂插值曲线进行了计算,并对计算结果进行了分析,表明该方法在工程应用中可获得满意效果.     

扁平潜器前进与倒航稳定性评估

基于现有条件和针对扁平潜器的特点,由拖曳水池模型试验确定了攻角、漂角水动力,用经验方法近似估算了旋转水动力.用所得到的线性水动力系数,按照线性稳定性理论方法评估了扁平潜器正航和倒航下水平面、垂直面内的运动稳定性.将正航下水平面、垂直面内的运动稳定性计算结果与资料中类似的扁平潜器进行了比对分析,结果表明两者具有相同的稳定性特征,即垂直面内具有运动稳定性,而水平面内不具有航向稳定性.最后采用主推进器PD控制方法,用非线性运动模型数值仿真计算了主推进器控制作用下扁平潜器的运动.仿真计算结果表明,除了水平面倒航运动外,垂直面正航与倒航、水平面正航运动都可以通过主推进器的控制实现扁平潜器的运动控制.仿真计算结果还表明,在相同的PD控制参数下,航速愈低倒航对深度响应时间愈长.     

两种改进Lagrange插值格式的对比分析

本文基于Lagrange插值多项式,给出了两种改进的Lagrange插值格式：Aitken插值和重心Lagrange插值。从算法的复杂性及数值稳定性两个方面进行了比较分析,结果表明重心形式的Lagrange插值是最优的。文末给出数值试验表明算法的有效性。     

陆空火力协同仿真推演验证系统设计

针对陆空联合作战中火力协同方案制订、验证手段方法的不足,采用计算机仿真的方法,从安全防误伤的角度对陆空火力协同方案进行了仿真推演评估。分析了功能需求和体系结构,建立了武器装备运动轨迹模型和陆空火力协同安全性判别模型,研究了仿真时钟推进机制和提高仿真速度的方法,设计了陆空火力协同仿真推演验证系统。作战演习应用表明：该系统仿真推演验证快速、准确、便捷、有效。     

装备保障能力评价参数体系设计与应用

为了及时发现装备作战单元在装备保障建设中存在的问题并确定原因,研究了装备保障能力评价参数体系的构建。在剖析装备保障能力概念的基础上,将能力评价参数分为综合层、系统层、子系统层及资源层。从参数内容、评价对象层次以及时域3个维度设计了评价参数体系框架,并据此对4个层次参数的选取及其关系分别进行了探讨。最后通过某防空旅装备保障能力评价实例,验证了参数体系设计方法的可操作性和有效性。     

某共享通讯塔加装天线后结构安全性校核

对某共享通讯铁塔加装天线后结构安全性进行校核,建立了基于不同梁杆单元及节点连接的通讯铁塔空间刚架和混合有限元模型,对其结构动态特性及静力分析结果进行了对比分析,指出两种不同模型的动态特性相差不大,采用刚架模型来复核偏于安全;对通讯塔在加装天线后在风荷载及塔自重作用下结构安全性评估,并对该铁塔底层塔段弦杆中点变形超限的特...