钢丝绳弹性联轴器特性建模

提出一个钢丝绳弹性联轴器特性的数学模型,该数学模型能很好地描述钢丝绳弹性联轴器的迟滞非线性特性.分析表明,钢丝绳弹性联轴器具有软刚度和阻尼大的特性,有利于抑制船舶轴系的振动.     

FIPA规范的防空导弹体系Agent建模方法

针对防空导弹体系建模的复杂性,探讨研究防空导弹体系的Agent建模方法.提出了基于G/A矩阵的Agent建模方法步骤,通过分析角色之间的关系描述了Agent组织结构,给出了角色类和Agent类的统一定义,并建立了Agent结构框架和类实现模型,最后构建了基于FIPA规范的MAS综合集成框架.该方法的提出,为防空导弹体系的进一步建模提供了方法依据.     

基于CISE环境的导弹武器仿真系统

数字仿真研究是导弹武器设计验证的有效手段,基于CISE环境设计了导弹武器仿真系统,介绍了CISE环境的特点,给出了仿真系统的模块组成、系统方案、软件界面,设计了系统工作流程和仿真系统各组成模块间信息交互定义及关系,介绍了仿真系统中的中末制导交班流程、攻击区计算流程。该平台各模块间具有良好的独立性和封装性,基于此系统开展了系统建模、作战模式、战技指标论证、逃逸方式等方面研究工作。     

National security,military spending and the business cycle

This paper develops a Dynamic Stochastic General Equilibrium model where national security is an argument in the agent’s utility function and the government chooses optimally the level of military spending to maximize social welfare. National defense depends on military expenditure and on the strategic environment reflecting a potential hostile external threat. We use aggregate data on consumption, investment, and military spending for the US economy to estimate the parameters of the model. Estimation results suggest that consumption and national defense are complements and that military spending variability is mainly explained by external threat shocks although it also depends on the macroeconomic conditions. We compute impulse response functions of the main macroeconomic variables to several shocks: a total factor productivity shock, a defense technology shock, and a strategic environment shock. Surprisingly, we find that the optimal response to an increase in the external threat (a worsening in the strategic environment) will rise output by reducing consumption and increasing investment.     

On efficient algorithms for finding efficient salvo policies

We consider the salvo policy problem, in which there are k moments, called salvos, at which we can fire multiple missiles simultaneously at an incoming object. Each salvo is characterized by a probability p_i: the hit probability of a single missile. After each salvo, we can assess whether the incoming object is still active. If it is, we fire the missiles assigned to the next salvo. In the salvo policy problem, the goal is to assign at most n missiles to salvos in order to minimize the expected number of missiles used. We consider three problem versions. In Gould's version, we have to assign all n missiles to salvos. In the Big Bomb version, a cost of B is incurred when all salvo's are unsuccessful. Finally, we consider the Quota version in which the kill probability should exceed some quota Q. We discuss the computational complexity and the approximability of these problem versions. In particular, we show that Gould's version and the Big Bomb version admit pseudopolynomial time exact algorithms and fully polynomial time approximation schemes. We also present an iterative approximation algorithm for the Quota version, and show that a related problem is NP-complete.     

基于3D打印的可移植人体外耳支架关键技术研究*

耳廓缺损是临床常见疾病，使用患者自体肋软骨雕刻为耳支架并植入缺损耳皮下是目前的主要治疗方法。该方法对手术者提出很高的技术要求，雕刻的外耳支架无法精确还原患者耳廓形状，同时肋软骨的切除会对患者带来并发症。本文探索使用医用硅胶制作患者个体外耳支架的关键技术，使用CT和逆向建模技术得到对应患者个体的外耳数字模型，利用3D打印技术制造人体外耳支架模具，并使用医用硅胶MED 4735完成人体外耳支架的制作成型。动物实验验证了其生物相容性，证明了该方法的可行性。通过该技术制作的硅胶人体外耳支架可以高度模仿患者特定的耳廓形状，支架精度高，制造周期短，无生物排异，可为替代肋软骨雕刻人体外耳支架进行耳廓缺损治疗提供依据。     

基于ANSYS／LS—DYNA的电子装备爆炸冲击振动损伤建模研究

针对电子装备爆炸冲击振动损伤问题，设计了损伤模拟的基本方案；采用ANSYS／LS—DYNA建立了二维“爆炸源-地面-弹性体-电子装备”模型；通过模型试验，获得了与实际爆炸冲击振动特性相吻合的加速度、位移和应力等数据。     

自由漂浮柔性机械臂系统的动力学建模与仿真

动量矩守恒约束使自由漂浮柔性机械臂系统成为非完整系统,其动力学模型通常是难以求解的微分—代数方程,因此提出将机械臂系统等效为一个完整系统进行建模。假设载体存在姿态控制力矩,此时由于不存在动量矩守恒约束,系统变成一个完整系统,采用Lagrange方法建立其动力学方程;令方程中载体的姿态控制力矩为零,即得到自由漂浮机械臂系统的动力学方程;采用数值方法求解动力学方程,并将动力学分析的结果与ADAMS中仿真的结果进行对比,验证了模型能够有效模拟自由漂浮柔性机械臂系统的动力学特性。     

A model of dynamic conflict in ethnocracies

We model an infinitely repeated Tullock contest, over the sharing of some given resource, between two ethnic groups. The resource is allocated by a composite state institution according to relative ethnic control; hence the ethnic groups contest the extent of institutional ethnic bias. The contest yields the per-period relative influence over institutions, which partly spills over into the next period, by affecting relative conflict efficiency. Our model generates non-monotone evolution of both conflict and distribution. Results suggest that external interventions, when effective in reducing current conflict and protecting weaker groups, may end up sowing the seeds of greater future conflict.     

Warranty claims modeling

A company wishes to estimate or predict its financial exposure in a reporting period of length T (typically one quarter) because of warranty claims. We propose a fairly general random measure model which allows computation of the Laplace transform of the total claim made against the company in the reporting interval due to warranty claims. When specialized to a Poisson process of both sales and warranty claims, statistical estimation of relevant quantities is possible. The methodology is illustrated by analyzing automobile sales and warranty claims data from a large car manufacturer for a single car model and model year. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008