给定任务和模式下指挥体系节点重要性评估方法

针对一般节点重要度评估方法没有考虑指挥体系网络与外界的交互以及自身运行机制的问题,研究了指挥节点的重要度评估方法,在一般网络结构重要度分析基础上,综合作战任务和指挥模式对节点的需求,提出了作战任务对节点依赖度以及指挥模式对节点依赖度的计算方法,最后设计了评估算法并给出具体算法流程,案例分析结果证明该算法合理、有效。     

一种钢管焊接结构焊接节点损伤识别的新方法

采用端部半刚性连接梁单元模型进行模拟焊接节点的损伤,并基于应变模态理论,提出了一种焊接节点损伤识别两步法。第一步,先整体测量结构的位移模态并推导出应变模态,然后采用改进后的目标函数,通过信赖域优化算法对损伤节点位置进行准确判定;第二步,采用提出的杆端应变模态变化比指标,实现焊接节点损伤程度的精确识别。经工程实例的数值仿真及试验分析,验证了该方法的有效性及优越性,为解决这类大型焊接结构焊接节点的损伤识别问题提供了新思路。     

无人机侦察效能研究

携带侦察设备对指定区域进行侦察是无人机在现代战场上的重要应用之一。以无人机为平台,以CCD摄像机为侦察设备,提供了一种无人机执行侦察任务时的效能评估模型。在给出了无人机及侦察设备模型的基础上,从影响无人机的侦察能力和侦察代价两个方面着手,建立了对无人机侦察方案进行效能评估的模型,从而解决了侦察方案优劣的评价问题,这对无人机高效的执行侦察任务提供了理论决策依据。     

基于任务和角色的分布式工作流安全模型

针对现有基于角色访问控制的缺陷和分布式工作流管理系统的特性,在传统的基于角色的访问控制模型中引入任务集(Tasks)、任务实例集(TaskInstances)和任务上下文(TaskContext)的概念,将传统的user role permission权限赋予结构修改为user role task permission权限赋予结构,建立了基于任务和角色的访问控制模型,给出了其形式化定义。该模型解决了传统的基于角色访问控制中的动态适应性差和最小权限约束假象的问题,用于分布式工作流管理系统,提高了安全性、实用性。     

防抱制动系统基于最佳滑移率的滑模变结构控制方法

建立了防抱制动系统的非线性、时变数学模型,实现了滑模变结构控制方法在防抱制动系统中的应用,提出了两种由递推最小二乘算法来计算最佳滑移率的估计方法:一种基于附着系数—滑移率曲线的数学模型,一种基于该曲线的形状。仿真结果表明了基于最佳滑移率的滑模变结构控制方案在车辆防抱制动系统中的可行性和有效性。     

21世纪无人机关键技术

无人机因其独特而优异的战术性能,在近几次现代局部战争中得到了越来越广泛的应用,执行的任务也越来越多。从未来无人机的军事需求及其战术性能入手,结合技术发展趋势和发展可行性,对未来无人机发展需要的一些关键技术进行了分析研究,这些关键技术对提高未来无人机的战术性能具有重要作用。     

Optimal inventory control policy for periodic‐review inventory systems with inventory‐level‐dependent demand

We consider a setting in which inventory plays both promotional and service roles; that is, higher inventories not only improve service levels but also stimulate demand by serving as a promotional tool (e.g., as the result of advertising effect by the enhanced product visibility). Specifically, we study the periodic‐review inventory systems in which the demand in each period is uncertain but increases with the inventory level. We investigate the multiperiod model with normal and expediting orders in each period, that is, any shortage will be met through emergency replenishment. Such a model takes the lost sales model as a special case. For the cases without and with fixed order costs, the optimal inventory replenishment policy is shown to be of the base‐stock type and of the (s,S) type, respectively. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

Partial equilibrium in risk‐based production decisions

Characteristically, a small subset of operational problems admit risk neutrality when contingent claims methodology were used in their analysis. That is, for the majority of manufacturing and production problems, operating cash flows are not directly linked to prices of traded assets. However, to the extent that correlations can be estimated, the methodology's applicability to a broader set of operational problems is supported. Our article addresses this issue with the objective of extending the use of contingent claims techniques to a larger set of operational problems. In broad terms, this objective entails a partial equilibrium approach to the problem of valuing uncertain cash flows. To this end, we assume risk aversion and cast our approach within Merton's intertemporal capital asset pricing model. In this context, we formulate a “generic” production valuation model that is framed as an exercise in stochastic optimal control. The model is versatile in its characterization and can easily be adapted to accommodate a wide‐ranging set of risk‐based operational problems where the underlying sources of uncertainty are not traded. To obtain results, the model is recast as a stochastic dynamic program to be solved numerically. The article addresses a number of fundamental issues in the analysis risk based decision problems in operations. First, in the approach provided, decisions are analyzed under a properly defined risk structure. Second, the process of analysis leads to suitably adjusted probability distributions through which, appropriately discounted expectations are derived. Third, through consolidating existing concepts into a standard and adaptable framework, we extend the applicability of contingent claims methodology to a broader set of operational problems. The approach is advantageous as it obviates the need for exogenously specifying utility functions or discount rates.© 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

组网雷达的改进粒子滤波算法

针对现代战争中有源雷达容易受到干扰和反辐射导弹的摧毁,以及无源雷达隐蔽性高,只能测量方位角度,测量精度小等特点,提出利用集中式有源雷达系统与无源雷达系统协同组网对目标进行跟踪。但是在实际环境中,噪声属性以及有源雷达,无源雷达接收信号的特点决定了组网雷达需要应用非线性滤波技术对信号进行处理。传统的非线性技术包括卡尔曼滤波、扩展卡尔曼滤波(EKF)或无迹卡尔曼滤波(UKF)等方法。非线性近似过程带来的误差相对较大,而且均要求观测噪声和过程噪声为独立或相关的高斯白噪声。而粒子滤波避免了传统非线性滤波方法的缺陷,但是存在粒子退化,于是用EKF和UKF在每一时刻更新粒子,用更新的粒子及其协方差构造重要性函数,然后重采样。仿真实验表明这两种改进粒子滤波方法有很好的效果。     

地方高校图书馆主动服务对军校图书馆的启示——对全国15所重点高校图书馆网站的调查与分析

从图书馆主动服务的理念入手,探讨利用网络开展主动服务的可能性,并结合对全国15所重点高校图书馆网站和实践开展的多种主动服务方式进行调查统计,分析总结其特点,由此得出对军校图书馆开展主动服务的启示。