基于BOM的HLA仿真系统可信性研究

可信性是系统仿真的关键要素.基于BOM的HIA仿真系统可以从仿真模型层次上提高系统的重用性和互操作性.为了确保该类仿真系统的可信性,在建模与仿真全生命周期中开展VV&A研究,十分必要.介绍了基于BOM的HLA仿真系统的FEDEP模型,并简要提出其VV&A过程,重点对用户模型、仿真模型组件及联邦成员的V&V展开研究,最后将这些研究应用于×××反舰导弹突防联邦仿真中.结果表明:提出的VV&A过程切实可行,保障了系统的可信性.     

脉冲等离子体推力器羽流的粒子模拟

目前微小卫星正在积极地发展中,脉冲等离子体推力器是其推进系统的一个重要发展方向,为了能够将PPT成功地运用于空间,需对其羽流进行研究.将DSMC(Direct Simulation Monte-Carlo)/PIC(Particle in Cell)流体混合算法与一维MHD放电模型相结合,一体化模拟NASA Glenn PPT羽流,对不同出口偏转角的羽流场进行模拟,并与实验结果进行了比较.计算结果显示引入出口速度的偏转角提高了模型的羽流扩散能力,羽流的扩散角是影响羽流的一个主要因素.     

Value management of diagnostic equipment with cancelation,no‐show,and emergency patients

Magnetic resonance imaging and other multifunctional diagnostic facilities, which are considered as scarce resources of hospitals, typically provide services to patients with different medical needs. This article examines the admission policies during the appointment management of such facilities. We consider two categories of patients: regular patients who are scheduled in advance through an appointment system and emergency patients with randomly generated demands during the workday that must be served as soon as possible. According to the actual medical needs of patients, regular patients are segmented into multiple classes with different cancelation rates, no‐show probabilities, unit value contributions, and average service times. Management makes admission decisions on whether or not to accept a service request from a regular patient during the booking horizon to improve the overall value that could be generated during the workday. The decisions should be made by considering the cancelation and no‐show behavior of booked patients as well as the emergency patients that would have to be served because any overtime service would lead to higher costs. We studied the optimal admission decision using a continuous‐time discrete‐state dynamic programming model. Identifying an optimal policy for this discrete model is analytically intractable and numerically inefficient because the state is multidimensional and infinite. We propose to study a deterministic counterpart of the problem (i.e., the fluid control problem) and to develop a time‐based fluid policy that is shown to be asymptotically optimal for large‐scale problems. Furthermore, we propose to adopt a mixed fluid policy that is developed based on the information obtained from the fluid control problem. Numerical experiments demonstrate that this improved policy works effectively for small‐scale problems. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 287–304, 2016     

载机扰动下SAR/GMTI旋转目标微多普勒特性分析

目标微动部件激励的雷达微多普勒信号稳定而独特,反映了该目标的本质特征。针对采用相位中心偏置技术(DPCA)的SAR/GMTI系统,研究存在载机扰动下的旋转目标的微多普勒特性。构建飞行平台与微动目标的几何模型,推导旋转目标的微多普勒信号模型,分析典型的载机纵向扰动对微多普勒时频特性构成的影响;并通过仿真实验,验证了上述理论分析的正确性。     

基于察打任务的无人机作战效能评估

首先根据时敏目标打击的特点,分析了察打任务模式下的察打一体无人机的作战使用。然后对评估体系中察打一体无人机的侦察能力与打击能力相关性进行了分析,同时将任务可执行度作为无人机效能评估的一项动态权衡标准,建立了基于察打任务的无人机效能评估模型,并基于效能指标体系建立了各分项模型。最后通过算例验证了模型的可行性。     

基于χ~2检验的惯性/卫星紧耦合系统故障检测与隔离方法

研究了一种基于χ~2检验的惯性/卫星紧耦合系统故障检测与隔离方法,该方法可利用故障检测函数自动识别单个卫导故障,并实时剔除故障星重构观测信息序列,从而避免了对紧耦合系统的影响。构建数字化仿真环境对所研究的故障检测与隔离方法进行了仿真,仿真结果表明,该方法可在卫星发生故障时及时检测并隔离故障星,并自动实现观测信息重构,保证了紧耦合系统的精度和完好性。     

0.18 μm CMOS工艺的GPS/BDS双模可重构接收机射频前端

采用低中频架构设计了一种0.18μm CMOS工艺的GPS/BDS双模可重构接收机射频前端,能在GPS L1模式或BDS B1模式下工作。通过频率自适应电路调整中频滤波器的时间常数,降低其频率不确定度;压控振荡器中加入4位开关电容阵列,以提高频率调谐范围和相位噪声性能;通过硬件复用的方式降低系统功耗。测试结果表明,在1.8 V电源电压下,功耗37.8 m W,电压增益为103 d B,GPS L1和BDS B1波段噪声系数均小于3.2 d B。     

A partial characterization of the optimal ordering/rationing policy for a periodic review system with two demand classes and backordering

We consider a finite horizon periodic review, single product inventory system with a fixed setup cost and two stochastic demand classes that differ in their backordering costs. In each period, one must decide whether and how much to order, and how much demand of the lower class should be satisfied. We show that the optimal ordering policy can be characterized as a state dependent (s,S) policy, and the rationing structure is partially obtained based on the subconvexity of the cost function. We then propose a simple heuristic rationing policy, which is easy to implement and close to optimal for intensive numerical examples. We further study the case when the first demand class is deterministic and must be satisfied immediately. We show the optimality of the state dependent (s,S) ordering policy, and obtain additional rationing structural properties. Based on these properties, the optimal ordering and rationing policy for any state can be generated by finding the optimal policy of only a finite set of states, and for each state in this set, the optimal policy is obtained simply by choosing a policy from at most two alternatives. An efficient algorithm is then proposed. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

基于HLA的维修保障仿真系统设计研究

针对作战单元维修保障能力评估的需求,提出建立基于HLA的维修保障仿真分析平台。在分析维修保障系统构成和运行过程的基础上,阐述了仿真联邦的设计思想和构建方法,并进行了系统设计。根据实际系统的运行逻辑开发了联邦剧情,基于HLA的开发和执行过程模型构建了联邦系统框架,设计了联邦对象模型,并指出了仿真实现的关键技术所在。     

基于HLA的网络攻防仿真系统设计

以设计网络攻防仿真系统为开发目的,阐述了网络攻防仿真系统结构组成、系统内各部分之间的逻辑关系、交互内容和过程,重点分析和设计了系统联邦成员、对象类/交互类,实现了网络攻防仿真系统。仿真实验结果表明,系统的设计是可行的。