滑片泵与离心泵串联运行流量与扬程特性实验

随着滑片泵技术的不断发展和广泛应用,在中、小口径长输管道系统中出现了滑片泵和离心泵串联运行的实际情况.构建了滑片泵和离心泵串联运行实验系统,通过调节串联系统阀门开度、改变管路阻力的方法进行了实验研究,总结了滑片泵与离心泵串联流量与扬程特性,并运用Matlab软件拟合出流量与扬程特性曲线.     

Sojourn times in G/M/1 fork‐join networks

We consider a processing network in which jobs arrive at a fork‐node according to a renewal process. Each job requires the completion of m tasks, which are instantaneously assigned by the fork‐node to m task‐processing nodes that operate like G/M/1 queueing stations. The job is completed when all of its m tasks are finished. The sojourn time (or response time) of a job in this G/M/1 fork‐join network is the total time it takes to complete the m tasks. Our main result is a closed‐form approximation of the sojourn‐time distribution of a job that arrives in equilibrium. This is obtained by the use of bounds, properties of D/M/1 and M/M/1 fork‐join networks, and exploratory simulations. Statistical tests show that our approximation distributions are good fits for the sojourn‐time distributions obtained from simulations. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

Bayesian enhanced decision making for deteriorating repairable systems with preventive maintenance

Since a system and its components usually deteriorate with age, preventive maintenance (PM) is often performed to restore or keep the function of a system in a good state. Furthermore, PM is capable of improving the health condition of the system and thus prolongs its effective age. There has been a vast amount of research to find optimal PM policies for deteriorating repairable systems. However, such decisions involve numerous uncertainties and the analyses are typically difficult to perform because of the scarcity of data. It is therefore important to make use of all information in an efficient way. In this article, a Bayesian decision model is developed to determine the optimal number of PM actions for systems which are maintained according to a periodic PM policy. A non‐homogeneous Poisson process with a power law failure intensity is used to describe the deteriorating behavior of the repairable system. It is assumed that the status of the system after a PM is somewhere between as good as new for a perfect repair and as good as old for a minimal repair, and for failures between two preventive maintenances, the system undergoes minimal repairs. Finally, a numerical example is given and the results of the proposed approach are discussed after performing sensitivity analysis. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

水下武器作战研制仿真系统中的想定生成研究

针对武器系统研制仿真中对对抗条件下的武器作战效能进行评估的需求,分析了研制仿真的目标与想定生成的关系,设计了一种基于条件-行为判断的脚本的作战想定系统,并通过想定索引表确定了实体、环境、状态的对应关系,实现了模块化的校本设计模式.该脚本简便易用,具有良好的通用性和可扩展性,并在水下武器作战对抗分布交互仿真系统中得到了成功的应用.     

地铁火灾灭火战斗原则探讨

从地铁火灾特点及地铁灭火救援战斗规律入手,探讨了消防部队参加地铁火灾救援的战斗原则及这些原则的运用,供消防部队进行地铁火灾灭火救援时参考。     

舰载软杀伤仿真中模型不确定性分析方法研究

舰栽软杀伤仿真系统中,不可避免地存在不确定性因素,分析仿真系统的不确定性是利用仿真系统进行效能评估的关键.研究了BMA方法在模型不确定性定量分析中的理论知识,介绍了软杀伤仿真中反舰导弹捕捉目标的数学模型,并把BMA方法应用到舰载软杀伤仿真系统.通过仿真结果比较,BMA方法的估值精度高,算法简单,计算速度快,BMA方法是分析模型不确定性的有效方法.     

一种雷达网系统误差校准方法及其精度分析

由于系统误差影响数据融合精度,提出了基于ECEF坐标转换的雷达网系统误差数据校准方法,定义了系统误差估计精度的评估方法,对系统误差估计精度采用克拉美-劳下限(CRLB)进行评估.最后进行了仿真分析,验证了该校准方法的可行性和误差估计精度评估方法的有效性.     

加强高校和谐校园建设的若干思考

当前,在全面贯彻落实科学发展观,推进社会主义和谐社会建设的新形势下,高校要加快步伐,推进教育事业全面、协调、可持续的发展,就必须要加强和谐校园建设,以和谐促发展。     

带落角约束的再入机动弹头的复合导引律

针对再入机动弹头垂直打击目标的要求,研究了具有末端落角约束的复合导引律.该导引律包括俯冲平面内的制导方程和转弯平面内的制导方程,通过在最优导引律的基础上引入滑模变结构控制,增强导引律的鲁棒性.为了减小控制量的抖振和能量损耗,提出了采用RBF(径向基函数)神经网络自适应调节切换项增益的方案,数学仿真验证了该方案的有效性.仿真结果还表明,与最优导引律相比,复合导引律在外界干扰的影响下仍能保持较高的制导精度.     

一种完全分布式的空间服务及组合模型

针对服务组合中控制流和数据流的不同协调机制,可将组合模型分为4种类型,分别是控制流集中式且数据流集中式、控制流集中式且数据流分布式、控制流分布式且数据流集中式、控制流分布式且数据流分布式.空间服务组合流程需处理较大规模的数据流,采用控制流分布式和数据流分布式的协调机制能有效降低组合过程中系统整体通信规模并减少空间服务组合响应时间.通过对各种不同组合类型建模的定量分析对上述观点进行了正确性论证.模拟实验证明,定量分析结果可信.