Preventive replacement policies with time of operations,mission durations,minimal repairs and maintenance triggering approaches

When a mission arrives at a random time and lasts for a duration, it becomes an interesting problem to plan replacement policies according to the health condition and repair history of the operating unit, as the reliability is required at mission time and no replacement can be done preventively during the mission duration. From this viewpoint, this paper proposes that effective replacement policies should be collaborative ones gathering data from time of operations, mission durations, minimal repairs and maintenance triggering approaches. We firstly discuss replacement policies with time of operations and random arrival times of mission durations, model the policies and find optimum replacement times and mission durations to minimize the expected replacement cost rates analytically. Secondly, replacement policies with minimal repairs and mission durations are discussed in a similar analytical way. Furthermore, the maintenance triggering approaches, i.e., replacement first and last, are also considered into respective replacement policies. Numerical examples are illustrated when the arrival time of the mission has a gamma distribution and the failure time of the unit has a Weibull distribution. In addition, simple case illustrations of maintaining the production system in glass factories are given based on the assumed data.     

Autonomous terrain-following for unmanned air vehicles

This paper presents an integrated guidance and control design scheme for an unmanned air vehicle (UAV), and its flight test results. The paper focuses on the longitudinal control and guidance aspects, with particular emphasis on the terrain-following problem. An introduction to the mission, and the terrain-following problem is given first. Waypoints for climb and descent are defined. Computation of the reference trajectory in the vertical plane is discussed, including a terrain-following (TF) algorithm for real-time calculation of climb/descent points and altitudes. The algorithm is particularly suited for online computation and is therefore useful for autonomous flight. The algorithm computes the height at which the vehicle should fly so that a specified clearance from the underlying terrain is always maintained, while ensuring that the vehicle’s rate of climb and rate of descent constraints are not violated. The output of the terrain-following algorithm is used to construct a smooth reference trajectory for the vehicle to track. The design of a robust controller for altitude tracking and stability augmentation of the vehicle is then presented. The controller uses elevators for pitch control in the inner loop, while the reference pitch commands are generated by the outer altitude control loop. The controller tracks the reference trajectory computed by the terrain-following algorithm. The design of an electromechanical actuator for actuating the control surfaces of the vehicle during flight is also discussed. The entire guidance and control scheme is implemented on an actual experimental vehicle and flight test results are presented and discussed.     

航空装备保障任务规划系统体系结构研究

航空装备保障任务规划系统，采用基于三层结构的数据管道方法，用MSSQL Server2000作为数据库开发平台，并利用SQL自带的OLAP Server建立大型多维数据库，前台软件选用Delphi7，通过开放式数据接口实现连接。系统由数据源，数据的知识化处理、辅助决策、可视化表达4部分组成，通过建立多维数据库，利用数据库分析工具从大量数据中提取有效信息。     

汽车排放检测技术与方法研究现状

汽车排放检测方法有传统检测法、遥感检测法、车载排放检测法。传统检测法是将底盘测功机和气体分析仪结合的一种实验室测试法,受测功机测工范围和实验场地的限制,不能真实地反映实际工况的排放情况。遥感检测法在汽车正常行驶过程中利用紫外线和红外光谱技术测出汽车排放的各组分含量,检测速度快,但对安置地点和交通状况较为苛刻。车载排放检测技术应用便携式尾气检测技术检测尾气中各组分的含量,方便快捷,具有发展前景。     

基本可靠性和任务可靠性模型研究

从分析基本可靠性 (R)和任务可靠性 (RM)的基本概念入手 ,并以某飞机为例 ,分别建立了任务可靠性模型和基本可靠性模型 ,并在假设系统寿命服从指数分布的基础上 ,计算了系统的基本可靠度和任务可靠度     

信息化装备的RMS对任务效能的影响分析

指挥信息系统的任务效能与其信息化装备的可靠性、维修性和保降性(RMS)密切相关.将指挥信息系统的任务效能指标分解到组成的信息化装备上,从而能够确定信息化装备的保障要求.分析信息化装备的RMS对其任务效能的影响,为权衡信息化装备的任务效能与保障资源的预计提供科学依据.     

多UCAV 任务分配的混合遗传算法与约束处理

针对多UCAV协同作战任务分配问题，建立了多目标整数规划模型，提出了基于整数编码的混合遗传算法．将约束分为全局约束和局部约束，根据局部约束将决策变量分为自由变量和非自由变量，仅对非自由变量进行编码，减少了染色体变化要素．设计了交叉算子和变异算子，以提高个体的约束满足率．以UCAV的SEAD任务为想定进行仿真，实验结果表明，该混合遗传算法可有效解决大规模整数规划问题，在求解效率和约束满足率上比标准遗传算法有显著提高．     

全局资源视图生成战术资源视图的方法研究

战术视图生成是从战役全局资源视图产生基于任务的作战视图，本文通过解决作战资源实体在作战任务上的聚类问题来生成战场战术态势图的基本要素之一——作战实体。基于功能能力、作战平台资源和作战任务的定义，提出了基于任务的作战资源实体生成方法。该方法包括两个部分：资源实体裁剪过程的数学描述以及作战资源实体分配到任务的匹配算法，并以联合战役为例，分析并设计了从联合战役作战资源的全局视图生成战术资源视图。     

基于任务空间概念模型（CMMS）的作战想定研究

任务空间概念模型是建模与仿真通用技术框架的三个组成部分之一，其目的是促进国防建模与仿真领域仿真部件的重用和互操作。而作战想定是综合电子信息系统建设过程中的重要组成部分，本文针对目前想定与仿真模型紧耦合而带来仿真系统重用性差等缺点，利用CMMS的思想，提出了一种能够实现想定与仿真系统相分离的处理机制，以促进想定的重用的和仿真的互操作性。     

综合电子战作战效能仿真系统研究

综合电子战作战效能仿真系统是用于研究和评估综合电子战系统在攻防对抗环境下作战效能的计算机仿真系统。该文首先分析了国内外在电子战作战效能仿真领域内的研究现状，然后重点论述了该信真系统的技术实现思路，最后对该仿真系统的应用前景进行了展望。