Reliability of a 2-Unit Standby Redundant System with Repair, Maintenance and Standby Failure

A repairable 2-unit warm-standby system with repair and preventive maintenance is discussed. Two models are presented. In each of the models the mean time to system failure and the steady state availability are calculated. Some numerical calculations illustrate the results.     

Reliability of a 2-Unit Standby Redundant System with Constrained Repair Time

This paper considers a 2-unit warm-standby redundant system with repair. The repair of a failed unit is constrained as follows: Associated with each failure of a unit is a random variable termed the Maximum-Repair-Time (MRT) of the failure. If the repair of a failed unit is not completed within the MRT, the unit is rejected for further use. Two types of failure stituations for the system are considered: 1) No allowed down time, and 2) Some allowed down time. Expressions for the Cdf of the Time to System Failure (TSF) and the mean TSF are derived by using Markov renewal processes.     

基于双机热备的可靠多播通讯设计

多播提供了一种以一对多的方式发送数据的有效通讯机制,它没有为上层提供任何服务质量和投递保证。为了提高其可靠性,设计了大量的可靠多播协议,但设计一种在各种不同应用情况下都适合的多播协议是不可能的。针对在C／S架构下,基于双机热备的系统,设计了一种简单弹性可靠多播协议——SFRM（simple Flexible Reliable Multicast）协议。     

A Reliability and Comparative Analysis of Two Standby System Configurations

Equations are derived which enable one to calculate the system reliability for parallel or triple modular redundant systems with standby spares. Software error detection is introduced into the TMR/Spares system configuration in order to utilize fully all of the units. An indication of the sensitivity of the system reliability to an increase in the number of spares, partitioning, switching, variations in the powered and unpowered failures rates, and time is presented. A comparison of the parallel and the TMR/Spares system configurations, under similar conditions, is given.     

Unreliability of a Standby System with Repair and Imperfect Switching

We evaluate and analyze a model of a 2-unit standby system with repair and imperfect switching. The model determines the cumulative probability that system failure occurs in a time interval 0 to T. In order to cope with arbitrary failure-time and repair-time distributions, a ``step by step' method is used which for practical purposes yields a sufficiently accurate result. The model results in explicit expressions which are very suitable for computer implementation. A simple illustrative example is given.     

A Two-Unit Cold Standby Repairable System with One Replaceable Repair Facility and Delay Repair: Some Reliability Problems

1 Model and Assumption In reliability analysis of repairable systems, it is usually assumed that the repair facility neither fails nor deteriorates as well as the repairman is instantaneously available. So that the repair is started immediately upon the failure of a unit provided that he is not busily repairing another unit. However, in actual practice, the repair facility in a repairable system is subject to failure and can be replaced (or can be repaired) after it fails, and certain delay ac…     

基于热备份的主备倒换在高端路由器中的应用

从高端路由器的可靠性出发，提出提高可靠性、减少故障持续时间的关键在于减少路由器主备倒换时间。文中通过对传统的主备倒换与热备份下的主备倒换进行比较，分析了热备份下的主备倒换在节省业务板和路由板的重启时间、业务板恢复配置时间、路由板路由学习聚合时间等方面的优势。同时详细介绍了基于热备份的主备倒换在高端路由器中的主要实现步骤，并对其技术特点和给用户提供的解决方案进行了阐述。     

Evaluation of Repairable System Reliability Using the ``Bad-As-Old' Concept

It is usually assumed that the underlying distribution of times to failure of systems is the exponential distribution. This is justified on the basis of the bathtub curve or Drenick's theorem, but the bathtub curve is merely a statement of plausibility and conflicts with Drenick's theorem. Even if exponentiality is not assumed, it is usually assumed that a system under study is as-good-as-new after repair. This is not a plausible assumption to make for a complex system. If failure data are available they should be tested for trend among successive failure times. If a trend exists, a time dependent (nonhomogeneous) Poisson process (called bad-as-old model in this paper) should be fitted and tested for adequacy. This paper is not intended to provide a rigorous, definitive treatment of bad-as-old models. Rather, it has three main purposes: 1) to point out the glaring, but somehow usually overlooked, inconsistency between the commonly accepted concept of wearout of repairable systems and the a priori use of renewal processes for modeling these systems; 2) to outline basic procedures for evaluating data from repairable systems and for formulating bad-as-old probabilistic models; and 3) to present the results of Monte Carlo simulations, which illustrate the grossly misleading results which can occur if independence of successive failure times is invalidly assumed.     

Evaluation of Generating System Reliability Indices Under Limited Repair Facility

A generating system having n units, where each unit is represented by a 2-state device, will have more than 2n possible states when repair facility of the system is limited, i.e. number of repair crews is less than the number of units. When the number of units failed is more than the number of repair crews available, the most recent failures queue for repairs. This paper gives a general equation to determine the number of system states under limited repair facility and an approximate technique to determine the probabilities of system states and reliability indices of the system.     

基于试验数据的雷达系统可靠性评估

利用雷达系统研制阶段的故障数据,综合评估系统可靠性水平,可以为雷达的定型及可靠性鉴定提供依据.为了对雷达研制阶段各试验数据进行可靠性综合评估,在可靠性增长的Duane模型基础上,引入不同试验条件下的环境折合系数,建立了一种可靠性综合评估模型,并给出了相应的综合评估方法.最后,给出了所述方法与模型的一个工程应用实例.     

PLC控制系统可靠性研究

PLC控制系统的可靠性从硬件和软件方面共同衡量。从电源的处理、连接线的方式、冗余设计、控制系统的输入电路和输出电路与PLC的软件程序编制等多个方面,论述了一些可行的方法和措施。     

Time Dependent Solution of a Complex Standby Redundant System under Preemptive Repeat Repair Discipline

The system has two classes of components. Each component in one of the classes is essential to operation. Components in the other class are helpful but not essential. The Laplace transforms of various state probabilities have been obtained; a particular case has been derived.     

基于图像拼接的双摄像机系统自动标定方法

主从摄像机监控系统是由一个(或多个)静态宽视野摄像机于一个(或多个)窄视野动态PTZ摄像机组成,主摄像机负责静态监控较大的区域,而随从摄像机负责动态扑捉目标细节信息。提出了一种基于图像拼接的系统标定方法,可以自动获得主从摄像机的位置关系。试验证明,该方法能够准确自动地标定主从摄像机系统。     

基于贝叶斯网络的导弹系统人因可靠性分析

分析了人在回路电视制导导弹系统研究飞行员可靠性的必要性。针对人的可靠性研究行为学策略,建立了飞行员可靠性评估的贝叶斯网络模型。论述了利用该模型进行评估的基本步骤,建立了其评价指标体系,并通过实例对飞行员人因可靠性进行了评估和研究。仿真结果证明了该模型的正确性和有效性,为飞行员发现自身不足提供了理论依据。     

陶瓷阵列封装的两种形式及其接头可靠性

介绍了CBGA及CCGA的基本结构,对它们的优缺点进行了对比,分析了在热循环过程中,CBGA、CCGA封装结构产生的热应变及接头的热疲劳寿命,对目前接头热疲劳失效机理的分析进行了对比,总结了影响接头热疲劳寿命的几种因素。     

变频器及PLC在热网首站控制系统中的应用

本文介绍了基于ABB变频器及西门子S7-300系列PLC的热网首站自控系统。讨论了控制系统的原理和功能，给出了控制系统的硬件组成，ABB变频器用于对循环水泵机及补水泵的控制，S7-300用于对现场仪表的数据采集和处理及调节阀的控制。     

两部件可修复温储备系统维修策略的改进

考虑由两个可修复元件、一个可修复的转换开关、一位固定的维修人员组成的两部件可修复温储备系统,为了提升系统可靠度,在维修策略上作了改进,提出了一位是固定维修工,两个及以上元件失效时雇佣一位临时工的方法。并建立了策略改进后所相应的Markov过程,通过Laplace变换给出了系统可靠性指标的计算模型,由案例分析获得策略改进后的模型可使系统的可靠性和可用度等指标在原有的基础上得以提高的结果,从而得到该策略的改进是合理和必要的结论。     

军用通信网系统可靠性分析与评估

军用通信网系统可靠性的综合性参数指标,由于受到工程试验的环境限制,多不具备可测性。例如:网络全功能、主要功能和最低功能的可用度,网络在70%、50%、30%失效(被毁)条件下的业务传输成功率,平均时延等。为此,基于分布式仿真环境,给出了军用通信网"故障关联"、"拓扑关联"、"有效性关联"的系统可靠性综合分析与评估方法。该方法结合系统可靠性工程试验,可实现对军用通信网系统可靠性进行综合分析与评估。