Use of concomitant variables for reliability exploration of microcomputer systems

The Weibull proportional hazards model is utilized for reliability exploration of microcomputer systems. The influence of two concomitant variables (temperature and mean daily user's exploitation time of the system) on system reliability is examined. The usefulness of the model for reliability exploration of microcomputer systems is shown.     

Application of expert systems to systems reliability evaluation

An expert system for diagnosing rough ride problems in heavy trucks has been developed and can be used on a personal computer. The system operates on two levels of knowledge data base: shallow — acquired from truck service personnel and causal obtained from a multiprobe vibration analysis system (MVAS) through a preprocessing neural network. The justification for selecting neural networks is presented as are virtues and drawbacks of the developed system.     

Modification of cutsets for reliability evaluation of communication systems

A general and simple technique for the evaluation of symbolic reliability expression in the case of practical systems such as a communication system having fixed channel capacities of its various communicating links, a computer communication network allowing a fixed amount of data exchange amongst different terminals of various computer centres and a power distribution system having limited power ratings of its various power lines, is presented. A system is considered reliable only if it successfully transmits at least the required system capacity from the transmitter to the receiver station. In this method, the various branch sets are obtained which completely disrupt the communication path, i.e. ensure system failure. It is observed that these branch sets are not necessarily the cutsets in the usual graph theoretic sense. The unreliability expression is then determined by adopting an existing method for making various terms disjoint. Two typical examples are solved by this method. It is observed that the method is computationally fast and efficient.     

Numerical methods for reliability evaluation of Markov closedfault-tolerant systems

This paper compares three numerical methods for reliability calculation of Markov, closed, fault-tolerant systems which give rise to continuous-time, time-homogeneous, finite-state, acyclic Markov chains. The authors consider a modified version of Jensen's method (a probabilistic method, also known as uniformization or randomization), a new version of ACE (acyclic Markov chain evaluator) algorithm with several enhancements, and a third-order implicit Runge-Kutta method (an ordinary-differential-equation solution method). Modifications to Jensen's method include incorporating stable calculation of Poisson probabilities and steady-state detection of the underlying discrete-time Markov chain. The new version of Jensen's method is not only more efficient but yields more accurate results. Modifications to ACE algorithm are proposed which incorporate scaling and other refinements to make it more stable and accurate. However, the new version no longer yields solution symbolic with respect to time variable. Implicit Runge-Kutta method can exploit the acyclic structure of the Markov chain and therefore becomes more efficient. All three methods are implemented. Several reliability models are numerically solved using these methods and the results are compared on the basis of accuracy and computation cost     

Analysis of a composite performance reliability evaluation for Markovian queueing systems

This paper considers analytical techniques for the evaluation of reliability, availability and combined performance and reliability measures. Markov models are common tools for system reliability evaluation. In this paper, we first compute the state probabilities of Markov model behaviour. We then investigate expected values of interval availability measures. The method is simple and easy to implement, yet very effective in dealing with the problem of computer systems.     

Time-series models for reliability evaluation of power systems including wind energy

An essential step in the reliability evaluation of a power system containing Wind Energy Conversion Systems (WECS) using sequential Monte Carlo analysis is to simulate the hourly wind speed. This paper presents two different time-series models generated using different available wind data. Wind data from Environment Canada and SaskPower are used to illustrate these models. No assumptions or previously estimated factors are included in the models. In order to check the adequacy of the proposed models, the F-criterion and Q-test are used, and the statistical characteristics of the simulated wind speeds are compared with those obtained from the actual wind speeds. The proposed wind models satisfy the basic statistical tests and preserve the high-order auto-correlation, seasonal property and diurnal distributions of the actual wind speed.     

Method of reliability analysis of control systems for nuclear power plants

High reliability is one of the main objectives of the design and operation of Control Systems in Nuclear Power Plants. This paper presents a method of reliability analysis for these systems using various reliability techniques and engineering judgement. The step-by-step analysis includes system study, field data, failure mode and effect analysis, common mode failures, fault trees, human factors, reliability targets, and design reviews. To illustrate this method, the Liquid Zone Control System for CANDU nuclear reactor control is used.     

微型计算机可靠性验收试验探讨

可靠性试验是对产品的可靠性进行分析评价的一种手段。以微型计算机为研究对象,对其进行可靠性试验。试验采用定时截尾方法,分别采用点估计和区间估计的方法对平均无故障时间(MTBF)进行处理。通过对试验数据的分析,对微型计算机做出了较为客观的可靠性评估。     

An evaluation of test methods for the detection and control ofinterconnect reliability

A number of fast, wafer-level test methods exist for interconnect reliability evaluation. The relative abilities of four such methods to detect the quality and reliability of the interconnect over very short test times are evaluated in this work. Four different test structure designs are also evaluated, and the results are compared with package-level median time to failure (MTF) results. The isothermal test method combined with standard wafer-level electromigration accelerated test (SWEAT)-type test structures is shown to be the most suitable combination for defect detection and interconnect reliability control over short test times     

A new developed transient-behaviour solution technique for reliability evaluation of electrical systems

Transient probability problems were studied in four three-state power system and one seven state telecommunication system. The study was carried out using the Adams Method and another method which is developed for this study. The new method is named as Stabilization Method (SM). The new method is compared with Adams method from stability and accuracy view points. It was found that the SM method required less programing effort compared to the Adams method. The accuracy of stabilization method (SM) compares well with Adams when sufficiently small time interval is chosen. The relationship between the CPU time and the number of states was found to be non-linear for the SM method.     

An evaluation of fast wafer level test methods for interconnect reliability control

A number of fast wafer level test methods exist for interconnect reliability evaluation. The relative abilities of three such methods to predict the quality and reliability of the interconnect over very short test times are evaluated in this work. Four different test structure designs are also evaluated and the results are compared with package level Median Time to Failure (MTF) results. The Isothermal test method combined with SWEAT-type test structures is shown to be the most suitable combination for interconnect reliability detection and control over very short times.     

Availability modelling of ring microcomputer systems

A model for the availability of ring systems has been derived using the frequency balancing approach.A computer program has been written to evaluate different microcomputer based architectures by taking into consideration various features such as bus interfaces, number of modules, repair, hardware and software failure interaction, recovery procedure.Isolation and self purging of faulty modules have been proved to be significant factors in the calculation.     

Wafer level reliability: Process control for reliability

Wafer Level Reliability test techniques can be used to provide fast feedback process control information regarding the reliability of the product of a semiconductor process. The purpose of wafer level reliability (WLR) tests is the measurement of variation in the materials comprising the semiconductor device. They are not intended as modeling tools for the quantification of the effect of stress on these materials. As such, WLR tests must provide a repeatable stress, independent of normal process variation. The results of these tests will be a measurement of the “rate of degradation” of the basic circuit elements caused by a standard stress.     

微机控制系统的抗干扰技术研究

为了提高微机系统的测控精度及稳定性,提出微机控制系统的抗干扰设计方法。详细介绍了微机控制系统的软、硬件抗干扰设计措施,硬件抗干扰措施主要包括电源系统抗干扰、I/O接口抗干扰等几部分,软件抗干扰措施包括指令冗余、软件陷阱和软件滤波等。同时,将一些抗干扰措施应用于卷烟机烟支重量控制系统中,实验结果表明,这些措施是有效的,能够较好地消除和抑制进入烟支重量控制系统的干扰信号。     

控制微机中键盘与显示的硬件和软件设计

本文分析了控制微机的基本工作流程,介绍了键盘和显示接口的硬件设计特点和计算公式,给出了键盘的处理程序的设计及使用方法.     

ZWK-100注塑机微机控制系统

ZWK-100注塑机微机控制系统,是新近研制开发的具有汉字和曲线显示功能,适用于1万克及其以上大型注塑机的微机电气控制系统.本文介绍其工作过程,硬软件结构及其性能等.     

Enhanced reliability evaluation for self-checking circuits

A first attempt at evaluating the reliability of the checkers used in self-checking circuits is presented. Simple theory is proposed to compare different checker implementations that, although totally self-checking in the conventional sense, may perform differently under more realistic fault conditions. As a significant example of application, the case of the 1-out-of-3 checker is explicitly treated     

Empirical formulas and global reliability evaluation of reliability graphs

Some formulas have been reported, in terms of elements and nodes, to calculate the number of reliability graphs of identical elements in series-parallel configurations. A simple and efficient algorithm has been proposed for enumeration of spanning trees using an incidence matrix which is used for global reliability evaluation of a graph. An example demonstrates the effectiveness of the algorithm.