Reliability evaluation and optimal design in heterogeneous multi-state series-parallel systems

This paper addresses the heterogeneous redundancy allocation problem in multi-state series-parallel reliability structures with the objective to minimize the total cost of system design satisfying the given reliability constraint and the consumer load demand. The demand distribution is presented as a piecewise cumulative load curve and each subsystem is allowed to consist of parallel redundant components of not more than three types. The system uses binary capacitated components chosen from a list of available products to provide redundancy so as to increase system performance and reliability. The components are characterized by their feeding capacity, reliability and cost. A system that consists of elements with different reliability and productivity parameters has the capacity strongly dependent upon the selection of constituent components. A binomial probability based method to compute exact system reliability index is suggested. To analyze the problem and suggest an optimal/near-optimal system structure, an ant colony optimization algorithm has been presented. The solution approach consists of a series of simple steps as used in early ant colony optimization algorithms dealing with other optimization problems and offers straightforward analysis. Four multi-state system design problems have been solved for illustration. Two problems are taken from the literature and solved to compare the algorithm with the other existing methods. The other two problems are based upon randomly generated data. The results show that the method can be appealing to many researchers with regard to the time efficiency and yet without compromising over the solution quality.     

两部件串联可修模型分析

本文研究典型的两部件串联可修模型.在一个部件的失效分布为Erlang分布,另一个 失效分布和两个维修分布均为连续型的假定下,利用补充变量方法求得了系统的全部可靠性 指标.这种模型能用来分析某些自动化系统的可靠性.     

An improved TRPD method for time-variant reliability analysis

In this paper, an improved time-variant reliability analysis method based on stochastic process discretization (iTRPD) is proposed. Firstly, the time-variant reliability problem is transformed into a time-invariant series system reliability problem. Then the first order reliability method (FORM) is employed to analyze the reliability of each component of the system, and a corresponding approach is given to calculate the correlation coefficient matrix of all the components’ performance functions. Finally, the target time-variant reliability can be obtained with the reliability index vector and the correlation coefficient matrix of the involved components. In this study, the iTRPD is further applied to the system reliability problems, and hence a corresponding time-variant system reliability analysis method is also developed. Four numerical examples are investigated to demonstrate the effectiveness of the proposed methods.     

Confidence measures for predictions in fuzzy inductive reasoning

This paper deals with the assessment of the reliability of predictions made in the context of the fuzzy inductive reasoning methodology. The reliability of predictions is assessed by means of two separate confidence measures, a proximity measure and a similarity measure. A time series and a single-input/single-output system are used as two different applications to study the viability of these confidence measures.     

PT100温度传感器在温度数据实时监测系统中的应用

PT100温度传感器是温度数据实时监测的常用传感器,简单介绍了 PT100铂热电阻测温原理,并详细的分析了由于接线方法的不同对测量结果产生的影响.同时,设计出一套温度采集系统,利用北京鼎升力创R8000系列模块和PT 100温度传感器的配合来完成对数据的采集,该系统具有精确度高、工作稳定、可靠的特点.     

RELIABILITY PREDICTION OF IMPERFECT SWITCHING SYSTEMS SUBJECT TO WEIBULL FAILURES

Reliability prediction plays a very important role in system design and evaluation. In order to accurately predict the system reliability, one should consider the system configuration and the failure distribution of its components. This paper discusses the imperfect switching system with one component in an active state and n spares in a standby state. When the operating component breaks down, the switch detects the failure via the sensor and the defective component is replaced with a functional spare, so the system can resume operation. The Weibull distribution is one of the most flexible failure distributions which is widely used because it can adequately describe the reliability behavior during the lifetime of present day components/systems. This paper assumes the operating components follow Weibull failures, but the spares, sensor and switch failures follow an exponential distribution. In addition, three assumptions are made with regard to its switch failures: (i) under the energized condition, (ii) under the failing-open condition, and (iii) under the failing-closed condition. Due to the intractability of the Weibull distribution in imperfect switching models, it is difficult to solve the multiple integration involved analytically. Therefore, a numerical integration method using Simpson's rule was selected as a tool to address the problem of multiple integration for the Weibull distribution. A recursive algorithm is developed for the reliability prediction of a series system with m imperfect switching sub-systems subject to Weibull failures. Finally, a sensitivity analysis is performed on the two parameters of the Weibull distribution, on the effect of spare addition, as well as different failing conditions (switch and sensor) on system reliability. A numerical example is also given to explain and demonstrate the practical application of the developed reliability prediction models.     

A differential evolution algorithm to solve redundancy allocation problems

To improve system reliability without changing its nature, three methods are proposed. The first method uses more reliable components and the second method provides redundant components within the system. The third method is a combination of these two methods. The redundancy allocation problem (RAP) finds the appropriate mix of components and redundancies within a system to maximize its reliability or minimize its cost due to several constraints, such as cost, weight, and volume. This paper presents a methodology to solve the RAP, which is an NP‐hard problem, modeled with discrete variables. In this paper, we use a metaheuristic to solve the RAP of a series–parallel system with a mix of components. Our metaheuristic offers a practical method with specific solution encoding, and combines a penalty function to solve large instances of the relaxed RAP, where different types of components can be used in parallel. The efficiency of the algorithm was tested through a set of well‐known benchmark problems from the literature. Testing of the algorithm achieved satisfactory results in reasonable computing time.     

System reliability for non-repairable multi-state series–parallel system using fuzzy Bayesian inference based on prior interval probabilities

In this article, the fuzzy concepts are applied in analysis of the system reliability problem. The fuzzy number is used to construct the fuzzy reliability of the non-repairable multi-state series–parallel system (NMSS). The fuzzy failure rate function is represented by an exponential fuzzy number. By using this innovative approach, the fuzzy system reliability of NMSS is created. In order to analyse this fuzzy system reliability, the fuzzy Bayesian point estimate of fuzzy system reliability is made by the conventional Bayesian formula. And, the posterior fuzzy system reliability of NMSS is developed by Bayesian inference with fuzzy probabilities. Finally, the performance of the method is measured by the mean square error of fuzzy Bayesian point estimate for the fuzzy system reliability of NMSS.     

Dynamic Bayesian networks based performance evaluation of subsea blowout preventers in presence of imperfect repair

This paper presents a quantitative reliability and availability evaluation method for subsea blowout preventer (BOP) system by translating fault tree (FT) into dynamic Bayesian networks (DBN) directly, taking account of imperfect repair. The FTs of series system and parallel system are translated into Bayesian networks, and extended to DBN subsequently. The multi-state degraded system is used to model the imperfect repair in the DBN. Using the proposed method, the DBN of subsea BOP system is established. The reliability and availability with respect to perfect repair and imperfect repair are evaluated. The mutual information is researched in order to assess the important degree of basic events. The effects of degradation probability on the performances are studied. The results show that the perfect and imperfect repairs can improve the performances of series, parallel and subsea BOP systems significantly, whereas the imperfect repair cannot degrade the performances significantly in comparison with the perfect repair. To improve the performances of subsea BOP system, eight basic events, involving LWHCO, LLPR, LCC, LLICV, SLPSV, LRPIL, PIHF and SVLPLE should given more attention, and the degradation probability of basic events, especially the ones with high sensitive to system failure, should be reduced as much as possible.     

基于集成气体传感器阵列的电子鼻系统

介绍一种基于集成气体传感器阵列的电子鼻系统硬件实现方法。描述了系统的一般组成,重点介绍了所采用的集成气体传感器及其信号拾取方法。该系统可实现对检测气体的自动数据采集、微机传送,具有高的灵敏性和可靠性。另外,对采用的集成气体传感器系列,该电子鼻系统具有一定的通用性。利用该系统对五种葡萄酒进行了检测,结果表明:该电子鼻系统可有效地用于葡萄酒的定性识别,识别准确率达到100%。     

Imprecise system reliability

The objective of the paper is to lay down a foundation for imprecise system reliability assessments based on coherent imprecise probabilities that are a particular case of coherent imprecise previsions. Previous attempts of wide implementation of other theories of imprecise probabilities in reliability analyses have not succeeded. The recent theory of coherent imprecise previsions appeared to be a promising tool for reliability and risk assessments and to be devoid of the drawbacks of its predecessors. This paper describes an approach to how the coherent imprecise reliabilities of series and parallel systems can be calculated. A set of theorems is proven to allow the calculation of the imprecise reliability of a system of an arbitrary structure, in particular with fault trees. An approach to calculate the imprecise reliability based on purely comparative judgements is described.     

基于面向对象技术的参数化CAD系统

介绍了面向对象方法学在开发参数化CAD系统过程中的应用，并根据参数化CAD系统的需要提出了一种基于对象多态性的面向功能／数据的数据结构，该结构实现了几何约束的显式表示，增强了系统的可靠性、稳定性和灵活性。在此基础．上开发的轮胎胶囊CAD系统已经用于工程实践，并取得良好效果。     

NEW METHOD FOR FUZZY SYSTEM RELIABILITY ANALYSIS

This paper presents a new method for fuzzy system reliability analysis based on fuzzy time series and the alpha-cuts arithmetic operations of fuzzy numbers, where we allow the reliabilities of the components of a system at different times t (t= ...,0,1,2,...) to be represented by different membership functions. Because the proposed method allows the reliabilities of the components of a system at different times t to have different membership functions, it is more flexible than the ones presented in Chen 1994 , Cheng and Mon 1993 , and Singer 1990 . Furthermore, because the proposed method uses the simple alpha -cuts arithmetic operations of fuzzy numbers rather than the complicated nonlinear programming techniques mentioned in Mon and Cheng 1994 , it is simpler in calculating fuzzy system reliability than the one presented in that paper.     

Space-repair cost optimal series-parallel systems

Optimization methods for reliability systems on diversified criteria for varied types of models are being increasingly developed. Venugopal et at. (1986–1989) have initiated notable lines of work in this direction for a large class of reliability models considering some comprehensive types of cost functions. This paper adds to this work in terms of considering the complex models, namely the series–parallel reliability system. A methodology is developed with the help of an algorithm to obtain cost-space optimal systems in a class of series parallel models based on practical cost considerations. The operational use of the theoretical work is brought out through some empirical results. A qualitative analysis is also provided as a useful companion study.     

基于VB的UCAM系列应变仪测控软件设计

为解决在我国结构测量领域广泛应用的UCAM-70A应变测量系统存在的缺乏合适的上位机测控软件导致测量及后处理效率低下的技术问题,通过对UCAM-70A技术手册的研究和串口侦测手段,掌握其串口通讯协议规则,运用Visual Basic编程工具结合第三方表格控件及数据库组件开发了基于PC机的上位机测控软件,实现了便捷的参数设置、高效的测量与后处理功能,极大地提升了测量及后处理效率及数据可靠性。并通过对UCAM-60B等其它系列应变仪通讯协议的比较研究,对软件的通讯协议部分作局部修改后可广泛适用于UCAM系列应变仪,该软件设计方法及成果在结构监测领域具有借鉴及推广应用价值。     

石材切割机械控制系统的设计与实现

介绍了一种以Ｉｎｔｅｌ－８０３１单片机为主体研制的石材切割机械控制系统的设计思想及实现技术,针对花岗岩硬度大,容易造成锯片和主电机损坏的情况,提出了一种行之有效的锯片及主电机保护方法和提高系统可靠性的综合措施。     

PLC系统中的数字滤波技术

介绍了基于西门子S7-000PLC控制系统的数字滤波方法.通过对输入信号滤波程序设计的探讨,阐述软件设计中如何消除干扰信号的影响,提高PLC控制系统的可靠性.     

An efficient coupling of FORM and Karhunen–Loève series expansion

The topic of this paper is the solution of reliability problems where failure is influenced by the spatial random fluctuations of loads and material properties. Homogeneous random fields are used to model this kind of uncertainty. The first step of the investigation is the random field discretization, which transforms a random field into a finite set of random variables. The second step is the reliability analysis, which is performed using the FORM in this paper. A parametric analysis of the reliability index is usually performed with respect to the random field discretization accuracy. This approach requires several independent reliability analyses. A new and efficient approach is proposed in this paper. The Karhunen–Loève series expansion is combined with the FEM for the discretization of the random fields. An efficient solution of the reliability problem is proposed to predict the reliability index as the discretization accuracy increases.     

基于MSP430单片机的远程束流诊断系统编程

通过RS-485总线和Intranet网络,来实现对柬流的远程测量与控制,并给出软件的C程序实现和部分硬件功能模块的程序流程图。系统功能模块VAC401采用TI公司的MSP430F169混合信号处理器,具有超低功耗和高集成度等优点。利用它构建的控制网络功能强大,结构简单,可靠性高,抗干扰能力强,一般不需扩展外围器件。本来流诊断系统能够完成对加速器中柬流的远距离测量与控制。