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Reliability, IEEE Transactions on

Issue 2 • Date Jun 1988

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Displaying Results 1 - 18 of 18
  • On-line hazard aversion and fault diagnosis in chemical processes: the digraph+fault-tree method

    Page(s): 171 - 177
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    A method for online hazard aversion and fault diagnosis in chemical processes is developed. The method uses a directed graph model of process operation and control. Fault trees developed from the directed graphs are combined with real-time data to provide online diagnosis for hazard aversion and fault detection. Both hardwired control and manual control are modeled. A single control loop illustrates the modeling technique and the diagnosis method. The method provides an advance alert to process problems and an identification of the problems' causes, based on the available real-time data and prior rates of equipment malfunctions and process disturbances View full abstract»

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  • Data bank for probabilistic risk-assessment of nuclear-fuel reprocessing plants

    Page(s): 138 - 143
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    The Savannah river laboratory maintains a compilation of operating problems and equipment failures that have occurred in the fuel reprocessing areas of the Savannah river plant. The data bank contains more than 175000 entries, ranging from minor equipment malfunctions to incidents with potential for injury or contamination of personnel, or for economic loss. The data bank has been used extensively for a wide variety of purposes such as probabilistic risk assessment, failure analysis, and trend analysis. An overview of the bank is given in terms of history of development, contents of the bank, management of data, uses for the bank and future development View full abstract»

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  • A comparison of algorithms for terminal-pair reliability

    Page(s): 210 - 215
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    Four algorithms for the terminal-pair-reliability problem are compared. Nelson (1970), Lin (1976), Shooman (1968), and Dotson (1979) algorithms are used in this study. It is shown that the Dotson algorithm is the fastest among the terminal-pair reliability algorithms analyzed. The Dotson algorithm is suited not only for numerical reliability, but for obtaining symbolic expression for the terminal-pair reliability with no additional effort. By modifying the Dotson algorithm the efficiency can be further improved. The modifications to this algorithm are listed and the reliability of the modified Dotson algorithm is computed View full abstract»

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  • Design-safety enhancement through the use of hazard and risk analysis

    Page(s): 149 - 158
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    The application of qualitative and quantitative hazards/risk analysis methods is discussed. Two examples of both qualitative and quantitative methods are discussed. The relative advantages of each, as well as relative manpower requirements for their application, are examined. The two qualitative analysis examples are: (1) hazards and operability (HAZOP) analysis, based on the conceptual design analysis of an offshore gas-processing platform, and (2) a qualitative fault-tree analysis based on a design review of a land-based oil-processing facility. The two quantitative analysis examples are: (1) the use of event sequence diagrams for the risk analysis of a batch chemical-operation plant, and (2) an event-tree analysis relative to the consequences of the loss of electric power for the same batch plant. In these examples, design operations and maintenance-safety enhancements that have been implemented are identified View full abstract»

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  • A Bayes sensitivity analysis when using the beta distribution as a prior

    Page(s): 239 - 247
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    Results that illustrate the determination of the parameters of a beta prior distribution when either the mean and one percentile or two percentiles are given are presented. Further results show how sensitive the parameters of the beta prior are to errors in the given values. The sensitivity of the probability distribution of the reliability of a system to errors in either the given mean and percentile or the given percentiles of the component beta priors is studied. Included in the study are several systems, ranging from simple ones that occur as subsystems of real systems up to a real type of system consisting of 74 components View full abstract»

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  • Reliability analysis of pumps for uranium solutions

    Page(s): 144 - 148
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    Air-operated diaphragm pumps transfer a solution of highly enriched uranyl nitrate in nitric acid between process steps and recirculate the solution for mixing and filtration. In evaluating the data from manufacturers and performing limited testing, certain limitations have been noted on the application of the air-operated dual-diaphragm pump. In particular, the potential detrimental effects due to relatively high inlet suction pressure have led to the recommendation that an alternative pump be used on tall tanks and that precautions be taken to limit spill-potential on pumps used with shorter tanks. By manifolding the air exhaust from each pump in a manner yet to be determined, the spill potential can be substantially reduced. The high noise levels (approaching 90 dB) should be reduced View full abstract»

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  • Estimation in a random censoring model with incomplete information: exponential lifetime distribution

    Page(s): 223 - 229
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    Analysis of methods and simulation results for estimating the exponential mean lifetime in a random-censoring model with incomplete information are presented. The instant of an item's failure is observed if it occurs before a randomly chosen inspection time and the failure is signaled. Otherwise, the experiment is terminated at the instant of inspection during which the true state of the item is discovered. The maximum-likelihood method (MLM) is used to obtain point and interval estimates for item mean lifetime, for the exponential model. It is demonstrated, using Monte Carlo simulation, that the MLM provides positively biased estimates for the mean lifetime and that the large-sample approximation to the log-likelihood ratio produces accurate confidence intervals. The quality of the estimates is slightly influenced by the value of the probability of failure to signal. Properties of the Fisher information in the censored sample are investigated theoretically and numerically View full abstract»

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  • Performability evaluation of multicomponent fault-tolerant systems

    Page(s): 216 - 222
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    A combined performance and reliability (performability) measure for gracefully degradable fault-tolerant systems is introduced and a closed-form, analytic solution is provided for computing the performability of a class of unrepairable systems which can be modeled by general acyclic Markov processes. This allows the study of models which consider the degradation of more than one type of system component, e.g. processors, memories, buses. An efficient evaluation algorithm is provided, with an extensive analysis of its time and space complexity. A numerical example is provided which shows how the combined performance/reliability measure provides for a complete evaluation of the relative merits of different multiprocessor structures View full abstract»

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  • How to improve the effectiveness of hazard and operability analysis

    Page(s): 167 - 170
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    The key elements that make the hazards and operability (HAZOP) technique effective for identifying chemical process hazards are outlined. Six categories of problems that can sometimes reduce the effectiveness of HAZOP and even prevent it from discovering some major hazards are explained. Several examples are included to show how lack of experience, failure to communicate, management shortcomings, complacency and poor loss-prevention practices, a shortage of technical information, and other limitations, each contribute to the problem. Practical solutions are recommended for countering the difficulties and for making the HAZOP a more effective risk-management tool View full abstract»

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  • An overview of collection, analysis, and application of reliability data in the process industries

    Page(s): 132 - 137
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    Issues relevant to the collection, analysis, and application of reliability data are discussed. In terms of analysis, attention is given to: current common practice and its limitations; the need for feedback-to-data collection process; lack of high-quality software for reliability analysis; contribution of exploratory analysis techniques; problems of small data sets and of over interpretations: and critical need for sensitivity analysis in reliability studies. In terms of applications, attention is given to the alternative purposes for which such reliability data can be used: safety, cost, legislation, and system availability evaluation; maintenance and replacement decisions; logistic support and spares provisioning; initial design and quality changes; and procedural and monitoring changes View full abstract»

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  • Reliability growth-Myth or mess

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    The author argues that reliability growth is not necessarily well defined in the literature. Therefore he suggests that in all papers on reliability growth the author should identify what kind of reliability growth process they have in mind and, if data are being analyzed, which factors are held constant or randomized to smooth out the effects View full abstract»

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  • Evaluation of off-normal release frequencies for a PCB incinerator under design

    Page(s): 192 - 198
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    The likelihood of off-normal atmospheric releases from a municipal incinerator burning a combination of municipal solid waste and PCB-contaminated landfill material is evaluated. Fault-tree analysis identifies potential system failures in the combustion and air-pollution control systems View full abstract»

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  • Robust estimators of the 2-parameter gamma distribution

    Page(s): 234 - 238
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    The available estimators for parameters of the gamma distribution are moment estimators, maximum-likelihood estimators, and approximations to the maximum-likelihood estimators. These estimators are not suitable for small samples; however, they are still being used at the present time. The proposed robust estimators for scale and shape parameters are more suitable for small samples. They have RMS (root-mean-square) errors that are considerably smaller than those of the other estimators. In addition, they are easier to calculate, and are therefore appropriate in many applications View full abstract»

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  • Application of a hazard and operability study to hazard evaluation of an absorption heat pump

    Page(s): 159 - 166
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    A hazard evaluation for a double-effect, absorption heat pump is presented. The primary technique for the hazard evaluation was a hazard and operability (HAZOP) study; this is a brainstorming approach conducted by a multidisciplinary team. The approach stimulates creativity of the team members to generate ideas. The team consisted of a HAZOP leader, the heat-pump project manager, a thermohydrologist, a corrosion specialist, a toxicologist, and a risk analyst. The majority of the team members were already involved in the design and analysis of the heat pump View full abstract»

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  • Chemical-system reliability: a review

    Page(s): 199 - 208
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    Selected published literature on chemical-system reliability is reviewed. The literature is classified into several categories. These categories include: reliability prediction and analysis; reliability/maintenance/safety; risk analysis, control and assessment; fault diagnosis and propagation; failure analysis and prevention; failure data and analysis; reliability optimization; human reliability; application of reliability engineering to process plant industries; availability analysis; and life-cycle cost and economy. The literature is collected mainly from major journals and conference proceedings. An extensive list of references is presented View full abstract»

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  • A Bayes empirical-Bayes model for software reliability

    Page(s): 248 - 254
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    The authors present a model for the behavior of software failures. Their model fits into the general framework of empirical Bayes problems; however, they take a proper Bayes approach for inference by viewing the situation as a Bayes empirical-Bayes problem. An approximation due to D.V. Lindley (1980) plays a central role in the analysis. They show that the Littlewood-Verall model (1973) is an empirical Bayes model and discuss a fully Bayes analysis of it using the Bayes empirical-Bayes setup. Finally, they apply both models to some actual software failure data and compare their predictive performance View full abstract»

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  • Efficiencies of MLE and BLUE for parameters of an accelerated life-test model

    Page(s): 230 - 233
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    Maximum-likelihood estimates (MLE) and best-linear-unbiased estimates (BLUE) of parameters of an accelerated life-test model were compared according to the mean-square error criterion in small and moderate sample size cases. A factorial experiment was used to investigate the effects of the: (1) number of levels of the acceleration variable, (2) percent censorship, and (3) sample size. Overall, the two kinds of estimators were of comparable efficiencies. However, where there were two or less uncensored observations, at any level(s) of the acceleration variable, the MLE was clearly favored. This is in accord with findings for single sample cases, where MLE and BLUE for location and scale parameters of the Weibull and the extreme-value distributions were compared View full abstract»

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  • Risk assessment of mixed-waste sites

    Page(s): 178 - 191
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    Techniques for assessing worker and public risks attributable to atmospherically-released contaminants from a mixed-waste site are presented. The techniques are used to assess, for several different remedial actions, the risk to workers and the public from nonradioactive chemicals atmospherically released from several waste sites. Other models and health risk procedures can be used to assess radioactive releases and other applicable environmental media, i.e. surface and ground water. The risks from nonradioactive contaminants that were calculated from the atmospheric pathway are low, no site or site remediation option, taken individually or summed, posed an unacceptable risk to the public. Risks to workers were also well below thresholds accepted by society View full abstract»

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Aims & Scope

IEEE Transactions on Reliability is concerned with the problems involved in attaining reliability, maintaining it through the life of the system or device, and measuring it.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Way Kuo
City University of Hong Kong