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Analysis of a two-unit parallel redundant system with phase type failure and general repair
World Abstracts on Microelectronics and Reliability with the BIT design-to-cost target form the baseline criteria for designing the BIT equipment during subsequent phases. The paper provides straightforward mathematical tools, sensitivity analyses, and tradeoff procedures.
Sequential life-testing with spacings, exponential model. G. S. LINGAPPAIAH. IEEE Trans. Reliab. R-30 (4), 370 (1981). Spacings (difference between two consecutive order statistics) and the linear combination of spacings (LCOS) are discussed in this paper. Prediction of LCOS in a life test based on the exponential model is attempted here. A stopping rule is suggested for prediction and is based on the minimum variance of the LCOS. Prediction of LCOS is also developed in terms of batches of items by considering the LCOS of batches. A few special cases are considered. A Bayesian approach is also used for the same purpose of prediction. The procedure is illustrated with simulated samples. Reliability techniques in the service of industry. ANDREW R. CHURCHLEY. IEEE Trans. Reliab. R-30 (4), 306 (1981). Failures which occur in any industrial activity reduce the profitability and safety of commercial ventures. Numerical estimates of reliability, availability, and profitability are based on an understanding of the fundamental concepts of reliability engineering. These estimates assist comparison of alternative design or improvement strategies for process plant. Although a reliability assessment is concerned largely with equipment failures, the important part played by human reliability can be estimated and included in such studies. Plant reliability interacts with the morale of the workforce; morale is unfortunately not easy to quantify. The methods and procedure of a reliability analysis are described. A degree of flexibility in the assessor's approach is useful when the rigour of the study must be adjusted to suit practical cost considerations. Direct optimisation for calculating maximum likelihood estimates of parameters of the Weibull distribution. BRIAN D. BUNDAY and IMAD AL-MUTWALI. IEEE Trans. Reliab. R-30 (4), 367 (1981). Computer software has been prepared to compute maximum likelihood estimates (MLE) for the parameters of a 2-parameter Weibull distribution using failure and survival time data. The procedure is the direct optimisation of the log-likelihood function by a method that evaluates the variance-covariance matrix of the estimates without a separate calculation of second derivatives. On profit evaluation in a two-unit maintained redundant system. M. C. GUPTA and A. KUMAR. Microelectron. Reliab. 21 (4), 605 (1981). A two-unit redundant system is considered and analytic expression for total expected profit earned in a given time is obtained after writing basic cost equations governing the behaviour of the system. A procedure is suggested to obtain optimal failure and repair rates so that expected steady state profit is maximum.
Analysis of a two-unit parallel redundant system with phase type failure and general repair. N. RAVICHANDRAN. Microelectron. Reliab. 21 (4), 569 (1981). Explicit expressions for the Laplace transform of the reliability and availability of a general two-unit parallel redundant system are obtained. The mean time to system failure and steady state availability are deduced as special cases. Some particular cases of our result are also obtained. A K-out-of-N:G three-state unit redundant system with common-cause failures and replacements. WHO KEE CHUNG. Microelectron. Reliab. 21 (4), 589 (1981). A mathematical model for predicting a k-out-of-N:G three-state unit redundant system with common-cause failures and failed system with replacement units has been developed. Laplace transforms of the state probabilities are derived. The steady-state probabilities, frequency of encountering and the average duration of residence in a state are also reported.
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Software aids to microcomputer system reliability. A. R. WOOD. Microelectron. Reliab. 21 (3), 391 (1981). The use of microcomputers in critical control or telemetry applications is becoming more common but it requires not only the hardware reliability brought about by advances in circuit integration, but also reliable operation of the control software. A distinction is made between error detecting software, and error detection and correction which requires both additional hardware and the software routines to detect fault conditions and apply the necessary correction algorithms. This paper describes some of the simple software techniques which can be used to perform self-test functions on microcomputers to check for hardware failure or software malfunction without the use of additional hardware. The use of self-test routines has obvious application in remote microcomputer systems controlling or monitoring critical processes where an immediate indication of a failure of the microcomputer is required. The detection of a failure could initiate fail-safe procedures to prevent damage to the plant being controlled or monitored. The self-test routines can be used in less exotic systems to provide fault detection and indication, and with the provision of suitable test points, can aid field fault diagnosis and rectification. A two non-identical three-state units redundant system with common-cause failures and one standby unit. WHO KEE CHUNG. Microelectron. Reliab. 21 (5), "/07 (1981). This paper presents a mathematical model for predicting a two nonidentical three-state active units redundant system with common-cause failures and one standby unit. The units may fail in either of two mutually exclusive failure modes or by the occurrence of common-cause failures. System is only repaired when all the units fail (including the standby unit). The failure rates of units are constant and system repair times are arbitrarily distributed. Laplace transforms of the state probabilities are derived. Fault diagnosis by mathematical programming. T. WATANABE,C. YASUNOBUand M. O'KUMA. IEEE Trans. Reliab. R30 (4), 345 (1981). This paper presents the problem of fault diagnosis for logically represented continuous systems that can be formulated through nonlinear mathematical programming. This problem is transformed to an integerprogramming problem and solved. Possible modifications and extensions of the problem are given. Although failure tables must be prepared in ordinary fault diagnosis, they are not necessary with this mathematical programming approach. By modifying constraints in the mathematical programming problem, difficulties such as multiple faults, correlated faults, modifications of test conditions and cycles in the system, which are encountered in the ordinary failure table approach, are made tractable. Test strategy enhances, speeds the development of a microprocessor. KARL GUTTAG, ROBERT PUCKETT, STEPHEN SACARISEN and THOMASDYE. Electronics, 84 (December 29, 1981 ). A part that met its design goals on first pass owes its success to a well-thought-out test plan designed to cover all bases. Failure-frequency evaluation of complex systems using cut-set approach. J. M. NAHMAN. IEEE Trans. Reliab. R-30 (4), 353 (1981). The paper develops a new method for evaluating failure frequency of complex systems with 2-state components, from corresponding cut sets. The method is derived by direct application of cut-set techniques to the failure frequency formula obtained by Buzacott and Singh. The method is suitable for computer implementation and can be used for cut-set diagrams with overlapping and non minimal cut-sets. Two examples are presented and the results are compared with those obtained by a common approximate approach. A new algorithm for the reliability analysis of multi-terminal networks. A. SATYANARAYANA and JANE N. HAGSTROM.
Sequential life-testing with spacings, exponential model. G. S. LINGAPPAIAH. IEEE Trans. Reliab. R-30 (4), 370 (1981). Spacings (difference between two consecutive order statistics) and the linear combination of spacings (LCOS) are discussed in this paper. Prediction of LCOS in a life test based on the exponential model is attempted here. A stopping rule is suggested for prediction and is based on the minimum variance of the LCOS. Prediction of LCOS is also developed in terms of batches of items by considering the LCOS of batches. A few special cases are considered. A Bayesian approach is also used for the same purpose of prediction. The procedure is illustrated with simulated samples. Reliability techniques in the service of industry. ANDREW R. CHURCHLEY. IEEE Trans. Reliab. R-30 (4), 306 (1981). Failures which occur in any industrial activity reduce the profitability and safety of commercial ventures. Numerical estimates of reliability, availability, and profitability are based on an understanding of the fundamental concepts of reliability engineering. These estimates assist comparison of alternative design or improvement strategies for process plant. Although a reliability assessment is concerned largely with equipment failures, the important part played by human reliability can be estimated and included in such studies. Plant reliability interacts with the morale of the workforce; morale is unfortunately not easy to quantify. The methods and procedure of a reliability analysis are described. A degree of flexibility in the assessor's approach is useful when the rigour of the study must be adjusted to suit practical cost considerations. Direct optimisation for calculating maximum likelihood estimates of parameters of the Weibull distribution. BRIAN D. BUNDAY and IMAD AL-MUTWALI. IEEE Trans. Reliab. R-30 (4), 367 (1981). Computer software has been prepared to compute maximum likelihood estimates (MLE) for the parameters of a 2-parameter Weibull distribution using failure and survival time data. The procedure is the direct optimisation of the log-likelihood function by a method that evaluates the variance-covariance matrix of the estimates without a separate calculation of second derivatives. On profit evaluation in a two-unit maintained redundant system. M. C. GUPTA and A. KUMAR. Microelectron. Reliab. 21 (4), 605 (1981). A two-unit redundant system is considered and analytic expression for total expected profit earned in a given time is obtained after writing basic cost equations governing the behaviour of the system. A procedure is suggested to obtain optimal failure and repair rates so that expected steady state profit is maximum.
Analysis of a two-unit parallel redundant system with phase type failure and general repair. N. RAVICHANDRAN. Microelectron. Reliab. 21 (4), 569 (1981). Explicit expressions for the Laplace transform of the reliability and availability of a general two-unit parallel redundant system are obtained. The mean time to system failure and steady state availability are deduced as special cases. Some particular cases of our result are also obtained. A K-out-of-N:G three-state unit redundant system with common-cause failures and replacements. WHO KEE CHUNG. Microelectron. Reliab. 21 (4), 589 (1981). A mathematical model for predicting a k-out-of-N:G three-state unit redundant system with common-cause failures and failed system with replacement units has been developed. Laplace transforms of the state probabilities are derived. The steady-state probabilities, frequency of encountering and the average duration of residence in a state are also reported.
1187
Software aids to microcomputer system reliability. A. R. WOOD. Microelectron. Reliab. 21 (3), 391 (1981). The use of microcomputers in critical control or telemetry applications is becoming more common but it requires not only the hardware reliability brought about by advances in circuit integration, but also reliable operation of the control software. A distinction is made between error detecting software, and error detection and correction which requires both additional hardware and the software routines to detect fault conditions and apply the necessary correction algorithms. This paper describes some of the simple software techniques which can be used to perform self-test functions on microcomputers to check for hardware failure or software malfunction without the use of additional hardware. The use of self-test routines has obvious application in remote microcomputer systems controlling or monitoring critical processes where an immediate indication of a failure of the microcomputer is required. The detection of a failure could initiate fail-safe procedures to prevent damage to the plant being controlled or monitored. The self-test routines can be used in less exotic systems to provide fault detection and indication, and with the provision of suitable test points, can aid field fault diagnosis and rectification. A two non-identical three-state units redundant system with common-cause failures and one standby unit. WHO KEE CHUNG. Microelectron. Reliab. 21 (5), "/07 (1981). This paper presents a mathematical model for predicting a two nonidentical three-state active units redundant system with common-cause failures and one standby unit. The units may fail in either of two mutually exclusive failure modes or by the occurrence of common-cause failures. System is only repaired when all the units fail (including the standby unit). The failure rates of units are constant and system repair times are arbitrarily distributed. Laplace transforms of the state probabilities are derived. Fault diagnosis by mathematical programming. T. WATANABE,C. YASUNOBUand M. O'KUMA. IEEE Trans. Reliab. R30 (4), 345 (1981). This paper presents the problem of fault diagnosis for logically represented continuous systems that can be formulated through nonlinear mathematical programming. This problem is transformed to an integerprogramming problem and solved. Possible modifications and extensions of the problem are given. Although failure tables must be prepared in ordinary fault diagnosis, they are not necessary with this mathematical programming approach. By modifying constraints in the mathematical programming problem, difficulties such as multiple faults, correlated faults, modifications of test conditions and cycles in the system, which are encountered in the ordinary failure table approach, are made tractable. Test strategy enhances, speeds the development of a microprocessor. KARL GUTTAG, ROBERT PUCKETT, STEPHEN SACARISEN and THOMASDYE. Electronics, 84 (December 29, 1981 ). A part that met its design goals on first pass owes its success to a well-thought-out test plan designed to cover all bases. Failure-frequency evaluation of complex systems using cut-set approach. J. M. NAHMAN. IEEE Trans. Reliab. R-30 (4), 353 (1981). The paper develops a new method for evaluating failure frequency of complex systems with 2-state components, from corresponding cut sets. The method is derived by direct application of cut-set techniques to the failure frequency formula obtained by Buzacott and Singh. The method is suitable for computer implementation and can be used for cut-set diagrams with overlapping and non minimal cut-sets. Two examples are presented and the results are compared with those obtained by a common approximate approach. A new algorithm for the reliability analysis of multi-terminal networks. A. SATYANARAYANA and JANE N. HAGSTROM.