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Censored life-data analysis using linguistic variables
892
World Abstracts on Microelectronics and Reliability
the system fails if and only if any k consecutive components all fail. Reliabilities for consecutive-k cycles are usually computed by recursive equations. However, most recursive equations proposed so far for the cycle involve reliabilities for consecutive-k lines. Thus we have to run two passes where the first pass computes only the line reliabilities. We propose a recursive equation involving cycles only. It is simpler in form but much harder to understand on intuitive grounds. Another advantage is that the new cycle recursion has the same form as a line recursion previously proposed. Thus a uniform treatment of lines and cycles is possible. We use this uniform approach to obtain some explicit solutions of both line and cycle reliabilities for 2 <~ k ~< 4.
Reliability of new semiconductor devices for long-distance optical submarine-cable systems. KOICHI TATEKURA and YASUHIKO NIIRO. IEEE Trans. Reliab. 37, 3 (1988). Highly reliable repeaters are indispensable to the operation of a long distance optical submarine-cable system. This paper reports final-stage results from reliability tests conducted on 3 newly developed semiconductor devices (laser diodes, photodetectors, and monolithic integrated circuits) used in optical repeaters. These devices proved suitable for use in a long distance optical submarine-cable system such as the third transpacific cable system.
Optimal continuous-wear limit replacement under periodic inspections. KYUNG S. PARK. IEEE Trans. Reliab. 37, 97 (1988). An item breaks down when it wears continuously beyond a certain threshold. The item is preventively replaced if the wear at periodic inspections exceeds a certain wear limit; on failure, it is replaced immediately. The optimal wear limit for preventive replacement which minimizes the longrun total average-cost rate is derived. A numerical example demonstrates its computability.
A Bayes sensitivity analysis when using the beta distribution as a prior. BENJAMIN S. DURAN and JANE M. BOOKER. IEEE Trans. Reliab. 37, 239 (1988). This paper presents results that illustrate the determination of the parameters of a beta prior distribution when 1) the mean and one percentile or 2) two percentiles are given. Further results show how sensitive the parameters of the beta prior are to errors in the given values. Finally, the sensitivity of the probability distribution of the reliability of a system to errors in 1) the given mean and percentile or 2) 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.
A test of the exponential MTBF and comparison of power functions in the random censoring case. JEE Soo KIM. IEEE Trans. Reliab. 37, 103 (1988). This paper presents an hypothesis test procedure for testing the parameter of an exponential distribution when the reliability data are randomly censored. The effects of the severity of the censoring are studied with respect to the power functions of the test. Some remarks are made on the inadequacy of the Epstein type of testing procedure in the random censoring case.
Reliability bounds for dependent failures. D. B. PARK1NSON. IEEE Trans. Reliab. 37, 54 (1988). Upper and lower bounds are obtained for the reliability of a series system with
statistically dependent component failures. The method can be applied to series subsystems when these are obtained by decomposing a complex system. Numerical examples illustrate the use of this method.
Data bank for probabilistic risk-assessment of nuclear-fuel reprocessing plants. WILLIAM S. DURANT, C. RAY Lux and WALLACED. GALLOWAY.IEEE Trans. Reliab. 37, 138 (1988). 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 that 175 000 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.
RAPID: recursive algorithmic Pivotal decomposition program for complex structural reliability analysis. KYUNG S. PARK and BYUNG C. CHO. IEEE Trans. Reliab. 37, 50 (1988). This paper presents a short PC program for complex structural reliability analysis. The program is written in BASIC and it pivots uni- or bi-directional components for decomposition fully automatically (without human intervention).
A method for microprocessor software reliability prediction. J. LUIS ROCA. IEEE Trans. Reliab. 37, 88 (1988). This paper presents a method for microprocessor software reliability prediction. In the last stages of microprocessor software development (validation phase) it is necessary to evaluate the failure rate. My method uses only a few assumptions to get an idea of the failure rate. A simple technique is derived by taking elements of graph theory and introducing a path decomposition micromodcl. Optimal preventive maintenance with repair. S. H. SIM and J. ENDRENYI. IEEE Trans. Reliab. 37, 92 (1988). A minimal preventive-maintenance model is developed for repairable, continuously-operating devices whose conditions deteriorate with the time in service. The times to preventive maintenance have an Erlang distribution and may be, in a limiting case, deterministic. The optimal value of the mean time to preventive maintenance is determined by minimizing the unavailability of the device due to preventive maintenance, to Poisson-distributed failures, and to deterioration failures. The model is useful for many devices, including electric power-system components such as coal pulverizers, circuit breakers, and transformers.
Bounding network-reliability using consecutive minimal cutsets. J. GEORGE SHANTHIKUMAR.IEEE Trans. Reliab. 37, 45 (1988). A subset of consecutive minimal cutsets of the set of cutsets is used to develop an efficient algorithm to compute an upper bound for the reliability of a network. The reliability is the probability that a path consisting only of functioning arcs exists between the source and the sink of the network. The nodes of this network are perfect but the arcs are independent and either function or fail with known probabilities. For the case of source to sink planar networks, an approach to obtain a lower bound for the reliability of the network is also presented. Examples illustrate the use of the algorithm and show that the upper bound is, in many cases, better than that obtained by Shogan.
Censored life-data analysis using linguistic variables. JYHHONEWANG, JOHN M. LIITTSCHWAGERand TzvI RAZ. IEEE Trans. Reliab. 37, 111 (1988). Parameter estimates for censored life data using ordinary censoring methods (noninformative censoring) can be biased when the cause of censoring for a unit is related to its final life (informative censoring). This paper presents an algorithm for obtaining estimated life times for informatively censored units based upon linguistic variable concepts from fuzzy set theory. These estimates are then combined with the life times for actually failed units to form a complete sample for parameter estimation purposes.
Reliability optimization in cable system design using a fuzzy uniform-cost algorithm. SUSHILDAS GUPTA and MUHAMMAD
World Abstracts on Microelectronics and Reliability
the system fails if and only if any k consecutive components all fail. Reliabilities for consecutive-k cycles are usually computed by recursive equations. However, most recursive equations proposed so far for the cycle involve reliabilities for consecutive-k lines. Thus we have to run two passes where the first pass computes only the line reliabilities. We propose a recursive equation involving cycles only. It is simpler in form but much harder to understand on intuitive grounds. Another advantage is that the new cycle recursion has the same form as a line recursion previously proposed. Thus a uniform treatment of lines and cycles is possible. We use this uniform approach to obtain some explicit solutions of both line and cycle reliabilities for 2 <~ k ~< 4.
Reliability of new semiconductor devices for long-distance optical submarine-cable systems. KOICHI TATEKURA and YASUHIKO NIIRO. IEEE Trans. Reliab. 37, 3 (1988). Highly reliable repeaters are indispensable to the operation of a long distance optical submarine-cable system. This paper reports final-stage results from reliability tests conducted on 3 newly developed semiconductor devices (laser diodes, photodetectors, and monolithic integrated circuits) used in optical repeaters. These devices proved suitable for use in a long distance optical submarine-cable system such as the third transpacific cable system.
Optimal continuous-wear limit replacement under periodic inspections. KYUNG S. PARK. IEEE Trans. Reliab. 37, 97 (1988). An item breaks down when it wears continuously beyond a certain threshold. The item is preventively replaced if the wear at periodic inspections exceeds a certain wear limit; on failure, it is replaced immediately. The optimal wear limit for preventive replacement which minimizes the longrun total average-cost rate is derived. A numerical example demonstrates its computability.
A Bayes sensitivity analysis when using the beta distribution as a prior. BENJAMIN S. DURAN and JANE M. BOOKER. IEEE Trans. Reliab. 37, 239 (1988). This paper presents results that illustrate the determination of the parameters of a beta prior distribution when 1) the mean and one percentile or 2) two percentiles are given. Further results show how sensitive the parameters of the beta prior are to errors in the given values. Finally, the sensitivity of the probability distribution of the reliability of a system to errors in 1) the given mean and percentile or 2) 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.
A test of the exponential MTBF and comparison of power functions in the random censoring case. JEE Soo KIM. IEEE Trans. Reliab. 37, 103 (1988). This paper presents an hypothesis test procedure for testing the parameter of an exponential distribution when the reliability data are randomly censored. The effects of the severity of the censoring are studied with respect to the power functions of the test. Some remarks are made on the inadequacy of the Epstein type of testing procedure in the random censoring case.
Reliability bounds for dependent failures. D. B. PARK1NSON. IEEE Trans. Reliab. 37, 54 (1988). Upper and lower bounds are obtained for the reliability of a series system with
statistically dependent component failures. The method can be applied to series subsystems when these are obtained by decomposing a complex system. Numerical examples illustrate the use of this method.
Data bank for probabilistic risk-assessment of nuclear-fuel reprocessing plants. WILLIAM S. DURANT, C. RAY Lux and WALLACED. GALLOWAY.IEEE Trans. Reliab. 37, 138 (1988). 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 that 175 000 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.
RAPID: recursive algorithmic Pivotal decomposition program for complex structural reliability analysis. KYUNG S. PARK and BYUNG C. CHO. IEEE Trans. Reliab. 37, 50 (1988). This paper presents a short PC program for complex structural reliability analysis. The program is written in BASIC and it pivots uni- or bi-directional components for decomposition fully automatically (without human intervention).
A method for microprocessor software reliability prediction. J. LUIS ROCA. IEEE Trans. Reliab. 37, 88 (1988). This paper presents a method for microprocessor software reliability prediction. In the last stages of microprocessor software development (validation phase) it is necessary to evaluate the failure rate. My method uses only a few assumptions to get an idea of the failure rate. A simple technique is derived by taking elements of graph theory and introducing a path decomposition micromodcl. Optimal preventive maintenance with repair. S. H. SIM and J. ENDRENYI. IEEE Trans. Reliab. 37, 92 (1988). A minimal preventive-maintenance model is developed for repairable, continuously-operating devices whose conditions deteriorate with the time in service. The times to preventive maintenance have an Erlang distribution and may be, in a limiting case, deterministic. The optimal value of the mean time to preventive maintenance is determined by minimizing the unavailability of the device due to preventive maintenance, to Poisson-distributed failures, and to deterioration failures. The model is useful for many devices, including electric power-system components such as coal pulverizers, circuit breakers, and transformers.
Bounding network-reliability using consecutive minimal cutsets. J. GEORGE SHANTHIKUMAR.IEEE Trans. Reliab. 37, 45 (1988). A subset of consecutive minimal cutsets of the set of cutsets is used to develop an efficient algorithm to compute an upper bound for the reliability of a network. The reliability is the probability that a path consisting only of functioning arcs exists between the source and the sink of the network. The nodes of this network are perfect but the arcs are independent and either function or fail with known probabilities. For the case of source to sink planar networks, an approach to obtain a lower bound for the reliability of the network is also presented. Examples illustrate the use of the algorithm and show that the upper bound is, in many cases, better than that obtained by Shogan.
Censored life-data analysis using linguistic variables. JYHHONEWANG, JOHN M. LIITTSCHWAGERand TzvI RAZ. IEEE Trans. Reliab. 37, 111 (1988). Parameter estimates for censored life data using ordinary censoring methods (noninformative censoring) can be biased when the cause of censoring for a unit is related to its final life (informative censoring). This paper presents an algorithm for obtaining estimated life times for informatively censored units based upon linguistic variable concepts from fuzzy set theory. These estimates are then combined with the life times for actually failed units to form a complete sample for parameter estimation purposes.
Reliability optimization in cable system design using a fuzzy uniform-cost algorithm. SUSHILDAS GUPTA and MUHAMMAD