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Allocation of man-machine reliability
522
World Abstracts on Microelectronics and Reliability
P. P. ZEMANICK.IEEE Trans. Reliab. R-25 (3), 191 (August 1976). The Reliability Program for the Clinch River Breeder Reactor Plant (CRBRP, a sodium-cooled fast breeder reactor) is an integral part of the overall CRBRP design philosophy of safety in depth. The purpose of this program is to assure that the likelihood of exceeding Nuclear Regulatory Commission dose guidelines at the plant site boundaries is less than 10 -6 per operating reactor year. This goal is conservatively interpreted for the purpose of a design objective as the requirement not to exceed loss of coolable core geometry to the same maximum likelihood of 10 -6 per reactor year. This requirement is allocated among shutdown systems, post-shutdown heat removal systems, and other systems whose failure could result in loss of coolable geometry, a potential initiating cause of dose limit violations. Assuring that the goal will be attained in the plant is based on reliability analysis, the redundancy and diversity inherent in the design, and the verification test program.
Reliability of a 2-unit priority-standby redundant system with finite repair capability. J. R. ARORA. IEEE Trans. Reliab. R-25 (3), 205 (August 1976). This paper analyses the reliability of a 2-unit standby redundant system consisting of two dissimilar units. Unit 1 performs the desired system function whenever available for use. Unit 2 operates only during those periods when unit 1 is undergoing repair. Unit 1 can be repaired at most N times. Expressions for the Laplace-Stieltjes transform of the distribution of the Time to System Failure (TSF) and the mean TSF are derived.
Bayesian limits for the reliability of pass/fail parallel units. DONALD R. SMITH and MELVIN D. SPRINGER. IEEE Trans. Reliab. R-25, (3), 213, (August 1976). This paper employs the Mellin transform to derive the exact posterior pdf and Cdf of the reliability of a system consisting of s-independent units in parallel, based on pass-fail data obtained from testing the units. From a tabulation of the posterior Cdf, arbitrary Bayesian limits can be obtained for the reliability of the parallel system. A computer program for determining the requisite posterior pdf and Cdf is operational.
Some current academic research in system refiability theory. RICHARD E. BARLOW and FRANK PROSCHAM. IEEE Trans. Reliab. R-25, (3), 198 (August 1976). This paper is an expository survey of some recent academic research in the theory of system reliability and safety, applicable in the analysis of large complex systems such as nuclear reactors, computers, and space vehicles. The survey emphasizes new approaches in reliability theory, many nonparametric, rather than standard parametric approaches.
Synthesis and analysis of a cost-effective, ultrarefiable, high speed, semiconductor memory system. E. W. HUSBAND and S. A. SZYGENDA. IEEE Trans. Reliab. R-25 (3), 217 (August 1976). This paper provides a detailed synthesis and analysis of a cost effective, ultrareliable, high speed, semiconductor memory system. The memory system has the capability of detecting and correcting over 99% of all single faults. The memory cycle time of 250 nsec is not compromised unless a fault is encountered. The increase in circuitry for the fault-tolerent system, over the simplex system, is less than 20°4. These results have been achieved through the use of special coding implementations, virtual codes, and selective redundance.
Reliability of a 2-unit standby redundant system with constrained repair time. J. R. ARORA. IEEE Trans. Reliab. R-25 (3) 203 (August 1976). This paper considers a 2-unit warmstandby redundant system with repair. The repair of a failed unit is constrained as follows: Associated with each
failure of a unit is a random variable termed the Maximum-Repair-Time (MRT) of the failure. If the repair of a failed unit is not completed within the MRT, the unit is rejected for further use. Two types of failure situations for the system are considered: (1) No allowed down time, and (2) Some allowed down time. Expressions for the Cdf of the Time to System Failure (TSF) and the mean TSF are derived by using Markov renewal processes.
Reliability of intermittently used systems. MASAFUMISASAK1 and TOSHIAKI HIRAMATSU IEEE Trans. Reliab. R-25 (3) 208 (August 1976). The reliability of three models is investigated. The system is not down unless it is failed when there is a demand. Model 1 is a 2-unit parallel system. Model 2 is similar to model 1 except that if there are 2 users, the system is used as two 1-unit systems, one for each user. Model 3 consists of two model 2 systems in series.
Allocation of man-machine reliability. KENNETH P. LASALA, Dr. A. I. SIEGEL and CARL SONTZ. Proc. A. Reliability and Maintainability" Symposium, Nevada, U.S.A.p. 4 (20-22 Jan. 1976). Conventional reliability allocation methods are not equipped to address the inclusion of the human as an integral part of the system. Similarly, they are not equipped to address the variety of operational roles or equipment acquisition constraints that are experienced frequently in the "real world," To correct this situation, a new allocation methodology is proposed. Since it is based on conventional optimization techniques, equipment acquisition constraints can be addressed readily. The most important aspect of the methodology is that it actively incorporates the human as part of the system. This is done by combining the human reliability results of Siegel et al. and Lamb and Sontz with conventional hardware reliability models. A simple example is provided to illustrate application of the methodology.
Bayesian reliability assessment from test data. JAMES E. WOLF. Proc. A. Reliability and Maintainability Symposium, Nevada, U.S.A.p. 411 (20-22 Jan. 1976). The general problem of making an assessment of reliability from test data is addressed. The exact calculation of Bayesian confidence limits for any type of system (serial, parallel, bridge, etc.) for test data of any assumed nature (binomial, exponential, etc.) is described for data obtained at the component level and/or system level.
Optimal redundancy allocation for non series-parallel networks. S. K. BANERJEE,K. RAJAMANI and S. S. DESHPANDE. IEEE Trans. Reliab. R-25 (2), 115 (June 1976). This paper presents general algorithms for solving redundancy optimization problem for non series-parallel networks. Using closed form expressions for star-delta and delta-star conversions, the exact system reliability expression (objective function) is written down in a straightforward manner. The Box method has been employed to get the optimal continuous solution. The integer solution is obtained by a modified Box method and Branch and bound technique. The scheme is illustrated with an example. The parametric method is used throughout.
The pay-off of R & M trade-off. DR. PAUL M. STAFFORD. Proc. A. Reliability and Maintainability Symposium, Nevada, U.S.A, p. 399 (20-22 Jan. 1976). The objectives of this paper are threefold: (1) to identify individual tasks which normally represent the program elements of an R & M management plan, (2) to evaluate the relative importance of each of these program elements in securing anticipated reliability and maintainability levels, (3) to make trade-off recommendations between R & M program elements while recognizing the inherent risks of such compromise.
World Abstracts on Microelectronics and Reliability
P. P. ZEMANICK.IEEE Trans. Reliab. R-25 (3), 191 (August 1976). The Reliability Program for the Clinch River Breeder Reactor Plant (CRBRP, a sodium-cooled fast breeder reactor) is an integral part of the overall CRBRP design philosophy of safety in depth. The purpose of this program is to assure that the likelihood of exceeding Nuclear Regulatory Commission dose guidelines at the plant site boundaries is less than 10 -6 per operating reactor year. This goal is conservatively interpreted for the purpose of a design objective as the requirement not to exceed loss of coolable core geometry to the same maximum likelihood of 10 -6 per reactor year. This requirement is allocated among shutdown systems, post-shutdown heat removal systems, and other systems whose failure could result in loss of coolable geometry, a potential initiating cause of dose limit violations. Assuring that the goal will be attained in the plant is based on reliability analysis, the redundancy and diversity inherent in the design, and the verification test program.
Reliability of a 2-unit priority-standby redundant system with finite repair capability. J. R. ARORA. IEEE Trans. Reliab. R-25 (3), 205 (August 1976). This paper analyses the reliability of a 2-unit standby redundant system consisting of two dissimilar units. Unit 1 performs the desired system function whenever available for use. Unit 2 operates only during those periods when unit 1 is undergoing repair. Unit 1 can be repaired at most N times. Expressions for the Laplace-Stieltjes transform of the distribution of the Time to System Failure (TSF) and the mean TSF are derived.
Bayesian limits for the reliability of pass/fail parallel units. DONALD R. SMITH and MELVIN D. SPRINGER. IEEE Trans. Reliab. R-25, (3), 213, (August 1976). This paper employs the Mellin transform to derive the exact posterior pdf and Cdf of the reliability of a system consisting of s-independent units in parallel, based on pass-fail data obtained from testing the units. From a tabulation of the posterior Cdf, arbitrary Bayesian limits can be obtained for the reliability of the parallel system. A computer program for determining the requisite posterior pdf and Cdf is operational.
Some current academic research in system refiability theory. RICHARD E. BARLOW and FRANK PROSCHAM. IEEE Trans. Reliab. R-25, (3), 198 (August 1976). This paper is an expository survey of some recent academic research in the theory of system reliability and safety, applicable in the analysis of large complex systems such as nuclear reactors, computers, and space vehicles. The survey emphasizes new approaches in reliability theory, many nonparametric, rather than standard parametric approaches.
Synthesis and analysis of a cost-effective, ultrarefiable, high speed, semiconductor memory system. E. W. HUSBAND and S. A. SZYGENDA. IEEE Trans. Reliab. R-25 (3), 217 (August 1976). This paper provides a detailed synthesis and analysis of a cost effective, ultrareliable, high speed, semiconductor memory system. The memory system has the capability of detecting and correcting over 99% of all single faults. The memory cycle time of 250 nsec is not compromised unless a fault is encountered. The increase in circuitry for the fault-tolerent system, over the simplex system, is less than 20°4. These results have been achieved through the use of special coding implementations, virtual codes, and selective redundance.
Reliability of a 2-unit standby redundant system with constrained repair time. J. R. ARORA. IEEE Trans. Reliab. R-25 (3) 203 (August 1976). This paper considers a 2-unit warmstandby redundant system with repair. The repair of a failed unit is constrained as follows: Associated with each
failure of a unit is a random variable termed the Maximum-Repair-Time (MRT) of the failure. If the repair of a failed unit is not completed within the MRT, the unit is rejected for further use. Two types of failure situations for the system are considered: (1) No allowed down time, and (2) Some allowed down time. Expressions for the Cdf of the Time to System Failure (TSF) and the mean TSF are derived by using Markov renewal processes.
Reliability of intermittently used systems. MASAFUMISASAK1 and TOSHIAKI HIRAMATSU IEEE Trans. Reliab. R-25 (3) 208 (August 1976). The reliability of three models is investigated. The system is not down unless it is failed when there is a demand. Model 1 is a 2-unit parallel system. Model 2 is similar to model 1 except that if there are 2 users, the system is used as two 1-unit systems, one for each user. Model 3 consists of two model 2 systems in series.
Allocation of man-machine reliability. KENNETH P. LASALA, Dr. A. I. SIEGEL and CARL SONTZ. Proc. A. Reliability and Maintainability" Symposium, Nevada, U.S.A.p. 4 (20-22 Jan. 1976). Conventional reliability allocation methods are not equipped to address the inclusion of the human as an integral part of the system. Similarly, they are not equipped to address the variety of operational roles or equipment acquisition constraints that are experienced frequently in the "real world," To correct this situation, a new allocation methodology is proposed. Since it is based on conventional optimization techniques, equipment acquisition constraints can be addressed readily. The most important aspect of the methodology is that it actively incorporates the human as part of the system. This is done by combining the human reliability results of Siegel et al. and Lamb and Sontz with conventional hardware reliability models. A simple example is provided to illustrate application of the methodology.
Bayesian reliability assessment from test data. JAMES E. WOLF. Proc. A. Reliability and Maintainability Symposium, Nevada, U.S.A.p. 411 (20-22 Jan. 1976). The general problem of making an assessment of reliability from test data is addressed. The exact calculation of Bayesian confidence limits for any type of system (serial, parallel, bridge, etc.) for test data of any assumed nature (binomial, exponential, etc.) is described for data obtained at the component level and/or system level.
Optimal redundancy allocation for non series-parallel networks. S. K. BANERJEE,K. RAJAMANI and S. S. DESHPANDE. IEEE Trans. Reliab. R-25 (2), 115 (June 1976). This paper presents general algorithms for solving redundancy optimization problem for non series-parallel networks. Using closed form expressions for star-delta and delta-star conversions, the exact system reliability expression (objective function) is written down in a straightforward manner. The Box method has been employed to get the optimal continuous solution. The integer solution is obtained by a modified Box method and Branch and bound technique. The scheme is illustrated with an example. The parametric method is used throughout.
The pay-off of R & M trade-off. DR. PAUL M. STAFFORD. Proc. A. Reliability and Maintainability Symposium, Nevada, U.S.A, p. 399 (20-22 Jan. 1976). The objectives of this paper are threefold: (1) to identify individual tasks which normally represent the program elements of an R & M management plan, (2) to evaluate the relative importance of each of these program elements in securing anticipated reliability and maintainability levels, (3) to make trade-off recommendations between R & M program elements while recognizing the inherent risks of such compromise.