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Automatic unit troubleshoots systems
752
World Abstracts on Microelectronics and Reliability 3. C I R C U I T
AND SYSTEMS
RELIABILITY,
A muitistate system with general repair time distribution. MITSUO YAMASHIRO. IEEE Trans. Reliab. R-29 (5) 433 (December 1980). This paper deals with a multistate system with general repair time distribution. Laplace transforms of state probability for such a system are obtained and particular cases are discussed. Applying signature analysis to existing processor-based products. ROBERT RHODES-BURKE. Electronics 127 (24 February 1981). With the advent of an off-board source of stimuli for signature analysis, it is possible to retrofit this efficient test method without extensive redesign. Reliability determination of a r-successive-out-of-n : F system. J. M. KONTOLEON. IEEE Trans. Reliab. R-29 (5) 437 (December 1980). A computer program is described for obtaining the reliability of a system composed of a number of interconnected subsystems. The interconnections are such that at least r successive interconnected subsystems must fail in order for the system to fail. The approach treats the system as a dynamic redundant system and is implemented in a digital computer program. The program listing and examples are given in a Supplement. Prediction intervals for IFR distributions. JAGDISH K. PATEL. IEEE Trans. Reliab. R-29 (5) 406 (December 1980). Several prediction intervals for the class of increasing failure rate distributions are obtained. They extend some known results on l- or 2-parameter exponential distributions. The use of these results requires no new tables. First-passage time distribution of Brownian motion as a reliability model. Y. S. SHER1Fand M. L. SMITH. IEEE Trans. Reliab. R-29 (5) 425 (December 1980). Since the inverse Gaussian distribution arises as the distribution of first passage time of Brownian motion, its applicability to lifetime or survival situations is a natural consequence. The failure rate for the inverse Gaussian distribution first increases until it reaches its maximum value somewhere to the right of the mode, then it decreases monotonically to a non-zero asymptotic value. This paper fits the inverse Gaussian distribution model to observed failure data of high speed steel tools in machining low carbon steel. Then the lognormal distribution model is hypothesized for the same failure data. The inverse Gaussian fits better. The drive for quality and reliability. Part 1. JERRY LYMAN. Electronics 125 (19 May 1981). Propelled by aggressive competition and customer demand, equipment and component makers are pushing to upgrade their products. Makers organize for quality. Part 2. Electronics 137 (19 May 1981). At every stage from design to delivery, component makers are reexamining their operations and reorganising them for quality. Users push for quality. Part 3. Electronics 141 (19 May 1981). Meeting the upsurge in demand for quality calls for new and closer relationships with suppliers, equipment makers find. Analytical techniques in product safety. VERNE L. ROBERTS and PHILLIP L. JONES. J. Products Liability 4, 67 (1981). The paper discusses the uses of Fault Tree Analysis, Failure Mode Effects and Criticality Analysis and Hazard Quantification as methods available to define product safety. The uses and limitations of the three techniques are defined. Automatic
unit troubleshoots systems. BRUCE LEBOSS. Electronics 183 (19 May 1981). With probe plugged into microprocessor socket, tester generates address map of system, checks bus, RAM, ROM, and 1/O.
MAINTENANCE
AND
REDUNDANCY
Analyzer fills debugging gap. BRUCE LEBOSS. Electronics 188 (19 May 1981). Trigger trace analyzer can handle more complex software assdciated with new families of 16-bit microprocessors. A continuous time model of multiple intermittent faults in digital systems. RICHARD JAY SPILLMAN. Comput. Elect. Engnff. 8, 27 (1981). Intermittent faults are the largest source of failure for digital systems. In order to provide an engineer with a method for detecting intermittent faults, a birth-death model of the intermittent fault process is developed. This model is continuous in time and considers the case of multiple intermittent faults. It subsumes several models already reported in the literature. Reliability analysis of a fluidized-bed boiler for a coal-fueled power plant. THOMASG. WOO. IEEE Trans. Reliab. R-29 (5) 422 (December 1980). This is a reliability study of an experimental fluidized-bed boiler for a coal-fueled plant. The study determined the major contributors to plant outage in terms of equipment failure and plant management. The major problems associated with fluidized-bed development and operation are related to a plant startup and research environment rather than to equipment reliability. Consequently, operations of this experimental facility were continued on the optimistic note that future plant performance could be appreciably improved by modifying operating practices to minimize plant outage attributed to: 1. Prolonged equipment maintenance due to the lack of readily available spare parts. 2. Delayed startup due to performing non-critical preventive maintenance. 3. Minimal repair activity performed on the second and third work shifts or for an entire weekend. 4. Delayed startups after the completion of repairs until a subsequent shift or until the end of a weekend. A clearer understanding of existing system and equipment problems enabled engineering to improve plant availability by: 1. Minimizing coal fines plugging of feed needles by increasing needle diameters from 1.5 to 2.0 inches. 2. Relieving excessive strain on the fuel handling system by eliminating stop and start operation of the coal bucket elevators under full load. 3. Eliminating dependence on outside plant services and facilities sharing host-plant feedwater. Multi-echelon multiple criteria spares allocation. RAD1VOJ PETROVIC, ALEKSANDAR SENBORN and MIRKO VUJOSEV1C. IEEE Trans. Reliab. R-29 (5) 392 (December 1980). This paper presents an approach for allocating spares on three echelons to increase system reliability and decrease plant down-time in a cost-effective manner. The usual assumptions are made: (a) the demands for spares have the Poisson distribution with known demand rates, (b) all the failures of plant parts are s-independent, (c) for the plant to be operating, all parts must be operating, thus forming 1-out-ofM : F configuration, To each echelon of the spatially distributed spare-support system is associated a relevant optimization criterion and a corresponding constraint. The algorithm for determining stock levels adapts the known "per-pound" procedure, applied in sequence from the first echelon to the third echelon. The sequential optimization is computationally efficient. The test examples have confirmed that the algorithms proposed can handle 3-echelon sparing problems with even thousands of part types. Experience in the shifting of responsibility for quality through introducing operator testing in industrial production. H. G. BABIC and H. KAMPA. Feinwerktech. Messtech. 89 (1) 6 (1981) (in German). The common no-longer satisfying
World Abstracts on Microelectronics and Reliability 3. C I R C U I T
AND SYSTEMS
RELIABILITY,
A muitistate system with general repair time distribution. MITSUO YAMASHIRO. IEEE Trans. Reliab. R-29 (5) 433 (December 1980). This paper deals with a multistate system with general repair time distribution. Laplace transforms of state probability for such a system are obtained and particular cases are discussed. Applying signature analysis to existing processor-based products. ROBERT RHODES-BURKE. Electronics 127 (24 February 1981). With the advent of an off-board source of stimuli for signature analysis, it is possible to retrofit this efficient test method without extensive redesign. Reliability determination of a r-successive-out-of-n : F system. J. M. KONTOLEON. IEEE Trans. Reliab. R-29 (5) 437 (December 1980). A computer program is described for obtaining the reliability of a system composed of a number of interconnected subsystems. The interconnections are such that at least r successive interconnected subsystems must fail in order for the system to fail. The approach treats the system as a dynamic redundant system and is implemented in a digital computer program. The program listing and examples are given in a Supplement. Prediction intervals for IFR distributions. JAGDISH K. PATEL. IEEE Trans. Reliab. R-29 (5) 406 (December 1980). Several prediction intervals for the class of increasing failure rate distributions are obtained. They extend some known results on l- or 2-parameter exponential distributions. The use of these results requires no new tables. First-passage time distribution of Brownian motion as a reliability model. Y. S. SHER1Fand M. L. SMITH. IEEE Trans. Reliab. R-29 (5) 425 (December 1980). Since the inverse Gaussian distribution arises as the distribution of first passage time of Brownian motion, its applicability to lifetime or survival situations is a natural consequence. The failure rate for the inverse Gaussian distribution first increases until it reaches its maximum value somewhere to the right of the mode, then it decreases monotonically to a non-zero asymptotic value. This paper fits the inverse Gaussian distribution model to observed failure data of high speed steel tools in machining low carbon steel. Then the lognormal distribution model is hypothesized for the same failure data. The inverse Gaussian fits better. The drive for quality and reliability. Part 1. JERRY LYMAN. Electronics 125 (19 May 1981). Propelled by aggressive competition and customer demand, equipment and component makers are pushing to upgrade their products. Makers organize for quality. Part 2. Electronics 137 (19 May 1981). At every stage from design to delivery, component makers are reexamining their operations and reorganising them for quality. Users push for quality. Part 3. Electronics 141 (19 May 1981). Meeting the upsurge in demand for quality calls for new and closer relationships with suppliers, equipment makers find. Analytical techniques in product safety. VERNE L. ROBERTS and PHILLIP L. JONES. J. Products Liability 4, 67 (1981). The paper discusses the uses of Fault Tree Analysis, Failure Mode Effects and Criticality Analysis and Hazard Quantification as methods available to define product safety. The uses and limitations of the three techniques are defined. Automatic
unit troubleshoots systems. BRUCE LEBOSS. Electronics 183 (19 May 1981). With probe plugged into microprocessor socket, tester generates address map of system, checks bus, RAM, ROM, and 1/O.
MAINTENANCE
AND
REDUNDANCY
Analyzer fills debugging gap. BRUCE LEBOSS. Electronics 188 (19 May 1981). Trigger trace analyzer can handle more complex software assdciated with new families of 16-bit microprocessors. A continuous time model of multiple intermittent faults in digital systems. RICHARD JAY SPILLMAN. Comput. Elect. Engnff. 8, 27 (1981). Intermittent faults are the largest source of failure for digital systems. In order to provide an engineer with a method for detecting intermittent faults, a birth-death model of the intermittent fault process is developed. This model is continuous in time and considers the case of multiple intermittent faults. It subsumes several models already reported in the literature. Reliability analysis of a fluidized-bed boiler for a coal-fueled power plant. THOMASG. WOO. IEEE Trans. Reliab. R-29 (5) 422 (December 1980). This is a reliability study of an experimental fluidized-bed boiler for a coal-fueled plant. The study determined the major contributors to plant outage in terms of equipment failure and plant management. The major problems associated with fluidized-bed development and operation are related to a plant startup and research environment rather than to equipment reliability. Consequently, operations of this experimental facility were continued on the optimistic note that future plant performance could be appreciably improved by modifying operating practices to minimize plant outage attributed to: 1. Prolonged equipment maintenance due to the lack of readily available spare parts. 2. Delayed startup due to performing non-critical preventive maintenance. 3. Minimal repair activity performed on the second and third work shifts or for an entire weekend. 4. Delayed startups after the completion of repairs until a subsequent shift or until the end of a weekend. A clearer understanding of existing system and equipment problems enabled engineering to improve plant availability by: 1. Minimizing coal fines plugging of feed needles by increasing needle diameters from 1.5 to 2.0 inches. 2. Relieving excessive strain on the fuel handling system by eliminating stop and start operation of the coal bucket elevators under full load. 3. Eliminating dependence on outside plant services and facilities sharing host-plant feedwater. Multi-echelon multiple criteria spares allocation. RAD1VOJ PETROVIC, ALEKSANDAR SENBORN and MIRKO VUJOSEV1C. IEEE Trans. Reliab. R-29 (5) 392 (December 1980). This paper presents an approach for allocating spares on three echelons to increase system reliability and decrease plant down-time in a cost-effective manner. The usual assumptions are made: (a) the demands for spares have the Poisson distribution with known demand rates, (b) all the failures of plant parts are s-independent, (c) for the plant to be operating, all parts must be operating, thus forming 1-out-ofM : F configuration, To each echelon of the spatially distributed spare-support system is associated a relevant optimization criterion and a corresponding constraint. The algorithm for determining stock levels adapts the known "per-pound" procedure, applied in sequence from the first echelon to the third echelon. The sequential optimization is computationally efficient. The test examples have confirmed that the algorithms proposed can handle 3-echelon sparing problems with even thousands of part types. Experience in the shifting of responsibility for quality through introducing operator testing in industrial production. H. G. BABIC and H. KAMPA. Feinwerktech. Messtech. 89 (1) 6 (1981) (in German). The common no-longer satisfying