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An approach to high reliability for a spacecraft IRU
190
World Abstracts on Microetectronics and Reliability
are further analyzed as a contribution to the continuing discussion of the utility of minimal forms vis-/t-vis the p.i?s, and of the consensus method.
Moments in terms of the mean residual life function. RAMESH C. GUPTA. IEEE Trans. Reliab. R-30 (5), 450 (1981). In reliability studies, the mean additional life time, given that a component has survived until time t, is called the mean residual life function (MRLF). This M R L F determines the distribution function uniquely. In this paper a method of obtaining the m o m e n t s in terms of the M R L F , by employing a result in the context of renewal theory, is developed. The method is illustrated by an example. 2-out-of-n:F intermittently-used system. M. SAMBANDHAM. IEEE Trans. Reliab. R-30 (5), 491 (1981). The expressions for the time to the first disappointment, distribution of the time between two successive need events, mean number of disappointments, and the mean square number of disappointments have been derived for a special 2-out-of-n : F system. Model for transient and permanent error-detection and faultisolation coverage. D. C. BOSSEN and M. Y. HSIAO. I B M Jl Res. Dev. 26 (1), 67 (1982). As computer technologies advance to achieve higher performance and density, intermittent failures become more dominant than solid failures, with the result that the effectiveness of any diagnostic procedure which relies on reproducing failures is greatly reduced. This problem is solved at the system level by a new strategy of dynamic error detection and fault isolation based on error checking and analysis of captured information. The model developed in this paper allows the system designer to project the dynamic error-detection and fault-isolation coverages of the system as a function of the failure rates of components and the types and placement of error checkers, which has resulted in significant improvements to both detection and isolation in the IBM 3081 Processor Unit. The model has also resulted in new probabilistic isolation strategies based on the likelihood of failures. Our experiences with this model on several IBM products, including the 3081, show good correlation between the model and practical experiments. A model of maintenance decision errors. GORDON W. SPRAY, CHARLES J. TEPLITZ, ALAN E. HERNER and RUSSELL M. GENET. IEEE Proc. Reliab., 373 (1982). The maintenance of highly complex equipments is somztimes plagued by maintenance decision errors. This paper discusses some of the causes of these errors. A simulation model of a highly-simplified maintenance process that includes sources of decision errors is discussed. Several logical hypotheses regarding decision errors in maintenance are then suggested, and the model is used to evaluate these hypotheses.
Microwave device transient-power failure mechanisms yield to computer analysis. J. S. SMITH and N. KUSNEZOV.Microwave Syst. News 12 (3), 67 (1982). Microwave device vulnerability to power transients has been very difficult to quantify. Recent improvements in computer analysis can now be used to reveal the secrets of a power/temperature relationship that ultimately causes device destruction. An approach to high reliability for a spacecraft IRU. CARL GRUBIN, ROBERT B. IRVINE and DEAN W. TRUNNELL. IEEE Proc. Reliab., 479 (1982). This paper presents a design approach and a methodology to extend the life of an existing inertial reference unit (IRU) with a mission probability of success (Ps) of 0.990 for a one.(1 ) year mission to a Ps of 0.999 for a five (5) year mission and 0.993 for an eight (8) year mission. The o p t i m u m configuration utilizing the m i n i m u m hardware was determined by design trade studies and reliability prediction analyses.
Prediction of nonrelevant failures. GERALD COREN. IEEE Proc. Reliab., 107 (1982). Depending upon the definition of failure used, there is a learning process which provides improvement to an equipment's reliability. For failures associated with the reliability equation R = e- Jr referred to in this paper as relevant because they are random, unpredictable and critical to equipment operation, occurrences cannot be reduced during field service. However, for nonrelevant failures (all failures are either relevant or nonrelevant) a large portion are human-induced, and these indeed indicate an ongoing learning process which acts to reduce their future occurrence. This paper presents a technique for determining the learning equation and thereby, for predicting nonrelevant failure occurrences. Although not all nonrelevant failures are human-induced, the analysis isn't affected because the ratio of h u m a n to total activities (human activities and machine actions which are not affected by learning) only changes the learning curve value in the equation. T M I rare event? Lessons to be learned. WILLIAM M. BLAND, JR. IEEE Proc. Reliab., 17 (1982). There continue to be questions about the safety of nuclear fission as a source of energy for generating electrical power. Many of these questions result from the accident at Three Mile lsland in 1979. It is possible that this accident could, under some conditions be classified as a rare event. Such a classification stems from the large numbers of things that went wrong or were done wrong to permit the accident to occur and to progress as it did. Three specific hardware contributors to the accident are discussed to illustrate some problems that existed. Lessons that can be learned from the accident are discussed as changes that should be adopted by the nuclear industry and the NRC.
The practical aspects of restarting a high reliability hybrid line. BERNHARD A. BANG. IEEE Proc. Reliab., 449 (1982). The interruption of production on a hybrid manufacturing line can be a blessing in disguise. It provides a significant opportunity to review past practices, to introduce new ideas, and to improve the product. O n the other hand, the loss of production will also initiate the loss of experienced personnel and some of the process capabilities which depend so heavily on continuous production. This paper describes some of the techniques used to provide improvements in component selection, design techniques, and process controls. These are intended to turn an interruption into an asset. In addition, the training techniques are outlined which were provided to replace the lost skills. Detecting and diagnosing latent quality losses. A. K. CHAUDHURI and K. K. CHOWDHURY. QR J. (India), 139 (September 1981). Certain types of quality deficiencies are traced to factors usually lost in identification and styled as "'latent losses". The need for their identification, diagnosis and correction are explained, illustrated by case studies from an Instrument Manufacturing Company, and a machine shop, where better quality and higher earnings are obtained. Pitfalls to avoid in maintability testing. RICHARD W. BENTZ. IEEE Proc. Reliab., 278 (1982). Control of life cycle costs and avoidance of equipment performance degradation with time, have long been problems for the military. They cannot be achieved without competent and effective field maintenance. Experiences with maintainability (M) tests have revealed problems with the M and Logistics engineering process, and with the methods typically used to test for M compliance. A case history approach is used to enumerate typical M problems encountered in test, and to delineate specific deficiencies with the methods contained in MIL-STD-471A, the M D e m o Test Standard (Ref. 1). The point of view is primarily that of the military customer. Pitfalls to avoid and recommendations for corrective action are given; these have direct implications for contractors. The engineering
World Abstracts on Microetectronics and Reliability
are further analyzed as a contribution to the continuing discussion of the utility of minimal forms vis-/t-vis the p.i?s, and of the consensus method.
Moments in terms of the mean residual life function. RAMESH C. GUPTA. IEEE Trans. Reliab. R-30 (5), 450 (1981). In reliability studies, the mean additional life time, given that a component has survived until time t, is called the mean residual life function (MRLF). This M R L F determines the distribution function uniquely. In this paper a method of obtaining the m o m e n t s in terms of the M R L F , by employing a result in the context of renewal theory, is developed. The method is illustrated by an example. 2-out-of-n:F intermittently-used system. M. SAMBANDHAM. IEEE Trans. Reliab. R-30 (5), 491 (1981). The expressions for the time to the first disappointment, distribution of the time between two successive need events, mean number of disappointments, and the mean square number of disappointments have been derived for a special 2-out-of-n : F system. Model for transient and permanent error-detection and faultisolation coverage. D. C. BOSSEN and M. Y. HSIAO. I B M Jl Res. Dev. 26 (1), 67 (1982). As computer technologies advance to achieve higher performance and density, intermittent failures become more dominant than solid failures, with the result that the effectiveness of any diagnostic procedure which relies on reproducing failures is greatly reduced. This problem is solved at the system level by a new strategy of dynamic error detection and fault isolation based on error checking and analysis of captured information. The model developed in this paper allows the system designer to project the dynamic error-detection and fault-isolation coverages of the system as a function of the failure rates of components and the types and placement of error checkers, which has resulted in significant improvements to both detection and isolation in the IBM 3081 Processor Unit. The model has also resulted in new probabilistic isolation strategies based on the likelihood of failures. Our experiences with this model on several IBM products, including the 3081, show good correlation between the model and practical experiments. A model of maintenance decision errors. GORDON W. SPRAY, CHARLES J. TEPLITZ, ALAN E. HERNER and RUSSELL M. GENET. IEEE Proc. Reliab., 373 (1982). The maintenance of highly complex equipments is somztimes plagued by maintenance decision errors. This paper discusses some of the causes of these errors. A simulation model of a highly-simplified maintenance process that includes sources of decision errors is discussed. Several logical hypotheses regarding decision errors in maintenance are then suggested, and the model is used to evaluate these hypotheses.
Microwave device transient-power failure mechanisms yield to computer analysis. J. S. SMITH and N. KUSNEZOV.Microwave Syst. News 12 (3), 67 (1982). Microwave device vulnerability to power transients has been very difficult to quantify. Recent improvements in computer analysis can now be used to reveal the secrets of a power/temperature relationship that ultimately causes device destruction. An approach to high reliability for a spacecraft IRU. CARL GRUBIN, ROBERT B. IRVINE and DEAN W. TRUNNELL. IEEE Proc. Reliab., 479 (1982). This paper presents a design approach and a methodology to extend the life of an existing inertial reference unit (IRU) with a mission probability of success (Ps) of 0.990 for a one.(1 ) year mission to a Ps of 0.999 for a five (5) year mission and 0.993 for an eight (8) year mission. The o p t i m u m configuration utilizing the m i n i m u m hardware was determined by design trade studies and reliability prediction analyses.
Prediction of nonrelevant failures. GERALD COREN. IEEE Proc. Reliab., 107 (1982). Depending upon the definition of failure used, there is a learning process which provides improvement to an equipment's reliability. For failures associated with the reliability equation R = e- Jr referred to in this paper as relevant because they are random, unpredictable and critical to equipment operation, occurrences cannot be reduced during field service. However, for nonrelevant failures (all failures are either relevant or nonrelevant) a large portion are human-induced, and these indeed indicate an ongoing learning process which acts to reduce their future occurrence. This paper presents a technique for determining the learning equation and thereby, for predicting nonrelevant failure occurrences. Although not all nonrelevant failures are human-induced, the analysis isn't affected because the ratio of h u m a n to total activities (human activities and machine actions which are not affected by learning) only changes the learning curve value in the equation. T M I rare event? Lessons to be learned. WILLIAM M. BLAND, JR. IEEE Proc. Reliab., 17 (1982). There continue to be questions about the safety of nuclear fission as a source of energy for generating electrical power. Many of these questions result from the accident at Three Mile lsland in 1979. It is possible that this accident could, under some conditions be classified as a rare event. Such a classification stems from the large numbers of things that went wrong or were done wrong to permit the accident to occur and to progress as it did. Three specific hardware contributors to the accident are discussed to illustrate some problems that existed. Lessons that can be learned from the accident are discussed as changes that should be adopted by the nuclear industry and the NRC.
The practical aspects of restarting a high reliability hybrid line. BERNHARD A. BANG. IEEE Proc. Reliab., 449 (1982). The interruption of production on a hybrid manufacturing line can be a blessing in disguise. It provides a significant opportunity to review past practices, to introduce new ideas, and to improve the product. O n the other hand, the loss of production will also initiate the loss of experienced personnel and some of the process capabilities which depend so heavily on continuous production. This paper describes some of the techniques used to provide improvements in component selection, design techniques, and process controls. These are intended to turn an interruption into an asset. In addition, the training techniques are outlined which were provided to replace the lost skills. Detecting and diagnosing latent quality losses. A. K. CHAUDHURI and K. K. CHOWDHURY. QR J. (India), 139 (September 1981). Certain types of quality deficiencies are traced to factors usually lost in identification and styled as "'latent losses". The need for their identification, diagnosis and correction are explained, illustrated by case studies from an Instrument Manufacturing Company, and a machine shop, where better quality and higher earnings are obtained. Pitfalls to avoid in maintability testing. RICHARD W. BENTZ. IEEE Proc. Reliab., 278 (1982). Control of life cycle costs and avoidance of equipment performance degradation with time, have long been problems for the military. They cannot be achieved without competent and effective field maintenance. Experiences with maintainability (M) tests have revealed problems with the M and Logistics engineering process, and with the methods typically used to test for M compliance. A case history approach is used to enumerate typical M problems encountered in test, and to delineate specific deficiencies with the methods contained in MIL-STD-471A, the M D e m o Test Standard (Ref. 1). The point of view is primarily that of the military customer. Pitfalls to avoid and recommendations for corrective action are given; these have direct implications for contractors. The engineering