- Email: [email protected]
Simulation models: Analysis and research tools
406
World Abstracts on Microelectronics and Reliability
the basic dissimilarities between repairable and nonrepairable system reliability concepts. The methods of statistical analysis and interpretation appropriate to repairable systems reliability data are highly emphasized. These methods are applied to most of the repairable system data sets which exist in the literature (to the best of the authors' knowledgeJ. It is shown that appropriate analyses of these data sets often result in drastically different conclusions than those originally obtained. Conclusions are drawn concerning future work in this area.
Timeseriesanalysis offailuredata. NOZER D. SINGPURWALLA. Proc. IEEE A, Reliab. Maintainab. Syrup., Los Angeles, 17-19 January 1978, p. 107. In this paper we present a powerful method for the analysis of "'messy" failure data which has been obtained from the field. Our method construes the observed failure data as a time series, and uses appropriate methods for its analysis. Using this approach, we can also analyze "reliability growth" data, as well as the interactions between failure times and maintenance times of complex systems. We illustrate our approach by considering three realistic case studies. A workable software quality/reliability plan. ROBERT H. DUNN and RICHARD S. ULLMAN. Proc. IEEE .4. Reliab. Maintainab. Syrup., Los Angeles, 17-19 January 1978, p. 210. The twin problems of the reliability and maintainability of embedded software are viewed as susceptible to solution by the disciplines of built-in quality assurance. Several facets to such an approach are presented. Emphasis is placed on the use of appropriate techniques and tools, with audits seen as the principal device for assuring a well-planned and orderly executed development cycle. The thrust of the paper is toward prgamatic solutions. Thus, the array of techniques and tools described is restricted to those that are readily available and have previously met with Success in the development of embedded software.
Test methods for steady state availability. CHARLESA. PELL, ROGER C. HALL and R. C. SCHNEIDER, Proc. IEEE A. Reliab. Maintainab. Syrup., Los Angeles, 17-19 January 1978, p. 167. Steady state availability, that proportion of time a system is in an "up" or operationally ready state, is a concern to those dealing with the effectiveness of systems which must operate over indefinitely long periods of time. Test methods, both fixed sample and sequential, are developed for direct demonstration of availability along with procedures for determining confidence bounds from existing test data. In addition, methods for determining test durations in the form of the requisite number of failure/restore cycles are given.
Achieving reliable consumer products through total program management of new models. JACK Q. REYNOLDS. Proc. IEEE A. Reliab, Maintainab. Syrup, Los Angeles, 17-19 January 1978, p. 22. The expectation of increased reliability of consumer products continues to grow in the minds of distributors, dealers and consumers. So compelling is this expectation, that it is becoming a major aspect of competition which may affect the survival of a company in the industry. The fact that the manufacturer must annually create many new models and design changes in order to be competitive, complicates the job. Gains have been made in the immediate past through application of better reliability techniques. Now, the system of total program management for the development of new and modified consumer products must be exploited to better integrate marketing, design, manufacturing and financial plans with the reliability program. This paper is intended to motivate the reliability professional to re-examine his company's operating methods, to urge incorporation of a program management system if it has none, or to refine the system it already has to assure
a full integration of reliability programs into the new products program plan.
Analysis of truncated SPRT: Exponential case. AMRIT L. GOEL and JEROMEKLION. Proc. IEEE A. Reliab. Maintainab. Syrup., Los Angeles, 17-19 January 1978, p. 312. This paper discusses the application of a new procedure for the design and study of truncated sequential probability ratio tests for reliability testing when the underlying distribution is exponential. Effects of changes in the truncation point, the truncation region, and the decision boundaries on the risks and the expected test time are investigated for some selected test plans from MIL-STD-781B.
Simulation models: Analysis and research tools. DONALD INGERMAN. Proc. IEEE ,4. Reliab. Maintainab. Syrup., Los Angeles, 17-19 January 1978, p. t84. The application of computer simulation techniques to problems in reliability, maintainability, availability, and logistics support is presented in this paper. Emphasis is placed on adaptability-the usefulness of the model in investigating problems other than the one for which it was developed. Case histories of the application of simulation to a variety of problems are also provided.
Mechanical reliability for low cycle fatigue. RONALD G. LAMBERT. Proc. IEEE ,4. Reliab. Maintainab. Syrup., Los Angeles, 17-19 January 1978, p. 179. Closed form analytical solutions have been derived to describe quantitatively several areas of interest regarding mechanical reliability under low cycle (plastic stress-strain) fatigue. The probability density function of cycles to failure, the failure rate, the hazard rate, the probability of failing in N cycles and cycles to first failure are expressed in terms of applied strain amplitude and the average and standard deviation of ductility for the material being strained. Examples are given for multilayer board plated-through holes and solder joints during thermal cycling. Experimental and analytical results show good agreement.
Reliability specifications rethinking Mission Profile Testing. HOWARD C. SCHAFER. Proc. IEEE A. Reliab. Maintainab. Syrup., Los Angeles, 17-19 January 1978, p. 222. The whole subject of "'Mission Profile Testing" has, to some extent, been approached by emotion instead of by reason. This paper attempts to set forth a logic that may assist in helping the reader to a more straightforward approach to this subject.
Operational influences on maintainability. LAWRENCE J. PHALLER. Proc. IEEE .4. Reliab. Maintainab. Syrup., Los Angeles, 17-19 January 1978, p. 218. Historical data collected by both D O D and its equipment suppliers on ground-based electronic equipment has shown that a large disparity exists between predicted and field-recorded maintenance times. Equipment procurement agencies impose many requirements and program controls on their suppliers in the form of contractually specified MTTR's, which are to be proven through detailed analyses and formal demonstrations; however, how many maintainability demonstration tests have you known a supplier to fail'?. Thus, there must be certain influences that cause this disparity between the predicted and field maintenance times. In a study conducted by Westinghouse on four ground electronic equipments, it was determined that there are two general categories of influences: those attributed to the manufacturer, and those attributable to the operational environment. The mathematical ranges for these relationships were determined to be as follows : (0.67) (predicted MTTR) < Zl < (1.87) Ipredicted MTTR}
World Abstracts on Microelectronics and Reliability
the basic dissimilarities between repairable and nonrepairable system reliability concepts. The methods of statistical analysis and interpretation appropriate to repairable systems reliability data are highly emphasized. These methods are applied to most of the repairable system data sets which exist in the literature (to the best of the authors' knowledgeJ. It is shown that appropriate analyses of these data sets often result in drastically different conclusions than those originally obtained. Conclusions are drawn concerning future work in this area.
Timeseriesanalysis offailuredata. NOZER D. SINGPURWALLA. Proc. IEEE A, Reliab. Maintainab. Syrup., Los Angeles, 17-19 January 1978, p. 107. In this paper we present a powerful method for the analysis of "'messy" failure data which has been obtained from the field. Our method construes the observed failure data as a time series, and uses appropriate methods for its analysis. Using this approach, we can also analyze "reliability growth" data, as well as the interactions between failure times and maintenance times of complex systems. We illustrate our approach by considering three realistic case studies. A workable software quality/reliability plan. ROBERT H. DUNN and RICHARD S. ULLMAN. Proc. IEEE .4. Reliab. Maintainab. Syrup., Los Angeles, 17-19 January 1978, p. 210. The twin problems of the reliability and maintainability of embedded software are viewed as susceptible to solution by the disciplines of built-in quality assurance. Several facets to such an approach are presented. Emphasis is placed on the use of appropriate techniques and tools, with audits seen as the principal device for assuring a well-planned and orderly executed development cycle. The thrust of the paper is toward prgamatic solutions. Thus, the array of techniques and tools described is restricted to those that are readily available and have previously met with Success in the development of embedded software.
Test methods for steady state availability. CHARLESA. PELL, ROGER C. HALL and R. C. SCHNEIDER, Proc. IEEE A. Reliab. Maintainab. Syrup., Los Angeles, 17-19 January 1978, p. 167. Steady state availability, that proportion of time a system is in an "up" or operationally ready state, is a concern to those dealing with the effectiveness of systems which must operate over indefinitely long periods of time. Test methods, both fixed sample and sequential, are developed for direct demonstration of availability along with procedures for determining confidence bounds from existing test data. In addition, methods for determining test durations in the form of the requisite number of failure/restore cycles are given.
Achieving reliable consumer products through total program management of new models. JACK Q. REYNOLDS. Proc. IEEE A. Reliab, Maintainab. Syrup, Los Angeles, 17-19 January 1978, p. 22. The expectation of increased reliability of consumer products continues to grow in the minds of distributors, dealers and consumers. So compelling is this expectation, that it is becoming a major aspect of competition which may affect the survival of a company in the industry. The fact that the manufacturer must annually create many new models and design changes in order to be competitive, complicates the job. Gains have been made in the immediate past through application of better reliability techniques. Now, the system of total program management for the development of new and modified consumer products must be exploited to better integrate marketing, design, manufacturing and financial plans with the reliability program. This paper is intended to motivate the reliability professional to re-examine his company's operating methods, to urge incorporation of a program management system if it has none, or to refine the system it already has to assure
a full integration of reliability programs into the new products program plan.
Analysis of truncated SPRT: Exponential case. AMRIT L. GOEL and JEROMEKLION. Proc. IEEE A. Reliab. Maintainab. Syrup., Los Angeles, 17-19 January 1978, p. 312. This paper discusses the application of a new procedure for the design and study of truncated sequential probability ratio tests for reliability testing when the underlying distribution is exponential. Effects of changes in the truncation point, the truncation region, and the decision boundaries on the risks and the expected test time are investigated for some selected test plans from MIL-STD-781B.
Simulation models: Analysis and research tools. DONALD INGERMAN. Proc. IEEE ,4. Reliab. Maintainab. Syrup., Los Angeles, 17-19 January 1978, p. t84. The application of computer simulation techniques to problems in reliability, maintainability, availability, and logistics support is presented in this paper. Emphasis is placed on adaptability-the usefulness of the model in investigating problems other than the one for which it was developed. Case histories of the application of simulation to a variety of problems are also provided.
Mechanical reliability for low cycle fatigue. RONALD G. LAMBERT. Proc. IEEE ,4. Reliab. Maintainab. Syrup., Los Angeles, 17-19 January 1978, p. 179. Closed form analytical solutions have been derived to describe quantitatively several areas of interest regarding mechanical reliability under low cycle (plastic stress-strain) fatigue. The probability density function of cycles to failure, the failure rate, the hazard rate, the probability of failing in N cycles and cycles to first failure are expressed in terms of applied strain amplitude and the average and standard deviation of ductility for the material being strained. Examples are given for multilayer board plated-through holes and solder joints during thermal cycling. Experimental and analytical results show good agreement.
Reliability specifications rethinking Mission Profile Testing. HOWARD C. SCHAFER. Proc. IEEE A. Reliab. Maintainab. Syrup., Los Angeles, 17-19 January 1978, p. 222. The whole subject of "'Mission Profile Testing" has, to some extent, been approached by emotion instead of by reason. This paper attempts to set forth a logic that may assist in helping the reader to a more straightforward approach to this subject.
Operational influences on maintainability. LAWRENCE J. PHALLER. Proc. IEEE .4. Reliab. Maintainab. Syrup., Los Angeles, 17-19 January 1978, p. 218. Historical data collected by both D O D and its equipment suppliers on ground-based electronic equipment has shown that a large disparity exists between predicted and field-recorded maintenance times. Equipment procurement agencies impose many requirements and program controls on their suppliers in the form of contractually specified MTTR's, which are to be proven through detailed analyses and formal demonstrations; however, how many maintainability demonstration tests have you known a supplier to fail'?. Thus, there must be certain influences that cause this disparity between the predicted and field maintenance times. In a study conducted by Westinghouse on four ground electronic equipments, it was determined that there are two general categories of influences: those attributed to the manufacturer, and those attributable to the operational environment. The mathematical ranges for these relationships were determined to be as follows : (0.67) (predicted MTTR) < Zl < (1.87) Ipredicted MTTR}