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Petri net approach to the analysis of a structured program
World Abstracts on Microelectronics and Reliability
A Heuristic approach to the generation of tests for faults on the intermediate lines. ALl ATHAR KHAN, HARPREET SINGH and N. K. NANDA. Cornput. Electl Engng 9 (2), 81 (1982). The paper deals with the study of test generation mechanisms for faults on the intermediate lines using Boolean matrices. The proposed technique is a novel approach to the problem and also aims at deriving the results heuristically, thus saving computational effort. The technique has been illustrated by suitable examples. Bounds of age replacement time. T. NAKAGAWA and K. YASUI. Microelectron. Reliab. 22 (3), 603 (1982). An age replacement policy with a planned replacement time t o is considered. Five approximations which give upper or lower bounds of an o p t i m u m time t* and are computed more easily than t* are derived. A numerical example shows, when the failure time has a Weibull distribution, that some approximations are fairly good. Weapons systems analysis, part I: system effectiveness. Y. S. SHERIF and N. A. KHEIR. Microelectron. Reliab. 22 (3), 531 (1982). Often, a weapon system may be approved based on a particular required military capability without due consideration given to other missions which it might or might not be able to perform. This paper puts forward a methodology for the analysis of weapons systems, and examines various criteria and attributes that relate to system effectiveness. Criteria and attributes included are system performance, operational readiness, life cycle costing, design to cost, reliability, availability, maintainability, producibility, operability, capability, adequacy and logistics. Replacing destructive by non-destructive testing. ASHIM ROY CHOWDHURY and E. KRUBAKARAN. QR J. (India), 117 (September 1982). An electrical component required for a m i n i m u m of 10,000 operations had a time consuming life test at high cost. The paper discusses an alternative nondestructive test devised, with an excellent correlation and successful results. Some stress-strength reliability models. WHO KEE CHUNG. Microelectron. Reliab. 22 (2), 277 (1982). This paper presents reliability expressions for five stress-strength models of parallel systems with non-identical units. Models are developed for the following systems: (1) when system stress probability density function is exponentially distributed, (2) the stress probability density function follows g a m m a distribution, (3) system stress probability density function can be described by beta distribution, (4) stress probability density function is given by a power series, (5) and finally, when system stress probability density function follows chi-square distribution. In these models, the unit strength probability density function is exponentially distributed with constant failure rate. Microcomputer real time software reliability and fault recovery. FABRIZIO LOMBARDI.Microelectron. Reliab. 22 (4), 693 (1982). An analysis of microcomputer software reliability is formulated; it is particularly applicable to real time control systems. Program structure and error recovery techniques are presented. An example of an oven controlled by a microcomputer is given and the practical implications of the theory are outlined and discussed. Weapons systems analysis, part II: simulation techniques and models. YOSEF S. SHERIF and N. A. KHIER. Microelectron. Reliab. 22 (4), 789 (1982). The simulation techniques, languages or models best suited for a particular simulation study depend upon the characteristics of the system and the programming skill of the individual conducting the study.
995
This paper identifies, defines, evaluates and classifies a spectrum of simulation techniques that are applicable to weapons systems analysis and air defence weaponry.
Quality improvement program addressed to M.O.S. microprocessors. CHARLES L. HUTCHINS and B. J. PAICIUS. Microelectron. Reliab. 22 (2), 207 (1982). The advantages of a microprocessor application enhanced system can be classified into three broad categories: engineering system advantages, h u m a n factors advantages, and economic advantages. Each class can show an advantage over the approach of the previous generation. These advantages converge in an improvement in the realm of product quality and reliability. Reliability analysis of time-dependent cascade system with deterministic cycle times. M. N. GOPALAN and P. VENKATESWARLU.Microelectron. Reliab. 22 (4), 841 (1982). Reliability analysis of time-dependent 2-cascade and 3cascade systems is carried out using stress/strength models by considering each of the stress and strength variables as deterministic or random fixed or r a n d o m independent. The number of cycles in any period of time t is assumed to be deterministic. The components are identical in the sense that the components have exactly the same strength if the strength variable is deterministic and have independent and identical distributions if the strength variable is random. Attenuation factors, Ki's , are constants. Expressions for system reliability are obtained and reliability values are computed for specific values of N, the number of cycles, when stress and strength distributions are exponential. Petri net approach to the analysis of a structured program. G. S. HURA. Microelectron. Reliab. 22 (3), 429 (1982). The analysis problem of complexity and execution time of a structured program has been tackled using the concept of Petri net (PN). This type of representation is useful due to its graphical and precise nature of representation scheme and also the established relationship between certain net structure and dynamic behaviour of P N can be used as a tool for analysing the behaviour of the system. A P N representation of various nested blocks of the structured program is given. The firing characteristic of the transitions in a P N has been used to give an interpretation to each of the blocks and it is shown how each of the blocks can be simplified with a view to calculating the total execution time of a program. It is simple as it gives a straightforward procedure for analysing the program. Software implemented fault tolerance: a methodology. F. LOMnARD! and V. OBAC RODA. Microelectron. Reliab. 22 (4), 873 (1982). A methodology for fault tolerance is proposed. This is based on the interactions between hardware and software in a scheme made of intelligent modules. This is particularly applicable to VLSI systems. Particular emphasis has been posed on the software implementation to reduce the external hardware, as this is the main source of hard core failures. A design of a duplex hybrid system with software implemented fault tolerance is presented to evidentiate the novel characteristics of this approach. A semi-regenerative process of two-unit warm standby system. KOHYU UEMATSU and MASASHI KOWADA. Microelectron. Reliab. 22 (3), 483 (1982). This paper deals with two identical units warm standby system; a failure of operating unit can be detected at any time but a failure of standby unit can not be done until a system is inspected. We are able to look upon the stochastic behaviour of our model as that of semiregenerative process. The pointwise unavailability and the steady state unavailability of the system are derived by using the limit theorem of semi-regenerative process. Further, we shall discuss the optimum inspection period minimizing the steady state unavailability. A numerical example is presented.
A Heuristic approach to the generation of tests for faults on the intermediate lines. ALl ATHAR KHAN, HARPREET SINGH and N. K. NANDA. Cornput. Electl Engng 9 (2), 81 (1982). The paper deals with the study of test generation mechanisms for faults on the intermediate lines using Boolean matrices. The proposed technique is a novel approach to the problem and also aims at deriving the results heuristically, thus saving computational effort. The technique has been illustrated by suitable examples. Bounds of age replacement time. T. NAKAGAWA and K. YASUI. Microelectron. Reliab. 22 (3), 603 (1982). An age replacement policy with a planned replacement time t o is considered. Five approximations which give upper or lower bounds of an o p t i m u m time t* and are computed more easily than t* are derived. A numerical example shows, when the failure time has a Weibull distribution, that some approximations are fairly good. Weapons systems analysis, part I: system effectiveness. Y. S. SHERIF and N. A. KHEIR. Microelectron. Reliab. 22 (3), 531 (1982). Often, a weapon system may be approved based on a particular required military capability without due consideration given to other missions which it might or might not be able to perform. This paper puts forward a methodology for the analysis of weapons systems, and examines various criteria and attributes that relate to system effectiveness. Criteria and attributes included are system performance, operational readiness, life cycle costing, design to cost, reliability, availability, maintainability, producibility, operability, capability, adequacy and logistics. Replacing destructive by non-destructive testing. ASHIM ROY CHOWDHURY and E. KRUBAKARAN. QR J. (India), 117 (September 1982). An electrical component required for a m i n i m u m of 10,000 operations had a time consuming life test at high cost. The paper discusses an alternative nondestructive test devised, with an excellent correlation and successful results. Some stress-strength reliability models. WHO KEE CHUNG. Microelectron. Reliab. 22 (2), 277 (1982). This paper presents reliability expressions for five stress-strength models of parallel systems with non-identical units. Models are developed for the following systems: (1) when system stress probability density function is exponentially distributed, (2) the stress probability density function follows g a m m a distribution, (3) system stress probability density function can be described by beta distribution, (4) stress probability density function is given by a power series, (5) and finally, when system stress probability density function follows chi-square distribution. In these models, the unit strength probability density function is exponentially distributed with constant failure rate. Microcomputer real time software reliability and fault recovery. FABRIZIO LOMBARDI.Microelectron. Reliab. 22 (4), 693 (1982). An analysis of microcomputer software reliability is formulated; it is particularly applicable to real time control systems. Program structure and error recovery techniques are presented. An example of an oven controlled by a microcomputer is given and the practical implications of the theory are outlined and discussed. Weapons systems analysis, part II: simulation techniques and models. YOSEF S. SHERIF and N. A. KHIER. Microelectron. Reliab. 22 (4), 789 (1982). The simulation techniques, languages or models best suited for a particular simulation study depend upon the characteristics of the system and the programming skill of the individual conducting the study.
995
This paper identifies, defines, evaluates and classifies a spectrum of simulation techniques that are applicable to weapons systems analysis and air defence weaponry.
Quality improvement program addressed to M.O.S. microprocessors. CHARLES L. HUTCHINS and B. J. PAICIUS. Microelectron. Reliab. 22 (2), 207 (1982). The advantages of a microprocessor application enhanced system can be classified into three broad categories: engineering system advantages, h u m a n factors advantages, and economic advantages. Each class can show an advantage over the approach of the previous generation. These advantages converge in an improvement in the realm of product quality and reliability. Reliability analysis of time-dependent cascade system with deterministic cycle times. M. N. GOPALAN and P. VENKATESWARLU.Microelectron. Reliab. 22 (4), 841 (1982). Reliability analysis of time-dependent 2-cascade and 3cascade systems is carried out using stress/strength models by considering each of the stress and strength variables as deterministic or random fixed or r a n d o m independent. The number of cycles in any period of time t is assumed to be deterministic. The components are identical in the sense that the components have exactly the same strength if the strength variable is deterministic and have independent and identical distributions if the strength variable is random. Attenuation factors, Ki's , are constants. Expressions for system reliability are obtained and reliability values are computed for specific values of N, the number of cycles, when stress and strength distributions are exponential. Petri net approach to the analysis of a structured program. G. S. HURA. Microelectron. Reliab. 22 (3), 429 (1982). The analysis problem of complexity and execution time of a structured program has been tackled using the concept of Petri net (PN). This type of representation is useful due to its graphical and precise nature of representation scheme and also the established relationship between certain net structure and dynamic behaviour of P N can be used as a tool for analysing the behaviour of the system. A P N representation of various nested blocks of the structured program is given. The firing characteristic of the transitions in a P N has been used to give an interpretation to each of the blocks and it is shown how each of the blocks can be simplified with a view to calculating the total execution time of a program. It is simple as it gives a straightforward procedure for analysing the program. Software implemented fault tolerance: a methodology. F. LOMnARD! and V. OBAC RODA. Microelectron. Reliab. 22 (4), 873 (1982). A methodology for fault tolerance is proposed. This is based on the interactions between hardware and software in a scheme made of intelligent modules. This is particularly applicable to VLSI systems. Particular emphasis has been posed on the software implementation to reduce the external hardware, as this is the main source of hard core failures. A design of a duplex hybrid system with software implemented fault tolerance is presented to evidentiate the novel characteristics of this approach. A semi-regenerative process of two-unit warm standby system. KOHYU UEMATSU and MASASHI KOWADA. Microelectron. Reliab. 22 (3), 483 (1982). This paper deals with two identical units warm standby system; a failure of operating unit can be detected at any time but a failure of standby unit can not be done until a system is inspected. We are able to look upon the stochastic behaviour of our model as that of semiregenerative process. The pointwise unavailability and the steady state unavailability of the system are derived by using the limit theorem of semi-regenerative process. Further, we shall discuss the optimum inspection period minimizing the steady state unavailability. A numerical example is presented.