Topological optimization of distributed computer networks subject to reliability constraints

Topological optimization of distributed computer networks subject to reliability constraints

1166 World Abstracts on Microelectronics and Reliability Reliab. Maintainab. Syrup. 82 (1985). The architecture of an expert system for the interact...

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1166

World Abstracts on Microelectronics and Reliability

Reliab. Maintainab. Syrup. 82 (1985). The architecture of an expert system for the interactive data-driven construction of fault trees is presented. Parts of the system are now under realization and testing. The system intends to offer a flexible and easy-to-operate tool to the analyst in reliability assessment of complex engineered installations. The expert system is organized according to a number of knowledgebased modules that contain metarules, allow the establishment of rules, and to collect and interpret data. The construction process bases upon a representation of the elementary components given a terms of multiple-valued logical (MVL) trees and results into an MVL-tree. This tree can be analyzed directly or when requested it can be reduced to a number of binary fault trees.

Independence bounds and approximations for system availability computations. MARTIN L. SHOOMAN. Proc. A. Reliab. Maintainab. Syrup. 115 (1985). This paper discusses various simplified bounds and approximations which can be used to simplify the computation of system availability via Markov model analysis. This is especially important when the system contains many states due to: (a) a large number of elements, (b) the extra states needed to model built-in-test, (c) the extra states needed to model hardware/software interactions. These simplified formulas can also be used to check the results of a computer simulation which is the conventional way of performing such complex computations. Analysis of a two unit standby system with partial failure and two types of repairs. L. R. GOEL, ASHOK KUMAR and A. K. RASTOGI. Microeleetron. Reliab. 24, 873 (1984). A two dissimilar unit standby system is analysed. The priority unit can either be in normal or partial operative mode. When the unit fails from the partial mode, it undergoes minor repair and the unit becomes operative with different failure rate. If this unit fails again, it goes to major repair after which it works as good as new. The standby unit while in use is either operative or failed. This non priority unit fails without passing through the partial failure mode and undergoes only one type of repair with different repair time distribution. Failure and repair time distributions are negative exponential and general respectively.Regenerative technique in M R P is applied to obtain several reliability characteristics of interest to system designers. Analysis of a k-out-of-n unit system with two types of failure and preventive maintenance. L. R. GOEL and PRAVEENGUPTA. Microeleetron. Reliab. 24, 877 (1984). A k-out-of-n unit system is analysed with two types of failure: (1) failure due to change in operating characteristics and (2) catastrophic failure. Preventive maintenance of the system is allowed at random epochs. All transition rates are taken to be general. Several measures of reliability useful for system designers and operations managers have been obtained by using regenerative point technique with Markov renewal process. Some important results obtained earlier are shown as particular cases. Performance-related dependability evaluation of supercomputer systems. J. ARLAT and J. C. LAPRIE. Microelectron. Reliab. 24, 717 (1984). The paper presents an example of performance-related dependability evaluation of a supercomputer structure corresponding to an M I M D multiprocessor system intended for high speed scientific computation. The approach presented addresses the problems of deriving a model that is tractable yet representative of the behaviour of a complex system. This is achieved by means of an intensive validation study, and through the evaluation of measures of interest which account for the specific operating requirements characterizing the system under investigation: (a) maintain very high throughput over a long period of time, and (b) provide an efficient operational life-cycle.

Topological optimization of distributed computer networks subject to reliability constraints. ANTONI ZABLUDOWSKIand ANDRZEJ SOBOLSKLMicroelectron. Reliab. 24, 1023 (1984). A method of topological optimization of the networks with minimum cost subject to reliability constraints is given in this paper. The proposed optimization algorithm is based on branch and bound method. The computational results of this algorithm are discussed. On power line carrier communication (PLC). YOSEFS. SHERIF and S. S. ZAmR. Microelectron. Reliab. 24, 781 (1984). Power line carrier communication (PLC) provides significant services for the electric utilities in particular and to the industrial and consumer sectors in general. Since its inception in the early 1920's, PLC has been used for voice communication, protective relaying telemetry and supervisory control. Lately PLC has proved to render the most efficient means for distribution automation and load management. This paper is a review of literature related to PLC and its applications.

Minimizing the cost of automated board testing. JANET PAGE WALTON. Electron. Prod. 39 (September 1984). While it is simplistic to believe that the total cost of Automatic Testing can be reduced by purchasing low cost equipment, only a limited number of companies can afford the high capital cost of sophisticated ATE. On multistate coherent systems. FUMIO OH1 and TOSHIO NISHIDA. IEEE Trans. Reliab. R-33, 284 (1984). Recently, several authors have treated multistate systems and given some results. This paper summarizes the several concepts of s-coherency and shows the relationships between them. An intresting theorem for the existence of series and parallel coherent systems is presented. We have proved IFRA and NBU closure theorems under more general situation than have E1-Neweihi et al. and Ross. We discuss our IFR closure theorem.

Stochastic behaviour of a maintained system with protection system. ASHOK KUMAR,VIPIN B. KAPOORand A. K. RASTOGI. Microelectron. Reliab. 24, 869 (1984). This paper deals with the analysis of a single unit system backed by a protection system (P.S.). Both are subject to failure with exponential failure time distribution. Repair time of working unit, fault detection and inspection time of protection system are assumed to follow general distribution. The system has been investigated in detail by the help of semi-Markov process and several parameters of interest are obtained. Optimum preventive maintenance policies for a computersystem with restart. TOSHIO NAKAGAWA,KENJIRO NISHI and KAZUM1 YASUI. IEEE Trans. Reliab. R-33, 272 (1984). This paper considers a computer system where an operation is restarted when the system stops on some faults. The restart does not succeed every time. Three preventive maintenance (pm) models are considered: (A) The pm is made at the scheduled time T. (B) The pm is made at the K-th successful restart. (C) The pm is made at the next scheduled time if the total number of successes of restart exceeds K. The availabilities of each model are obtained and the optimum pm policies are discussed. Cost analysis of a two-unit standby system with two types of repairmen. VIBHA GOYAL and K. MURARI. Microelectron. Reliab. 24, 849 (1984). This paper is concerned with a twounit cold standby system with two types of repairmen. One "regular" repairman is kept for repairing the units as soon as they fail. It is assumed that sometimes he might not be able to do the repairs within some tolerable time (patience time). Another "expert" repairman, assumed to be perfect, is called on to do the repairs on the completion of this patience time or on the failure of the system, whichever is later.