A two failure modes system with cold stand-by units

World Abstracts on Microelectronics and Reliability law. Finally, the MTBF expression has been obtained for a particular case with r parallel repair facilities for the failed units. In the end, variations in m and r have been allowed and results tabulated for a particular system. Stochastic behaviour of a I-server 2-unit hot standby system. PARVATHAM VENKATACHALAM. Microelectron. Reliab. 17, 603 (1978). This paper deals with the availability and reliability analysis of a single-server two-unit hot standby system subject to preventive maintenance and repair. The time to failure, the times for repair and preventive maintenance of a unit are all assumed to be arbitrarily distributed. The operating unit is taken up for preventive maintenance only when the other unit is available for operation. The analysis is carried out by identifying suitable imbedded regenerative stochastic processes. Electronic troubleshooter. CHARLES HENDERSON. Telecommunications p. 102 (September 1978). An electronic troubleshooter called NETCON-5 may soon be scanning modems at General Telephone Company of the Northwest, Inc. (GTNW). The device would identify malfunctioning portions of the teleprocessing network associated with a mechanized service-order entry system and provide accurate reporting and on-line restoration procedures. A new method for reliability optimization. KRISHNA GOPAL, K. K. AGGARWAL and J. S. GUPTA. Microelectron. Reliab. 17, 605 (1978). A new method for optimizing reliability by use of redundancy in systems which may be complex or series, is described. The system is subject to multiple constraints which need not be linear. The redundant units are allocated to various subsystems of the system in direct proportion to the normalized partial derivative of the system reliability with respect to component reliability of the subsystem. This solution is converted into integer solution by rounding to the nearest integer and an optimal allocation is then obtained by modifying the above integer solution. The method is computationally simple, fast and does not use complicated mathematics. Examples have been included to illustrate the method. On a two unit standby redundant system with imperfect switehover. R. SUBRAMANIAN and N. RAVICHANDRAN, Microelectron. Reliab. 17, 585 (1978). The Laplace transform of the availability of a two unit standby redundant system with imperfect switchover is obtained by identifying suitable regeneration points. The steady state behaviour is also discussed. Partitioning of modular equipment for fault isolation. THEODORE J. ~HESKIN. Microelectron. Reliab. 17, p. 597 (1978). The purpose of this research is to investigate new approaches to the cost effective design of fault isolation procedures. This effort is oriented specifically toward the design of built-in-test (BIT) diagnostic subsystems for modular military electronics equipment. The objective is to minimize the average costs associated with the repair of electronic systems. Following an equipment malfunction the BIT automatically executes diagnostic tests to isolate the group of modules which contains the faulty unit. Secondary isolation is then performed, by semi-automatic or manual means, to locate the failed unit within a group of modules identified by the BIT primary diagnostic. A basic problem which has been investigated is how to partition the equipment into near optimum groups of modules, such that the average cost of isolating the faulty unit is minimized. A new heuristic approach applied to this problem involves the use of dynamic programming to derive weights for the groups of modules, and a binary program to produce a low cost partition based on these weights.

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Intermittently used redundant system. P. K. KAPUR and K. R. KAPOOR. Microelectron. Reliab. 17, 593 (1978). This paper discusses the stochastic behaviour of a 2-unit coldstandby intermittently used system and derives the LaplaceStieltjes Transform of (i) the distribution of first disappointment time ; (ii) probability that the system is under disappointment at time t ; (iii) the expected number of occurrences of disappointment during (0, t]. We employ Markov renewal processes technique to obtain these measures. In conclusion it has been shown how our intermittently used system changes to an intermittently available system. Stochastic behaviour of a 2-unit system with l-server subject to delayed maintenance. M. N. GOPALAN and A. R. SAXENA. Microelectron. Reliab. 17, 587 (1978). This paper considers a 2-unit redundant system with arbitrary failure and repair time distributions and the repair facility is subject to preventive maintenance. The pdfs of time to preventive maintenance (i.e. the waiting time) and the time for preventive maintenance of the repair facility are arbitrary. The following characteristics of the system are discussed : (i) the availability of the system in a given interval, (ill the probability of first passage time to system failure and (iii) the mean up-time of the system in a given interval. LSl-board testing bedevils users. BRUCE LE Boss and ALBERT F. SHACKLE. Electronics p. 81 (26 October 1978). Another Battle of Cherry Hill shapes up as annual conference will attract 1,500 device vendors, OEMSs, and tester makers. Compressing test patterns to fit into LSI testers. TRENT CAVE. Electronics p. 136 (12 October 1978). By identifying repeated elements and manipulating them intelligently, technique shortens lengthy patterns needed to test complex devices. Optimum inspection-ordering policies with salvage cost. NAOTO KAIO and SHUNJI OSAKI. Microelectron. Reliab. 18, p. 253 (1978). In this paper we consider an inspection ordering policy for a single-unit system with two kinds of lead times. Introducing the cost structures including salvage cost, we derive the cost effectiveness defined by (The steady-state availability)/(The expected cost per unit time in the steady-state). We show that under certain conditions there exists a finite and unique optimum policy maximizing that cost effectiveness. We also present the numerical examples for illustration. A two failure modes system with cold stand-by units. BALBIR S. DHILLON. Microelectron. Reliab. 18, 251 (1978). This short paper presents a system with two mutually exclusive failures modes and N stand-by units. The repair is considered at one failure mode. The state probability equations are developed in Laplace transform. The design of a solid state trip system for nuclear power plants. A. I. OZKAYNAK.Microelectron. Reliab. 18, 243 (1978). In this paper, a new nuclear safety system has been devised that promises a great reduction in the unavailability of conventional systems of compatible arrangement. Four principal design approaches are combined to realize this improvement. The first is the employment of solid state devices throughout the system for achieving not only a much faster system response, but also a better reliability. The second involves the application of sequential redundancy, so that the effective system operation can be maintained by a standby unit in the event of a failure in the principal system.