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Complex system reliability with general repair time distributions under head-of-line-repair-discipline
World Abstracts on Microelectronics and Reliability A new method lot system reliability evaluation. K. K. AG~IARWAL,J. S. GUPTA and K. B. MISRA. Microelectron. & Reliub. 12, 435 (1973). A method is presented for computing system reliability in terms of the reliabilities of constituent elements. The method is applicable to both series parallel as well as non-series-parallel systems of any complexity, A technique of finding out all transmission paths of a general network is provided, which leads to the network reliability expression. A minimization technique is introduced to simplify this expression, which will have a lesser number of terms than obtained by any existing method. The reduced expression helps a design engineer to evaluate the system reliability speedily. The reliability of coherent structures--a parametric approach. L. A. CUNNINfJHAM. Microelectron. & Reliab. 12, 441 (1973). In a paper by the same author with Singh, the reliability of complex coherent structures consisting of systems within systems was considered. This paper re-examines these systems with the aim of obtaining system reliability by parametric means. Complex system reliability with general repair time distributions under head-of-line-repair-discipline. P. P. GUPTA. Microelectron. & Reliah. 12, 445 (1973). The behaviour of a complex system having "'N'" components in series, say class Lj and M identical components in parallel redundancy say class L 2, has been investigated. It has been assumed that the repair of the failed components in the classes L~ and L 2 is carried out under the "Head-of-Line-Repair-Discipline". Laplace Transforms of various state probabilities, viz. the system is in normal efficiency, operable state, reduced efficiency and in down state, have been obtained. In the end, asymptotic behaviour of the complex system, has also been examined. Insuring the reliability of heavy-current electrical equipment. V. L. Cto~u. IEEE Trans. Reliab. 272 (Dec. 1973). Some particular methods must be used in the investigation and insurance of the reliability of the complex small-production systems: like in the heavy-current electrical industry of Romania, which is more and more diversified. Theoretically, the scarcity of data leads to erroneous predictions of wearout, or to very large confidence intervals. Therefore, the use of statistical techniques in these situations is limited. The author presents his experience in utilizing both the physics of failure approach (analytical method); and the laboratory/field tests {experimental method), on both the systems and parts. Models of appropriate inquiry-sheets for the analysis of electric machines running performances, used by the author are presented; and some Romanian equipment is exemplified. The original organization of the
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reliability activity in a modern Romanian electric plant is graphically illustrated, A new method to determine the failure frequency of a complex system. C. SINGH and R. BILLINTON. Microelectron. & Reliab. 12, 459 (1973). Two key indices in system reliability evaluation are the probability and frequency of failure. Other measures such as, the mean cycle time and the mean down time can be easily derived from these quantities. This paper deals with the reliability evaluation of a complex maintainable system using a cut set approach. The available literature on this subject generally gives thc probabilities of failure. Buzacott has given a method to determine the frequency of failure but his method has the drawback that explicit formulae for system availability must be derived and numerical values are then obtained by further manipulation, This approach is, therefore, not suitable for computer application. The contribution of this paper is in developing a new formula for the failure frequency using cut set approach, wherein the numerical values can be directly obtained. This method therefore overcomes the drawback of Buzacott's method and is suitable for computer application. An upper bound approximation for frequency is also given and the method is illustrated by an example. Reliability optimization with integer constraint coefficients. K. B. MISRA and J. SHARMA. Microelectron. & Reliab. 12, 431 {1973). This paper describes a method of reliability optimization of a system subject to multiple constraints with integer coefficients. The coefficients are generally integers; in case they are not, they can be converted into integer form by simple manipulation. The reliability problem with many constraints is transformed to an equivalent problem, having a single constraint. This equivalent problem can easily be solved by any standard procedure. An illustration is provided. Improvement in adjustment failures of crossbar switches. J. WATANABE and T. KASAHARA. Abstracts Trans. Inst. Electron. Commun. Engers Jap. 56, 8 (Nov. 1973). In Japan crossbar automatic switching systems for the purpose of public service are manufactured according to the specifications of the Nippon Telegraph and Telephone Public Corporation ( N . T . T . P . C + The number of failures of crossbar switches manufactured in 1966 was 0.4 per 100 switches in the tests during installation period. As the result of analysis for the defects at manufacturing stage and the failures at installation stage or at initial operation stage, in each stage the defects due to poor finger adjustment were more than 73 per cent. And when the cause of the failures was investigated, we found that the adjustment value varied, especially dislocation of finger point, due to frames being moved during manufacturing stage and installation stage.
4. MICROELECTRONICS--GENERAL Microelectronics: a new dimension of electronics. F. lWlLLIPPAZZI. Alta Frequenza XLII (9) 402 (1973). (In Italian). This article focuses the general aspects of the impact of microelectronics on systems design. Microelectronics is much more than an evolution of technology: it is a conceptual change deeply affecting the way systems are designed, and impacting on both individuals and organizations. Microelectronics opens new possibilities to designers ingenuity and makes feasible once unimaginable applications. Therefore, microelectronics is really a new dimension of electronics.
A bibliography on semiconductor wafer preparation. A. H. AGAJANIAN. Solid St. Technol. 73 (Dec. 1973). l'his bibliography of 220 references relating to semiconductor wafer preparation was compiled from a literature search of the abstracts that appeared in Electric. Electron. Abstr. from Jan. 1967 to Nov. 1972. For easy access to the needed references the bibliography has been divided into ten sections.
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reliability activity in a modern Romanian electric plant is graphically illustrated, A new method to determine the failure frequency of a complex system. C. SINGH and R. BILLINTON. Microelectron. & Reliab. 12, 459 (1973). Two key indices in system reliability evaluation are the probability and frequency of failure. Other measures such as, the mean cycle time and the mean down time can be easily derived from these quantities. This paper deals with the reliability evaluation of a complex maintainable system using a cut set approach. The available literature on this subject generally gives thc probabilities of failure. Buzacott has given a method to determine the frequency of failure but his method has the drawback that explicit formulae for system availability must be derived and numerical values are then obtained by further manipulation, This approach is, therefore, not suitable for computer application. The contribution of this paper is in developing a new formula for the failure frequency using cut set approach, wherein the numerical values can be directly obtained. This method therefore overcomes the drawback of Buzacott's method and is suitable for computer application. An upper bound approximation for frequency is also given and the method is illustrated by an example. Reliability optimization with integer constraint coefficients. K. B. MISRA and J. SHARMA. Microelectron. & Reliab. 12, 431 {1973). This paper describes a method of reliability optimization of a system subject to multiple constraints with integer coefficients. The coefficients are generally integers; in case they are not, they can be converted into integer form by simple manipulation. The reliability problem with many constraints is transformed to an equivalent problem, having a single constraint. This equivalent problem can easily be solved by any standard procedure. An illustration is provided. Improvement in adjustment failures of crossbar switches. J. WATANABE and T. KASAHARA. Abstracts Trans. Inst. Electron. Commun. Engers Jap. 56, 8 (Nov. 1973). In Japan crossbar automatic switching systems for the purpose of public service are manufactured according to the specifications of the Nippon Telegraph and Telephone Public Corporation ( N . T . T . P . C + The number of failures of crossbar switches manufactured in 1966 was 0.4 per 100 switches in the tests during installation period. As the result of analysis for the defects at manufacturing stage and the failures at installation stage or at initial operation stage, in each stage the defects due to poor finger adjustment were more than 73 per cent. And when the cause of the failures was investigated, we found that the adjustment value varied, especially dislocation of finger point, due to frames being moved during manufacturing stage and installation stage.
4. MICROELECTRONICS--GENERAL Microelectronics: a new dimension of electronics. F. lWlLLIPPAZZI. Alta Frequenza XLII (9) 402 (1973). (In Italian). This article focuses the general aspects of the impact of microelectronics on systems design. Microelectronics is much more than an evolution of technology: it is a conceptual change deeply affecting the way systems are designed, and impacting on both individuals and organizations. Microelectronics opens new possibilities to designers ingenuity and makes feasible once unimaginable applications. Therefore, microelectronics is really a new dimension of electronics.
A bibliography on semiconductor wafer preparation. A. H. AGAJANIAN. Solid St. Technol. 73 (Dec. 1973). l'his bibliography of 220 references relating to semiconductor wafer preparation was compiled from a literature search of the abstracts that appeared in Electric. Electron. Abstr. from Jan. 1967 to Nov. 1972. For easy access to the needed references the bibliography has been divided into ten sections.