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ISSN (Print) 2307-9045 - ISSN (Online) 2307-9045
• Asymptotic sampling distribution of inverse coeﬃcient of variation and its applications: revisited
• Authors: Ahmed N. Albatineh|B.M Golam Kibria|Bashar Zogheib
Abstract: Sharma and Krishna (1994) derived mathematically an appealing asymptotic confidence interval for the population signal-to-noise ratio (SNR). In this paper, an evaluation of the performance of this interval using monte carlo simulations using randomly generated data from normal, log-normal, $\chi^2$, Gamma, and Weibull distributions three of which are discussed in Sharma and Krishna (1994). Simulations revealed that its performance, as measured by coverage probability, is totally dependent on the amount of noise introduced. A proposal for using ranked set sampling (RSS) instead of simple random sampling (SRS) improved its performance. It is recommended against using this confidence interval for data from a log-normal distribution. Moreover, this interval performs poorly in all other distributions unless the SNR is around one.Keywords: Signal-to-noise ratio, coefficient of variation, sampling distribution, confidence interval, ranked set sample, simple random sample.
PubDate: 2014-01-15
Issue No: Vol. 2 (2014)

• Comparative analysis of some reliability characteristics between two dissimilar redundant systems with replacement at common cause failure
• Authors: Ibrahim Yusuf|Bashir Yusuf
Abstract: In this paper, probabilistic models for two dissimilar redundant systems with replacement at each common cause failure have been developed to analyze and compare some reliability characteristics. Two configurations are studied under the assumption that each system is replaced at the occurrence of common cause failure. Configuration I is a 3-out-of-4 cold standby system, while configuration II is 3-out-of-5 cold standby system. Explicit expressions for mean time to system failure (MTSF), steady-state availability, busy period and profit function for the three models are analyzed using Kolmogorov’s forward equations method. Comparisons are performed for specific values of system parameters. Furthermore, we compare these reliability characteristics for the two configurations and find that configuration II is more reliable and efficient than configuration I.   Keywords: Redundancy, replacement, Common cause failure.
PubDate: 2013-12-29
Issue No: Vol. 2 (2013)

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