Reliability graph with general gates (RGGG): A novel method for reliability analysis

SEONG Poong-Hyun^{1, 2}, and SHIN Seung-Ki¹

1. Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon, Republic of Korea, 305-701 (phseong@kaist.ac.kr, kankani@kaist.ac.kr)

2. Department of Nuclear Engineering, Khalifa University of Science, Technology & Research, P.O. Box 127788, Abu Dhabi, UAE

Abstract: There are several methods for system reliability analysis such as reliability graphs, fault tree analyses, Markov chains, and Monte Carlo simulations. Among the existing methods, the reliability graphs are the most intuitive modeling method, but they are not widely used due to their limited expression power. In this paper, an intuitive and practical method for system reliability analysis named the reliability graph with general gates (RGGG) is reviewed. The proposed method introduces general gates to the conventional reliability graph method, which creates a one-to-one match from the actual structure of the system to the reliability graph of the system. A quantitative evaluation method is proposed by transforming the RGGG to an equivalent Bayesian network without losing the intuitiveness of the model. In addition, a method of analyzing the dynamic systems and repairable systems which uses the RGGG is introduced, and appropriate algorithms for the quantitative analyses are explained. It is concluded that the RGGG method is intuitive and easy-to-use in the analyses of static, dynamic, and repairable systems compared with other methods while its analysis results are the same as those of other methods.

Keywords: reliability graph; fault tree; Bayesian network; dynamic systems; repairable systems