An Intuitive and Practical Method for Reliability Analysis of Complex Systems

System reliability analysis refers to the evaluation of the reliability of a system based on the reliabilities of its elements. Several methods can be applied to the system reliability analysis, such as reliability graph, fault tree analysis, Markov chain, and Monte Carlo simulation. Each method has its own characteristics, merits and demerits. Among the existing methods, the fault tree analysis is most widely used due to its expression power, applicability to complex systems and various tool supports. But, drawing a fault tree is a cumbersome task even for the experts who is familiar to it, and requires a great amount of attention and caution to represent a system correctly. This is mainly because the fault tree analysis is not an intuitive method. A fault tree has to be drawn based on the structure of a system and the reliabilities of the system's elements. Because drawing and verifying fault trees are the tasks that human analysts have to perform, there are always possibilities of human errors. In order to reduce necessary works for the analysis and verification, and the possibilities of human errors, we believe that an intuitive method for system reliability analysis should be developed.