Inequality-based reliability estimates for complex systems

Full-system testing for large-scale systems is often infeasible or very costly. Thus, when estimating system reliability, it is desirable to employ a method that uses subsystem tests, which are often less expensive and more feasible. This paper presents a method for calculating full-system reliability based on subsystem tests. The method does not require that subsystems be independent. It accounts for dependencies through use of certain probability inequalities. The inequalities provide the basis for valid reliability calculations while not requiring full-system tests or information on greater-than-pairwise subsystem failure modes. We illustrate the method in an example