ABSTRACT
This chapter presents some of the most important analytic methods for combinatorial models. These methods were divided into two groups: exact methods and methods for computing bounds. The enumeration method is based on the explicit representation of all system states and on the respective structure-function that specifies the operational states. The factoring method is particularly interesting for systems that parallel-series compositions can not represent due to more complex relations between the system components. It presents a set of transformations that allows calculating the system probability (reliability or availability) by computing the respective probability of its subsystems and combining the individual results. The chapter presents how the inclusion-exclusion method is applied to estimate reliability and availability of system.
