An inhomogenous state graph model and application for a phased mission and tolerable downtime problem

This paper provides a modelling framework for the use of inhomogenous state graph techniques for components and systems, where the duration, any given group of states is assumed, may be limited by a given value. The behavior of this type of process, including discontinuities in the transition rates, is elaborated in detail. This approach is useful e.g. to build component models with constant repair times, and to model systems with tolerable down times. An example for a problem involving tolerable down times and phases mission is provided. A systematic state graph approach applied to systems composed of several components allows the treatment of dependencies between the components precisely, which may cause large conservatisms, if Boolean modelling technique is applied.