2. '. The Model
Based on the definition of multi-state system given
by Barlow and Wu (1978), the state of a parallel
system is determined by the component in the best
state while the state of a series system is determined
by the component in the worst state. For a parallelseries
system with N subsystems, the state of the
system is determined by the subsystem in the worst
state, which in turn is determined by the component
in the subsystem in the best state. Thus, given the
distributions of the components in various possible
states, we may find the expression of the
probabilities for the system to be in various possible
states.