This paper considers the reliability analysis of systems whose operation time is managed with regard to criticality of faults. Several analysis approaches are proposed for the numerical probability analysis of one such operational scenario: FOTM (flight operation time management). The equations derived for the Markov chain based method are novel and their implementation in the tool SPNP (Stochastic Petri Net Program) could help in assessing the risk reduction due to FOTM. The analysis methods are quite general and can be applied to other similar situations where system-failure risk is decreased by operation-time management.

We consider the sensitivity of transient solutions of Markov models to perturbations in their generator matrices. The perturbations can either be of a certain structure or can be very general. We consider two different measures of sensitivity and derive upper bounds on them. The derived bounds are sharper than previously reported bounds in the literature. Since the sensitivity analysis of transient solutions is intimately related to the condition of the exponential of the CTMC matrix, we derive an expression for the condition number of the CTMC matrix exponential which leads to some interesting implications. We compare the derived sensitivity bounds both numerically and analytically with those reported in the literature.

The behavior of the multiprocessor system is described as a continuous Markov chain, and a reward rate (performance measure) is associated with each state. The distribution of performability is evaluated for analytical models of a multiprocessor system using a polynomial-time algorithm that obtains the distribution of performability for repairable, as well as nonrepairable, systems with heterogeneous components with a substantial speedup over earlier work. Numerical results indicate that distributions of cumulative performance measures over finite intervals reveal behavior of multiprocessor systems not indicates by either steady-state or expected values alone.>