Modeling the effect of reliability on performance

In many high-reliability systems, subsystem or component failures that do not cause a system failure can still degrade system performance. When modeling such systems, ignoring the effect of reliability on performance can lead to incomplete or inaccurate results. In the present work, performability modeling, the combined analysis of reliability and performance, is introduced; some examples of applications where performance and reliability need to be modeled together are given; a strategy for modeling the effect of reliability on performance is outlined and metrics that help quantify this effect are discussed. Some mathematical models for performability are introduced and an example is used to illustrate how such models can be applied