Critical systems and tolerable inputs

Abstract A system that is subjected to random inputs is said to be critical if the output is required to be strictly within prescribed bounds. Any violation of these bounds results in unacceptable, and perhaps catastrophic, operation. An input that does not cause the bounds to be violated is said to be tolerable. This paper determines various classes of tolerable inputs which, when maximized, encompass a significant class, if not all, of the inputs that can arise in practice.