A constraint is an implementation of an explicit rule ( examples).
The guide relies on the STAMP paradigm, which means that the system should constrain its operation according to operational rules, prohibiting unexpected states.
Following STAMP ( Leveson, 2004 ) Resilience assurance is based on constraining the system activity to stay in a design scope, of well-supported situations.
Often, the trigger for the system malfunction is a normal event, arriving when the system is in an exceptional situations. The normal event may transit the system to an unexpected state ( Perrow, 1984 ). Therefore, the constraints should depend on the situation, namely they should be scenario-based.
Updated on 13 Jul 2016.