Stateful Priorities for Precise Restriction of System Behavior

We present the notion of stateful priorities for imposing precise restrictions on system actions, in order to meet safety constraints. By using stateful priorities we are able to exclusively restrict erroneous system behavior as specified by the constraint, whereas safe system behavior remains unrestricted. Given a system modeled as a network of discrete automata and an error constraint, we present algorithms which use those inputs to synthesize stateful priorities. We present as well a network transformation which uses synthesized priorities for blocking all system actions leading to the input error. The applicability of our approach is demonstrated on three real-world examples.