How to reuse supervisors when discrete event system models evolve

System evolution, such as addition or replacement of a component, reconfiguration upon a diagnosed failure, or process changes leading to new requirements on the system behavior, may often necessitate complete redesign of the existing supervisors for a discrete event dynamic system. Such redesign may occur because the supervisors are synthesized based on the models of the system and the specifications, and these models may have to be modified, or “refined”, upon the evolution of the system. The objectives of this work are to: (i) study conditions on the evolution of the system model under which it is possible to reuse the existing supervisors for the original set of specifications, and (ii) propose a systematic method for this reuse of the supervisors, based on the automatic synthesis of input and output “interfaces”, when the conditions identified in (i) hold