On efficient relabeling of symmetric discrete‐event systems

Abstract

AbstractSymmetric discrete‐event systems (SDES) are composed of classes of components with identical structures. By utilizing such symmetry, for specifications irrelevant to the detailed component information, the supervisory control of SDES can be achieved in the relabeled level. Namely, for events fulfilling the same task (similar events) in a class of components, they are relabeled to the same symbol. The relabeling mechanism is first implemented by directly renaming similar events to the same symbol. Then by employing the subset construction algorithm (SCA), the resultant nondeterministic automaton is converted to its deterministic counterpart. As the SCA is computationally intensive, the relabeling algorithm is inefficient, especially when the number of components increases. In this paper, inspired by the construction process of quotient automata, we first employ symmetry to generate the state set of the relabeled automaton. Then the relabeled automaton is generated based on the generated state set and transition information among these states. As we avoid using the SCA to eliminate nondeterminism, the relabeling process is more efficient. A running example is given throughout the paper.