Synthesis of supervisors for discrete event systems allowing concurrent behavior

Abstract

We propose an algorithm for the synthesis of supervisors in discrete event systems. The proposed algorithm is based on a learning algorithm of regular languages proposed by Angluin (1987), and construct a supervisor realizing a specification given by two kinds of queries, membership query and equivalence query. We also consider the synthesis of supervisors for systems consisting of several processes which behave concurrently. One of serious problems for dealing with such a concurrent system is that the number of states required for describing the global behavior often grows exponentially in the size of the model. To improve this situation, we introduce the concept of dependency defined on the set of events. With this assumption, we can omit redundant queries to the designer. This idea works effectively when the system becomes large.