We propose an algorithm for the synthesis of supervisors in discrete event
systems. The algorithm is based on a learning algorithm of regular language
s proposed by Angluin, and constructs a supervisor realizing an unknown spe
cification which is identified through the interaction between the designer
and the algorithm. We also consider the synthesis problem for systems cons
isting of several processes which behave concurrently. One of serious probl
ems in dealing with such a concurrent system is that the number of states r
equired 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. It prevents the algorithm from con
sidering all interleavings of independent occurrences of events.