Composition of Services with Nondeterministic Observable Behavior

In [3] we started studying an advanced form of service composition where available services were modeled as deterministic finite transition systems, describing the possible conversations they can have with clients, and where the client request was itself expressed as a (virtual) service making use of the same alphabet of actions. In [4] we extended our studies by considering the case in which the client request was loosen by allowing don’t care nondeterminism in expressing the required target service. In the present paper we complete such a line of investigation, by considering the case in which the available services are only partially controllable and must be modeled as nondeterministic finite transition systems, possibly because of our lack of information on their exact behavior. Notably such services display a “devilish” form of nondeterminism, since we want to model the inability of the orchestrator to actually choose between different executions of the same action. We investigate how to automatically perform the synthesis of the composition under these circumstances.