Parametrized automata simulation and application to service composition

The service composition problem asks whether, given a client and a community of available services, there exists an agent (called the mediator) that suitably delegates the actions requested by the client to the available community of services. We address this problem in a general setting where the agents communication actions are parametrized by data from an infinite domain and possibly subject to constraints. For this purpose, we define parametrized automata (PAs), where transitions are guarded by conjunction of equalities and disequalities. We solve the service composition problem by showing that the simulation preorder of PAs is decidable and devising a procedure to synthesize a mediator out of a simulation preorder. We also show that the Nonemptiness problem of PAs is PSPACE-complete.