Some Models and Tools for Open Systems

In computer science, there is a distinction between closed systems, whose behavior is totally determined in advance, and open systems, that are systems maintaining a constant interaction with an unspecified environment. Closed systems are naturally modeled by transitions systems. Open systems have been modeled in various ways, including process algebras, I/O automata, “modules”, and interfaces. Games provide a uniform setting in which all these models can be cast and compared. In this extended abstract, we discuss the features and costs related to the gamebased approach to open systems, referring to some of the existing models. Finally, we describe a new model of interface, called sociable interface, which is geared towards easier specification, improved reusability of models, and efficient symbolic implementation.