Hierarchical states in the compositional interchange format

CIF is a language designed for two purposes, namely as a specification language for hybrid systems and as an interchange format for allowing model transformations between other languages for hybrid systems. To facilitate the top-down development of a hybrid system and also to be able to express models more succinctly in the CIF formalism, we need a mechanism for stepwise refinement. In this paper, we add the notion of hierarchy to a subset of the CIF language, which we call hCIF¿ . The semantic domain of the CIF formalism is a hybrid transition system, constructed using structural operational semantics. The goal of this paper is to present a semantics for hierarchy in such a way that only the SOS rules for atomic entities in hCIF¿ are redesigned in comparison to CIF . Furthermore, to be able to reuse existing tools like simulators of the CIF language, a procedure to eliminate hierarchy from an automaton is given