SHERBROOKE Algebraic State Transition Diagrams

This paper introduces a graphical notation called algebraic state transition diagrams (ASTD), which allows for the combination of state transition diagrams using classical process algebra operators like sequence, iteration, parallel composition, quantified choice and quantified synchronization. It is inspired from automata, statecharts and process algebras. Hence, it combines the strength of all these notations: graphical representation, hierarchy, orthogonality, compositionality, abstraction. Quantification is one of the salient features of ASTDs, because it provides a powerful mechanism for modeling an arbitrary number of instances of an ASTD. A formal operational semantics is given. Our target application domain is the specification of information systems, but ASTDs are presented in a generic manner.