Branching Time Semantics for UML 2.0 Sequence Diagrams

This paper presents formal definitions for UML Sequences Diagrams based on branching time semantics and partial orders in a denotational style. The obtained graphs are close to lattices and specify faithfully the intended behaviors rather than trace based semantics. We also define few generalized algebraic operations on graphs so that it makes it easy to provide formal definitions in a compositional manner to interaction operators. Next we extend our formalism with logical clocks and time formulas over values of these clocks to express timing constraints of complex systems. We present also some algorithms to extract time annotations that adorn sequence diagrams and transform them into timing constraints in our timed graphs. Obviously, this approach alleviates more the hard task of consistency checking between UML diagrams, specifically interaction diagrams with regards to state diagrams. Timeliness and performance analysis of timed graphs related to sequence diagrams could take advantages of works on model checking of timed automata.