Checking compositions of UML sequence diagrams for timing inconsistency

For real-time systems, UML sequence diagrams describe interactions among objects, which show scenarios of the system behaviour. A simple UML sequence diagram describes exactly one scenario. For describing multiple scenarios and specifying real-time systems, we need to consider the compositions of UML sequence diagrams. In this paper, we introduce high-level graphs to describe compositions of UML sequence diagrams, and develop an algorithm for checking them for timing inconsistencies.