Consistent design of embedded real-time systems with UML-RT

Modeling embedded real time systems consisting of different components with UML-RT leads to a design model using various diagrams. Sequence diagrams describe possible interactions between system components and may be annotated with specific real time constraints. Statechart diagrams are used for describing each component´s behavior. In order to be able to get a consistent model, a consistency concept for different diagram types is needed that takes into account real time constraints. A consistency concept for sequence diagrams and statechart diagrams is presented which focuses on the establishment of timing constraints. Our consistency concept distinguishes between syntactical, semantic and real time consistency and takes into account the influence of processor allocation and scheduling. Using the consistency concept, we describe a method for ensuring the consistency based on worst case execution time analysis of statecharts and schedulability analysis of tasks, thereby enabling a precise answer to the question of consistency