Abstract
The modeling language UML-RT, a dialect of the UML, supports the development of complex, hierarchical systems following a component-oriented approach. However, for a solid foundation of model analysis and model transformations a formal semantics definition of UML-RT is missing. Therefore, this paper presents a precise syntax and semantics definition of a sublanguage of UML-RT. This sublanguage puts an emphasis on the specification of complex, hierarchical state-based models. It considers atomic capsules - containing a statechart - and complex capsules that recursively consist of capsules communicating asynchronously with each other over connectors. Labeled transition systems are chosen as semantic domain, such that the UML-RT semantics can be defined in an SOS style a la Plotkin.
