Using UML for modeling complex real-time systems

Real-time software systems encountered in telecommunications, aerospace, and defense often tend to be very large and extremely complex. It is crucial in such systems that the software has a well-defined architecture. This not only facilitates construction of the initial system, it also simplifies system evolution. We describe a set of modeling constructs that facilitate the specification of complex software architectures for real-time systems. These constructs are derived from field-proven concepts originally defined in the ROOM modeling language. Furthermore, we show how they can be represented using the industry-standard Unified Modeling Language (UML) by using the powerful extensibility mechanisms of UML.