Abstract: This paper describes a model for representing the temporal and logical elements of real-time applications, called MAST. This model allows a very rich description of the system, including the effects of event or message-based synchronization, multiprocessor and distributed architectures as well as shared resource synchronization. The model is directly obtainable from a description of the system design using a UML tool. A system representation using this model is analyzable through a set of tools that has been developed within the MAST suite, including worst-case schedulability analysis for hard timing requirements, and discrete-event simulation for soft timing requirements. Although the current model only includes fixed priority systems, it is conceived as an open model and is easily extensible to accommodate other kinds of systems.