Abstract

Real-Time Systems (RTS) should not only function correctly but should also satisfy time constraints. RTS include embedded systems, which are used nowadays in a variety of applications. These are, for instance, house appliances, automotive, aeronautic/aerospace, and health monitoring systems, to mention just a few. The design of such systems is complex and challenging. In order to cope with the complexity of RTS, there is shift in their development to follow a model-driven approach, such as the Model Driven Architecture (MDA), which relies on using models of high level of abstraction. The Unified Modeling Language (UML) is the Object Management Group (OMG) standard modeling language to support MDA. UML is appropriate for software systems because it allows for a multi-view modeling approach through its multitude of diagrams covering the structure, the behavior and the deployment architecture. Moreover, UML is also used in the domain of real-time software systems. This is achieved through its profiles, including, the OMG standard profile for Schedulability, Performance and Time (UML/SPT) or the upcoming standard UML Profile for Modeling and Analysis of Real-Time and Embedded Systems (MARTE). However, UML modeling faces some challenging issues such as model consistency. This issue becomes worse in the context of real-time software systems because additional aspects should be taken into consideration, including time, concurrency and schedulability. In this thesis, we address several issues related to modeling and validation of RTS with UML. We focus in particular on the consistency of UML/SPT models. We adopt an incremental approach to check the consistency of these models by distinguishing the syntactic and semantic levels. The latter is further decomposed into behavioral, concurrency-related and time consistency. Our contributions in this thesis are fourfold. First, we leverage the extensibility mechanisms of UML to propose an extension to UML/SPT. This extension enables the modeling of multicast communications, which is required for the description of the behavior of certain real-time protocols. Second, we propose a formalization of the concurrency modeling capability in UML/SPT using timed automata. This formal semantics allows for applying well-established model checking techniques to check concurrency related consistency in UML/SPT models. Third, we propose an MDA-compliant approach to enable schedulability analysis of UML/SPT models. We present a proof of concept for this approach through a prototype implementation using the Atlas Transformation Language (ATL) and XML-based technologies. Finally, we use the schedulability analysis applied to UML/SPT models in order to check the time consistency of a system design modeled by means of a set of state machines with respect to time constraints modeled using a set of sequence diagrams annotated with UML/SPT time stereotypes. Keywords : Real-time systems, Model-driven Architecture, UML, UML/SPT, Model transformation, ATL, XML, XSLT, Consistency, Concurrency, Model Checking, Schedulability Analysis.