An Open-Source simulator for Real-Time sysML models

The term “model-based engineering” was coined to denote a set of engineering activities that consider the use of modeling languages as of primary concern. The expected benefits of using a modeling language include the opportunity to detect design errors as early as possible in the life cycle of the system under design. Model simulation is the avenue we intend to explore to achieve that objective. The paper addresses model simulation in the context of real-time systems and presents TTool, an open-source toolkit running on Unix, Windows and MAC-OS platforms. In terms of modeling language, we selected SysML (the System Modeling Language standardized by the Object Management Group) for its increasing acceptance in industry and its customizability. TTool indeed supports AVATAR, a variant of SysML designed with real-time systems in mind. An AVATAR model includes a set of diagrams that enable requirement capture, modeling assumptions elicitation, use-case-driven analysis, architectural design and behavioural design. TTool enables simulation of AVATAR models by animating the set of timed communicating state machines that describe the inner working of the blocks included in the system’s architecture. TTool generates simulation traces in terms of scenarios that identify how block instances internally evolve and communicate with one another. Also, TTools graphically animates the state machines and makes it easy for the designer to connect simulation results to the original AVATAR model. Usual functions like scenario replay and statistics are also available. The use of TTool is particularly recommended for life-critical systems that fall in the category of hard real-time systems. An isolated calculator may thus be modeled and simulated. TTools also enables distributed systems modeling. Therefore the communication software associated with an embedded calculator may also been modeled and simulated. So far, TTool has been used in industry projects that not only use the simulation functions addressed by the paper but also the formal verification capabilities offered by the interfaces from AVATAR to UPPAAL and ProVerif. The latter respectively enable formal checking of security and safety properties at the push of a button. At last, the toolset made up of TTool, UPPAAL and ProVerif is also used for teaching real-time and distributed systems modeling at Master level