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FP5

OMEGA Résumé de rapport

Project ID: IST-2001-33522
Financé au titre de: FP5-IST
Pays: France

IFx tool for simulation and verification of UML with time extensions (XMI based)

Within the Omega project, VERIMAG has developed the IFx toolset for timed verification, simulation and scheduling analysis of Omega-UML models. The approach that was chosen is to reuse the timed validation techniques that VERIMAG developed for dynamic communicating timed automata extended with data and actions, as well as the already existing IF toolbox which implements state-of-the-art validation and verification techniques (see http://www-verimag.imag.fr/~async/IF/). A more detailed description focusing on the IF language - including extensions made, can be found there as well.

The main functionalities provided by IF/IFx are:
Simulation allows the user to interactively explore a model's execution graph. The user may perform operations that are similar to those offered by advanced debuggers: step by step execution, inspection of the system state, conditional breakpoints, scenario rewind/replay, manual resolution of non-determinism, control of scheduling policy and time related parameters, etc. Verification of simple consistency conditions like deadlocks, timelocks and satisfaction of state invariants. Verification of dynamic and timing properties using the model-checkers provided by the IF tool.
The properties may be expressed within the UML editor by means of the following notations provided by the Omega UML profile;
observer classes: classes with special state machines reacting to events and conditions occurring in the system execution
timing constraints: constraints on durations between system events

Finally, verification techniques implemented in the tool allow performing scheduling analysis, by specifying scheduling objectives (e.g., deadlines) as properties to be verified (observers). Other types of functionality, like comparing models modulo simulation and bisimulation relations, are also available in tools connected to IF.

The architecture of the IF/IFx toolset is depicted below;
<http://www-omega.imag.fr/icons/IFx-300dpi.png>. The upper part shows the UML tools specific to IFx, while the lower part shows the components of the IF toolset, including some modules developed in the OMEGA project (in blue).

The main components of IFx (in addition to the IF toolset), are:
The UML-to-IF translator, which takes as input a UML model stored in XMI format. The model may use standard UML constructs and extensions defined by the Omega profile: actions written in the Omega action language, timing annotations and observers expressing model properties. The translator generates an IF specification corresponding to the UML model, according to the Omega semantics. The UML front-end provides an interface specifically targeted at UML modellers for the IF validation tools. The interface hides IF and the details of translation and presents simulation and verification result in the vocabulary of the initial UML model. The interface supports all compilation and simulation features mentioned before, and offers customisable views on the analysed system.

The tool has been applied on three of the Omega case studies:
On the Ariane-5 case study (EADS), to statically validate the well-formedness of the model, to prove 9 safety properties of the flight regulation and configuration components, and to analyse the schedulability under the assumption of fixed priority pre-emptive scheduling policy.
On the MARS case study (NLR), to prove 4 safety properties and to discover reactivity limits of some system components and fine-tune their behaviour in order to improve reactivity. On this case study, we have also applied compositional verification, which is partly supported by the tool through the existence of simulation checkers, minimization with respect to bisimulation and abstraction.

On the Sensor Voting a Monitoring case study (IAI), to prove 4 safety properties and timing properties. The IF/IFx tool is freely distributed on the web (either through the Omega webpage<http://www-omega.imag.fr/tools.php> or <http://www-verimag.imag.fr/~async/IF/>

Informations connexes

Contact

Susanne GRAF, (senior scientist)
Tél.: +33-4-56520352
Fax: +33-4-56520344
E-mail