Section: New Results

Modeling AADL in a polychronous model of computation

Participants : Loïc Besnard, Thierry Gautier, Paul Le Guernic, Jean-Pierre Talpin, Huafeng Yu.

Architecture Analysis and Design Language (AADL) is an SAE standard aimed at high level design and evaluation of architecture of embedded systems. We are interested in the analysis, simulation and verification of timed systems specified in AADL. Polychrony is well suited for the GALS architecture, and it enables deterministic specifications and formal analysis for the design of safety-critical systems. In order to benefit from the advantages provided by Polychrony, a proposition of a methodology for system-level modeling and validation of embedded systems specified in AADL via the polychronous model of computation is proposed.

By studying the different timing semantics of AADL and Polychrony, we have proposed an approach that automatically translates AADL models to a polychronous model of computation (SSME model). In the Polychrony framework, the Signal program can be generated, and an executable model can be obtained. The systems can be analyzed by tools and technologies associated with Polychrony allowing early simulation, testing and verification.

We implemented a plug-in for Eclipse framework to perform model transformation from AADL to SSME (new meta model of Signal). This transformation is implemented in Java. The following new features have been developed this year:

• Temporal interpretation of AADL model. Due to the different timing semantics between AADL and Signal, we keep the ideal view of instantaneous computations of polychronous model, moving computing latencies and communication delays to specific memory process, that introduce delays and well suited synchronizations. Each component modeled in Polychrony is composed of a behavior process (which models the functional behaviors) and a property process (which models the temporal properties).

• Architecture restructures. The architecture of the transformation is optimized. Functional architecture and meta architecture are described to give a global view of the transformation. The translation is recursive. Each AADL component is separated into a java class. The hierarchy of classes are reserved.

• Library developments. We define a Signal library containing the Signal process models representing some basic AADL concepts.

• Documentation. A new technical documentation of the transformation from AADL to SSME has been developed to accompany its implementation. This document aims to provide a global view of our implementation, from a high-level structural view to low-level implementation technical details of components.

• Programming language updates. This version of model transformation uses Java as the programming language. It avoids the disadvantages of dependent on other model transformation languages, and it provides more conveniences and flexibility. The new version is integrated as a plug-in in the Eclipse platform.

• Papers published. Three papers [14] , [18] , [21] are published this year.