Overall Objectives
Research Program
Highlights of the Year
New Software and Platforms
New Results
Partnerships and Cooperations
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Section: New Results

Contracts for Systems Design

Participants : Albert Benveniste, Benoît Caillaud.

Contracts for Systems Design: Theory, Methodology and Application Cases

Aircrafts, trains, cars, plants, distributed telecommunication military or health care systems, and more, involve systems design as a critical step. Complexity has caused system design times and costs to go severely over budget so as to threaten the health of entire industrial sectors. Heuristic methods and standard practices do not seem to scale with complexity so that novel design methods and tools based on a strong theoretical foundation are sorely needed. Model-based design as well as other methodologies such as layered and compositional design have been used recently but a unified intellectual framework with a complete design flow supported by formal tools is still lacking. Recently an “orthogonal” approach has been proposed that can be applied to all methodologies introduced thus far to provide a rigorous scaffolding for verification, analysis and abstraction/refinement: contract-based design. Several results have been obtained in this domain but a unified treatment of the topic that can help in putting contract-based design in perspective is missing. We have published two research reports [13] , [12] , that intend to provide such treatment where contracts are precisely defined and characterized so that they can be used in design methodologies such as the ones mentioned above with no ambiguity. In addition, the first report [13] provides an important link between interface and contract theories to show similarities and correspondences. This report is complemented by a companion report [12] where contract based design is illustrated through use cases.

Contracts for Schedulability Analysis

In [10] we proposed a framework of Assume / Guarantee contracts for schedulability analysis. Unlike previous work addressing compositional scheduling analysis, our objective is to provide support for the OEM / supplier subcontracting relation. The adaptation of Assume / Guarantee contracts to schedulability analysis requires some care, due to the handling of conflicts caused by shared resources. We illustrate our framework in the context of Autosar methodology now popular in the automotive industry sector.