Tools for the Analysis of Hybrid Systems


Keywords: hybrid systems, timed automata, duration calculus, real time, formal specification

Start Date: 1 January 95 / Status: finished / Duration: 24 months

[ participants / contact]

Objectivies and Approach

The objectives of this project are to develop a theoretical basis for analysing hybrid systems, which combine discrete and continuous components, and to build tools for improving the development of computer controlled systems. Most embedded systems are hybrid, since they operate and interact with a continuous environment and are expected to provide real time responses to continuously varying situations.

The work will bring together prominent researchers who represent different approaches to the problem, thus increasing mutual understanding between the control and computer science communities.

Progress and Results

Regarding timed automata, the work consisted in applying the CRONOS tool to real-world case studies and in studying the expressive power of real time logics, the translation of asynchronous circuits into timed automata and the problem of controller synthesis. For linear hybrid systems, linear hybrid automata and their semi-decision procedure have been introduced and positive decidability results have been obtained for hybrid systems combined with discrete data structures; the relation between linear hybrid systems, as well as between continuous and hybrid systems, and the duration calculus has been investigated. An object oriented modelling environment for simulation of hybrid systems has been developed, and work is performed on logic-based switching of multicontrollers. The study on the fundamental nature of hybrid systems focuses on modular modelling, compositionality and the ability to use multiform time.

Future directions in the research will include models of time dependent discrete-valued signals and work on case studies.

Information Dissemination Activities and/or Exploitation

Within HYBRID, the second European workshop on real time and hybrid systems has been organised in Grenoble in My-June 1995. This workshop has been the major European event in the domain. Another important activity was the publication of a special isssue of the journal "Theoretical Computer Science" dedicated to hybrid systems and edited by J. Sifakis and A. Pnueli. This issue constitutes the first archived publication of a variety of results in hybrid systems.


Miniparc Zirst
Rue Lavoisier
38330 Montbonnot, F

EU Partners

Technical University of Denmark, DK
Lund Institute of Technology, S
Institut National Polytechnique de Grenoble, F

Non-EU Partners

Cornell University, USA


Dr. Oded Maler
Tel: +33 76 90 96 35
Fax: +33 76 41 36 20

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HYBRID - EC-US043, May 1997

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html version of synopsis by Nick Cook