The new address of Christophe Joubert's home page is:

http://www.dsic.upv.es/~joubert

R esearch

current activity 10/2002 - onwards

My PhD thesis is about algorithmic aspects of parallel formal verification, more precisely on distributed model-checking approaches. That is a rather wide subject, isn't it ? :-)

So far, my work can be divided in two parts: distributed verification engine based on Boolean Equation Systems and distributed model-checking applications using the previous engine.

If you want more information, check out the presentation slide (513 Kb in french) I made for the MSTII'04 doctoral symposium last december.

You may also consult my list of publications for further information.

Hereafter is a small description of my Ph.D. project:

place:
INRIA, Rhône-Alpes research unit, VASY project, Grenoble (France)
title:
massively parallel on-the-fly verification of finite-state systems
domain:
formal verification methods
advisors:
Hubert Garavel (director) and Radu Mateescu (scientific advisor)
funding:
french research ministry grant
project:
research work part of Standard Process Algebra Research and Tools SENVA, Associated Team INRIA program between INRIA/VASY and CWI/SEN, section distributed algorithms for the verification of finite-state systems
abstract:
The verification of concurrent finite-state systems is confronted in practice with the state explosion problem (prohibitive size of the underlying state spaces), which occurs for realistic systems containing many parallel processes and complex data structures. Various techniques for fighting against state explosion have been proposed, such as on-the-fly verification, partial order reduction, and distributed verification. However, practical experience has shown that none of these techniques alone is always sufficient to handle large-scale systems. In this thesis, we propose a combination of these techniques in order to scale up their capabilities. Our approach is based upon Boolean Equation Systems (BESs), which provide an elegant intermediate representation for verification problems defined on Labeled Transition Systems (LTSs) such as equivalence checking, tau-confluence reduction, model checking of alternation-free mu-calculus and test-case generation. We propose DSolve (Joubert - Mateescu - PDP - 05), a new algorithm for distributed on-the-fly resolution of BESs, and employ it as computing engine for four on-the-fly verification tools developed within the CADP toolbox using the OPEN/CAESAR environment: the Bisimulator equivalence checker (Joubert - Mateescu - PDMC - 04, Bergamini - et - al - TACAS - 05 - a), the Tau_Confluence reductor, the Evaluator model checker, and the Extractor test-case generator. Experimental measures performed on clusters of machines show quasi-linear speedups and a good scalability of the distributed versions of these tools w.r.t. their sequential counterparts.
keywords:
boolean equation systems, distributed memory algorithm, on-the-fly verification, equivalence checking, partial order reduction, model checking, test case generation
publications:
Bergamini - et - al - TACAS - 05 - a
Joubert - Mateescu - PDP - 05
Joubert - Mateescu - PDMC - 04
Joubert - PDMC - 03
talks:
Joubert - MSTII - 04
Joubert - SENVA - 04
Joubert - EJCP - 03
tool demonstration:
Bergamini - et - al - TACAS - 05 - b

past activities

performance evaluation 06/2002 - 09/2002

place:
Department of computer science, Universiteit Twente, FMT group, Enschede (Holland)
position:
visiting scientist
title:
a set of performance and dependability analysis components for CADP
domain:
formal verification methods
advisors:
Ed Brinksma (director) and Holger Hermanns (scientific advisor)
funding:
Isère department grant
project:
research work part of Advanced Methods for Timed Systems AMETIST, european project IST-2001-35304, EC 5th Framework Program, section analysis and tools: stochastic techniques
abstract:
This work aimed at designing a set of analysis components that open the way to perform performance and dependability analysis with the CADP toolbox, originally designed for verifying the functional correctness of LOTOS specifications. Three new tools (named BCG_STEADY, BCG_TRANSIENT, and DETERMINATOR) have been added to the toolbox. The approach taken fits well within the existing architecture of CADP, which doesn't need to be altered to enable performance evaluation.
keywords:
performance evaluation, functional verification, state space, steady state and transient analysis, on-the-fly elimination of non-determinism for stochastic systems
publication:
Hermanns - Joubert - TACAS - 03 - a
talks:
Joubert - VASY - 03
Joubert - VASY - 02
tool demonstration:
Hermanns - Joubert - TACAS - 03 - b

parallel generation 10/2001 - 06/2002

place:
INRIA, Rhône-Alpes research unit, VASY project, Grenoble (France)
position:
master student
title:
massively parallel generation of very large transition systems
domain:
formal methods
advisors:
Hubert Garavel (director) and Radu Mateescu (scientific advisor)
funding:
merit grant according to academic honors
project:
research work part of Architecture Evolvable Software ARCHWARE, european project IST-2001-32360, EC 5th Framework Program, section description and verification of functional properties
abstract:
This master research work aimed at designing and implementing new algorithms for the massively parallel generation of large transition systems problem, in order to prepare distributed model checking. We gave a complete state of the art of research works on parallel generation of models. Then, we proposed a new algorithm for the parallel construction of models obtained from programs described with high level languages, such as LOTOS. One novel aspect of our approach is the distributed management of dynamic data structures (lists, trees, etc.) between several machines. We also specified our algorithm in LOTOS and verified its functional properties (absence of deadlock, termination detection, safety) by mean of the CADP toolbox. A prototype implementation of our algorithm has been implemented in DISTRIBUTOR tool of CADP. The experiments on a cluster of PCs confirmed the good behavior of our algorithm and showed important performance gain in memory and time execution.
keywords:
state space, on-the-fly generation, distributed memory algorithm, partitioned LTS
publication:
Joubert - MASTER - 02
talk:
Joubert - VASY - 02 - b

shape analysis 04/2001 - 07/2001

place:
Department of computer science, University of California, Santa Barbara (USA)
position:
bachelor student
title:
integrating shape analysis, a static computation of program memory configuration topology, into Action Language Verifier
domain:
formal verification methods
advisors:
Saddek Bensalem (director) and Tevfik Bultan (scientific advisor)
funding:
Rhône-Alpes region grant
keywords:
shape analysis, static analysis, infinite state symbolic model

multi-agent systems 11/1999 - 07/2000

place:
IMAG, LEIBNIZ laboratory, MAGMA project, Grenoble (France)
position:
licence student
title:
a communication model for multi-agent systems in the context of ROBOCUP simulation
advisors:
Yves Demazeau (director) and Christof Baeijs (scientific advisor)
keywords:
cooperation, communication, ROBOCUP simulation, AEIO model
Valid XHTML 1.0!
Christophe.Joubert@inrialpes.fr

Last modification : 05/04/27 15:35:15

Valid CSS!