A formal approach for correct-by-construction system substitution

The substitution of a system with another one may occur in several situations like system adaptation, system failure management, system resilience, system reconfiguration, etc. It consists in replacing a running system by another one when given conditions hold. This contribution summarizes our proposal to define a formal setting for proving the correctness of system substitution. It relies on refinement and on the Event-B method.Comment: EDCC-2014, Student-Forum, System Substitution, state rRecovery, correct-bycorrection, Event-B, refinemen

Étude et comparaison de scénarios de développements formels d'interfaces multi-modales fondés sur la preuve et le raffinement.

International audienceLes architectures d'un système interactif reposent sur la séparation du noyau fonctionnel de l'interface utilisateur du logiciel. Le développement de ces deux modules implique l'utilisation de techniques et d'approches différentes. La validation du système interactif peut être une étape complexe puisque ces modules sont développés séparément. Dans le cadre du projet RNRT Verbatim*, l'étude de différents scénarios de développement formels des systèmes interactifs multi-modaux, a été menée en utilisant la méthode B dans sa version "B événementiel". Cet article présente une partie des résultats de cette étude. Le raffinement est mis en œuvre pour structurer les développements et la preuve pour établir les propriétés. Il s'intéresse principalement à la liaison (lors de leur composition) entre les deux modules d'un système interactif que sont le noyau fonctionnel et l'interface utilisateur. Quatre scénarios de développement différents, représentant formellement cette liaison, sont étudiés et comparés. Cette comparaison est réalisée sur la base du nombre d'obligations de preuve générées et relatives aux propriétés décrites dans les spécifications. Une étude de cas décrivant un système interactif multi-modal, illustrant ces scénarios et leur comparaison est utilisée tout au long de cet article

IEEE/NASA Workshop on Leveraging Applications of Formal Methods, Verification, and Validation

This volume contains the Preliminary Proceedings of the 2005 IEEE ISoLA Workshop on Leveraging Applications of Formal Methods, Verification, and Validation, with a special track on the theme of Formal Methods in Human and Robotic Space Exploration. The workshop was held on 23-24 September 2005 at the Loyola College Graduate Center, Columbia, MD, USA. The idea behind the Workshop arose from the experience and feedback of ISoLA 2004, the 1st International Symposium on Leveraging Applications of Formal Methods held in Paphos (Cyprus) last October-November. ISoLA 2004 served the need of providing a forum for developers, users, and researchers to discuss issues related to the adoption and use of rigorous tools and methods for the specification, analysis, verification, certification, construction, test, and maintenance of systems from the point of view of their different application domains

Un processus formel d'intégration de politiques de contrôle d'accès dans les systèmes d'information

Security is a key aspect in information systems (IS) development. One cannot build a bank IS without security in mind. In medical IS, security is one of the most important features of the software. Access control is one of many security aspects of an IS. It defines permitted or forbidden execution of system's actions by an user. Between the conception of an access control policy and its effective deployment on an IS, several steps can introduce unacceptable errors. Using formal methods may be an answer to reduce errors during the modeling of access control policies. Using the process algebra EB[superscript 3], one can formally model IS. Its extension, EB[superscript 3]SEC, was created in order to model access control policies. The ASTD notation combines Harel's Statecharts and EB[superscript 3] operators into a graphical and formal notation that can be used in order to model IS. However, both methods lack tools allowing a designer to prove or verify security properties in order to validate an access control policy. Furthermore, the implementation of an access control policy must correspond to its abstract specification. This thesis defines translation rules from EB[superscript 3] to ASTD, from ASTD to Event-B and from ASTD to B. It also introduces a formal architecture expressed using the B notation in order to enforce a policy over an IS. This modeling of access control policies in B can be used in order to prove properties, thanks to the B prover, but also to verify properties using ProB, a model checker for B. Finally, a refinement strategy for the access control policy into an implementation is proposed. B refinements are proved, this ensures that the implementation corresponds to the initial model of the access control policy

ABSTRACT Encoding a process algebra using the Event B Method. Application to the validation of user interfaces

This paper presents the use of the B technique in its event based definition. We show that it is possible to encode, using Event B, the models i.e. transition systems associated to a process algebra with asynchronous semantics. The Event B obtained encoding considers that the Event B model associated to the left hand side of a BNF rule defining the algebra expressions is refined by a model corresponding to the right hand side of the same rule. The translation rules of each operator of a basic process algebra are given. Then, an example illustrating each translation rule is given. This approach is based on a proof technique and therefore it does not suffer from the state number explosion problem occurring in classical model checking. The interest of this work is the capability to validate user tasks or scenarios when using a given system and particulary a critical system. Finally, we discuss the application of this approach for validating user interfaces tasks in the Human Computer Interaction (HCI) area