Christian Attiogbé

Abdelkader Khouass, christian attiogbé, mohamed messabihi

Nowadays, there are several complex systems in different sectors such as aviation, air traffic control ...etc. These systems do not have a precise perimeter, they are open and made of various specific components built with different languages and environments. The modeling, assembly and analysis of such open and complex heterogeneous systems are challenges in software engineering. This paper describes how the Minarets method decreases the difficulty of modeling, composition and analysis of the well known case study of the landing gear system. The method consists in: equipping individual components with generalized contracts that integrate various facets related to different concerns, composing these components according to their facets and verifying the resulting system with respect to the involved facets as well. The proposed method may be used or extended to cover more facets, and by strengthening assistance tool through proactive aspects in modeling, composing multi-facets contracts and finally the verification of the heterogeneous systems.

Abdelkader Khouass, Christian Attiogbé, Mohamed Messabihi

Critical and cyber-physical systems (CPS) that exist in large industries, such as nuclear power plants, railway, automotive or aeronautical industries are complex heterogeneous systems. They are complex because they are open, perimeter-less, often built by assembling various heterogeneous and interacting components which are frequently reconfigured due to requirements. Consequently, the modeling and analysis of such systems is a challenge in software engineering. We introduce a new method for modeling and verifying heterogeneous systems. The method consists in: equipping individual components with generalized contract, ordering these contracts according to given facets, composing these components and verifying the resulting system with respect to the facets. We illustrate the use of the method by a case study. The proposed method may be extended to cover more facets, and by strengthening assistance tool through proactive aspects in modelling and property verification.

Christian Attiogbé, Jérôme Rocheteau

Internet of Things applications impact more and more industrial areas such as smart manufacturing, smart health monitoring and home automation; physical objects or devices equipped with sensors and actuators are interconnected and then controlled with software applications. Ensuring the correct construction, the well-functioning and the reliability of these applications constitute important issues for some of these applications which can be critical in case of dysfunction. We propose on the basis of the formal model of their common architectural properties, a generic framework for the formal modelling of IoT-based applications, the rigorous analysis of their consistency properties, their rigorous construction and evolution. Specific properties can be gradually added and checked. The proposed framework is then implemented and experimented using Event-B. We exploit the observation that the main requirements of the IoT-based physical architectures and control software are common to all IoT-based applications; this leaded us to the definition of the generic formal model together with invariant architectural and consistency properties. The proposed approach is generic, extensible, and can be profitably adapted to more general hybrid or cyber-physical systems. Our current implementation is independent of the formal model, it can be achieved in various other formal analysis environments.

Christian Attiogbé

Software Defined Networking (SDN) brings flexibility in the construction and managment of distributed applications by reducing the constraints imposed by physical networks and by moving the control of networks closer to the applications. However mastering SDN still poses numerous challenges among which the design of correct SDN components (more specifically controller and switches). In this work we use a formal stepwise approach to model and reason on SDN. Although formal approaches have already been used in this area, this contribution is the first state-based approach; it is based on the Event-B formal method, and it enables a correct-by-construction of SDN components. We provide the steps to build, using several refinements, a global formal model of a SDN system; correct SDN components are then systematically built from the global formal model satisfying the desired properties. Event-B is used to experiment the approach.

Pascal André, Christian Attiogbé, Arnaud Lanoix

This paper presents a solution to the landing gear system case study using Event-B and Rodin. We study the whole system (both the digital part and the controlled part). We use feature augmentation to build an abstract model of the whole system and structural refinement to detail more specifically the digital part. The required safety properties are formalised and proved. We propose a specific approach to deal with a family of reachability properties. The experimentations conducted during the study are supported by the Rodin tools. We show that the presented solution is systematic and it can be applied to similar case studies.