On formalizing UML2 activities using TPNets: case studies

ABSTRACT: Transactional Petri Nets (TPNets) are a new class of high-level Zero-Safe Nets (ZSNs), defined as a more suitable semantic framework for UML2 activity diagrams. Indeed, they ensure reactivity and synchronization of concurrent flows triggering with their junction. Reactivity is guaranteed due to the real time massive cancellation semantics based on the definition of new dynamic enabling rules and the imposed priority among executions. Global synchronization in turn is assured thanks to non-locality principle, an outcome of exploiting atomic stable transactions. Rewriting logic is defined as the operational semantics framework of TPNets

On Adding Some Mobility Primitives to an Architecture Description Language

In mobile software systems specification, we focus on the movement of software elements across a network of locations and on how their execution environment may change without altering or changing their internal structure or behavior. It seems evident that we are more interested on the topology of the system and its possible evolutions; by means of components movement; rather than the detailed code of each component. Consequentely, it is necessary that the global structure, of the system under specification, emerges at an early stage. Architecture Description Languages (ADLs for short) seem to be the adequate framework. However, most of the existing ADLs define system structure statiquely, i.e. these ADLs do not support mobility of components, and/or their semantics is not well defined. In this work, we attempt to extend an ADL, the CBabel language, by defining a new notion of components location-mobility space of components- and a set of primitives governing components mobility. CBabel language is chosen for its simple syntax and rigorous semantics, based on rewriting logic, allowing formal verification of system properties

Description formelle du Déploiement d'Architectures AADL basée sur les Systèmes Réactifs Bigraphiques

International audienceLe déploiement constitue une phase importante dans le cycle de vie d?un logiciel, souvent construite de façon ad-hoc. Les préoccupations des architectes s?articulent autour de la définition d?un processus de déploiement générique permettant d?assembler et de distribuer correctement des applications logicielles quelle que soit leur technologie d?implémentation. Nous montrons dans ce travail la pertinence des systèmes réactifs bigraphiques (BRS) pour la description formelle de l?opération de déploiement d?une application logicielle dans un environnement cible. Le modèle formel proposé permet en particulier de définir d?une part, les deux structures d?une architecture spécifiées en AADL à savoir la plateforme et le scénario de l?application et d?autre part, l?opération d?installation correspondante décrite usuellement dans ce langage par un ensemble de propriétés. Nous montrons également la capacité du modèle proposé, une fois enrichi par des règles de réaction associées à un bigraphe, à prendre en charge la dynamique définie dans une spécification AADL

Modeling the Dynamic Reconfiguration in Smart Crisis Response Systems

International audienceCrises response systems form the majority of today's complex systems; they generate situations characterized by harmful consequence, low probability, and short decision time. The decision-making in these systems constitute a challenging issue and must be conscientiously supported. The aim of this paper is twofold, we derive a referential architecture for crisis response system-of-systems in one hand, the role of communication and the characteristics of constituent systems that are needed to adapt their dynamic behavior are added to the architecture standard of IEEE. In the other hand, we define a formal model on the basis of the Maude Strategy language, to deal with the dynamic reconfiguration of these system types

A Bigraphical Model for Specifying Cloud-Based Elastic Systems and Their Behaviour

International audienceThe few recent years have witnessed the appearance of a new kind of self-adaptive systems called cloud based-elastic systems. These systems are particularly appealing for their ability to maintain a decent quality of service and reduce a system's operating cost at the same time. They achieve this by dynamically adjusting resources allocation in terms of elasticity. Meanwhile, complexity of structural and behavioural aspects related to cloud-based elastic systems increase the difficulty of designing and developing such systems. In this paper, we address this challenge by proposing a formal approach based on bigraphical reactive systems for modelling both structural and behavioural aspects of cloud-based elastic systems. In particular, we represent their behaviour in terms of client/application interactions and elasticity methods at different levels using bigraphical reaction rules. The feasibility of the proposed approach is illustrated through a motivating example running on the top of an Amazon Elastic Compute Cloud (EC2) infrastructure. \textcopyright 2016 Informa UK Limited, trading as Taylor & Francis Group

A Maude-based rewriting approach to model and verify Cloud/Fog self-adaptation and orchestration

International audienceIn the IoT-Fog-Cloud landscape, IoT devices are connected to numerous software applications in order to fully operate. Some applications are deployed on the Fog layer, providing low-latency access to resource, whilst others are deployed on the Cloud to provide important resource capabilities and process heavy computation. In this distributed landscape, the deployment infrastructure has to adapt to the highly dynamic requirements of the IoT layer. However, due to their intrinsic properties, the Fog layer may lack of providing sufficient amount of resource while the Cloud layer fails ensuring low-latency requirements. In this paper, we present a rewriting-based approach to design and verify the Cloud-Fog self-adaption and orchestration behaviors in order to manage infrastructure reconfiguration towards achieving low-latency and resources quantity trade-offs. We rely of the formal specification language Maude to provide an executable solution of these behaviors basing on the rewriting logic and we express properties with linear temporal logic (LTL) to qualitatively verify the adaptations correctness.KeywordsSelf-adaptation; Orchestration; Fog computing; Cloud computing; Formal methods; Rewriting logic; Linear Temporal Logic; Maud

Implémentation Orientée Objet d'ABAReL en Maude

A paraîtreABAReL (AADL Behavioral Annex based on revised Rewriting Logic) associe à un thread AADL un modèle mathématique représenté par une théorie de réécriture étendue décrivant sa structure statique et comportementale. Elle offre un cadre sémantique général approprié pour raisonner sur le comportement des threads, dans un plan architectural d?un système embarqué temps réel, sans altérer le métamodèle AADL. L?objectif de cet article est double. D?une part, nous situons le modèle formel d?ABAReL dans le contexte d?une théorie orientée objet temps réel et nous exploitons le système RT-Maude pour exécuter et analyser l?architecture AADL correspondante vis-à-vis des flux qui la traversent et des propriétés d?exécution déclarées. D?autre part, nous enrichissons ABAReL par la sémantique d?exécution d?une composition architecturale de threads et leurs connexions possibles, tout en supervisant l?effet du passage du temps sur la transmission des flux de données et/ou événements à travers ces connexions

A Tile Logic Based Approach for Software Architecture Description Analysis

International audienceA main advantage of Architecture Description Languages (ADL) is their aptitude to facilitate formal analysis and verification of complex software architectures. Since some researchers try to extend them by new techniques, we show in this paper how the use of tile logic as extension of rewriting logic can enforce the ability of existing ADL formalisms to cope with hierarchy and composition features which are more and more present in such software architectures. In order to cover ADL key and generic concepts, our approach is explained through LfP (Language for rapid Prototyping) as ADL offering the possibility to specify the hierarchical behaviour of software components. Then, our contribution goal is to exploit a suitable logic that allows reasoning naturally about software system behaviour, possibly hierarchical and modular, in terms of its basic components and their interactions