10 research outputs found
Using Temporal Logic for Dynamic Reconfigurations of Components
International audienceDynamic reconfigurations increase the availability and the reliability of component-based systems by allowing their architectures to evolve at run-time. This paper deals with the formal specification and verification of dynamic reconfigurations of those systems using architectural constraints and temporal logic patterns. The proposals of the paper are applied to the Fractal component model. Given a Fractal reference implementation of a component-based system, we specify its dynamic reconfigurations using a temporal pattern logic for Fractal, called FTPL, characterizing the correct behaviour of the system under some architectural constraints. We study system reconfigurations on which we verify these requirements, in particular by reusing the FPath and FScript tools
Component Substitution through Dynamic Reconfigurations
Component substitution has numerous practical applications and constitutes an
active research topic. This paper proposes to enrich an existing
component-based framework--a model with dynamic reconfigurations making the
system evolve--with a new reconfiguration operation which "substitutes"
components by other components, and to study its impact on sequences of dynamic
reconfigurations.
Firstly, we define substitutability constraints which ensure the component
encapsulation while performing reconfigurations by component substitutions.
Then, we integrate them into a substitutability-based simulation to take these
substituting reconfigurations into account on sequences of dynamic
reconfigurations. Thirdly, as this new relation being in general undecidable
for infinite-state systems, we propose a semi-algorithm to check it on the fly.
Finally, we report on experimentations using the B tools to show the
feasibility of the developed approach, and to illustrate the paper's proposals
on an example of the HTTP server.Comment: In Proceedings FESCA 2014, arXiv:1404.043
Runtime Enforcement for Component-Based Systems
Runtime enforcement is an increasingly popular and effective dynamic
validation technique aiming to ensure the correct runtime behavior (w.r.t. a
formal specification) of systems using a so-called enforcement monitor. In this
paper we introduce runtime enforcement of specifications on component-based
systems (CBS) modeled in the BIP (Behavior, Interaction and Priority)
framework. BIP is a powerful and expressive component-based framework for
formal construction of heterogeneous systems. However, because of BIP
expressiveness, it remains difficult to enforce at design-time complex
behavioral properties.
First we propose a theoretical runtime enforcement framework for CBS where we
delineate a hierarchy of sets of enforceable properties (i.e., properties that
can be enforced) according to the number of observational steps a system is
allowed to deviate from the property (i.e., the notion of k-step
enforceability). To ensure the observational equivalence between the correct
executions of the initial system and the monitored system, we show that i) only
stutter-invariant properties should be enforced on CBS with our monitors, ii)
safety properties are 1-step enforceable. Given an abstract enforcement monitor
(as a finite-state machine) for some 1-step enforceable specification, we
formally instrument (at relevant locations) a given BIP system to integrate the
monitor. At runtime, the monitor observes and automatically avoids any error in
the behavior of the system w.r.t. the specification. Our approach is fully
implemented in an available tool that we used to i) avoid deadlock occurrences
on a dining philosophers benchmark, and ii) ensure the correct placement of
robots on a map.Comment: arXiv admin note: text overlap with arXiv:1109.5505 by other author
Реконфигурирование компонентно-ориентированных систем на базе графовых грамматик
Dynamic reconfigurations can modify the architecture of component-based systems without incurring any system downtime. In this context, the main contribution of the present article is the establishment of correctness results proving component-based systems reconfigurations using graph grammars. New guarded reconfigurations allow us to build reconfigurations based on primitive reconfiguration operations using sequences of reconfigurations and the alternative and the repetitive constructs, while preserving configuration consistency. A practical contribution consists of the implementation of a component-based model using the GROOVE graph transformation tool. Then, after enriching the model with interpreted configurations and reconfigurations in a consistency compatible manner, a simulation relation is exploited to validate component systems’ implementations. This sound implementation is illustrated on a cloud-based multitier application hosting environment managed as a component-based system.Динамические реконфигурирования могут изменять архитектуру компонентно-ориентированных систем, не подвергаясь никакому системному простою. В этом контексте основной вклад данной статьи – доказательство результатов корректности реконфигурирования систем, используя графовые грамматики. В этой статье предложены новые охраняемые реконфигурирования на базе логики Хоара, которые построены на основе примитивных операций по реконфигурированию и включают последовательности реконфигурирований, альтернативные и повторяющиеся конструкции, сохраняя при этом непротиворечивость конфигураций. Практический вклад состоит в описании имплементации компонентно-ориентированной модели, используя программный инструмент GROOVE для преобразования графов. После обогащения модели интерпретированными конфигурациями и реконфигурированиями, совместимого с непротиворечивостью, отношение симуляции используется для доказательства корректности имплементации, выполненной под GROOVE. Эта имплементация иллюстрирована на примере многоуровневого облачно-ориентированного приложения
Synchronous Control of Reconfiguration in Fractal Component-based Systems -- a Case Study
In the context of component-based embedded systems, the management of dynamic reconfiguration in adaptive systems is an increasingly important feature. The Fractal component-based framework, and its industrial instantiation MIND, provide for support for control operations in the lifecycle of components. Nevertheless, the use of complex and integrated architectures make the management of this reconfiguration operations difficult to handle by programmers. To address this issue, we propose to use Synchronous languages, which are a complete approach to the design of reactive systems, based on behavior models in the form of transition systems. Furthermore, the design of closed-loop reactive managers of reconfigurations can benefit from formal tools like Discrete Controller Synthesis. In this paper we describe an approach to concretely integrate synchronous reconfiguration managers in Fractal component-based systems. We describe how to model the state space of the control problem, and how to specify the control objectives. We describe the implementation of the resulting manager with the Fractal/Cecilia programming environment, taking advantage of the Comete distributed middleware. We illustrate and validate it with the case study of the Comanche HTTP server on a multi-core execution platform.Dans le contexte des composants pour systèmes embarqués, la gestion de la reconfiguration dynamique devient de plus en plus importante. Le modèle à composants Fractal et son implémentation MIND, fournissent des moyens de contrôle de cycle de vie des composants ainsi que des moyen pour le contrôle des architectures. L'utilisation des architectures intégrées de plus en plus complexes, rend la gestion des opérations de reconfiguration difficile à maintenir par le programmeur. Cette gestion devient plus complexe quand des propriétés globales sur le systèmes doivent être assurées. Nous proposons d'utiliser des langages synchrones réactifs, reposant sur des modèles comportementaux sous la forme de systèmes de transitions. De plus, notre approches, qui produit un manager synchrone pour la reconfiguration dynamique profite des techniques formelles comme la Synthèse de Contrôleurs Discrets. Ce papier décrit l'intégration concrète d'un manager synchrone pour la reconfiguration de systèmes-à-composants Fractal. Nous détaillerons notre approche en commençant par la partie modélisation du problème de contrôle sous forme d'espace d'états de configurations, ainsi que la description des propriétés de contrôle. Ensuite, nous aborderons la partie implémentation du manager résultant en Fractal/Cecilia et son intégration dans des applications Fractal distribuées en utilisant le middleware Comete. Nous validerons notre approche au moyen d'un cas d'étude sur le serveur HTTP Comanche sur une plateforme d'exécution multicoeurs
Concurrency-preserving and sound monitoring of multi-threaded component-based systems: theory, algorithms, implementation, and evaluation
International audienceThis paper addresses the monitoring of logic-independent linear-time user-provided properties in multi-threaded component-based systems. We consider intrinsically independent components that can be executed concurrently with a centralized coordination for multiparty interactions. In this context, the problem that arises is that a global state of the system is not available to the monitor. A naive solution to this problem would be to plug in a monitor which would force the system to synchronize in order to obtain the sequence of global states at runtime. Such a solution would defeat the whole purpose of having concurrent components. Instead, we reconstruct on-the-fly the global states by accumulating the partial states traversed by the system at runtime. We define transformations of components that preserve their semantics and con-currency and, at the same time, allow to monitor global-state properties. Moreover, we present RVMT-BIP, a prototype tool implementing the transformations for monitoring multi-threaded systems described in the BIP (Behavior, Interaction, Priority) framework, an expressive framework for the formal construction of heterogeneous systems. Our experiments on several multi-threaded BIP systems show that RVMT-BIP induces a cheap runtime overhead
Using Temporal Logic for Dynamic Reconfigurations of Components
Abstract. Dynamic reconfigurations increase the availability and the reliability of component-based systems by allowing their architectures to evolve at run-time. This paper deals with the formal specification and verification of dynamic reconfigurations of those systems using architectural constraints and temporal logic patterns. The proposals of the paper are applied to the Fractal component model. Given a Fractal reference implementation of a component-based system, we specify its dynamic reconfigurations using a temporal pattern logic for Fractal, called FTPL, characterizing the correct behaviour of the system under some architectural constraints. We study system reconfigurations on which we verify these requirements, in particular by reusing the FPath and FScript tools.
Using Temporal Logic for Dynamic Reconfigurations of Components
Abstract. Dynamic reconfigurations increase the availability and the reliability of component-based systems by allowing their architectures to evolve at run-time. This paper deals with the formal specification and verification of dynamic reconfigurations of those systems using architectural constraints and temporal logic patterns. The proposals of the paper are applied to the Fractal component model. Given a Fractal reference implementation of a component-based system, we specify its dynamic reconfigurations using a temporal pattern logic for Fractal, called FTPL, characterizing the correct behaviour of the system under some architectural constraints. We study system reconfigurations on which we verify these requirements, in particular by reusing the FPath and FScript tools.