Runtime Verification of Temporal Patterns 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 runtime. Recently we have proposed a temporal pattern logic, called FTPL, to characterize the correct reconfigurations of component-based systems under some temporal and architectural constraints. As component-based architectures evolve at runtime, there is a need to check these FTPL constraints on the fly, even if only a partial information is expected. Firstly, given a generic component-based model, we review FTPL from a runtime verification point of view. To this end we introduce a new four-valued logic, called RV-FTPL (Runtime Verification for FTPL), characterizing the "potential" (un)satisfiability of the architectural constraints in addition to the basic FTPL semantics. Potential true and potential false values are chosen whenever an observed behaviour has not yet lead to a violation or satisfiability of the property under consideration. Secondly, we present a prototype developed to check at runtime the satisfiability of RV-FTPL formulas when reconfiguring a Fractal component-based system. The feasability of a runtime property enforcement is also shown. It consists in supervising on the fly the reconfiguration execution against desired RV-FTPL properties. The main contributions are illustrated on the example of a HTTP server architecture

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

Adaptive Service Composition Based on Runtime Verification of Formal Properties

Service-Oriented Computing (SOC) has been used in business environments in order to integrate heterogeneous systems. The dynamic nature of these environments causes \ changes in the application requirements. As a result, service composition must be flexible, dynamic and adaptive, which motivate the need to ensure the service composition behavior \ at runtime. The development of adaptive service compositions is still an opportunity due to the complexity of dealing with adaptation issues, for example, how to provide runtime verification \ and automatic adaptation. Formal description techniques can be used to detect runtime undesirable behaviors that help in adaptation process. However, formal techniques have been \ used only at design-time. In this paper, we propose an adaptive service composition approach based on the lightweight use of formal methods. The aim is detecting undesirable behaviors in \ the execution trace. Once an undesirable behavior is detected during the execution of a service composition, our approach triggers an adequate reconfiguration plan for the problem at \ runtime. In order to evaluate the effectiveness of the proposal, we illustrate it with a running example

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

SPaCIFY: a Formal Model-Driven Engineering for Spacecraft On-Board Software

International audienceThe aim of this article is to present a model- driven approach proposed by the SPaCIFY project for spacecraft on-board software development. This ap- proach is based on a formal globally asynchronous lo- cally synchronous language called Synoptic, and on a set of transformations allowing code generation and model verification