Self-Configuration and Self-Optimization Autonomic Skeletons using Events

International audienceThis paper presents a novel way to introduce self-configuration and self-optimization autonomic characteristics to algorithmic skeletons using event driven programming techniques. Based on an algorithmic skeleton language, we show that the use of events greatly improves the estimation of the remaining computation time for skeleton execution. Events allow us to precisely monitor the status of the execution of algorithmic skeletons. Using such events, we provide a framework for the execution of skeletons with a very high level of adaptability. We focus mainly on guaranteeing a given execution time for a skeleton, by optimizing autonomically the number of threads allocated. The proposed solution is independent from the platform chosen for executing the skeleton for example we illustrate our approach in a multicore setting, but it could also be adapted to a distributed execution environment

A ProActive Backend for ABS: from Modelling to Deployment

ABS is an object-oriented modeling language that is based on a concurrent object group model, derived itself from the active object model. Its goal is to describe distributed and concurrent applications in order to verify their properties and make them safer. Thanks to the ABS Tool Suite, ABS programs can be translated into the Java programming language (among others), and executed in the JVM. This paper presents a new ABS backend that translates ABS programs into ProActive programs. ProActive is a well known active object Java library that provides support for distribution of applications across clusters or grids. The benefit of this work is to be able to easily distribute ABS programs, so that ABS models can also be experimented in a large scale setting. Our contribution includes the ProActive backend itself, the complete description of our translation strategy, and a realistic experiment that shows the benefits of the ProActive backend

Asynchonous distributed components: concurrency and determinacy

Based on the imp&-calculus, ASP (Asynchronous Sequential Processes) de nes distributed applications behaving deterministically. This article extends ASP by building hierarchical and asynchronous distributed components. Components are hierarchical - a composite can be built from other components, and distributed - a composite can span over several machines. This article also shows how the asynchronous component model can be used to statically assert component determinism.4th IFIP International Conference on Theoretical Computer ScienceRed de Universidades con Carreras en Informática (RedUNCI

Book review: Spirit of rebellion. Labor and religion in the new cotton south

International audienceThis article provides formal definitions characterizing well-formed composition of components in order to guarantee their safe deployment and execution. Our work focuses on the structural aspects of component composition; it puts together most of the concepts common to many component models, but never formalized as a whole. Our formalization characterizes correct component architectures made of functional and non-functional aspects, both structured as component assemblies. Interceptor chains can be used for a safe and controlled interaction between the two aspects. Our well-formed components guarantee a set of properties ensuring that the deployed component system has a correct architecture and can run safely. Finally, those definitions constitute the formal basis for our Eclipse-based environment for the development and specification of component-based applications

Functional Active Objects: Noninterference and Distributed Consensus

In this report, we present recent work on the language of functional active objects ASPfun. We first introduce briefly the language ASPfun, its syntax and semantics. Then, we present a method for static security checking for our functional distributed active object language. We show how the type system of ASPfun is easily extensible for noninterference: a type system that enables analyzing an ASPfun program statically – prior to execution – detects information flows that contradict a given security policy. To prove this conjecture, we introduce the definition of an indistinguishability relation and prove the noninterference theorem that shows that this indistinguishability relation is a bisimulation on ASPfun executions. In a second part, we investigate the question of distributed consensus in ASPfun. We implement Paxos, a distributed consensus algorithm due to Lamport, in ASPfun. This implementation illustrates how functional active objects behave when stateful operations occur

Experiments with distributed Model-Checking of group-based applications

National audienceGroup-based distributed systems are specific cases of distributed applications with a parameterized topology. They are naturally modelled by systems with a very large state space. We encode the behavioural semantics of group-based applications using the intermediate format FIACRE. We have experimented with model-checking of such systems, using the CADP verification toolset, and in particular the distributor tool. This allowed us to generate very large but finite state-space on the PacaGrid cloud infrastructure. We have then been able to compare different techniques for generating state-spaces, and experiment with different sizes of the modelled system and of the experimental platform

A Mechanized Model of the Theory of Objects

In this paper we present a formalization of Abadi's and Cardelli's theory of ob jects in the interactive theorem prover Isabelle/HOL. Our motivation is to build a mechanized HOL-framework for the analysis of a functional calculus for distributed ob jects. In particular, we present (a) a formal model of ob jects and its operational semantics based on de Bruijn indices (b) a parallel reduction relation for ob jects (c) the proof of confluence for the theory of ob jects reusing Nipkow's HOL-framework for the lambda calculus. We expect this framework to be highly reusable and allow further development and mechanized proofs of various aspects of ob ject theory, e.g., distribution, aspect orientation, typing

Programming distributed and adaptable autonomous components--the GCM/ProActive framework

International audienceComponent-oriented software has become a useful tool to build larger and more complex systems by describing the application in terms of encapsulated, loosely coupled entities called components. At the same time, asynchronous programming patterns allow for the development of efficient distributed applications. While several component models and frameworks have been proposed, most of them tightly integrate the component model with the middleware they run upon. This intertwining is generally implicit and not discussed, leading to entangled, hard to maintain code. This article describes our efforts in the development of the GCM/ProActive framework for providing distributed and adaptable autonomous components. GCM/ProActive integrates a component model designed for execution on large-scale environments, with a programming model based on active objects allowing a high degree of distribution and concurrency. This new integrated model provides a more powerful development, composition, and execution environment than other distributed component frameworks. We illustrate that GCM/ProActive is particularly adapted to the programming of autonomic component systems, and to the integration into a service-oriented environment

Bringing Coq Into the World of GCM Distributed Applications

International audienceAmong all programming paradigms, component-based engineering stands as one of the most followed approaches for real world software devel- opment. Its emphasis on clean separation of concerns and reusability makes it appealing for both industrial and research purposes. The Grid Component Model (GCM) endorses this approach in the con- text of distributed systems by providing all the means to define, compose and dynamically reconfigure component-based applications. While structural re- configuration is one of the key features of GCM applications, this ability to evolve at runtime poses several challenges w.r.t reliability. In this paper we present Mefresa, a framework for reasoning on the struc- ture of GCM applications. This contribution comes in the form of a formal specification mechanized in the Coq Proof Assistant. Our aim is to demon- strate the benefits of interactive theorem proving for the reasoning on software architectures. We provide a configuration and reconfiguration language for the safe instantiation of distributed systems