Contracts and Behavioral Patterns for SoS: The EU IP DANSE approach

This paper presents some of the results of the first year of DANSE, one of the first EU IP projects dedicated to SoS. Concretely, we offer a tool chain that allows to specify SoS and SoS requirements at high level, and analyse them using powerful toolsets coming from the formal verification area. At the high level, we use UPDM, the system model provided by the british army as well as a new type of contract based on behavioral patterns. At low level, we rely on a powerful simulation toolset combined with recent advances from the area of statistical model checking. The approach has been applied to a case study developed at EADS Innovation Works.Comment: In Proceedings AiSoS 2013, arXiv:1311.319

On the impact of pull request decisions on future contributions

The pull-based development process has become prevalent on platforms such as GitHub as a form of distributed software development. Potential contributors can create and submit a set of changes to a software project through pull requests. These changes can be accepted, discussed or rejected by the maintainers of the software project, and can influence further contribution proposals. As such, it is important to examine the practices that encourage contributors to a project to submit pull requests. Specifically, we consider the impact of prior pull requests on the acceptance or rejection of subsequent pull requests. We also consider the potential effect of rejecting or ignoring pull requests on further contributions. In this preliminary research, we study three large projects on \textsf{GitHub}, using pull request data obtained through the \textsf{GitHub} API, and we perform empirical analyses to investigate the above questions. Our results show that continued contribution to a project is correlated with higher pull request acceptance rates and that pull request rejections lead to fewer future contributions.Comment: 6 pages. Presented at BENEVOL 2018 software evolution seminar, Delft, The Netherlands (11 December 2018). Published in open access CEUR Workshop Proceedings (ceur-ws.org). Researchsupported by the FRQ-FNRS collaborative research project R.60.04.18.F SECOHealth, the Excellence of Science project 30446992 SECO-ASSIST financed by FWO-Vlaanderen and F.R.S.-FNRS, and F.R.S.-FNRS Grant T.0017.18, CEUR Workshop Proceedings 201

Statistical Model Checking of Dynamic Networks of Stochastic Hybrid Automata

In this paper we present a modelling formalism for dynamic networksof stochastic hybrid automata. In particular, our formalism is based on primitivesfor the dynamic creation and termination of hybrid automata components duringthe execution of a system. In this way we allow for natural modelling of conceptssuch as multiple threads found in various programming paradigms, as well as thedynamic evolution of biological systems.We provide a natural stochastic semantics of the modelling formalism based on re-peated output races between the dynamic evolving components of a system. Asspecification language we present a quantified extension of the logic Metric Tempo-ral Logic (MTL). As a main contribution of this paper, the statistical model checkingengine of U PPAAL has been extended to the setting of dynamic networks of hybridsystems and quantified MTL. We demonstrate the usefulness of the extended for-malisms in an analysis of a dynamic version of the well-known Train Gate example,as well as in natural monitoring of a MTL formula, where observations may lead todynamic creation of monitors for sub-formulas

A Few Considerations on Structural and Logical Composition in Specification Theories

Over the last 20 years a large number of automata-based specification theories have been proposed for modeling of discrete,real-time and probabilistic systems. We have observed a lot of shared algebraic structure between these formalisms. In this short abstract, we collect results of our work in progress on describing and systematizing the algebraic assumptions in specification theories.Comment: In Proceedings FIT 2010, arXiv:1101.426

Contracts and Behavioral Patterns for Systems of systems: The EU IP DANSE approach

This report presents some of the results of the first year of Danse, one of the first EU IP projects dedicated to System of Systems. Concretely, we offer a tool chain that allows to specify SoS and SoS requirements at high level, and analyse them using powerful toolsets coming from the formal verification area. At the high level, we use UPDM, the system model provided by the british army as well as a new type of contract based on behavioral patterns. At low level, we rely on a powerful simulation toolset combined with recent advances from the area of statistical model checking. The approach has been applied to a case study developed at EADS Innovation Works.Ce document présente les résultats de la première année du projet Danse, un des premiers projets IP de recherche portant sur les systèmes de Systèmes (SoS en anglais). Concrètement, une chaîne d'outils a été développée de façon à spécifier à "haut niveau" puis à analyser formellement un SoS avec un ensemble prérequis, c'est à dire un ensemble de propriétés que le SoS doit valider. L'analyse du SoS repose sur l'utilisation d'outils efficaces de vérification formelle. À "haut niveau", le SoS est décrit en UPDML, le langage dédié à la modélisation des SoS que l'armée britannique à développé, alors que les prérequis du SoS sont spécifiés au moyen d'un langage de contrats décrivant les comportements attendus du systèmes. Cette spécification "haut niveau" est compilée en une représentation "bas-niveau" qui est simulée et analysée grâce à des outils émanant des récentes techniques de vérification statistique. L'approche a en particulier été appliquée sur un cas d'étude développé par EADS Innovation Works

A Quantitative Assessment of Package Freshness in Linux Distributions

peer reviewedLinux users expect fresh packages in the official repositories of their distributions. Yet, due to philosophical divergences, the packages available in various distributions do not all have the same degree of freshness. Users therefore need to be informed as to those differences. Through quantitative empirical analyses, we assess and compare the freshness of 890 common packages in six mainstream Linux distributions. We find that at least one out of ten packages is outdated, but the proportion of outdated packages varies greatly between these distributions. Using the metrics of update delay and time lag, we find that the majority of packages are using versions less than 3 months behind the upstream in 5 of those 6 distributions. We contrast the user perception of package freshness with our analyses and order the considered distributions in terms of package freshness to help Linux users in choosing a distribution that most fits their needs and expectations

Statistical Model Checking for Stochastic Hybrid Systems

This paper presents novel extensions and applications of the UPPAAL-SMC model checker. The extensions allow for statistical model checking of stochastic hybrid systems. We show how our race-based stochastic semantics extends to networks of hybrid systems, and indicate the integration technique applied for implementing this semantics in the UPPAAL-SMC simulation engine. We report on two applications of the resulting tool-set coming from systems biology and energy aware buildings.Comment: In Proceedings HSB 2012, arXiv:1208.315