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Mathematical modelling of single spillways is well documented in literature. For parallel spillways however, there is a lack of documented, verified, and validated cases. Here, in this article, ANSYS-CFX is used to simulate the flow over three parallel ogee-crested spillways. For mesh size verification, a grid convergence study is performed by Richardson extrapolation. The turbulence model chosen for this simulation is the k-ε model and the volume of fluid method is used to simulate the water-air interface. This article details the models ability to accurately predict flow distribution at the spillways, and the water levels. The mesh is kept relatively coarse at the channel inlet with increased mesh density at the spillways. The results are validated against experimental data from Vattenfall AB, R&Ds laboratories. The geometry and boundary conditions of the experiment are tailored for CFD. The flow rate of each spillway is measured separately with high accuracy, and for several different inlet volumetric flows. The simulation results lie within the error estimates of the measuring tools used in the experiments, within ±1%. The volume flow rate differences between the three outlets is very small, within ±1%. ISBN för värdpublikation: 978-1-74272-309-9

The development of medical devices is a safety-critical process, because a failure or a malfunction of the device can cause serious injuries to the patients whom use it. The application of a rigorous process for their development reduces the risk of failures since validation and verification activities can be performed in a objective, reproducible, and documentable manner. In this paper we present an approach based on the Abstract State Machine (ASM) formal method. Starting from the model, validation and verification (V&V) techniques can be applied. Furthermore, by step-wise refinement, a final model can be obtained, which can be automatically translated to Open image in new window code. The process is applied to the smart pill box case study. Starting from the ASM model, we generate Open image in new window code for the Arduino platform after the application of V&V activities. Furthermore, we introduce regulation (IEC62304) and guidelines (FDA General Principles of Software Validation) that support the developer in medical software development. In particular, we explain how ASMs formal process can be compliant with them.

Phase-field models, sometimes referred to as gradient damage or smeared crack models, are widely used methods for the numerical simulation of crack propagation in brittle materials. Theoretical results and numerical evidences show that they can predict the propagation of a pre-existing crack according to Griffith’ criterion. For a one-dimensional problem, it has been shown that they can predict nucleation upon a critical stress, provided that the regularization parameter be identified with the material’s internal or characteristic length. In this article, we draw on numerical simulations to study crack nucleation in commonly encountered geometries for which closed-form solutions are not available. We use U- and V-notches to show that the nucleation load varies smoothly from that predicted by a strength criterion to that of a toughness criterion when the strength of the stress concentration or singularity varies. We present validation and verification numerical simulations for both types of geometries. We consider the problem of an elliptic cavity in an infinite or elongated domain to show that variational phase field models properly account for structural and material size effects. Our main claim, supported by validation and verification in a broad range of materials and geometries, is that crack nucleation can be accurately predicted by minimization of a nonlinear energy in variational phase field models, and does not require the introduction of ad-hoc criteria.

Most enterprises, and especially SMEs, must develop their business in very competitive and rapidly changing fields. Where they have to adapt to volatile customers who want to find cheaper products and services and that are more corresponding to their needs. The SME is then confronted with problems of responsiveness and flexibility in responding to these customers. As an effect, it seeks to reduce the costs and time to market and to provide high quality and innovative goods and services. The SME’s information system is an asset on which it can rely to implement this strategy and so to maximize its responsiveness and flexibility but also to reach the sought profitability and quality. These are key qualities that guarantee autonomy and recognition, qualities that are highly needed by any SME. The Information system is indeed the drive belt of information not only inside the enterprise, between decision and operational systems proving added value of the enterprise, but also within its environment that includes its external partners. Part of this information system is computerized. It stores and processes the information needed by the different decision-making, business and support processes that serve the enterprise’s strategy. It is crucial to understand the features, interfaces and data that make up this computerized system and develop them according to the needs of SME. The SME is therefore tempted to embark, alone or accompanied, in so-called computerization projects i.e. projects for the development or improvement of its computerized system. We are interested in projects aimed at developing management applications of SMEs. The SME – then assuming the role of project owner – along with the development team – supporting the role of project management – have to share a common vision of the computerization needs. They are then called upon to carry out jointly requirements engineering (RE) activities. RE guides the SMEs to be able to describe and formalize its needs. It then allows the development team to specify more formally these needs as requirements which then define the required development work. RE is often carried out with the assistance of project owner support. This crucial step remains difficult for SMEs. It is most often performed by the development team itself to address the lack of resources, time and skills of SMEs. However, the involvement of the SME’s members is vital to the success of any computerization project, especially if it permanently affects the functioning of the enterprise. This work, developed through a collaborative with the company RESULIS, consisted in developing a requirements engineering method which offers SMEs concepts, simple languages, modeling and verification means that are easily and intuitively manipulated and provide sufficient and relevant formalization of the SME’s requirements. This method is based on principles derived from both enterprise modeling and systems engineering fields for requirements elicitation. Semi-formal verification and validation means are applied to guarantee some expected qualities of the resulting requirements. The method is also integrated in the model driven development cycle to enable a posteriori the production of prototypes and make interoperable the languages and tools used by both the SME and the development team., Une entreprise, et particulièrement une PME ou une PMI, doit être apte à évoluer sur des secteurs d’activités souvent très concurrentiels qui évoluent rapidement, par exemple, en fonction d’une clientèle volatile et soucieuse de trouver des produits et des services moins chers et plus adaptés à ses besoins. La PME se trouve alors confrontée à des problèmes de réactivité et de flexibilité face à cette clientèle. Par effet direct, elle recherche à réduire les délais et les coûts de réalisation tout en privilégiant aussi la qualité et le degré d’innovation des biens et des services qu’elle propose. Le sys-tème d’information de cette PME est un enjeu essentiel pour mettre en œuvre cette stratégie et maximiser donc la réactivité et la flexibilité mais aussi la rentabilité et la qualité recherchées. Ce sont des qualités incontournables, garantes d’une autonomie et d’une reconnaissance dont la PME a grand besoin. Le système d’information est en effet la courroie de transmission entre le système de décision et le système productif qui génère la valeur ajoutée de la PME. Il fait le lien entre les différents acteurs de l’organisation mais aussi avec les partenaires externes de l’entreprise. Une partie de ce système d’information est de fait informatisée. Celui-ci supporte, mémorise et traite les informations nécessaires aux différents processus de décision, métiers et supports qui tapissent l’organisation pour servir la stratégie de l’entreprise. Les fonctionnalités, les interfaces et les données qui forment ce système informatisé sont donc cruciales à comprendre, à développer en accord avec les besoins de la PME, à améliorer au fur et à mesure de l’évolution de ces besoins. La PME est donc tentée de se lancer, seule ou accompagnée, dans des projets dits d’informatisation i.e. des projets visant le développement ou l’amélioration de son système informatisé. Nous nous intéressons ici à des projets visant à développer des applicatifs de gestion et de pilotage de la PME. La PME – prenant alors le rôle de la maîtrise d’ouvrage (MOA) – tout comme la société de services qui l’accompagne – prenant alors en charge le rôle de maîtrise d’œuvre (MOE) – doivent partager une vision commune des besoins d’informatisation. Elles sont alors appelées à mener en commun des activités d’ingénierie des besoins et des exigences (IBE). L’IBE guide et accompagne la PME pour arriver à décrire et formaliser ses besoins. Elle permet ensuite à la société de service de spécifier de manière plus formelle ces besoins sous forme d’exigences qui définissent alors les travaux de développement souhaités. L’IBE est souvent réalisée avec une assistance à maîtrise d’ouvrage. Cette étape cruciale reste cependant difficile pour une PME. Elle est de plus souvent réalisée par la MOE elle-même pour faire face au manque de moyens, de temps et de compétences de la PME. Or, l’implication des collaborateurs de la PME est primordiale pour la réussite de tout projet d’informatisation, surtout si celui-ci impacte durablement le fonctionnement de la PME. Ces travaux, développés dans le cadre d’une collaboration Industrie/recherche avec la SSII RESULIS, ont consisté à déve-lopper une méthode d’IBE qui offre aux PME des concepts, des langages et des moyens de modélisation et de vérification simples mais suffisants tout en tant aisément manipulables de manière intuitive et donnant lieu à une formalisation perti-nente pour la MOE. Cette méthode est basée sur le croisement et la complémentarité de principes issus de la Modélisation d’Entreprise et de l’Ingénierie Système pour l’élicitation de besoins. Des moyens de vérification et de validation semi-formels sont appliqués pour garantir certaines qualités attendues des exigences résultantes. La méthode s’intègre égale-ment au cycle de développement basé sur les modèles pour permettre a posteriori d’accélérer la production de prototypes et de rendre interopérables les langages et outils de la MOA et de la MOE.

Since 1990’s, Agent Based Modelling are commonly used by geographers to study complex systems like cities. However, very few technical platforms are advanced by searchers to assist in the construction and evaluation of models of simulation. With the help of ERC program GeoDiverCity and the formation of an expert interdisciplinary team, we try to solve these problematic following two objectives. Relying on the support of OpenMOLE platform developed at the Institute of Complex System Paris-Ile-de-France in order to make it simple the distribution of simulation on distributed computing environments, we identify, use or build new tools and methodology to construct and explore model of simulation. To anchor this work in practice, we use this platform to build and explore a new model of simulation: SimpopLocal. This very practical work is accompanied by an historical and epistemological reading of simulation, and the means of simulation in geography. These contextualisation permits us to examine, and perhaps to anticipate, the historical link between the old problematic of “Validation”, very important to consider for knowledge justification, and the building and exploration of models of simulation.; Depuis son adoption en géographie dans les années 1990, le méta-formalisme Agent pour la simulation est mobilisé avec succès et de façon croissante dans l'étude des systèmes dynamiques complexes que sont les villes. Peu de solutions techniques ont été avancées ces dernières années dans la littérature pour encadrer la construction et l'évaluation plus systématique de ces modèles de simulation. Au regard de cette insuffisance, et grâce au soutien d'un projet ERC et la formation d'une équipe interdisciplinaire, ce sont deux objectifs simultanés qui ont été avancés pour aborder et tenter de solutionner cette problématique. En s'appuyant sur la plateforme OpenMOLE développée ces dernières années à l'Institut des Systèmes Complexes Paris-Ile-de-France et conçue pour démocratiser l'accès à des ressources de calculs distribués, il s'agit d'identifier, d'utiliser, ou de construire des outils et des méthodes innovantes pour la construction et l'exploration des modèles de simulation. Afin d'ancrer cette étude dans une réalité de pratiques, le choix est fait d’associer à ces développements la construction et l'exploration d'un tout nouveau modèle de simulation : SimpopLocal. Ce travail est accompagné par une double lecture à la fois historique et épistémologique de la simulation et des moyens de la simulation en géographie. Cette remise en contexte permet de réinterroger, et d’anticiper par la mise en œuvre d’outils et de méthodes que l’on espère plus adaptées, le rapport historique entretenu entre cette problématique ancienne de la «Validation» des modèles de simulation, centrale dans la justification des connaissances, avec la construction et l’exploration de modèle de simulation.

International audience; This report documents the program and the outcomes of Dagstuhl Seminar 14062 "The Pacemaker Challenge: Developing Certifiable Medical Devices". The aim of the seminar was to bring together leading researchers and industrial partners of this field; the seminary ended up with 24 participants from 8 countries: Canada, Denmark, France, The Unites States, Germany, United Kingdom, Brazil. Through a series of presentations, discussions, and working group meetings, the seminar attempted to get a general view of the field of medical devices and certification issues through the pacemaker challenge. The seminar brought together, on the one hand, researchers from the different notations and various tools. The main outcome of the seminar is the exchange of information between different groups and the project of a book.

This thesis researches the role of software architectural patterns and lightweight formal methods in safety-critical software development. We present a framework that relates the different activities and products from system engineering, safety engineering, system and software requirements, and software architecture explicitly, and demonstrate the proposed framework with a case study involving the architectural design of the software to control the arming device of a fictitious Surface-to-Air Missile. We describe the safety engineering steps for the identification of the system hazards and the critical functions that the software has to provide to avoid premature detonation, resulting in four safety requirements for the software that controls the missiles Electronic Safe Arm Device (ESAD). We formalize the software safety requirements as statechart assertions and validate their correctness via JUnit test. We develop a software architecture for the control software using the Safety Executive pattern, and implement the design in C++ to support a simple time-step simulation to produce the required log files for the automated verification of the design. http://archive.org/details/applicationofrch1094537646 Lieutenant, Hellenic Navy Approved for public release; distribution is unlimited.

In Model-Driven Development, the main artefacts are conceptual schemas, and efforts are focused on their creation, testing and evolution at different levels of abstraction through transformations. If a conceptual schema has defects, these are passed on to the following stages, including coding. Therefore, techniques for improving the quality of conceptual schemas must be implemented to assure the correct generation of final software products. One of the challenges in Model-Driven Development is being able to identify defects early on, at the level of conceptual schemas, as this would help reduce development costs and improve software quality. In this research proposal we suggest an approach for testing-based conceptual schema validation in order to improve quality. Valencia

Timeline-based planners have been shown quite successful in addressing real world problems. Nevertheless they are considered as a niche technology in AI P&S research as an application synthesis with such techniques is still considered a sort of "black art". Authors are currently developing a knowledge engineering tool around a timeline-based problem solving environment; in this framework we aim at integrating verification and validation methods. This work presents a verification process suitable for a timeline-based planner. It shows how a problem of flexible temporal plan verification can be cast as model-checking on timed game automata. Additionally it provides formal properties and checks the effectiveness of the proposed approach with a detailed experimental analysis.

Aerospace industry is experiencing exponential growth in the size and complexity of onboard software. It is also seeing a significant increase in errors and rework of that software. All of those factors contribute to greater cost; the current development process is reaching the limit of affordability of building safe aircraft. An international consortium of aerospace companies with government participation has initiated the System Architecture Virtual Integration (SAVI) program, whose goal is to achieve an affordable solution through a paradigm shift of―integrate then build. A key concept of this paradigm shift is an architecture- centric approach to analysis of virtually integrated system models with respect to multiple operational quality attributes such as performance, safety, and reliability. By doing so early and throughout the life cycle at different levels of fidelity, system-level faults are discovered earlier in the life cycle—reducing risk, cost, and development time. The first phase of this program demonstrated the feasibility of this new development process through a proof of concept demonstration and a return on investment analysis, which are the topics of this paper.

From 04.11. to 09.11.2007, the Dagstuhl Seminar 07451 ``Model-Based Engineering of Embedded Real-Time Systems'' was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available.

ISBN 2-866012-283-6; International audience; Cet article décrit le protocole FDDI et présente les caractéristiques temporelles nécessaires à la transmission d'images en, temps réel. Nous nous intéresserons tout particulièrement au mode synchrone de la méthode d'accès au medium du protocole FDDI. Nous prouvons que ce mode garantit la transmission des images en respectant les contraintes temporelles.

Timeline-based planning techniques have demonstrated wide application possibilities in heterogeneous real world domains. For a wider diffusion of this technology, a more thorough investigation of the connections with formal methods is needed. This paper is part of a research program aimed at studying the interconnections between timeline-based planning and standard techniques for formal validation and verification (V&V). In this line, an open issue consists of studying the link between plan generation and plan execution from the particular perspective of verifying temporal plans before their actual execution. The present work addresses the problem of verifying flexible temporal plans, i.e., those plans usually produced by least-commitment temporal planners. Such plans only impose minimal temporal constraints among the planned activities, hence are able to adapt to on-line environmental changes by trading some of the retained flexibility. This work shows how a model-checking verification tool based on Timed Game Automata (TGA) can be used to verify such plans. In particular, flexible plan verification is cast as a model-checking problem on those automata. The effectiveness of the proposed approach is shown by presenting a detailed experimental analysis with a real world domain which is used as a flexible benchmark.