Spécification, validation et satisfiabilité [i.e. satisfaisabilité] de contraintes hybrides par réduction à la logique temporelle

Depuis quelques années, de nombreux champs de l'informatique ont été transformés par l'introduction d'une nouvelle vision de la conception et de l'utilisation d'un système, appelée approche déclarative. Contrairement à l'approche dite impérative, qui consiste à décrire au moyen d'un langage formelles opérations à effectuer pour obtenir un résultat, l'approche déclarative suggère plutôt de décrire le résultat désiré, sans spécifier comment ce «but» doit être atteint. L'approche déclarative peut être vue comme le prolongement d'une tendance ayant cours depuis les débuts de l'informatique et visant à résoudre des problèmes en manipulant des concepts d'un niveau d'abstraction toujours plus élevé. Le passage à un paradigme déclaratif pose cependant certains problèmes: les outils actuels sont peu appropriés à une utilisation déclarative. On identifie trois questions fondamentales qui doivent être résolues pour souscrire à ce nouveau paradigme: l'expression de contraintes dans un langage formel, la validation de ces contraintes sur une structure, et enfin la construction d'une structure satisfaisant une contrainte donnée. Cette thèse étudie ces trois problèmes selon l'angle de la logique mathématique. On verra qu'en utilisant une logique comme fondement formel d'un langage de « buts », les questions de validation et de construction d'une structure se transposent en deux questions mathématiques, le model checking et la satisfiabilité, qui sont fondamentales et largement étudiées. En utilisant comme motivation deux contextes concrets, la gestion de réseaux et les architectures orientées services, le travail montrera qu'il est possible d'utiliser la logique mathématique pour décrire, vérifier et construire des configurations de réseaux ou des compositions de services web. L'aboutissement de la recherche consiste en le développement de la logique CTLFO+, permettant d'exprimer des contraintes sur les données, sur la séquences des opérations\ud d'un système, ainsi que des contraintes dites «hybrides». Une réduction de CTL-FO+ à la logique temporelle CTL permet de réutiliser de manière efficace des outils de vérification existants. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Méthodes formelles, Services web, Réseaux

Large-Scale Client/Server Migration Methodology

The purpose of this dissertation is to explain how to migrate a medium-sized or large company to client/server computing. It draws heavily on the recent IBM Boca Raton migration experience. The client/server computing model is introduced and related, by a Business Reengineering Model, to the major trends that are affecting most businesses today, including business process reengineering, empowered teams, and quality management. A recommended information technology strategy is presented. A business case development approach, necessary to justify the large expenditures required for a client/server migration, is discussed. A five-phase migration management methodology is presented to explain how a business can be transformed from mid-range or mainframe-centric computing to client/server computing. Requirements definition, selection methodology, and development alternatives for client/server applications are presented. Applications are broadly categorized for use by individuals (personal applications) or teams. Client systems, server systems, and network infrastructures are described along with discussions of requirements definition, selection, installation, and support. The issues of user communication, education, and support with respect to a large client/server infrastructure are explored. Measurements for evaluation of a client/server computing environment are discussed with actual results achieved at the IBM Boca Raton site during the 1994 migration. The dissertation concludes with critical success factors for client/server computing investments and perspectives regarding future technology in each major area

3D-in-2D Displays for ATC.

This paper reports on the efforts and accomplishments of the 3D-in-2D Displays for ATC project at the end of Year 1. We describe the invention of 10 novel 3D/2D visualisations that were mostly implemented in the Augmented Reality ARToolkit. These prototype implementations of visualisation and interaction elements can be viewed on the accompanying video. We have identified six candidate design concepts which we will further research and develop. These designs correspond with the early feasibility studies stage of maturity as defined by the NASA Technology Readiness Level framework. We developed the Combination Display Framework from a review of the literature, and used it for analysing display designs in terms of display technique used and how they are combined. The insights we gained from this framework then guided our inventions and the human-centered innovation process we use to iteratively invent. Our designs are based on an understanding of user work practices. We also developed a simple ATC simulator that we used for rapid experimentation and evaluation of design ideas. We expect that if this project continues, the effort in Year 2 and 3 will be focus on maturing the concepts and employment in a operational laboratory settings

Remote Sensing and Geosciences for Archaeology

This book collects more than 20 papers, written by renowned experts and scientists from across the globe, that showcase the state-of-the-art and forefront research in archaeological remote sensing and the use of geoscientific techniques to investigate archaeological records and cultural heritage. Very high resolution satellite images from optical and radar space-borne sensors, airborne multi-spectral images, ground penetrating radar, terrestrial laser scanning, 3D modelling, Geographyc Information Systems (GIS) are among the techniques used in the archaeological studies published in this book. The reader can learn how to use these instruments and sensors, also in combination, to investigate cultural landscapes, discover new sites, reconstruct paleo-landscapes, augment the knowledge of monuments, and assess the condition of heritage at risk. Case studies scattered across Europe, Asia and America are presented: from the World UNESCO World Heritage Site of Lines and Geoglyphs of Nasca and Palpa to heritage under threat in the Middle East and North Africa, from coastal heritage in the intertidal flats of the German North Sea to Early and Neolithic settlements in Thessaly. Beginners will learn robust research methodologies and take inspiration; mature scholars will for sure derive inputs for new research and applications

Social work with airports passengers

Social work at the airport is in to offer to passengers social services. The main methodological position is that people are under stress, which characterized by a particular set of characteristics in appearance and behavior. In such circumstances passenger attracts in his actions some attention. Only person whom he trusts can help him with the documents or psychologically

FAA Center of Excellence for Alternative Jet Fuels & Environment: Annual Technical Report 2021: For the Period October 1, 2020 - September 30, 2021: Volume 1

FAA Award Number 13-C.This report covers the period October 1, 2020, through September 30, 2021. The Center was established by the authority of FAA solicitation 13-C-AJFE-Solicitation. During that time the ASCENT team launched a new website, which can be viewed at ascent.aero. The next meeting will be held April 5-7, 2022, in Alexandria, VA