Ce travail de recherche porte sur la spécification et l'opérationnalisation des scénarios pédagogiques sur les plateformes de formation à distance dans une perspective d'ingénierie et de réingénierie des EIAH (Environnements Informatique pour l'Apprentissage Humain). En se situant dans une approche centrée plateformes, nous supposons que les plateformes disposent de leur propre paradigme de conception. Pour cela, nous proposons aux développeurs et à la communauté de développement des plateformes un processus spécifique d'identification et d'explicitation du langage de conception pédagogique des plateformes de formation par le biais d'un métamodèle. Nous exploitons l'approche outillée Domain-Specific Modeling comme cadre pratique pour le développement de langages et d'outils de conception graphiques basés sur le métamodèle du langage de conception pédagogique. Afin de répondre à des besoins récurrents d'opérationnalisation de scénarios pédagogiques, nous utilisons également ce métamodèle pour la spécification des modules d'import/export intégrés au sein des plateformes. Ces modules permettent d'opérationnaliser les scénarios conformes au langage identifié et également d'exporter les scénarios existants sur les plateformes afin de permettre leur adaptation par les outils développés. Nous avons expérimenté nos propositions théoriques sur deux plateformes de formation Moodle et Ganesha. Enfin, nous avons vérifié la cohérence de notre approche par la mise à l'essai des outils développés. Par le biais de notre approche, nous favorisons une opérationnalisation de ces scénarios sans pertes d'information ni de sémantique.

A domain-specific embedded language (DSEL) is a domain-specific programming language with no concrete syntax of its own. Defined as a set of combinators encapsulated in a module, it borrows the syntax and tools (such as type-checkers and compilers) of its host language; hence it is economical to design, introduce, and maintain. Unfortunately, this economy is counterbalanced by a lack of room for growth. DSELs cannot match sophisticated domain-specific languages that offer tools for domainspecific error-checking and optimisation. These tools are usually based on syntactic analyses, so they do not work on DSELs. Abstract interpretation is a technique ideally suited to the analysis of DSELs, due to its semantic, rather than syntactic, approach. It is based upon the observation that analysing a program is equivalent to evaluating it over an abstract semantic domain. The mathematical properties of the abstract domain are such that evaluation reduces to solving a mutually recursive set of equations. This dissertation shows how abstract interpretation can be applied to a DSEL by replacing it with an abstract implementation of the same interface; evaluating a program with the abstract implementation yields an analysis result, rather than an executable. The abstract interpretation of DSELs provides a foundation upon which to build sophisticated error-checking and optimisation tools. This is illustrated with three examples: an alphabet analyser for CSP, an ambiguity test for parser combinators, and a definedness test for attribute grammars. Of these, the ambiguity test for parser combinators is probably the most important example, due to the prominence of parser combinators and their rather conspicuous lack of support for the well-known LL(k) test. In this dissertation, DSELs and their signatures are encoded using the polymorphic lambda calculus. This allows the correctness of the abstract interpretation of DSELs to be proved using the parametricity theorem: safety is derived for free from the polymorphic type of a program. Crucially, parametricity also solves a problem commonly encountered by other analysis methods: it ensures the correctness of the approach in the presence of higher-order functions.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Additional advisors: Marjan Mernik, Jeffrey G. Gray, Alan P. Sprague, Elliot J. Lefkowitz. Description based on contents viewed May 29, 2008; title from title screen. Includes bibliographical references (p. 140-152).

In a scope where continuous innovations are seen each day, the cyberspace can be seen as the tech-entrepreneurs’ playground for delivering new solutions to customers. Digital start-ups who interact through the cyberspace operate with little to no restriction despite having limiting resource. In 2008 a man named Satoshi Nakamoto developed a new technology called blockchain. The new breed of firms providing blockchain solutions have been painted to live in a borderless world with little technical restrictions. Exploring the effects that blockchain brings to their internationalisation has brought our attention to study the early internationalisation of blockchain born globals and their business ecosystem. The deductive and qualitative approach gave the results from four different companies that were involved in blockchain technology. By using previous theory on internationalisation and a deductive approach a conceptual synthesis was developed. The synthesis was later applied in the case-companies to observe the results. The findings have shown that the firms implementing blockchain in the core offering has resulted in an accelerated internationalisation. The major factors contributing to this quick internationalisations is the spread of knowledge between buyers and sellers, trough the cyberspace. However, the authors were unable to find a relationship between the accelerated internationalisation and to the extent in which a firm has implemented blockchain in its core offering. The finding has given the authors prominent answers to the research question and has highlighted the complexity of the subject. The, authors conclude the thesis by displaying the importance of cyberspace in the business ecosystem; how it attracts customers and the importance of the company’s business model. Blockchain technology proved to have effects on the process of internationalisation due to superior technological performance, but also its hype.

The forms discovered by our proposal can be directly used as training data by some form classifiers. Our experimental validation used thousands of real Web forms, divided into six domains, including a representative subset of the publicly available DeepPeep form base (DEEPPEEP, 2010; DEEPPEEP REPOSITORY, 2011). Our results show that it is feasible to mitigate the demanding manual work required by two cutting-edge form classifiers (i.e., GFC and DSFC (BARBOSA; FREIRE, 2007a)), at the cost of a relatively small loss in effectiveness.

Les travaux de cette thèse s'inscrivent dans le contexte général des réseaux logiciels, dits "Software-Defined Networking" (SDN). Ce paradigme récent est l'une des initiatives les plus notables pour rendre les réseaux actuels programmables ou, en d'autres termes, plus simple à configurer, à tester, à corriger et à faire évoluer. Dans un écosystème SDN, l'interface nord (Northbound API) est utilisée par l'administrateur réseaux pour définir ses politiques et programmer le plan de contrôle, elle représente donc un enjeu majeur. Idéalement, cette interface nord devrait permettre aux administrateurs de décrire, le plus simplement possible, des services réseaux et leurs interactions, plutôt que de spécifier comment et sur quels équipements physiques ils doivent être déployés. Des travaux existants montrent que cela peut être notamment réalisé grâce à des solutions de virtualisation de réseaux et des langages de programmation dédiés de haut niveau. L'objectif de ce travail de thèse est de proposer une nouvelle interface nord qui, d'une part, exploiterait la virtualisation de réseau et, d'autre part, exposerait ses services sous la forme d'un langage de programmation dédié. Actuellement, plusieurs langages intégrant des solutions de virtualisation de réseau existent. Néanmoins, nous pensons que les modèles d'abstraction qu'ils utilisent pour construire des réseaux virtuels restent inappropriés pour assurer des critères de simplicité, modularité et flexibilité des topologies virtuelles et des programmes de contrôle. Dans ce contexte, nous proposons un nouveau langage de contrôle de réseaux nommé AirNet. Ce dernier intègre un modèle d'abstraction dont la principale caractéristique est d'offrir une séparation nette entre les équipements de bordure (Edge) et de cœur de réseau (Fabric). Cette idée est bien connue et acceptée dans le domaine des architectures réseaux. L'originalité de notre contribution étant de faire remonter ce concept au niveau du plan de contrôle virtuel et non de le restreindre au seul plan physique. Ainsi, des frontières logiques entre les différents types de politiques existeront (fonctions de contrôle et de données vs. fonctions de transport), garantissant ainsi la modularité et la réutilisabilité de tout ou partie du programme de contrôle. De plus, dans l'approche proposée, la définition du réseau virtuel et des politiques peut être totalement dissociée de l'infrastructure physique cible, favorisant ainsi la portabilité des applications de contrôle. Une implémentation du langage AirNet a également été réalisée. Ce prototype inclut en particulier une bibliothèque des primitives et opérateurs du langage, ainsi qu'un hyperviseur qui assure la composition des politiques de contrôle sur un réseau virtuel, et leur transposition (mapping) sur l'infrastructure physique. Afin de s'appuyer sur des contrôleurs SDN existants, l'hyperviseur inclut des modules d'intégration des contrôleurs POX et RYU. Une validation expérimentale a été menée sur différents cas d'étude (filtrage, répartition de charge, authentification dynamique, limitation de bande passante, etc.) dont les résultats attestent de la faisabilité de la solution. Enfin, des mesures de performances ont montré que le surcoût apporté par cette nouvelle couche d'abstraction est parfaitement acceptable. / The work of this thesis falls within the general context of software-defined networking (SDN). This new paradigm is one of the most significant initiatives to enable networks programmability or, in other words, to make current networks easier to configure, test, debug and evolve. Within an SDN ecosystem, the Northbound interface is used by network administrators to define policies and to program the control plane, it thus represents a major challenge. Ideally, this northbound interface should allow administrators to describe, as simply as possible, network services and their interactions, rather than specifying how and on what physical device they need to be deployed. Current related works show that this can be partly achieved through virtualization solutions and high-level domain specific languages (DSL). The objective of this thesis is to propose a new Northbound interface which will, on the one hand, rely on network virtualization and, on the other hand, expose its services as a domain specific programming language. Currently, several languages that include network virtualization solutions exist. Nevertheless, we believe that the abstract models they are using to build virtual networks remain inadequate to ensure simplicity, modularity and flexibility of virtual topologies and control programs. In this context, we propose a new network control language named AirNet. Our language is built on top of an abstraction model whose main feature is to provide a clear separation between edge and core network devices. This concept is a well-known and accepted idea within the network designer community. The originality of our contribution is to lift up this concept at the virtual control plane, not limiting it solely at the physical plane. Thus, logical boundaries between different types of policies will exist (control and data functions vs. transport functions), ensuring modularity and reusability of the control program. Moreover, in the proposed approach, the definition of the virtual network and policies is totally dissociated from the target physical infrastructure, promoting the portability of control applications. An implementation of the AirNet language has also been done. This prototype includes in particular a library that implements the primitives and operators of the language, and a hypervisor that achieves the composition of the control policies on the virtual network, and their mapping on the physical infrastructure. In order to rely on existing SDN controllers, the hypervisor includes integration modules for the POX and RYU controllers. An experimental validation has been also conducted on different use cases (filtering, load balancing, dynamic authentication, bandwidth throttling, etc.), whose results demonstrate the feasibility of our solution. Finally, performance measurements have shown that the additional cost brought by this new abstraction layer is perfectly acceptable.

The forms discovered by our proposal can be directly used as training data by some form classifiers. Our experimental validation used thousands of real Web forms, divided into six domains, including a representative subset of the publicly available DeepPeep form base (DEEPPEEP, 2010; DEEPPEEP REPOSITORY, 2011). Our results show that it is feasible to mitigate the demanding manual work required by two cutting-edge form classifiers (i.e., GFC and DSFC (BARBOSA; FREIRE, 2007a)), at the cost of a relatively small loss in effectiveness.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / In ubiquitous systems, due to the complexity added by the use of contextual information, the application of context aware exception handling (CAEH) techniques has many challenges and in the literature several approaches have been found to define concepts and abstractions useful for modeling CAEH. However, only one of these approaches proposes a method for specification and verification of models in the field of ubiquitous systems, which provides a tool for specifying the CAEH model using a Java API, and also generates an error report to a text file. The disadvantage of this approach is that the designer should strive to understand programming details that are irrelevant to the analysis process of the exceptional behavior of the system. Then, this work aims to propose a domain specific language for modeling CAEH, which provides abstractions and constructors that allow to express relevant concepts and make the task of designing CAEH models simpler and more intuitive. In addition, the language is integrated with the tool mentioned before that allows automatic model verification. The errors generated by the verifier are now shown directly in the source code making their identification and correction easier for the designer. In order to evaluate the language, a case study is conducted to provide evidence of its viability as an alternative to modeling CAEH. / Em sistemas ubÃquos, devido à complexidade inserida pela utilizaÃÃo de informaÃÃes contextuais, a aplicaÃÃo de tÃcnicas de tratamento de exceÃÃo sensÃvel ao contexto (TESC) tem sido objeto de estudo para muitos pesquisadores. Na literatura sÃo encontradas diversas abordagens que definem conceitos e abstraÃÃes Ãteis para modelagem de TESC. Entretanto, apenas uma dessas abordagens propÃe um mÃtodo para especificaÃÃo e verificaÃÃo de modelos no domÃnio de sistemas ubÃquos o qual fornece uma ferramenta para especificaÃÃo do modelo de TESC atravÃs de uma API Java, e gera ainda um relatÃrio de erros em um arquivo texto. A desvantagem dessa abordagem à que o projetista deve se esforÃar para entender detalhes de programaÃÃo irrelevantes ao processo de anÃlise do comportamento excepcional do sistema. Esta dissertaÃÃo tem portanto como objetivo propor uma linguagem de domÃnio especÃfico para modelagem de TESC, com o intuito de oferecer abstraÃÃes e construtores que permitem expressar conceitos pertinentes e tornar a tarefa de projetar modelos de TESC mais simples e intuitiva. AlÃm disso, a linguagem à integrada com a ferramenta citada anteriormente, o que permite realizar a verificaÃÃo do modelo de forma automÃtica. Os erros gerados pelo verificador sÃo mostrados agora diretamente no cÃdigo do modelo facilitando a identificaÃÃo e correÃÃo dos mesmos pelo projetista. A fim de avaliar a linguagem, um estudo de caso à realizado para fornecer indÃcios de sua viabilidade como alternativa para modelagem de TESC.

The forms discovered by our proposal can be directly used as training data by some form classifiers. Our experimental validation used thousands of real Web forms, divided into six domains, including a representative subset of the publicly available DeepPeep form base (DEEPPEEP, 2010; DEEPPEEP REPOSITORY, 2011). Our results show that it is feasible to mitigate the demanding manual work required by two cutting-edge form classifiers (i.e., GFC and DSFC (BARBOSA; FREIRE, 2007a)), at the cost of a relatively small loss in effectiveness.

Au vu des dernières avancées dans le domaine de l’ingénierie web, ainsi qu’avec la baisse de coût du cloud computing, les architectures orientées services sont rapidement devenues la solution prépondérante pour fournir des services à valeur ajoutée aux clients. Suite à cette tendance, la composition de services tiers est devenue un paradigme de référence pour le développement d’applications robustes et riches, ou encore pour l’automatisation de processus métiers. Avec la disponibilité de centaines de milliers de services et APIs web, la réalisation de telles intégrations devient lourde et fastidieuse quand effectuée manuellement. Par ailleurs, chaque client peut exiger des besoins et politiques d’intégration différentes, ce qui complexifie davantage la tâche. De plus, fournir une telle solution qui soit à la fois robuste et scalable est une tâche non-triviale. Il est donc primordial d’étudier comment coordonner de manière efficace les interactions entre les services web existants. Ainsi, cette thèse vise à étudier les problématiques liées à la composition de services web dans le contexte des pratiques de développement web modernes. Nous présentons un cadre architectural permettant la spécification de compositions de services web grâce à une approche orientée langage, et montrons comment supporter leur exécution de manière scalable grâce à MEDLEY, une plateforme légère et orientée événements. / In light of the recent advances in the field of web engineering, along with the decrease of cost of cloud computing, service-oriented architectures rapidly became the leading solution in providing valuable services to clients. Following this trend, the composition of third-party services has become a successful paradigm for the development of robust and rich distributed applications, as well as automating business processes. With the availability of hundreds of thousands of web services and APIs, such integrations become cumbersome and tedious when performed manually. Furthermore, different clients may require different integration requirements and policies, which further complexifies the task. Moreover, providing such a solution that is both robust and scalable is a non-trivial task. Therefore, it becomes crucial to investigate how to efficiently coordinate the interactions between existing web services. As such, this thesis aims at investigating the underlying challenges in web service composition in the context of modern web development practices. We present an architectural framework to support the specification of web service compositions using a language-based approach, and show how we support their execution in a scalable manner using MEDLEY, a lightweight, event-driven platform.