In this paper we motivate an Architecture Description Language (ADL) for mobile distributed systems based on the π-calculus. Different from other approaches, the non-functional properties, which are essential when mobile architectures are described, are treated in a flexible manner by inserting logical formulae for expressing and checking non-functional properties into π-calculus processes. A formal example is given to illustrate the approach before the constituents of the ADL are sketched.

This dissertation addresses the confidentiality aspect of the information security problem from the viewpoint of the software architecture. It presents a new approach to secure system design in which the desired security properties, in particular, confidentiality, of the system are proven to hold at the architectural level. The architecture description language Wright is extended so that confidentiality authorizations can be specified. An architectural description in Wright/c, the extended language, assigns clearance to the ports of the components and treats security labels as a part of data type information. The security labels are declared along with clearance assignments in an access control lattice model, also expressed in Wright/c. This enables the static analysis of data flow over the architecture subject to confidentiality requirements as per Bell-LaPadula principles. An algorithm takes the Wright/c description and the lattice model as inputs, and checks if there is a potential violation of the Bell-LaPadula principles. The algorithm also detects excess privileges. A software tool, which features an XML-based front-end to the algorithm is constructed. Finally, the algorithm is analyzed for its soundness, completeness and computational complexity.

Les approches basées sur les composants permettent de développer des logiciels en réutilisant des composants existant dans des bibliothèques. La structure d'un tel logiciel produit par assemblage de composants est définie à l'aide d'un langage de description d'architectures (ADL). Les processus de développement sont encore peu adaptés à ce paradigme. Ainsi, les ADL existants ne fournissent pas de véritable support au développement et à l'évolution des architectures logicielles à composants. Cette thèse propose Dedal, un ADL permettant de définir une architecture logicielle à différents niveaux d'abstraction qui correspondent aux étapes du cycle de vie du logiciel : sa spécification, son implémentation et son déploiement. La définition de l'architecture est complétée par un modèle du logiciel à l'exécution. La cohérence entre les différentes définitions d'une architecture doit être assurée : sa définition à un niveau d'abstraction doit être conforme à sa définition à un niveau supérieur. Ce principe permet de contrôler l'évolution d'une architecture, en validant les modifications réalisées à un certain niveau d'abstraction ou en motivant la création d'une nouvelle version pour propager les modifications entre niveaux d'abstraction et rétablir la cohérence. Ces mécanismes préviennent les problèmes d'érosion ou de dérive qui surviennent lors des évolutions entre les différents niveaux de définition des architectures. Un environnement couvrant le cycle de vie complet d'un logiciel à base de composants a été prototypé. Il comporte un atelier, permettant de décrire des architectures avec Dedal, puis un environnement d'exécution, extension des outils Fractal, capable de contrôler l'évolution des architectures déployées. L'évolution à l'exécution est réalisée de façon graduelle, de manière à faire fonctionner et à instrumenter les nouvelles versions pendant une phase de transition, avant de valider définitivement une modification. / Component-based approaches promote software development by reuse of existing components from a repository. The structure of such software is described as an assembly of software components using an architecture description language (ADL). Software development processes often do not comply with this paradigm yet. Consequently, existing ADLs do not fully support component-based software architecture development and evolution. This thesis proposes Dedal, an ADL to describe software architectures at several abstraction levels that correspond to the steps of software lifecycle: its specification, its implementation and its deployment. The architecture definition is completed with a runtime model of the software. Consistency between the various definitions of a given architecture must be maintained: its definition at some abstraction level must conform to its definition at a higher abstraction level. This consistency principle enables to control the evolution of architectures either validating changes performed at an abstraction level or motivating the creation of a new version, to propagate changes from an abstraction level to the other and restore their consistency. These mechanisms prevent from architecture erosion or drift which might occur between two different description levels after evolution. An environment that covers the whole lifecycle of component-based software has been prototyped. It includes a CASE tool that supports the Dedal-based description of architectures and a runtime environment that extends Fractal tools to control the evolution of the deployed software. Runtime evolution is performed gradually in order to have new versions run and instrumented during a transition phase before committing changes.

L'Orienté Service (SOA) est un paradigme de conception qui facilite la construction d’applications extensibles et reconfigurables basées sur des artefacts réutilisables qui sont les services. Ceux-ci sont structurés via des interfaces bien définies et publiables et qui peuvent être dynamiquement découvertes.Beaucoup d’approches ont été proposées dans la littérature pour la réingénierie d’applications existantes développées dans des paradigmes pré-services, principalement l’orienté objet, vers SOA. L’objectif est de permettre de sauvegarder la valeur métier de ces d’applications tout en leur permettant de bénéficier des avantages de SOA. Le problème est que ces approches s'appuient sur des critères ad-hoc pour identifier correctement des services dans le code source des applications existantes.Par ailleurs, l'une des caractéristiques les plus distinctives d'une application orientée service est sa capacité de se reconfigurer dynamiquement et d'adapter son comportement en fonction de son contexte d'exécution. Cependant, dans les langages de description d'architecture (ADL) existants dont l’aspect de reconfiguration et pris en compte, les règles de reconfiguration sont représentées d'une manière ad-hoc; en général, elles ne sont pas modélisées d'une manière explicite mais enfouillées dans la description de l'architecture. D'une part, ceci engendre une difficulté de la gestion de la reconfiguration dynamique au niveau de l'architecture et d’autre part, la traçabilité de la description de la reconfiguration dynamique à travers les différents niveaux d'abstraction est difficile à représenter et à gérer.Afin de surmonter les problèmes précédents, nous proposons dans le cadre de cette thèse deux contributions. D'abord, nous proposons une approche d'identification de services basée sur un modèle de qualité où les caractéristiques des services sont étudiées, raffinées et réifiées en une fonction que nous utilisons pour mesurer la validité sémantique de ces services. La deuxième contribution consiste en une proposition d'un langage de description d'architecture orientée service (ADL) qui intègre la description de la variabilité architecturale. Dans cette ADL les services qui peuvent constituer l’architecture, les éléments de contexte dont les changements d’état sont à l’origine des changements architecturaux, les variantes des éléments architecturaux sélectionnées en fonction des états des éléments de contexte et le comportement architectural dynamique sont ainsi spécifiés de façon modulaire. / Service Oriented Architecture (SOA) is an architectural design paradigm which facilitates building and composing flexible, extensible and reusable service-oriented assets. These latter are encapsulated behind well-defined and published interfaces that can be dynamically discovered by third-party services. Before the advent of SOA, several software systems were developed using older technologies. Many of these systems still afford a business value, however they suffer from evolution and maintenance problems. It is advantageous to modernize those software systems towards service-based ones. In this sense, several re-engineering techniques propose migrating object-oriented applications towards SOA. Nonetheless, these approaches rely on ad-hoc criteria to correctly identify services in object-oriented legacy source code.Besides, one of the most distinguishing features of a service-oriented application is the ability to dynamically reconfigure and adjust its behavior to cope with changing environment during execution. However, in existing architecture description languages handling this aspect, reconfiguration rules are represented in an ad-hoc manner; reconfiguration scenarios are often implicit. This fact hinders a full management of dynamic reconfiguration at architecture level. Moreover, it constitutes a challenge to trace dynamic reconfiguration description/management at different levels of abstraction.In order to overcome the aforementioned problems, our contributions are presented in two axes: First, in the context of migrating legacy software towards SOA, we propose a service identification approach based on a quality measurement model, where service characteristics are considered, refined to measurable metrics in order to measure the semantic correctness of identified services. The second axis is dedicated to an Architecture Description Language (ADL) proposition that describes a variant-rich service-based architecture. In this modular ADL, dynamic reconfigurations are specified at architecture level. Moreover, the description is enriched with context and variability information, in order to enable a variability-based self-reconfiguration of architecture in response to context changes at runtime.

<p>In this thesis we address the problem of optimal code generation for irregular architectures such as Digital Signal Processors (DSPs).</p><p>Code generation consists mainly of three interrelated optimization tasks: instruction selection (with resource allocation), instruction scheduling and register allocation. These tasks have been discovered to be NP-hard for most architectures and most situations. A common approach to code generation consists in solving each task separately, i.e. in a decoupled manner, which is easier from a software engineering point of view. Phase-decoupled compilers produce good code quality for regular architectures, but if applied to DSPs the resulting code is of significantly lower performance due to strong interdependences between the different tasks.</p><p>We developed a novel method for fully integrated code generation at the basic block level, based on dynamic programming. It handles the most important tasks of code generation in a single optimization step and produces an optimal code sequence. Our dynamic programming algorithm is applicable to small, yet not trivial problem instances with up to 50 instructions per basic block if data locality is not an issue, and up to 20 instructions if we take data locality with optimal scheduling of data transfers on irregular processor architectures into account. For larger problem instances we have developed heuristic relaxations.</p><p>In order to obtain a retargetable framework we developed a structured architecture specification language, xADML, which is based on XML. We implemented such a framework, called OPTIMIST that is parameterized by an xADML architecture specification.</p><p>The thesis further provides an Integer Linear Programming formulation of fully integrated optimal code generation for VLIW architectures with a homogeneous register file. Where it terminates successfully, the ILP-based optimizer mostly works faster than the dynamic programming approach; on the other hand, it fails for several larger examples where dynamic programming still provides a solution. Hence, the two approaches complement each other. In particular, we show how the dynamic programming approach can be used to precondition the ILP formulation.</p><p>As far as we know from the literature, this is for the first time that the main tasks of code generation are solved optimally in a single and fully integrated optimization step that additionally considers data placement in register sets and optimal scheduling of data transfers between different registers sets.</p>

In this thesis we address the problem of optimal code generation for irregular architectures such as Digital Signal Processors (DSPs). Code generation consists mainly of three interrelated optimization tasks: instruction selection (with resource allocation), instruction scheduling and register allocation. These tasks have been discovered to be NP-hard for most architectures and most situations. A common approach to code generation consists in solving each task separately, i.e. in a decoupled manner, which is easier from a software engineering point of view. Phase-decoupled compilers produce good code quality for regular architectures, but if applied to DSPs the resulting code is of significantly lower performance due to strong interdependences between the different tasks. We developed a novel method for fully integrated code generation at the basic block level, based on dynamic programming. It handles the most important tasks of code generation in a single optimization step and produces an optimal code sequence. Our dynamic programming algorithm is applicable to small, yet not trivial problem instances with up to 50 instructions per basic block if data locality is not an issue, and up to 20 instructions if we take data locality with optimal scheduling of data transfers on irregular processor architectures into account. For larger problem instances we have developed heuristic relaxations. In order to obtain a retargetable framework we developed a structured architecture specification language, xADML, which is based on XML. We implemented such a framework, called OPTIMIST that is parameterized by an xADML architecture specification. The thesis further provides an Integer Linear Programming formulation of fully integrated optimal code generation for VLIW architectures with a homogeneous register file. Where it terminates successfully, the ILP-based optimizer mostly works faster than the dynamic programming approach; on the other hand, it fails for several larger examples where dynamic programming still provides a solution. Hence, the two approaches complement each other. In particular, we show how the dynamic programming approach can be used to precondition the ILP formulation. As far as we know from the literature, this is for the first time that the main tasks of code generation are solved optimally in a single and fully integrated optimization step that additionally considers data placement in register sets and optimal scheduling of data transfers between different registers sets.

La complexité croissante des Systèmes de Systèmes et autres grandes fédérations d’acteurs pose de nouvelles problématiques de conception et de réalisation. Cette complexité, induite par des structures de management toujours plus sophistiquées et un cycle de vie long, doit être maîtrisée au plus tôt dans la conception des entreprises. Cette maîtrise permet à l’ensemble des intervenants au cours du cycle de vie d’une entreprise d’identifier ses points clés et de prendre confiance en sa capacité à atteindre ses objectifs. En particulier, il importe de savoir estimer les capacités de l’entreprise à s’adapter à des situations imprévues ou exceptionnelles afin d’assurer ses missions en toutes circonstances. En réaction, de nouvelles démarches d’ingénierie émergent. Elles s’appuient sur la modélisation et la simulation de l’architecture de ces systèmes aux différents stades de leur développement et de leur fonctionnement. Dans le cadre d’une de ces démarches nommée IDEA, nous avons enrichi le langage de description d’architecture avec des concepts et des mécanismes ayant pour but d’adresser l’adaptabilité et des capacités de reconfiguration des entreprises. Ces apports ont été expérimentés avec succès par prototypage et dans des contextes d’affaires industrielles. / As the complexity of large civilian and military Systems of Systems and system federations increases, new system architecture and engineering challenge emerge. This complexity is mainly due to intricate management structures and a long lifecycle, and needs to be mastered from the early stages of architecting. All engineering stakeholders need to identify the key aspects of the enterprise and gain confidence in its ability to fulfill its missions. To ensure that the enterprise is able to satisfy its objectives despite evolving situations, there is a need to focus on its capability to adapt through reconfiguration. New engineering approaches emphasize architecture modelling and simulation to tackle the complexity of the enterprise in all stages of its lifecycle in a flexible and global way. In the context of such an approach named IDEA, we updated the architecture description language to include concepts and mechanisms dedicated to the adaptability and reconfiguration of the enterprise. We also focused on ensuring model consistency. The results were experimented through prototyping and application on industrial affairs.

L'hétérogénéité et l'énergie sont deux considérations fondamentales pour les environnements informatiques ubiquitaires. Dans cette thèse, nous présentons notre approche pour gérer l'hétérogénéité et pour économiser l'énergie via des canevas de programmation intégrés. Pour gérer l'hétérogénéité, nous proposons une méthodologie et un support de programmation qui vise à faire communiquer les différentes entités de l’environnement ubiquitaire en utilisant le protocole SIP considéré alors comme un bus logique universel de communication. Nous avons intégré ce bus SIP dans le langage de description d’architecture DiaSpec développé par notre équipe Phoenix. Concernant la consommation d’énergie, nous proposons une méthodologie qui utilise les techniques d’offloading et de compression de données pour minimiser la consommation d'énergie des applications mobiles. Nous avons ainsi construit une stratégie d’aide à la conception au travers d’un outil qui permet de déterminer le meilleur mode d’exécution pour une tâche donnée que nous proposons d’intégrer dans le langage de description DiaSpec. / The topics of heterogeneity and energy are two fundamental considerations for pervasive computing environments. Inthis thesis, we describe our approach to manage heterogeneity and to handle energy concerns via a high-level programming framework.To manage heterogeneity, we describe a methodology and a programming support that use the SIP protocol as a universal communication bus in pervasive computing environments. Ourwork enables homogeneous communications between heterogeneous distributed entities. In doing so, we integrate the SIP communication bus into our programming framework. We rely on adeclarative language named DiaSpec to describe the architecture of pervasive applications. This description is passed to a generator for producing a Java programming framework dedicated to the application area. We leverage the generated framework with SIP adaptations to raise the abstraction level of SIP operations.We then present a classification of a wide variety of entities interms of features, capabilities and network connectors. Based on this classification, a methodology and a programming supportare described for connecting entities on the SIP communication bus. This work has been validated by applications using theSIP communication bus to coordinate widely varying entities,including serial-based sensors (RS232, 1-Wire), ZigBee devices,X10 devices, PDA, native SIP entities, and software components.Regarding the energy concerns, we describe a methodology that uses two strategies, namely computation offloading and data compression, to minimize energy cost of mobile applications.In doing so, we present an execution and transfer model for atask of a mobile application and define its five different stubs forthree program execution and data transfer modes. Based on this model and our two strategies, we construct a strategy scheme to determine the most efficient stub in terms of energy consumption.We then design the OffDeci tool, using this strategy scheme, toprovide energy feedback for the developer and to analyze thebalance between local and remote computing with consideration of data compression. Our experimental study demonstrates thefeasibility of the strategy scheme of our approach. Finally, weextend DiaSpec with declarations dedicated to manage energy concerns during the application design phase. We sketched the integration of this energy-handling declaration and OffDeci intoour high-level programming framework. This integration permitsto determine the best stub of a declared DiaSpec component interms of its energy cost.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Architectural specification of real-time software systems is an activity that conveys analysis, knowledge and understanding of both the application domain and the parties involved in software construction. Architecture plays a key role in communication between stakeholders, in addition to planning the entire architectural process involved in the project. However, Architecture Description Languages (ADLs) have not been widely used in the industry. Another limiting factor for the e ff ective use of ADLs is the di ffi culty of these languages in e ff ectively expressing the architecture of complex systems. Considering this situation of di ffi culty in the e ff ective use of ADLs, the UML has been used in recent years to model the architecture. However, UML can not represent the important characteristics pertinent to real-time systems, such as security or real-time constraints. One of the advantages of the UML is the extensibility allowing the creation of profiles. In this sense, this work proposes using Systems Modeling Language (SysML), a UML profile, to model real-time systems architecture in two automotive systems, the airbag control system and the light control system. The objective of this work is to use UML and SysML to model and document the architecture and design of requirements traceability between software and systems elements, increasing the understanding of the project among the parties involved, and finally presenting SysML as a language for description of real-time software architecture. The ADL Architecture Analysis and Design Language (AADL) and SysML languages were compared to show the advantages of SysML. As a result, it was noticed that abstract features such as conditional deviations, loop, characteristics that are related to reality and consequently to the system can not be described in AADL. SysML has proved to be relevant in the context of architecture description, analysis, classification and modeling of real-time systems. The SysML Requirements diagram explicitly shows the various types of relationships between di ff erent requirements, the Block diagram enables the global view of the systems involved in a single project, the Internal Block diagram allows the internal view of the system under construction, the Activity diagram considers the behavioral view of the system. SysML concepts, articulated in the SysML Requirements, Activities, Blocks and Internal Blocks diagrams, are complementary, covering the purposes needed to describe the architecture of real-time systems. It is concluded that the proposed UML and SysML join technique provides elements to describe software requirements and their relationships with the system, to manage changes, to evolve and to trace requirements more easily, in addition to the communication being e ff ectively carried out between the stakeholders. This is important for the development of real-time systems because of the diversity of people / teams involved and influencing a wide range of design decisions. / A especificação da arquitetura de sistemas de software de tempo real é uma atividade que depreende análise, conhecimento e compreensão tanto do domínio da aplicação quanto das partes envolvidas na construção do software. A arquitetura tem um papel primordial na comunicação entre os stakeholders, além do planejamento de todo o processo arquitetural envolvido no projeto. Contudo, as Linguagens de Descrição de Arquiteturas (ADLs) não têm sido amplamente usadas na indústria. Outro fator limitador para o uso efetivo de ADLs é a dificuldade dessas linguagens em expressar efetivamente a arquitetura de sistemas complexos. Considerando essa situação de dificuldade do uso efetivo de ADLs, a UML tem sido utilizada nos últimos anos para modelagem da arquitetura. No entanto, a UML não consegue representar características importantes pertinentes a sistemas de tempo real, tais como segurança ou restrições de tempo real. Uma das vantagens da UML é a capacidade de extensão permitindo a criação de profiles. Neste sentido, este trabalho apresenta a Systems Modeling Language (SysML), um profile da UML, para modelagem da arquitetura de sistemas de tempo real em dois sistemas automotivos, o sistema de controle de airbag e o sistema de controle de faróis. Neste trabalho tem-se como objetivos utilizar a UML e a SysML para modelagem e documentação da arquitetura e delineamento de rastreabilidade de requisitos entre software e sistema, ampliando o entendimento do projeto entre as partes envolvidas, e por fim apresentar a SysML como uma linguagem para descrição da arquitetura de software de tempo real. As linguagens SysML e a ADL Architecture Analysis & Design Language (AADL) foram comparadas para mostrar as vantagens da SysML. Como resultado, foi percebido que características abstratas, tais como tomadas de decisão, repetição de uma funcionalidade (loop), características que são relacionadas a realidade e, consequentemente, ao sistema, não podem ser descritas em AADL. A SysML mostrou-se relevante no contexto da descrição, análise, classificação e modelagem de arquitetura para sistemas de tempo real. O diagrama de Requisitos da SysML mostra explicitamente os diversos tipos de relacionamentos entre diferentes requisitos, o diagrama de Blocos viabiliza a visão global dos sistemas envolvidos num único projeto, o diagrama de Blocos Internos possibilita a visão interna do sistema em construção, o diagrama de Atividades considera a visão comportamental do sistema. Os conceitos de SysML, articulados nos diagramas de Requisitos, Atividades, Blocos e Blocos Internos da SysML são complementares cobrindo os propósitos necessários para a descrição da arquitetura de sistemas de tempo real. Conclui-se que a técnica proposta da junção de UML e SysML fornece elementos para descrever requisitos de software e seus relacionamentos com o sistema, gerenciar mudanças, evoluir e rastrear requisitos mais facilmente, além da comunicação ser efetivamente realizada entre os stakeholders. Este aspecto é importante ao desenvolvimento de sistemas de tempo real, por causa da diversidade de pessoas / equipes envolvidas e que influenciam uma ampla série de decisões de projeto.

Předmětem dizertační práce je návrh nových technik pro verifikaci hardwaru, které jsou optimalizovány pro použití v procesu souběžného vývoje hardwaru a softwaru. V rámci tohoto typu vývoje je hardware spolu se software vyvíjen paralelně s cílem urychlit vývoj nových systémů. Současné nástroje pro tvorbu mikroprocesorů stavějící na tomto stylu vývoje obvykle umožňují vývojářům ověřit jejich návrh využitím různých simulačních technik a/nebo za pomoci tzv. funkční verifikace. Společnou nevýhodou těchto přístupů je, že se zaměřují pouze na hledání chyb. Výsledný produkt tedy může stále obsahovat nenalezené netriviální defekty. Z tohoto důvodu se v posledních letech stává stále více žádané nasazení formálních metod. Na rozdíl od výše uvedených přístupů založených na hledání chyb, se formální verifikace zaměřuje na dodání rigorózního důkazu, že daný systém skutečně splňuje požadované vlastnosti. I když bylo v uplynulých letech v této oblasti dosaženo značného pokroku, tak aktuální formální přístupy nemají zdaleka schopnost plně automaticky prověřit všechny relevantní vlastnosti verifikovaného návrhu bez výrazného a často nákladného zapojení lidí v rámci verifikačního procesu. Tato práce se snaží řešit problém s automatizací verifikačního procesu jejím zaměřením na verifikační techniky, ve kterých je záměrně kladen menší důraz na jejich přesnost a obecnost, za cenu dosažení plné automatizace (např. vyloučením potřeby ručně vytvářet modely prostředí). Dále se práce také zaměřuje na efektivitu navrhovaných technik a jejich schopnost poskytovat nepřetržitou zpětnou vazbu o verifikačním procesu (např. v podobě podání informace o aktuálním stavu pokrytí). Zvláštní pozornost je pak věnována vývoji formálních metod ověřujících ekvivalenci návrhů mikroprocesorů na různých úrovních abstrakce. Tyto návrhy se mohou lišit ve způsobu, jakým jsou vnitřně zpracovány programové instrukce, nicméně z vnějšího pohledu (daného např. obsahem registrů viditelných z pozice programátora) musí být jejich chování při provádění stejného vstupního programu shodné. Kromě těchto témat se práce také zabývá problematikou návrhu metod pro verifikaci správnosti mechanismů zabraňujících výskytu datových a řídících hazardů v rámci linky zřetězeného zpracování instrukcí. Veškeré metody popsané v této práci byly implementovány ve formě několika nástrojů. Aplikací těchto nástrojů pro verifikaci návrhů netriviálních procesorů bylo dosaženo slibných experimentálních výsledků.