CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / XML tornou-se um padrÃo amplamente utilizado na representaÃÃo e troca de dados entre aplicaÃÃes na Web. Com isso, grande volume desses dados està distribuÃdo na Web e armazenado em diversos meios de persistÃncia. SGBD relacionais que suportam XML fornecem tÃcnicas de controle de concorrÃncia para gerenciar esses dados. A estrutura dos dados XML, entretanto, dificulta a aplicaÃÃo dessas tÃcnicas. Trabalhos estÃo sendo propostos e fornecem gerenciamento de documentos XML. A maioria destes trabalhos, todavia, nÃo oferecem um controle de concorrÃncia eficiente para dados distribuÃdos. Outros trabalhos dÃo suporte ao controle distribuÃdo de dados XML, mas estes possuem protocolos com baixo grau de concorrÃncia e limitaÃÃes. Para prover um gerenciamento eficaz em ambientes distribuÃdos, este trabalho apresenta o DTX, como mecanismo para o controle de concorrÃncia distribuÃdo para dados XML, que leva em consideraÃÃo caracterÃsticas estruturais destes dados. O DTX visa a um gerenciamento eficaz de dados XML e contemplar as propriedades de isolamento e consistÃncia em transaÃÃes, utilizando um protocolo para controle de concorrÃncia multigranular que aumenta o paralelismo entre as transaÃÃes e possui uma estrutura otimizada para representaÃÃo dos dados. A soluÃÃo proposta possui uma arquitetura modular e flexÃvel, o que facilita sua integraÃÃo com diferentes estruturas de armazenamento XML, alÃm de poder ser estendido, adicionando novos recursos. Para validar o DTX, diversos testes foram feitos, comparando o DTX descrito neste trabalho com uma variaÃÃo do DTX, utilizando um protocolo de maior granulosidade, visando a simular as estratÃgias dos trabalhos relacionados. Os resultados obtidos atestam a eficÃcia do DTX, considerando diferentes aspectos em transaÃÃes distribuÃdas a dados XML, melhorando o desempenho, ou seja, o tempo de execuÃÃo destas transaÃÃes. / XML has become a widely used standard for data representation and exchange among Web applications. Consequently, a large volume of such data is distributed all over the Web and stored using several persistence methods. DBMSs provide concurrency control techniques to manage data. However, the structure of XML data makes it difficult to use these techniques. Projects are being proposed and they provide management of XML documents. Nevertheless, most of these projects do not provide efficient concurrency control mechanisms for distributed data. Some of them do provide support for distributed control of XML data, but use protocols that have limitations and offer low concurrency levels. In order to provide effective data management in distributed environments, we present DTX, a distributed concurrency control mechanism for XML data that takes into account its structural characteristics. DTX aims to provide effective management of XML data and contemplate properties such as isolation and consistency in transactions, using a multi-granular concurrency control protocol that increases parallelism among transactions and that has an optimized structure for data representation. DTX has a modular and flexible architecture, allowing for easy integration with any XML storage mechanisms. Moreover, DTX can be extended by adding new features to it. In order to evaluate DTX, several experiments were conducted comparing DTX as it is with a variation of DTX that uses a fine-grained protocol, in an attempt to simulate existing strategies in related work. Results confirm DTXâs effectiveness considering different aspects of distributed transactions on XML data, improving their performance, i.e., transaction execution time.

MOREIRA, Leonardo Oliveira. DTX: um mecanismo de controle de concorrência distribuído para dados XML. 2008. 89 f. Dissertação (Mestrado em ciência da computação)- Universidade Federal do Ceará, Fortaleza-CE, 2008. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-07-11T17:50:32Z No. of bitstreams: 1 2008_dis_lomoreira.pdf: 5597130 bytes, checksum: 9a74d13a49d1367fd13d8ff4c140fdc4 (MD5) / Approved for entry into archive by Rocilda Sales (rocilda@ufc.br) on 2016-07-18T16:01:30Z (GMT) No. of bitstreams: 1 2008_dis_lomoreira.pdf: 5597130 bytes, checksum: 9a74d13a49d1367fd13d8ff4c140fdc4 (MD5) / Made available in DSpace on 2016-07-18T16:01:30Z (GMT). No. of bitstreams: 1 2008_dis_lomoreira.pdf: 5597130 bytes, checksum: 9a74d13a49d1367fd13d8ff4c140fdc4 (MD5) Previous issue date: 2008 / XML has become a widely used standard for data representation and exchange among Web applications. Consequently, a large volume of such data is distributed all over the Web and stored using several persistence methods. DBMSs provide concurrency control techniques to manage data. However, the structure of XML data makes it difficult to use these techniques. Projects are being proposed and they provide management of XML documents. Nevertheless, most of these projects do not provide efficient concurrency control mechanisms for distributed data. Some of them do provide support for distributed control of XML data, but use protocols that have limitations and offer low concurrency levels. In order to provide effective data management in distributed environments, we present DTX, a distributed concurrency control mechanism for XML data that takes into account its structural characteristics. DTX aims to provide effective management of XML data and contemplate properties such as isolation and consistency in transactions, using a multi-granular concurrency control protocol that increases parallelism among transactions and that has an optimized structure for data representation. DTX has a modular and flexible architecture, allowing for easy integration with any XML storage mechanisms. Moreover, DTX can be extended by adding new features to it. In order to evaluate DTX, several experiments were conducted comparing DTX as it is with a variation of DTX that uses a fine-grained protocol, in an attempt to simulate existing strategies in related work. Results confirm DTX’s effectiveness considering different aspects of distributed transactions on XML data, improving their performance, i.e., transaction execution time. / XML tornou-se um padrão amplamente utilizado na representação e troca de dados entre aplicações na Web. Com isso, grande volume desses dados está distribuído na Web e armazenado em diversos meios de persistência. SGBD relacionais que suportam XML fornecem técnicas de controle de concorrência para gerenciar esses dados. A estrutura dos dados XML, entretanto, dificulta a aplicação dessas técnicas. Trabalhos estão sendo propostos e fornecem gerenciamento de documentos XML. A maioria destes trabalhos, todavia, não oferecem um controle de concorrência eficiente para dados distribuídos. Outros trabalhos dão suporte ao controle distribuído de dados XML, mas estes possuem protocolos com baixo grau de concorrência e limitações. Para prover um gerenciamento eficaz em ambientes distribuídos, este trabalho apresenta o DTX, como mecanismo para o controle de concorrência distribuído para dados XML, que leva em consideração características estruturais destes dados. O DTX visa a um gerenciamento eficaz de dados XML e contemplar as propriedades de isolamento e consistência em transações, utilizando um protocolo para controle de concorrência multigranular que aumenta o paralelismo entre as transações e possui uma estrutura otimizada para representação dos dados. A solução proposta possui uma arquitetura modular e flexível, o que facilita sua integração com diferentes estruturas de armazenamento XML, além de poder ser estendido, adicionando novos recursos. Para validar o DTX, diversos testes foram feitos, comparando o DTX descrito neste trabalho com uma variação do DTX, utilizando um protocolo de maior granulosidade, visando a simular as estratégias dos trabalhos relacionados. Os resultados obtidos atestam a eficácia do DTX, considerando diferentes aspectos em transações distribuídas a dados XML, melhorando o desempenho, ou seja, o tempo de execução destas transações.

Dans le contexte de l’informatique pervasive et de l’internet des objets, les systèmes sonthétérogènes, distribués et adaptatifs (p. ex., systèmes de gestion des transports, bâtimentsintelligents). La conception et le déploiement de ces systèmes sont rendus difficiles par leurnature hétérogène et distribuée mais aussi le risque de décisions d’adaptation conflictuelleset d’inconsistances à l’exécution. Les inconsistances sont causées par des pannes matériellesou des erreurs de communication. Elles surviennent lorsque des actions correspondant auxdécisions d’adaptation sont supposées être effectuées alors qu’elles ne le sont pas.Cette thèse propose un support intergiciel, appelé SICODAF, pour la conception et ledéploiement de systèmes adaptatifs fiables. SICODAF combine une fiabilité comportementale(absence de décisions conflictuelles) au moyen de systèmes de transitions et une fiabilitéd’exécution (absence d’inconsistances) à l’aide d’un intergiciel transactionnel. SICODAF estbasé sur le calcul autonomique. Il permet de concevoir et de déployer un système adaptatifsous la forme d’une boucle autonomique qui est constituée d’une couche d’abstraction, d’unmécanisme d’exécution transactionnelle et d’un contrôleur. SICODAF supporte trois typesde contrôleurs (basés sur des règles, sur la théorie du contrôle continu ou discret). Il permetégalement la reconfiguration d’une boucle, afin de gérer les changements d’objectifs quisurviennent dans le système considéré, et l’intégration d’un système de détection de pannesmatérielles. Enfin, SICODAF permet la conception de boucles multiples pour des systèmesqui sont constitués de nombreuses entités ou qui requièrent des contrôleurs de types différents.Ces boucles peuvent être combinées en parallèle, coordonnées ou hiérarchiques.SICODAF a été mis en oeuvre à l’aide de l’intergiciel transactionnel LINC, de l’environnementd’abstraction PUTUTU et du langage Heptagon/BZR qui est basé sur des systèmesde transitions. SICODAF a été également évalué à l’aide de trois études de cas. / In the context of pervasive computing and internet of things, systems are heterogeneous,distributed and adaptive (e.g., transport management systems, building automation). Thedesign and the deployment of these systems are made difficult by their heterogeneous anddistributed nature but also by the risk of conflicting adaptation decisions and inconsistenciesat runtime. Inconsistencies are caused by hardware failures or communication errors. Theyoccur when actions corresponding to the adaptation decisions are assumed to be performedbut are not done.This thesis proposes a middleware support, called SICODAF, for the design and thedeployment of reliable adaptive systems. SICODAF combines a behavioral reliability (absenceof conflicting decisions) by means of transitions systems and an execution reliability(absence of inconsistencies) through a transactional middleware. SICODAF is based on autonomiccomputing. It allows to design and deploy an adaptive system in the form of anautonomic loop which consists of an abstraction layer, a transactional execution mechanismand a controller. SICODAF supports three types of controllers (based on rules, on continuousor discrete control theory). SICODAF also allows for loop reconfiguration, to dealwith changing objectives in the considered system, and the integration of a hardware failuredetection system. Finally, SICODAF allows for the design of multiple loops for systems thatconsist of a high number of entities or that require controllers of different types. These loopscan be combined in parallel, coordinated or hierarchical.SICODAF was implemented using the transactional middleware LINC, the abstractionenvironment PUTUTU and the language Heptagon/BZR that is based on transitionssystems. SICODAF was also evaluated using three case studies.