Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-01-26T17:46:31Z No. of bitstreams: 1 GustavoNogueiraAlves_DISSERT.pdf: 7390589 bytes, checksum: 622ffc2952552ee8688415a6acdb97f1 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-01-28T17:44:43Z (GMT) No. of bitstreams: 1 GustavoNogueiraAlves_DISSERT.pdf: 7390589 bytes, checksum: 622ffc2952552ee8688415a6acdb97f1 (MD5) / Made available in DSpace on 2016-01-28T17:44:43Z (GMT). No. of bitstreams: 1 GustavoNogueiraAlves_DISSERT.pdf: 7390589 bytes, checksum: 622ffc2952552ee8688415a6acdb97f1 (MD5) Previous issue date: 2015-01-28 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / Computa??o em Nuvem ? um paradigma computacional que possibilita o acesso de forma simples e pervasiva, via rede, a recursos compartilhados e configur?veis de computa??o. Tais recursos s?o oferecidos sob demanda para o usu?rio atrav?s de um modelo de uso em que s? se paga pelo uso do recurso. Com o avan?o desse paradigma, um ?nico servi?o oferecido por uma plataforma de nuvem pode n?o ser suficiente para prover todos os requisitos dos clientes, sendo necess?rio uma composi??o de servi?os providos por diferentes plataformas de nuvem. No entanto, as plataformas de nuvem atuais n?o s?o implementadas usando padr?es comuns, cada uma possui sua pr?pria API e ferramenta de desenvolvimento, o que dificulta a cria??o da composi??o. Para facilitar a cria??o de composi??es existe o Cloud Integrator, uma plataforma de middleware orientada a servi?os que prov? um ambiente que facilita o desenvolvimento e a execu??o de aplica??es. Essas aplica??es s?o composi??es de servi?os de diferentes plataformas de nuvem e representadas atrav?s de workflows abstratos. No entanto, o Cloud Integrator possui algumas limita??es: (i) as aplica??es criadas s?o executadas localmente; (ii) usu?rios n?o podem especificar a aplica??o apenas pelas suas entradas e sa?das, e; (iii) os usu?rios n?o podem selecionar diretamente qual os servi?os que v?o executar as atividades do workflow. A fim de tratar essas limita??es, esse trabalho prop?e o Cloud Stratus, uma plataforma de middleware que estende o Cloud Integrator e oferece diferentes formas de especificar aplica??es, permitindo se definir um workflow abstrato ou fluxo de execu??o completo ou parcial. A plataforma possibilita a implanta??o da aplica??o em m?quinas virtuais na nuvem, de forma que v?rios usu?rios podem acess?-la atrav?s da Internet. O Cloud Stratus ainda realiza o acesso e gerenciamento de m?quinas virtuais de diferentes plataformas de nuvem e fornece mecanismos para monitoramento de servi?os e aferi??o de par?metros de QoS. A valida??o do Cloud Stratus ? realizada atrav?s de um estudo de caso que consiste de uma aplica??o que utiliza diversos servi?os de nuvem providos por diferentes plataformas de nuvem. O Cloud Stratus ainda ? avaliado atrav?s de experimentos computacionais que analisam o desempenho de seus processos. / Cloud Computing is a paradigm that enables the access, in a simple and pervasive way, through the network, to shared and configurable computing resources. Such resources can be offered on demand to users in a pay-per-use model. With the advance of this paradigm, a single service offered by a cloud platform might not be enough to meet all the requirements of clients. Ergo, it is needed to compose services provided by different cloud platforms. However, current cloud platforms are not implemented using common standards, each one has its own APIs and development tools, which is a barrier for composing different services. In this context, the Cloud Integrator, a service-oriented middleware platform, provides an environment to facilitate the development and execution of multi-cloud applications. The applications are compositions of services, from different cloud platforms and, represented by abstract workflows. However, Cloud Integrator has some limitations, such as: (i) applications are locally executed; (ii) users cannot specify the application in terms of its inputs and outputs, and; (iii) experienced users cannot directly determine the concrete Web services that will perform the workflow. In order to deal with such limitations, this work proposes Cloud Stratus, a middleware platform that extends Cloud Integrator and offers different ways to specify an application: as an abstract workflow or a complete/partial execution flow. The platform enables the application deployment in cloud virtual machines, so that several users can access it through the Internet. It also supports the access and management of virtual machines in different cloud platforms and provides services monitoring mechanisms and assessment of QoS parameters. Cloud Stratus was validated through a case study that consists of an application that uses different services provided by different cloud platforms. Cloud Stratus was also evaluated through computing experiments that analyze the performance of its processes.