Mestrado em Ciência da Computação (INF)

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Navegando Mestrado em Ciência da Computação (INF) por Por Orientador "COSTA, Fábio Moreira"

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    Grades Computacionais Oportunistas: Alternativas para Melhorar o Desempenho das Aplicações
    (Universidade Federal de Goiás, 2009-04-13) GOMES, Raphael de Aquino; GEORGES, Fouad Joseph; http://lattes.cnpq.br/3758021312498294; COSTA, Fábio Moreira; http://lattes.cnpq.br/0925150626762308
    Scavenging grid computing environments are being even more used as an alternative aside traditional processing categories. This kind of system is characterized by using of communal and shared workstations and its main concern is the guarantee of performance for the user who gives its resources to the grid. This concern, and because it is an extremaly dynamic environment, causes the adoption of treatments limited to best-effort. However, this effort hardly ever is fulfilled in an optimal way due the fact that are usually used treatments which doesn t create an effective managing of resources, doing the competitiveness of the grid applications with the local applications always penalize the grid s tasks, lowing the its performance. This work presents an architecture for the performance improvement to the grid applications, which takes into account using profiles of resources for locals applications, trying to identify when it is temporary and avoid taking actions as grid tasks migration. As alternative way or additional is proposed the using of adaptive technics who focus allowing the grade tasks maintenance on the actual node or the system improvement. The architecture was partially implemented on InteGrade middleware. We describe the developed implementation an its evaluation
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    Uso de um Modelo de Interceptadores para Prover Adaptação Dinâmica no InteGrade
    (Universidade Federal de Goiás, 2008-04-25) OLIVEIRA NETO, Jesus José de; COSTA, Fábio Moreira; http://lattes.cnpq.br/0925150626762308
    Computer grids are sets of computational resources that provide diverse types of services, such as storage and processing, on behalf of applications spread across different administrative domains. Many companies and academic institutions have demonstrated interest in their use for the execution of applications that demand huge amounts of computation power and storage. However, computer grids are complex and diversified execution environments, which exhibit high variation of resource availability, node instability and variations on load distribution, among other problems. This work presents a model of dynamic interceptors and its use in InteGrade, an opportunistic grid middleware. The use of interceptors aims to provide dynamic adaptation in InteGrade through its communication middleware, thus contributing to make InteGrade able to deal with the highly variable execution environment of computer grids without requiring changes to its implementation. Therefore, this work aims to offer dynamic adaptation capabilities to InteGrade and not to grid applications. Nevertheless, these applications will be able to benefit from adaptation provided by InteGrade
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    Uma Plataforma de Middleware reflexivo com suporte para auto-adaptação
    (Universidade Federal de Goiás, 2009-04-06) PROVENSI, Lucas Luiz; RODRIGUES, Vagner José do Sacramento; http://lattes.cnpq.br/4148896613580056; COSTA, Fábio Moreira; http://lattes.cnpq.br/0925150626762308
    The distributed computing environment today is characterized by increasing diversity, the dynamism and increasingly complex applications. Applications for this type of environment they need autonomy to conduct management activities such as installation, configuration and maintenance, with the aim of decreasing the cost and effort involved in such activities. In mobile environments, for example, applications need to adapt due to changes in the environment (available bandwidth, signal level, etc..), Which can affect the quality of service offered to users. This paper presents a proposal for self-adaptation based on the architecture of Meta-ORB reflective middleware. The fluffy main purpose is to provide support to self-adaptation for applications that have requirements of service quality. In this paper, the concept of adaptation policies was introduced in the meta-model middleware, allowing the developer to define both the model of adaptive behavior as their applications using the same modeling language. This unified model is available at run time, being used by a mechanism of self-adaptation to the embedded middleware. The proposed architecture was implemented in a prototype called MetaORB.NET, employed in a case study to evaluate the use of architecture in the development of self-adaptive applications