Publications (4)0 Total impact
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ABSTRACT: A model was introduced in [Fraga97] for integrating replication techniques in heterogeneous systems. The model adopts a reflective structure based on the meta-object approach [10]. Also, this model is founded in ORBs that support group communication in heterogeneous environments. The OMG still does not have specifications for fault tolerance. The MetaFT model has a great flexibility allowing, for instance, to modify the coordination protocols according to the fault tolerance level desired, without any implications for the application code. The advantage is that it allows to use different meta-object protocol to assist different quality of service (QoS) parameters to fault tolerance. This paper explicit our experiences in developing replication techniques following the model using two different CORBA platforms and presents some performance analyzes.
05/2004;
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ABSTRACT: A model was introduced in [Fraga97] for integrating replication techniques in heterogeneous systems. The model adopts a reflective structure based on the meta-object approach [10]. Also, this model is founded in ORBs that support group communication in heterogeneous environments. The OMG still does not have specifications for fault tolerance. The MetaFT model has a great flexibility allowing, for instance, to modify the coordination protocols according to the fault tolerance level desired, without any implications for the application code. The advantage is that it allows to use different meta-object protocol to assist different quality of service (QoS) parameters to fault tolerance. This paper explicit our experiences in developing replication techniques following the model using two different CORBA platforms and presents some performance analyzes.
03/2001;
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ABSTRACT: Resumo. Este artigo propõe um suporte para desenvolvimento de aplicações baseadas em componentes de software CORBA (CCM) com requisitos de tolerância a faltas. O modelo TFA-CCM permite que requisitos de QoS norteiem a seleção da configuração de serviços replicados em tempo de execução, utilizando um conjunto de componentes que tratam dos aspectos não-funcionais da aplicação. As características deste modelo e os resultados obtidos com a sua implementação são descritos ao longo deste artigo. Abstract. This paper proposes a support for building distributed applications with fault-tolerance requirements by using software components. The TFA-CCM model allows that QoS requirements be used to select the configuration of replicated services at execution time, employing a set of components that deal with the non-functional aspects of the application. The characteristics of this model and the results obtained with its implementation are described along this paper.
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ABSTRACT: Resumo Este artigo apresenta um modelo para aplicações distribuídas com restrições tempo-real em sistemas abertos. O modelo proposto utiliza o paradigma de reflexão computacional segundo a abordagem de meta-objetos, que provê a separação entre funcionalidade e gerenciamento na programação de aplicações. Conseqüentemente, o modelo possui dois níveis : um nível-base que trata da funcionalidade do sistema, e um nível-meta que lida com escalonamento, restrições temporais e de sincronização, assim como tratamento de exceções. O modelo é implementado utilizando o padrão para sistemas distribuídos abertos CORBA, e tratando as restrições de tempo localmente a partir da especificação de um timeout no cliente e do deadline associado no servidor. Desta forma, o modelo garante um tratamento adequado para aplicações tempo-real do tipo melhor esforço em ambientes distribuídos abertos. Finalmente, as características principais do modelo proposto são ilustradas em um exemplo de aplicação de multimídia distribuída. Abstract This paper presents a model for distributed applications with real-time constraints in open systems. The proposed model adopts the reflective paradigm according to the meta-object approach, which provides the separation among functionality and management when programming applications. Consequently, the model has two levels : a base-level which deals with system functionality, and a meta-level which manages scheduling, time and synchronization constraints, as well as exception handling. The model is implemented using the CORBA standard for open distributed systems, and dealing with timing constraints locally, specifying timeouts in the client and the associated deadlines in the server. Then, the model ensures an adequate treatment of best-effort real-time applications in open distributed systems. Finally, the main characteristics of the proposed model are shown in an example of a distributed multimedia application.
