Esta dissertação apresenta o Modelo de Componentes CORBA, que é parte da especificação CORBA 3.0. Esse modelo representa uma das mudanças mais significativas em relação às versões anteriores de CORBA. O desenvolvimento de sistemas distribuídos é uma tarefa complexa, envolvendo fatores como a organização de conjuntos de objetos que devem ser implantados e executados em servidores distintos. Aqui estes conjuntos são denominados componentes, conceito já existente em outras especificações, como a dos Enterprise Java Beans. O texto da especificação dos Componentes CORBA, apesar de conter exemplos, mostra-se de difícil compreensão para o desenvolvedor de sistemas. Este trabalho se propõe a facilitar a tarefa de entendimento e utilização de Componentes CORBA, procurando ser didático e ilustrativo o suficiente para que diferentes perfis de leitores possam compreender os diversos conceitos apresentados, seja como uma visão geral, ou ainda como auxílio no desenvolvimento de componentes. / This thesis presents the CORBA Component Model, which is part of the CORBA 3.0 specification. The model is one of the most significant additions with respect to previous versions of CORBA. The development of distributed systems is a complex task, involving factors such as the organization of sets of objects that must be deployed and executed in separate servers. Here, these sets are called components, a concept that already exists in other specifications, such as Enterprise Java Beans. Even though it contains examples, the CORBA Components specification text is not an easy reading for systems developers. Our text intends to facilitate the task of understanding and using CORBA Components, trying to be didactic and illustrative enough so that different profiles of readers are able to understand the many concepts presented, either as an overview, or still as an aid in components development.

Esta dissertação apresenta o Modelo de Componentes CORBA, que é parte da especificação CORBA 3.0. Esse modelo representa uma das mudanças mais significativas em relação às versões anteriores de CORBA. O desenvolvimento de sistemas distribuídos é uma tarefa complexa, envolvendo fatores como a organização de conjuntos de objetos que devem ser implantados e executados em servidores distintos. Aqui estes conjuntos são denominados componentes, conceito já existente em outras especificações, como a dos Enterprise Java Beans. O texto da especificação dos Componentes CORBA, apesar de conter exemplos, mostra-se de difícil compreensão para o desenvolvedor de sistemas. Este trabalho se propõe a facilitar a tarefa de entendimento e utilização de Componentes CORBA, procurando ser didático e ilustrativo o suficiente para que diferentes perfis de leitores possam compreender os diversos conceitos apresentados, seja como uma visão geral, ou ainda como auxílio no desenvolvimento de componentes. / This thesis presents the CORBA Component Model, which is part of the CORBA 3.0 specification. The model is one of the most significant additions with respect to previous versions of CORBA. The development of distributed systems is a complex task, involving factors such as the organization of sets of objects that must be deployed and executed in separate servers. Here, these sets are called components, a concept that already exists in other specifications, such as Enterprise Java Beans. Even though it contains examples, the CORBA Components specification text is not an easy reading for systems developers. Our text intends to facilitate the task of understanding and using CORBA Components, trying to be didactic and illustrative enough so that different profiles of readers are able to understand the many concepts presented, either as an overview, or still as an aid in components development.

Until now, the performance improvement of computing machines was a mostly a result of shrinking transistor geometries and increasing clock speeds. With the advent of signal processing applications that have stringent performance requirements from processing hardware, the field of configurable computing has received a lot of attention. Efforts are being made to improve computation bandwidth by architectural innovations. Among these, the wormhole runtime reconfigurable architecture introduces the concept of stream processing. It enables dynamic reconfiguration of hardware with little overheads and is very much suited for data-path based computations with deep computational pipelines. Stallion, second in the generation of Wormhole runtime reconfigurable processors, demonstrates the efficacy of wormhole runtime reconfiguration. The work presented here deals with the VLSI implementation of Stallion and discusses the full-custom physical design flow adopted for Stallion. Also, the tools and techniques to customize this flow are detailed. The Stallion design methodology offers a possible solution that can be pursued for executing similar efforts in future. / Master of Science

In recent years, interest in the area of custom computing machines (CCMs) has been on a steady increase. Much of the activity surrounding CCMs has centered around Field-Programmable Gate Array (FPGA) technology and rapid prototyping applications. While higher performance has been a concern in some applications, the solutions are limited by the relatively small FPGA bandwidth, density and throughput. This leads to area, speed, power, and application-specific constraints. In recent months, an integrated circuit known as the VT Colt has been developed to address some high performance digital signal processing (DSP) problems that conventional processors, CCMs, and ASICs cannot do under the space and power constraints. The Colt chip takes a data-flow approach to processing and is highly reconfigurable to suit the many computationally demanding tasks that new DSP applications present. A significant portion of the development of the Colt chip is architectural justification, functional verification, and configurability. This thesis explores verification of the Colt chip at various levels of development including mapping arithmetic computations and DSP algorithms that the Colt architecture was designed to solve. / Master of Science

This thesis presents the design and implementation of the Image Wavelet Compression (IWC) algorithm on Field Programmable Gate Arrays (FPGAs) by using the run-time reconfigurable custom computing machine design tool Janus. The four routines implementing the IWC are discussed. The structure of Janus is introduced and the IWC implementation design framework to use Janus structure is described in detail. The Janus hardware circuit design model, which has been used in the IWC implementation, is demonstrated here. The hardware implementation results are presented and analyzed, focusing on reconfiguration and computing time. Future research areas are suggested to improve the Janus tool. / Master of Science

Made available in DSpace on 2014-06-12T15:58:40Z (GMT). No. of bitstreams: 2 arquivo4666_1.pdf: 508294 bytes, checksum: 58673e0c55e863402989bbbc70536bc5 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2004 / A área de trabalho cooperativo apoiado por computador (CSCW - Computer Supported Cooperative Work) estuda como as pessoas podem cooperar para a solução de problemas e como tais cooperações podem ser estabelecidas e desenvolvidas utilizando-se recursos computacionais. As aplicações cooperativas síncronas provêem funcionalidades que permitem a interação síncrona entre os membros de um grupo, estando estes em um mesmo local ou dispersos geograficamente. Tais aplicações necessitam de mecanismos de controle que possibilitem o gerenciamento dos usuários que fazem parte das sessões cooperativas, e permitam que os participantes acessem, de forma compartilhada, os recursos disponíveis durante a sessão. Dentre as tecnologias utilizadas na implementação de soluções de suporte a sessões cooperativas síncronas, CORBA (Common Object Request Broker Architecture) mostra-se de grande valor ao prover interoperabilidade entre aplicações implementadas em diferentes linguagens, independentemente de plataforma, protocolos e tecnologias de rede. O CCM (CORBA Component Model ) representa o modelo de componente para a arquitetura CORBA, cujo objetivo principal é facilitar o desenvolvimento de aplicações que utilizam CORBA como plataforma de distribuição. Dessa forma, o objetivo deste trabalho é prover um serviço de suporte a sessões cooperativas síncronas (CSMS - Cooperative Session Management Service), utilizando a tecnologia de componentes proposta pelo CCM. Os principais aspectos abordados por esse serviço são o gerenciamento de usuários que fazem parte da sessão e o mecanismo de controle utilizado no acesso aos recursos compartilhados durante a sessão.

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Recent advancements in FPGA technology have provided devices which are not only suited for digital logic prototyping, but also are capable of implementing complex computations. The use of these devices in multi-FPGA Custom Computing Machines (CCMs) has provided the potential to execute large sections of programs entirely in custom hardware which can provide a substantial speedup over execution in a general-purpose sequential processor. Unfortunately, the development tools currently available for CCMs do not allow users to easily configure multi-FPGA platforms. In order to exploit the capabilities of such an architecture, a procedure has been developed to perform a dataflow analysis of programs written in C which is capable of several hardware-specific optimizations. This, together with other software tools developed for this purpose, allows CCMs and their host processors to be targeted from the same high-level specification. / Master of Science

Very High Temperature Reactors are complex reactors and various system codes have been developed to design different aspects such as neutronics, thermal hydraulics etc. Flownex is one of the system codes and it has been used to model the flow and heat transfer for a pebble fuel element and pebble-bed reactor. Although Flownex has been used to model the High Temperature Test Reactor, the prismatic block was modelled in a simplified manner. The aim of this study was to develop a more integrated model for a single block. A one sixth block was modelled in Flownex and the results were validated by comparing the results with results obtained using the Computational Fluid Dynamics (CFD) code STAR-CCM+. The conduction heat transfer through the prismatic blocks containing the fuel elements in a Very High Temperature Reactor is of crucial importance for the proper operation of the reactor under normal operating conditions and upset conditions. In this study, a model developed in a system code, Flownex is discussed. The model comprised of a collection of 1-D solid conduction heat transfer, convection heat transfer and pipe elements that were arranged in such a manner to represent the heat transfer and fluid flow in the prismatic block using a network approach. The validity of the model was investigated by comparing the heat transfer and temperature distribution in the block for various scenarios with the corresponding values obtained using a detailed CFD model of one twelfth of a prismatic block. Cubical and triangular block verification cases were conducted in Flownex and the results were validated by STAR-CCM+. The results were very comparable; however one issue has to be addressed. The one sixth integrated prismatic block was then modelled for a steady state and the results were also comparable. The outlet helium temperatures predicted by the STAR-CCM+ model was 542.94 C, at the same time the Flownex model predicted 542.98 C. Although the Flownex model did not provide the same detail as the STAR-CCM+ model the agreement between the results obtained with the two codes was satisfactory. Based on these findings it was concluded that Flownex could be used to build a representative integrated network model for a prismatic block reactor. / MIng (Nuclear Engineering), North-West University, Potchefstroom Campus, 2015

Very High Temperature Reactors are complex reactors and various system codes have been developed to design different aspects such as neutronics, thermal hydraulics etc. Flownex is one of the system codes and it has been used to model the flow and heat transfer for a pebble fuel element and pebble-bed reactor. Although Flownex has been used to model the High Temperature Test Reactor, the prismatic block was modelled in a simplified manner. The aim of this study was to develop a more integrated model for a single block. A one sixth block was modelled in Flownex and the results were validated by comparing the results with results obtained using the Computational Fluid Dynamics (CFD) code STAR-CCM+. The conduction heat transfer through the prismatic blocks containing the fuel elements in a Very High Temperature Reactor is of crucial importance for the proper operation of the reactor under normal operating conditions and upset conditions. In this study, a model developed in a system code, Flownex is discussed. The model comprised of a collection of 1-D solid conduction heat transfer, convection heat transfer and pipe elements that were arranged in such a manner to represent the heat transfer and fluid flow in the prismatic block using a network approach. The validity of the model was investigated by comparing the heat transfer and temperature distribution in the block for various scenarios with the corresponding values obtained using a detailed CFD model of one twelfth of a prismatic block. Cubical and triangular block verification cases were conducted in Flownex and the results were validated by STAR-CCM+. The results were very comparable; however one issue has to be addressed. The one sixth integrated prismatic block was then modelled for a steady state and the results were also comparable. The outlet helium temperatures predicted by the STAR-CCM+ model was 542.94 C, at the same time the Flownex model predicted 542.98 C. Although the Flownex model did not provide the same detail as the STAR-CCM+ model the agreement between the results obtained with the two codes was satisfactory. Based on these findings it was concluded that Flownex could be used to build a representative integrated network model for a prismatic block reactor. / MIng (Nuclear Engineering), North-West University, Potchefstroom Campus, 2015