http://hdl.handle.net/10362/416 DEE Fri, 17 May 2013 03:51:06 GMT 2013-05-17T03:51:06Z http://hdl.handle.net/10362/9414 Title: NEGOSEIO: framework for the sustainability of model-oriented enterprise interoperability Authors: Coutinho, Carlos Eduardo Dias Abstract: This dissertation tackles the problematic of Enterprise Interoperability in the current globally connected world. The evolution of the Information and Communication Technologies has endorsed the establishment of fast, secure and robust data exchanges, promoting the development of networked solutions. This allowed the specialisation of enterprises (particularly SMEs) and favoured the development of complex and heterogeneous provider systems. Enterprises are abandoning their self-centrism and working together on the development of more complete solutions. Entire business solutions are built integrating several enterprises (e.g., in supply chains, enterprise nesting) towards a common objective. Additionally, technologies, platforms, trends, standards and regulations keep evolving and demanding enterprises compliance. This evolution needs to be continuous, and is naturally followed by a constant update of each networked enterprise’s interfaces, assets, methods and processes. This unstable environment of perpetual change is causing major concerns in both SMEs and customers as the current interoperability grounds are frail, easily leading to periods of downtime, where business is not possible. The pressure to restore interoperability rapidly often leads to patching and to the adoption of immature solutions, contributing to deteriorate even more the interoperable environment. This dissertation proposes the adoption of NEGOSEIO, a framework that tackles interoperability issues by developing strong model-based knowledge assets and promoting continuous improvement and adaptation for increasing the sustainability of interoperability on enterprise systems. It presents the research motivations and the developed framework’s main blocks, which include model-based knowledge management, collaboration service-oriented architectures implemented over a cloud-based solution, and focusing particularly on its negotiation core mechanism to handle inconsistencies and solutions for the detected interoperability problems. It concludes by validating the research and the proposed framework, presenting its application in a real business case of aerospace mission design on the European Space Agency (ESA). Description: Dissertation to obtain the degree of Doctor of Philosophy in Electrical and Computer Engineering(Industrial Information Systems) Sun, 01 Jan 2012 00:00:00 GMT http://hdl.handle.net/10362/9414 2012-01-01T00:00:00Z http://hdl.handle.net/10362/9368 Title: Time diversity solutions to cope with lost packets Authors: Pereira, Miguel Ramos Abstract: Modern broadband wireless systems require high throughputs and can also have very high Quality-of-Service (QoS) requirements, namely small error rates and short delays. A high spectral efficiency is needed to meet these requirements. Lost packets, either due to errors or collisions, are usually discarded and need to be retransmitted, leading to performance degradation. An alternative to simple retransmission that can improve both power and spectral efficiency is to combine the signals associated to different transmission attempts. This thesis analyses two time diversity approaches to cope with lost packets that are relatively similar at physical layer but handle different packet loss causes. The first is a lowcomplexity Diversity-Combining (DC) Automatic Repeat reQuest (ARQ) scheme employed in a Time Division Multiple Access (TDMA) architecture, adapted for channels dedicated to a single user. The second is a Network-assisted Diversity Multiple Access (NDMA) scheme, which is a multi-packet detection approach able to separate multiple mobile terminals transmitting simultaneously in one slot using temporal diversity. This thesis combines these techniques with Single Carrier with Frequency Division Equalizer (SC-FDE) systems, which are widely recognized as the best candidates for the uplink of future broadband wireless systems. It proposes a new NDMA scheme capable of handling more Mobile Terminals (MTs) than the user separation capacity of the receiver. This thesis also proposes a set of analytical tools that can be used to analyse and optimize the use of these two systems. These tools are then employed to compare both approaches in terms of error rate, throughput and delay performances, and taking the implementation complexity into consideration. Finally, it is shown that both approaches represent viable solutions for future broadband wireless communications complementing each other. Description: A dissertation submitted to Departamento de Engenharia Electrotécnica of Faculdade de Ciências e Tecnologia of Universidade Nova de Lisboa in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Engenharia Electrotécnica e de Computadores Sun, 01 Jan 2012 00:00:00 GMT http://hdl.handle.net/10362/9368 2012-01-01T00:00:00Z http://hdl.handle.net/10362/9326 Title: Serviços integrados de engenharia electrotécnica no apoio ao projecto, execução e exploração de instalações eléctricas Authors: Freire, Rui Filipe Ramos da Veiga Abstract: A actividade de engenharia não se resume apenas ao facto individual de: - Criar ou dimensionar “elementos (dispositivos, estruturas, aparelhos, etc) úteis para a sociedade; - Executar ou implementar os “elementos” por outros colegas desenvolvidos; - ou manter os mesmos em perfeito estado de funcionamento. A engenharia é uma conjugação dos actos de criação, implementação e manutenção. No domínio electrotécnico e em particular no ramo de energia, poderá se pensar a actividade como a concretização de três “tarefas” essenciais, a saber: projecto; execução; e exploração, indo assim de encontro da visão anteriormente exposta. O trabalho aqui apresentado visa em função dos requisitos particulares dos clientes mostrar num ou mais casos concretos o modo, forma e trâmites das três vertentes reconhecidas da engenharia electrotécnica no ramo das instalações eléctricas. Mostra-se assim a forma de criação de um projecto, o modo e padrão de controlo de implementação e execução do projecto e por fim a manutenção do produto final com o intuito de garantir os propósitos para o qual foram projectados e criados. Description: Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores Sun, 01 Jan 2012 00:00:00 GMT http://hdl.handle.net/10362/9326 2012-01-01T00:00:00Z http://hdl.handle.net/10362/9298 Title: Laboratório remoto de automação industrial (Lab-RAI) Authors: Borracha, António Manuel Lira Gomes Abstract: Tendo como premissa juntar as necessidades do ensino prático à evolução da automação industrial e às tecnologias de informação disponíveis, foi desenvolvido este trabalho que é um laboratório remoto de automação industrial. Considerando todas as necessidades pedagógicas inerentes a um laboratório e todas as condições físicas e práticas a que a automação industrial está sujeita, foi desenvolvida uma arquitectura genérica que cumpre os requisitos formulados. Posteriormente foi implementada uma possível aplicação dessa arquitectura com dois laboratórios remotos físicos. O remotelab1 permite a programação de um PLC TSX Micro 3721 da Schneider controlando um simulador de tráfego rodoviário e o remotelab2 permite a programação de um PLC M340 também da Schneider que controla um simulador de monta-cargas industrial. Utilizando tecnologias como Servidores Web, bases de dados, acesso remoto, programação PHP, JavaScript e outras, é permitido aos utilizadores destes laboratórios terem uma experiência muito semelhante à presença num laboratório real. Ao administrador do sistema foram disponibilizadas diversas ferramentas, de modo a poder gerir remotamente este laboratório de forma simples e eficaz. Description: Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e Computadores Sun, 01 Jan 2012 00:00:00 GMT http://hdl.handle.net/10362/9298 2012-01-01T00:00:00Z