10 resultados para Box girder bridges Design and construction Evaluation Data processing


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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores

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The design of anchorage blisters of internal continuity post-tensioning tendons of bridges built by the cantilever method, presents some peculiarities, not only because they are intermediate anchorages but also because these anchorages are located in blisters, so the prestressing force has to be transferred from the blister the bottom slab and web of the girder. The high density of steel reinforcement in anchorage blisters is the most common reason for problems with concrete cast in situ, resulting in zones with low concrete compacity, leading to concrete crushing failures under the anchor plates. A solution may involve improving the concrete compression and tensile strength. To meet these requirements a high-performance fibre reinforced self-compacting mix- ture (HPFRC) was used in anchorage corner blisters of post-tensioning tendons, reducing the concrete cross-section and decreasing the reinforcement needed. To assess the ultimate capacity and the adequate serviceability of the local anchorage zone after reducing the minimum concrete cross-section and the confining reinforcement, specified by the anchorage device supplier for the particular tendon, load transfer tests were performed. To investigate the behaviour of anchorage blisters regarding the transmission of stresses to the web and the bottom slab of the girder, and the feasibility of using high performance concrete only in the blister, two half scale models of the inferior corner of a box girder existing bridge were studied: a reference specimen of ordinary reinforced concrete and a HPFRC blister specimen. The design of the reinforcement was based in the tensile forces obtained on strut-and-tie models. An experimental program was carried out to assess the models used in design and to study the feasibility of using high performance concrete only in the blister, either with casting in situ, or with precast solutions. A non-linear finite element analysis of the tested specimens was also performed and the results compared.

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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do Grau de Mestre em Engenharia Informática.

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Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial Technologies

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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Electrotécnica e de Computadores

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Impact Assessment and Project Appraisal, vol. 22, n.1, March 2004, p. 47–62

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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

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Companies are increasingly more and more dependent on distributed web-based software systems to support their businesses. This increases the need to maintain and extend software systems with up-to-date new features. Thus, the development process to introduce new features usually needs to be swift and agile, and the supporting software evolution process needs to be safe, fast, and efficient. However, this is usually a difficult and challenging task for a developer due to the lack of support offered by programming environments, frameworks, and database management systems. Changes needed at the code level, database model, and the actual data contained in the database must be planned and developed together and executed in a synchronized way. Even under a careful development discipline, the impact of changing an application data model is hard to predict. The lifetime of an application comprises changes and updates designed and tested using data, which is usually far from the real, production, data. So, coding DDL and DML SQL scripts to update database schema and data, is the usual (and hard) approach taken by developers. Such manual approach is error prone and disconnected from the real data in production, because developers may not know the exact impact of their changes. This work aims to improve the maintenance process in the context of Agile Platform by Outsystems. Our goal is to design and implement new data-model evolution features that ensure a safe support for change and a sound migration process. Our solution includes impact analysis mechanisms targeting the data model and the data itself. This provides, to developers, a safe, simple, and guided evolution process.

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RESUMO: Introdução As normas de orientação clínica são ferramentas úteis na translação de conhecimentos desde a investigação para a prática clínica diária. Estratégias ativas de implementação de normas de orientação clínica requerem elevado esforço organizacional e financeiro. Quando os recursos são escassos, as estratégias passivas podem ser a única opção de disseminação. Desde 2011 a Direção Geral da Saúde publicou cento e cinquenta e nove normas de orientação clínica. Nesta Tese é feita uma avaliação do impacto que estratégias de disseminação de normas de orientação clínica têm no padrão de prescrição dos médicos e uma avaliação qualitativa do processo das normas de orientação clínica em Portugal. Métodos: O primeiro artigo é um estudo quasi experimental usando uma série de análises temporais interrompida para comparar os níveis observados e esperados de prescrição de inibidores da ciclooxigenasa-2, antes e depois da publicação da norma de orientação clínica sobre a utilização de anti-inflamatórios não esteroides. O segundo estudo é um artigo de opinião e debate no qual numa primeira parte contextualiza o processo das normas da Direcção Geral da Saúde, na segunda parte aponta virtudes e defeitos no processo e a terceira parte constitui uma contribuição com vista à melhoria do processo. Discussão A produção de normas de orientação clínica requer metodologia rigorosa e complexa. A literatura médica revela que a translação de conhecimento é uma tarefa árdua. Estratégias de implementação ativas requerem recursos financeiros e organizacionais sólidos. Estratégias de implementação passivas podem representar uma solução aceitável se os recursos financeiros e organizacionais escasseiam. Pouco é conhecido sobre a eficácia destas estratégias fora do contexto de investigação. Com esta Tese pretendo contribuir para a clarificação desta resposta, outros países e instituições podem ver utilidade nesta informação, bem como pretendo contribuir para a discussão e melhoria do processo das normas de orientação clínica em Portugal. ------------------ ABSTRACT: Introduction Clinical practice guidelines can help address the failure to translate research findings into clinical practice. Active clinical practice guidelines implementation strategies require active efforts from organizations and are resource and financially demanding. Passive implementation strategies may represent the only option if resources are scarce. Out of research environment, real world efficacy of passive implementation strategies is still undetermined. Since 2011 the Portuguese General Health Directorate published one hundred and fifty nine guidelines. In this Thesis I evaluate the impact of passive dissemination of clinical practice guideline in clinician’s prescription behavior and review, from a qualitative point of view, the Portuguese clinical practice guideline process. Methods The first study is a quasi-experimental study using a retrospective interrupted time-series analysis design to compare the observed and expected prescription of cyclooxygenase-2 before and after the non steroidal antiinflammatory guideline publication. The second study is an opinion and debate article in which I firstly review the General Health Directorate guideline process. The second part states positive and negative aspects in the process and the third part is a contribution aimed at improving the process in the future. Discussion Clinical practice guidelines production demands a rigorous and complex methodology. medical iterature reveals that knowledge translation is a difficult task. Active implementation strategies demand solid financial and organizational resources. Passive implementation strategies may represent an acceptable solution if financial and organizational resources are scarce. Little is known about the efficacy of these strategies out of the research context. With this Thesis I intend to contribute to clarify this question, other countries and institutions with similar conditions may find this information useful, and also to contribute for the discussion and general improvement of national clinical practice guidelines process.

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The report addresses the question of what are the preferences of broadband consumers on the Portuguese telecommunication market. A triple play bundle is being investigated. The discrete choice analysis, adopted in the study, base on 110 responses, mainly from NOVA students. The data for the analysis was collected via manually designed on-line survey. The results show that the price attribute is relatively the most important one while the television attribute is being overlooked in the decision making process. Main effects examined in the research are robust. In addition, "extras" components are being tested in terms of users' preferences.