989 resultados para Multimedia Application
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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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The increasing integration of wind energy in power systems can be responsible for the occurrence of over-generation, especially during the off-peak periods. This paper presents a dedicated methodology to identify and quantify the occurrence of this over-generation and to evaluate some of the solutions that can be adopted to mitigate this problem. The methodology is applied to the Portuguese power system, in which the wind energy is expected to represent more than 25% of the installed capacity in a near future. The results show that the pumped-hydro units will not provide enough energy storage capacity and, therefore, wind curtailments are expected to occur in the Portuguese system. Additional energy storage devices can be implemented to offset the wind energy curtailments. However, the investment analysis performed show that they are not economically viable, due to the present high capital costs involved.
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O objectivo da tese é demonstrar a adequação do paradigma dos mercados electrónicos baseados em agentes para transaccionar objectos multimédia em função do perfil dos espectadores. Esta dissertação descreve o projecto realizado no âmbito da plataforma de personalização de conteúdos em construção. O domínio de aplicação adoptado foi a personalização dos intervalos publicitários difundidos pelos distribuidores de conteúdos multimédia, i.e., pretende-se gerar em tempo útil o alinhamento de anúncios publicitários que melhor se adeqúe ao perfil de um espectador ou de um grupo de espectadores. O projecto focou-se no estudo e selecção das tecnologias de suporte, na concepção da arquitectura e no desenvolvimento de um protótipo que permitisse realizar diversas experiências nomeadamente com diferentes estratégias e tipos de mercado. A arquitectura proposta para a plataforma consiste num sistema multiagente organizado em três camadas que disponibiliza interfaces do tipo serviço Web com o exterior. A camada de topo é constituída por agentes de interface com o exterior. Na camada intermédia encontram-se os agentes autónomos que modelam as entidades produtoras e consumidoras de componentes multimédia assim como a entidade reguladora do mercado. Estes agentes registam-se num serviço de registo próprio onde especificam os componentes multimédia que pretendem negociar. Na camada inferior realiza-se o mercado que é constituído por agentes delegados dos agentes da camada superior. O lançamento do mercado é efectuado através de uma interface e consiste na escolha do tipo de mercado e no tipo de itens a negociar. Este projecto centrou-se na realização da camada do mercado e da parte da camada intermédia de apoio às actividades de negociação no mercado. A negociação é efectuada em relação ao preço da transmissão do anúncio no intervalo em preenchimento. Foram implementados diferentes perfis de negociação com tácticas, incrementos e limites de variação de preço distintos. Em termos de protocolos de negociação, adoptou-se uma variante do Iterated Contract Net – o Fixed Iterated Contract Net. O protótipo resultante foi testado e depurado com sucesso.
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This paper presents a low-cost scaled model of a silo for drying and airing cereal grains. It allows the control and monitor of several parameters associated to the silo's operation, through a remote accessible infrastructure. The scaled model consists of a 2.50 m wide × 2.10 m long plant with all control and monitor capacities provided by micro-Web servers. An application running on the micro-Web servers enables storing all parameters in a data basis for later analysis. The implemented model aims to support a remote experimentation facility for technological education, research-oriented tutorials, and industrial applications. Given the low-cost requirement, this remote facility can be easily replicated in other institutions to support a network of remote labs, which encompasses the concurrent access of several users (e.g. students).
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A sociedade moderna encontra-se numa evolução progressiva e vertiginosa nomeadamente no que respeita às novas tecnologias. Independentemente da área de conhecimento, é de senso comum que cada vez mais é necessária uma formação sólida, sendo fundamental a preparação e a consolidação das futuras gerações na utilização das novas tecnologias. As plataformas de e-learning são hoje em dia uma realidade mais que afirmada e com aplicação em todos os setores de atividade. Na área da saúde, e mais concretamente no que diz respeito ao tema de Suporte Básico de Vida (SBV), foi-nos possível verificar que a maioria das pessoas revela falta de conhecimentos sobre o tema e, não obstante existirem cursos sobre este tema, a disponibilidade para a sua frequência nem sempre é possível pela distância, falta de tempo e disponibilidade para a sua frequência, bem como pelos custos envolvidos. O presente estudo pretende contribuir para uma análise e investigação sobre o potencial de utilização das novas Tecnologias Multimédia, aplicando-as ao ensino concreto de primeiros socorros e especialmente de Suporte Básico de Vida, num recurso educativo digital com o formato de Objeto de Aprendizagem. Para o efeito, será construído um Objeto de Aprendizagem temático, focalizando o tema de SBV. O repositório MERLOT foi utilizado como meio de distribuição global, no sentido de aferir o potencial e facilidade de distribuição e catalogação com metadados. Foi ainda colocado on-line o “SBVOA” (Objeto de Aprendizagem desenvolvido no presente estudo), numa página criada apenas para o efeito. Esta dissertação apresenta o estudo desenvolvido para investigação do potencial de aprendizagem proporcionado pelo Objeto de Aprendizagem desenvolvido, validando se pode ser uma alternativa interativa de educação em SBV, contribuindo deste modo para a diminuição de eventuais perdas de vida.
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Scope of study: welding operations result in harmful emissions of nanoparticles; the aim of emissions monitorisation is to evaluate exposure levels and to derive protection measures in order to protect exposed workers; however, the traditional approach of comparing measured concentrations with exposure limits cannot be used; but risk levels can be quantified by using Control Banding Strategies.
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Glass fibre-reinforced plastics (GFRP), nowadays commonly used in the construction, transportation and automobile sectors, have been considered inherently difficult to recycle due to both: cross-linked nature of thermoset resins, which cannot be remolded, and complex composition of the composite itself, which includes glass fibres, matrix and different types of inorganic fillers. Presently, most of the GFRP waste is landfilled leading to negative environmental impacts and supplementary added costs. With an increasing awareness of environmental matters and the subsequent desire to save resources, recycling would convert an expensive waste disposal into a profitable reusable material. There are several methods to recycle GFR thermostable materials: (a) incineration, with partial energy recovery due to the heat generated during organic part combustion; (b) thermal and/or chemical recycling, such as solvolysis, pyrolisis and similar thermal decomposition processes, with glass fibre recovering; and (c) mechanical recycling or size reduction, in which the material is subjected to a milling process in order to obtain a specific grain size that makes the material suitable as reinforcement in new formulations. This last method has important advantages over the previous ones: there is no atmospheric pollution by gas emission, a much simpler equipment is required as compared with ovens necessary for thermal recycling processes, and does not require the use of chemical solvents with subsequent environmental impacts. In this study the effect of incorporation of recycled GFRP waste materials, obtained by means of milling processes, on mechanical behavior of polyester polymer mortars was assessed. For this purpose, different contents of recycled GFRP waste materials, with distinct size gradings, were incorporated into polyester polymer mortars as sand aggregates and filler replacements. The effect of GFRP waste treatment with silane coupling agent was also assessed. Design of experiments and data treatment were accomplish by means of factorial design and analysis of variance ANOVA. The use of factorial experiment design, instead of the one factor at-a-time method is efficient at allowing the evaluation of the effects and possible interactions of the different material factors involved. Experimental results were promising toward the recyclability of GFRP waste materials as polymer mortar aggregates, without significant loss of mechanical properties with regard to non-modified polymer mortars.
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Applied Physics B Lasers and Optics, vol.71
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Based on the paper presented at the International Conference “Autonomous Systems: inter-relations of technical and societal issues”, organized by IET with the support of the Portuguese-German collaboration project on “Technology Assessment of Autonomous Robotics” (DAAD/CRUP) at FCT-UNL, Biblioteca da UNL, Campus de Caparica on 5-6 November 2009.
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Glass fibre-reinforced plastics (GFRP), nowadays commonly used in the construction, transportation and automobile sectors, have been considered inherently difficult to recycle due to both: cross-linked nature of thermoset resins, which cannot be remolded, and complex composition of the composite itself, which includes glass fibres, matrix and different types of inorganic fillers. Presently, most of the GFRP waste is landfilled leading to negative environmental impacts and supplementary added costs. With an increasing awareness of environmental matters and the subsequent desire to save resources, recycling would convert an expensive waste disposal into a profitable reusable material. There are several methods to recycle GFR thermostable materials: (a) incineration, with partial energy recovery due to the heat generated during organic part combustion; (b) thermal and/or chemical recycling, such as solvolysis, pyrolisis and similar thermal decomposition processes, with glass fibre recovering; and (c) mechanical recycling or size reduction, in which the material is subjected to a milling process in order to obtain a specific grain size that makes the material suitable as reinforcement in new formulations. This last method has important advantages over the previous ones: there is no atmospheric pollution by gas emission, a much simpler equipment is required as compared with ovens necessary for thermal recycling processes, and does not require the use of chemical solvents with subsequent environmental impacts. In this study the effect of incorporation of recycled GFRP waste materials, obtained by means of milling processes, on mechanical behavior of polyester polymer mortars was assessed. For this purpose, different contents of recycled GFRP waste materials, with distinct size gradings, were incorporated into polyester polymer mortars as sand aggregates and filler replacements. The effect of GFRP waste treatment with silane coupling agent was also assessed. Design of experiments and data treatment were accomplish by means of factorial design and analysis of variance ANOVA. The use of factorial experiment design, instead of the one-factor-at-a-time method is efficient at allowing the evaluation of the effects and possible interactions of the different material factors involved. Experimental results were promising toward the recyclability of GFRP waste materials as aggregates and filler replacements for polymer mortar, with significant gain of mechanical properties with regard to non-modified polymer mortars.
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The World Business Council for Sustainable Development (WBCSD) defines Eco-Efficiency as follows: ‘Eco- Efficiency is achieved by the delivery of competitively priced-goods and services that satisfy human needs and bring quality of life, while progressively reducing ecological impacts and resource intensity throughout the life-cycle to a level at least in line with the earth’s estimated carrying capacity’. Eco-Efficiency is under this point of view a key concept for sustainable development, bringing together economic and ecological progress. Measuring the Eco-Efficiency of a company, factory or business, is a complex process that involves the measurement and control of several and relevant parameters or indicators, globally applied to all companies in general, or specific according to the nature and specificities of the business itself. In this study, an attempt was made in order to measure and evaluate the eco-efficiency of a pultruded composite processing company. For this purpose the recommendations of WBCSD [1] and the directives of ISO 14301 standard [2] were followed and applied. The analysis was restricted to the main business branch of the company: the production and sale of standard GFRP pultrusion profiles. The main general indicators of eco-efficiency, as well as the specific indicators, were defined and determined according to ISO 14031 recommendations. With basis on indicators’ figures, the value profile, the environmental profile, and the pertinent eco-efficiency’s ratios were established and analyzed. In order to evaluate potential improvements on company eco-performance, new indicators values and ecoefficiency ratios were estimated taking into account the implementation of new proceedings and procedures, both in upstream and downstream of the production process, namely: a) Adoption of new heating system for pultrusion die in the manufacturing process, more effective and with minor heat losses; b) Implementation of new software for stock management (raw materials and final products) that minimize production failures and delivery delays to final consumer; c) Recycling approach, with partial waste reuse of scrap material derived from manufacturing, cutting and assembly processes of GFRP profiles. In particular, the last approach seems to significantly improve the eco-efficient performance of the company. Currently, by-products and wastes generated in the manufacturing process of GFRP profiles are landfilled, with supplementary added costs to this company traduced by transport of scrap, landfill taxes and required test analysis to waste materials. However, mechanical recycling of GFRP waste materials, with reduction to powdered and fibrous particulates, constitutes a recycling process that can be easily attained on heavy-duty cutting mills. The posterior reuse of obtained recyclates, either into a close-looping process, as filler replacement of resin matrix of GFRP profiles, or as reinforcement of other composite materials produced by the company, will drive to both costs reduction in raw materials and landfill process, and minimization of waste landfill. These features lead to significant improvements on the sequent assessed eco-efficiency ratios of the present case study, yielding to a more sustainable product and manufacturing process of pultruded GFRP profiles.
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International Biodeterioration & Biodegradation 64(2010)388 e 396
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Submitted in part fulfillment of the requirements for the degree of Master in Computer Science
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Generally, the evolution process of applications has impact on their underlining data models, thus becoming a time-consuming problem for programmers and database administrators. In this paper we address this problem within an aspect-oriented approach, which is based on a meta-model for orthogonal persistent programming systems. Applying reflection techniques, our meta-model aims to be simpler than its competitors. Furthermore, it enables database multi-version schemas. We also discuss two case studies in order to demonstrate the advantages of our approach.
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The need for better adaptation of networks to transported flows has led to research on new approaches such as content aware networks and network aware applications. In parallel, recent developments of multimedia and content oriented services and applications such as IPTV, video streaming, video on demand, and Internet TV reinforced interest in multicast technologies. IP multicast has not been widely deployed due to interdomain and QoS support problems; therefore, alternative solutions have been investigated. This article proposes a management driven hybrid multicast solution that is multi-domain and media oriented, and combines overlay multicast, IP multicast, and P2P. The architecture is developed in a content aware network and network aware application environment, based on light network virtualization. The multicast trees can be seen as parallel virtual content aware networks, spanning a single or multiple IP domains, customized to the type of content to be transported while fulfilling the quality of service requirements of the service provider.