3,278 research outputs found

    The impact of the oil spill of the tanker “Aragon” on the littoral fish fauna of Porto Santo (NE Atlantic Ocean) in 1991 and ten years later

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    Bocagiana, 217: 1-8Em Janeiro de 1990, a Ilha de Porto Santo (Arquipélago da Madeira), foi atingida por uma maré negra proveniente de um derrame do navio petroleiro “Aragon”. Um ano depois, avaliou-se a ictiofauna costeira. Dez anos depois da maré negra, uma nova amostragem foi realizada com a mesma metodologia, de forma a comparar com os dados recolhidos anteriormente. A análise dos resultados obtidos parece revelar que os efeitos da maré negra nos peixes litorais foram reduzidos. Este trabalho constitui a primeira contribuição para a “check-list” da ictiofauna costeira da Ilha de Porto Santo.In January 1990, the tanker “Aragon” oil spill reached Porto Santo Island (Madeira Archipelago). One year later, in 1991 the littoral fish fauna was evaluated. Ten years after the “Aragon” oil spill, a new survey was made using the same methods, to compare data. From the results it seems that the effects of the oil were rather small. As a result of this work, as a check-list of the littoral fish fauna of this Island is presented

    Structural Transformation and the role of Foreign Direct Investment in Portugal: a descriptive analysis for the period 1990-2005

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    In this paper we use a recent measure of the “income level of a country’s exports” proposed by Hausmann et al. (2007) to characterize the structure of the Portuguese export basket, its recent evolution and the role of FDI in this process. We find that between 1990 and 2005 the improvement in the income content of the Portuguese export basket was achieved through a positive “structural transformation effect” that more than offset the negative effect of having a significant share of products exposed to an increasing competition from emerging economies. We find that the weight of exports with “high” and “very high” income content increased considerably in this period, with these two classes explaining more than half of the total export growth. Analysing the presence of FDI in the different export products, we find a higher than average share of foreign affiliated firms in products with “High” and “Very High” income content. These and other pieces of evidence suggest that FDI has played a relevant role both in the growth of Portuguese exports and in the increase of their income content.International trade, Foreign Direct Investment, The Portuguese Economy, Structural transformation

    The planning and creation of an e-learning and recreational platform for seniors

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    Europe is facing great demographic changes. It is predicted that seniors will represent almost 30% of the European population by the year 2050. Ambient Assisted Living (AAL) solutions may provide an answer to the challenges that these demographic changes bring. AAL as a concept is to interconnect Information and Communication Technology (ICT) with certain devices in order to create products and services to assist its users in all periods of life (e.g. difficulty in climbing stairs can be compensated for by a mechanical stair lift). One important area of AAL is lifelong learning which aims to allow continuous education during the course of a person's life. One way of enabling lifelong learning for seniors is by using electronic-learning platforms (E-Learning). These platforms enable their users to access learning content from almost any location. However, the level of complexity of these platforms may arise as an obstacle for seniors. The Ambient Assisted Living for All (AAL4ALL) project was launched to create a wide range of AAL-related products and services. One of the services which will be offered by this project is an E-Learning and recreational platform especially designed for seniors. The objective of this dissertation is to plan and create the prototype of such a platform. In order to develop a prototype of this nature, we required assistance from the senior population to carry out two different types of studies. First a requirements study was performed in order to gather feedback from our target group before moving on to the development phase. Once the development phase was complete, a usability study was performed to test how seniors interacted with the prototype.A Europa está a enfrentar grandes alterações demográficas. Está previsto que a população idosa representará quase 30% da população Europeia em 2050. O Ambient Assisted Living (AAL) pode oferecer soluções para responder aos desafios que resultam destas alterações demográficas. O AAL significa a ligação de Tecnologias de Informação e Comunicação (TIC) com determinados dispositivos, visando a criação de produtos e serviços que permitem auxiliar os seus utilizadores ao longo das suas vidas (por exemplo: a dificuldade de subir escadas pode ser compensada pelo uso de um elevador de escadas mecânico). Uma área importante do AAL consiste na aprendizagem ao longo da vida, que permite uma educação contínua no percurso da vida de uma pessoa. Uma forma de possibilitar a aprendizagem ao longo da vida à população idosa é através do uso de plataformas de E-Learning, as quais permitem aos seus utilizadores acederem a conteúdos de aprendizagem de praticamente qualquer local. Contudo, o interface utilizado neste tipo de plataformas tende a ser muito complexo para esta faixa etária. Neste sentido, o projecto chamado Ambient Assisted Living for All (AAL4ALL) foi lançado para criar uma vasta gama de produtos e serviços do AAL. Um dos serviços que será disponibilizado por este projecto é uma plataforma E-Learning especialmente concebida para idosos. O objetivo desta dissertação é planear e criar o protótipo desta plataforma. Com o intuito de desenvolver um protótipo desta natureza pedimos a colaboração de alguns seniores para realizar estudos de duas tipologias diferentes. Primeiro, foi elaborado um estudo de requisitos para obter as suas opiniões sobre o planeamento do protótipo. Por fim, após o desenvolvimento do protótipo, foi elaborado um estudo de usabilidade para testar como os idosos interagem com o mesmo

    The growing tendency of selling luxury goods in online platforms, and strategies that luxury houses can implement

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    Researchers state that luxury houses should only use online platforms to communicate with consumers and never to sell products, because, in order to be successful in selling the product, one should be able to replicate the hedonic experience through the web (Kapferer & Bastien, 2009). However, there has been a growing tendency of selling luxury products through their websites and mobile applications (Deloitte, 2017). Thus, this dissertation looks to explore and test consumers’ associations while purchasing online, and whether this applies or not into luxury products, hypothesizing if there are strategies that can be implemented to improve it. To investigate the subject, it was conducted a study, where it was tested the already suggested tendency of consumers to look for more utilitarian products, while purchasing online, and if it extends to the luxury industry. Moreover, it was assessed if psychological distance, through temporal distance, could be a factor that influences consumers’ behaviour in purchasing luxury goods online. This study evaluated participants’ decisions between utilitarian and hedonic descriptions, regarding luxury products, both in online and offline platforms; and also assessing the participants’ attitudes towards utilitarian and hedonic dimensions of a product. Results suggest that the previously mentioned tendency can be extended to luxury products. However, it was not clear that temporal distance constituted a good manipulation, once it only presented significant differences in the way participants evaluated the utilitarian dimensions of product characteristics, when going from low to high temporal distance. The fact that consumers’ behaviour can be justified, not-only but also, by the nature of the product (if it is utilitarian or hedonic) constitutes a main insight to take from this dissertation. Also, the fact that psychological distance can be a relevant manipulation for creating strategies to improve one’s performance in online platforms, originates a series of new possible researches that can be conducted in the future.Estudiosos afirmam que as marcas de luxo devem apenas utilizar plataformas online para comunicar com os consumidores, mas nunca para vender os produtos, dado que, para uma marca de luxo ter sucesso a vender produtos online, esta deveria ser capaz de replicar a experiência hedónica, através da Internet (Kapferer & Bastien, 2009). No entanto, tem-se verificado uma tendência, cada vez maior, de vender produtos de luxo através de websites e aplicações móveis (Deloitte, 2017). Desta forma, esta dissertação procura explorar e testar associações que os consumidores tenham, enquanto compram online, e se estas se aplicam ou não a produtos de luxo, questionando se existem estratégias que possam ser aplicadas para melhorar este processo. Para explorar este assunto, foi realizado um estudo, onde foi testado uma possível associação dos consumidores em procurar produtos utilitários, ao realizar compras online e, se esta associação é extensível para a indústria do luxo. Foi ainda avaliada a possibilidade da distância psicológica, através de distância temporal, constituir um fator que influencie o comportamento dos consumidores, ao comprar produtos de luxo, online. Este estudo analisou as decisões dos consumidores entre descrições hedónicas e utilitárias, relativas a produtos de luxo, quer em plataformas online como offline. Estudou também as atitudes dos consumidores relativamente às dimensões utilitárias e hedónicas dos produtos. Os resultados sugeriram que a tendência mencionada anteriormente é extensível para produtos de luxo. No entanto, não foi claro se a distância temporal constituí uma boa manipulação, uma vez que só revelou diferenças significativas na maneira como os participantes avaliaram a dimensão utilitária das características de um produto, ao passar de uma pequena para uma grande distância temporal. O facto do comportamento dos consumidores ser justificado, não só mas também, pela natureza do produto (se é utilitário ou hedónico) constituí uma informação importante a retirar desta tese. O facto da distância psicológica poder ainda ser uma manipulação relevante para criar estratégias para melhorar a prestação em plataformas online, origina ainda uma séria de novos possíveis estudos, a serem conduzidos no futuro

    Multi-objective optimization for school buildings retrofit combining artificial neural networks and life cycle cost

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    The renovation of a school building should be regarded as a process of combining a number of variables and objectives, sometimes conflicting, including energy, indoor environmental quality and costs (initial, operational and maintenance), on a search for an "optimum solution". This multi-objective optimization procedure is particularly important in a time of severe economic crisis, with few available financial resources and, as such, their management and the investment decisions require great prudence from the decision maker. In this research a methodology to optimize the insulation thickness of external walls and roof, in the retrofit of two school buildings, is proposed. The school performance was defined considering two objectives: the annual heating load and the discomfort in the classrooms due to overheating. The calculation of the performance functions implies an annual simulation of the building and Artificial Neural Networks were training to approximate them. The minimization of the Life Cycle Cost of external walls and roof retrofit allowed the economic optimization of the insulation width

    Numerical study of the unsteadiness of a ground vortex

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    Single impinging jets in a crossflow are typical in impingement cooling applications in industry, as well as of the flow beneath a V/STOL aircraft. In this latter application, a primary design consideration is the flow environment induced by the propulsion system during hover with zero or small forward momentum. Ground effect phenomena may occur and change the lift forces on the aircraft, cause re-ingestion of exhaust gases into the engine intake and raise fuselage skin temperatures. An important source of each is the ground vortex which forms far upstream of the impinging jet when the resulting radial wall jet meets a crossflow. Numerical and experimental studies have also been performed in this area. Some were dedicated to the study of the more fundamental configurations: single or multiple impinging jets through a crossflow. The present thesis extends the analysis of (Pandya, Murman, & Sankaran, 2003) to a wider range of velocity ratios, VR, from 0.065 to 0.2. The impact zone of a wall jet with a boundary layer was studied computationally using a Reynolds Averaged Navier-Stokes (RANS) approach with the “k-ε” turbulence model. The computational domain corresponds to complete experimental rig of (Cimbala, Billet, Gaublomme, & Oefelein, 1991) and the measured boundary conditions were used. It was found that the gross features of the flow are well predicted, and the fluctuations of the flowfield around the ground vortex occur in a very small region near the wall where the impact between each flow occurs. The computational results showed a cyclic formation of two small secondary vortexes that appear and disappear cyclically around the separation and maximum penetration points of the ground vortex. This result confirms the observation of (Pandya, Murman, & Sankaran, 2003). The frequency of the “puffing” was found to compare well with the experimental results for VR=0.1, and the structure of the impact zone is similar. First, the wall jet fluid start to penetrate into the boundary layer side until a very small counterclockwise rotating vortex appears. Then it starts to grow blocking the passage of the clockwise rotating fluid of the wall jet, and a new small vortex appears, but now with clockwise vorticity. A particular result was obtained for VR=0.175. The flow exhibits a periodic behaviour, but no secondary vortexes are detected. Nevertheless, in this case the frequency was found to correlate well with the values obtained for VR=0.1, 0.125, and 0.15. For the case of very low velocity crossflow (small VR) the computations exhibit a stationary solution, which is in agreement with previous experimental results. For strong crossflows (large VR) the flow is also stationary, although there is a transition region of some unsteadiness without secondary vortexes present. The present work has shown that for a finite interval of velocity ratios between the impinging jet and the crossflow periodic oscillations of the ground vortex are observed. The results indicate a pattern similar to the “puffing” mechanism described by (Cimbala, Billet, Gaublomme, & Oefelein, 1991)

    2D elementary cellular automata with four neighbors

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    This paper is concerned with the study of square boolean synchronous four-neighbor peripheral cellular automata. It is rst shown that, due to conjugation and plane re ection symmetry transformations, the number of dynamically nonequivalent such automata is equal to 4 856. The cellular automata for which the homogeneous nal states play a signi cant role are then identi ed. Finally, it is shown that, contrary to what happens in the case of one-dimensional boolean three-neighbor cellular automata, for some peripheral automata there is coexistence between a homogeneous nal state and other dynamics

    Declarative approach to data extraction of web pages

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    Thesis submitted to Faculdade de CiĂŞncias e Tecnologia of the Universidade Nova de Lisboa, in partial fulfilment of the requirements for the degree of Master in Computer ScienceIn the last few years, we have been witnessing a noticeable WEB evolution with the introduction of significant improvements at technological level, such as the emergence of XHTML, CSS,Javascript, and Web2.0, just to name ones. This, combined with other factors such as physical expansion of the Web, as well as its low cost, have been the great motivator for the organizations and the general public to join, with a consequent growth in the number of users and thus influencing the volume of the largest global data repository. In consequence, there was an increasing need for regular data acquisition from the WEB, and because of its frequency, length or complexity, it would only be viable to obtain through automatic extractors. However, two main difficulties are inherent to automatic extractors. First, much of the Web's information is presented in visual formats mainly directed for human reading. Secondly, the introduction of dynamic webpages, which are brought together in local memory from different sources, causing some pages not to have a source file. Therefore, this thesis proposes a new and more modern extractor, capable of supporting the Web evolution, as well as being generic, so as to be able to be used in any situation, and capable of being extended and easily adaptable to a more particular use. This project is an extension of an earlier one which had the capability of extractions on semi-structured text files. However it evolved to a modular extraction system capable of extracting data from webpages, semi-structured text files and be expanded to support other data source types. It also contains a more complete and generic validation system and a new data delivery system capable of performing the earlier deliveries as well as new generic ones. A graphical editor was also developed to support the extraction system features and to allow a domain expert without computer knowledge to create extractions with only a few simple and intuitive interactions on the rendered webpage
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