169 resultados para Renato Jardim


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Na continuidade da publicação das Atas do I Encontro dos Mestrados em Educação da ESELx (1.º EME), realizado em 2013, a publicação dos artigos reunidos neste volume de atas, submetidos a revisão científica anónima, pretende tornar acessível, a um público mais vasto e diversificado, as comunicações apresentadas no II Encontro dos Mestrados em Educação e Ensino da ESELx (2.º EME), que decorreu na Escola Superior de Educação de Lisboa, no dia 8 de março de 2014. O Encontro foi dinamizado pela Comissão Coordenadora de Mestrados, instância do Conselho Técnico-Científico, em colaboração com o Centro Interdisciplinar de Estudos Educacionais – CIED, em que se inscrevem os projetos e programas de investigação desenvolvidos na ESELx. Prevendo-se que venha a ter, futuramente, uma periodicidade bianual, o Encontro dos Mestrados em Educação e Ensino da ESELx tem como objetivos centrais divulgar a investigação produzida no âmbito dos vários Mestrados na ESELx, e simultaneamente, constituir-se como um fórum de discussão, não só dos resultados obtidos, mas também das diversas abordagens metodológicas adotadas. Com este II Encontro de Mestrados, pretendeu-se ampliar a divulgação da investigação desenvolvida na ESELx, ao contemplar, quer a formação de natureza pós-profissional, no âmbito de mestrados dirigidos a profissionais em educação já no terreno, quer a formação inicial desses profissionais, no âmbito dos mestrados que habilitam para a docência nos contextos da Educação Pré-Escolar e do Ensino Básico (1.º e 2.º Ciclos). Este Encontro inaugura, como foi referido, a apresentação dos trabalhos desenvolvidos pelos estudantes do Mestrado em Educação Pré-Escolar, realizados no âmbito da Prática Profissional Supervisionada nos contextos de creche e jardim de infância. Neste âmbito as nove comunicações apresentadas enquadram-se numa discussão mais ampla sobre a formação de educadores/as de infância na academia portuguesa, que tem vindo a considerar a necessidade de densificar, entre outros objetivos, uma formação que dê corpo, considere e promova o desenvolvimento de uma atitude de natureza investigativa e reflexiva do/no exercício da profissão. Considerando que a investigação possa ser também entendida numa dimensão social e cultural, envolvida com o contexto em que está inserida, a apresentação oral e escrita dos trabalhos desenvolvidos configurou-se como uma oportunidade de divulgação de processos de saber compartilhado, o que, em fim último, caracteriza a própria função pedagógica da investigação no exercício da profissão docente. Os dezassete artigos, situados no contexto dos mestrados pós-profissionalização, abrangem áreas diferenciadas, tais como a intervenção precoce, o teatro, as artes plásticas, a educação matemática, a supervisão e a didática da língua portuguesa. Os percursos metodológicos privilegiados contemplam as abordagens de natureza qualitativa, quantitativa, e ainda abordagens mistas. Alguns dos estudos desenvolvidos adotaram o design de estudo de caso e outros de investigação-ação.A grande diversidade de temas, domínios e abordagens apresentados faz desta publicação um pertinente recurso para apoio epistemológico e metodológico aos estudantes inseridos em processos investigativos diversificados e, ainda, um contributo para a divulgação de conhecimento no âmbito da educação e do ensino, no contexto da realidade educativa portuguesa.

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Dissertação apresentada à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Publicidade e Marketing.

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This paper presents the design methodology for the creation of corrugated horn antennas for the CosmoGal satellite. The mission will collect the radiation of the cosmic microwave background, by a radiometer in three different radio astronomy frequency bands (10.6-10.7GHz; 15.35-15.4GHz; 23.6-24GHz). It is discussed the design of several types of horns, simulated with the CST software. The best result points to a choked Gaussian corrugated horn antenna, with directivity of 23 dBi, side lobes 35 dB below and cross polarization better than -45 dB. Plus, with the advantage of having a small dimension, with a total length of only 7.43λ © 2014 IEEE.

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Radio frequency (RF) energy harvesting is an emerging technology that will enable to drive the next generation of wireless sensor networks (WSNs) without the need of using batteries. In this paper, we present RF energy harvesting circuits specifically developed for GSM bands (900/1800) and a wearable dual-band antenna suitable for possible implementation within clothes for body worn applications. Besides, we address the development and experimental characterization of three different prototypes of a five-stage Dickson voltage multiplier (with match impedance circuit) responsible for harvesting the RF energy. Different printed circuit board (PCB) fabrication techniques to produce the prototypes result in different values of conversion efficiency. Therefore, we conclude that if the PCB fabrication is achieved by means of a rigorous control in the photo-positive method and chemical bath procedure applied to the PCB it allows for attaining better values for the conversion efficiency. All three prototypes (1, 2 and 3) can power supply the IRIS sensor node for RF received powers of -4 dBm, -6 dBm and -5 dBm, and conversion efficiencies of 20, 32 and 26%, respectively. © 2014 IEEE.

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In this work a mixed integer optimization linear programming (MILP) model was applied to mixed line rate (MLR) IP over WDM and IP over OTN over WDM (with and without OTN grooming) networks, with aim to reduce network energy consumption. Energy-aware and energy-aware & short-path routing techniques were used. Simulations were made based on a real network topology as well as on forecasts of traffic matrix based on statistical data from 2005 up to 2017. Energy aware routing optimization model on IPoWDM network, showed the lowest energy consumption along all years, and once compared with energy-aware & short-path routing, has led to an overall reduction in energy consumption up to 29%, expecting to save even more than shortest-path routing. © 2014 IEEE.

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Due to the application of active components into antennas these became a source of distortion on wireless communication systems. In this paper we explore the nonlinear effects occurring in a frequency reconfigurable antenna operating with a PIN Diode. We describe the measurement setup used to check the antenna intermodulation products and the measured compression and third order intermodulation limitations of a frequency reconfigurable antenna, operating at the UMTS and WLAN frequencies.

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The urgent need to mitigate traffic problems such as accidents, road hazards, pollution and traffic jam have strongly driven the development of vehicular communications. DSRC (Dedicated Short Range Communications) is the technology of choice in vehicular communications, enabling real time information exchange among vehicles V2V (Vehicle-to-Vehicle) and between vehicles and infrastructure V2I (Vehicle-Infrastructure). This paper presents a receiving antenna for a single lane DSRC control unit. The antenna is a non-uniform array with five microstrip patches. The obtained beam width, bandwidth and circular polarization quality, among other characteristics, are compatible with the DSRC standards, making this antenna suitable for this application. © 2014 IEEE.

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In this paper we propose a possible design for a RFID tag antenna embedded into cork. The antenna is small and conformal and intended to be used into bottle stoppers for tracking and logging purposes of wine or other beverages. The proposed design is based on an inductive ring and an added resistance in order to modify the current distributions of the antenna. The resulting antenna has a relatively directive radiation pattern and despite the small efficiency it is able to operate with a commercial RFID reader at a reasonable distance. © 2014 IEEE.

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This paper discusses the technology of smart floors as a enabler of smart cities. The discussion will be based on technology that is embedded into the environment that enable location, navigation but also wireless power transmission for powering up elements siting on it, typically mobile devices. One of those examples is the smart floor, this implementation follows two paths, one where the floor is passive, and normally passive RFID's are embedded into the floor, they are used to provide intelligence into the surrounding space, this is normally complemented with a battery powered mobile unit that scans the floor for the sensors and communicates the information to a database which locates the mobile device in the environment. The other path for the smart city enabler is where the floor is active and delivers energy for the objects standing on top of it. In this paper these two approaches will be presented, by discussing the technology behind it. © 2014 IEEE.

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Wireless communications are widely used for various applications, requiring antennas with different features. Often, to achieve the desired radiation pattern, is necessary to employ antenna arrays, using non-uniform excitation on its elements. Power dividers can be used and the best known are the T-junction and the Wilkinson power divider, whose main advantage is the isolation between output ports. In this paper the impact of this isolation on the overall performance of a circularly polarized planar antenna array using non-uniform excitation is investigated. Results show a huge decrease of the array bandwidths either in terms of return loss or in polarization, without resistors. © 2014 IEEE.

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In this paper we present a possible design for a passive RFID tag antenna on paper substrate to be integrated into bottle labels. Considering the application scenario, we verified and determined the permittivity and dissipation factor of the materials in order to simulate all the possible sources that would influence the antenna performance. The measured results reported a maximum reading range of 1.45 m even though the efficiency obtained with the antenna integrated into the bottle was only of 3%. © 2014 IEEE.

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This paper describes the hardware implementation of a High-Rate MIMO Receiver in an FPGA for three modulations, namely BPSK, QPSK and 16-QAM based on the Alamouti scheme. The implementation with 16-QAM achieves more than 1.6 Gbps with 66% of the resources of a medium-sized Virtex-4 FPGA. This results indicate that the Alamouti scheme is a good design option for hardware implementation of a high-rate MIMO receiver. Also, using an FPGA, the modulation can be dynamically changed on demand.

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This paper provides a review of antennas applied for indoor positioning or localization systems. The desired requirements of those antennas when integrated in anchor nodes (reference nodes) are discussed, according to different localization techniques and their performance. The described antennas will be subdivided into the following sections according to the nature of measurements: received signal strength (RSS), time of flight (ToF), and direction of arrival (DoA). This paper intends to provide a useful guide for antenna designers who are interested in developing suitable antennas for indoor localization systems.

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This paper proposes a possible implementation of a compact printed monopole antenna, useful to operate in UMTS and WLAN bands. In order to accomplish that, a miniaturization technique based on the application of chip inductors is used in conjunction with frequency reconfiguration capability. The chip inductors change the impedance response of the monopole, allowing to reduce the resonant frequency. In order to be able to operate the antenna in these two different frequencies, an antenna reconfiguration technique based on PIN diodes is applied. This procedure allows the change of the active form of the antenna leading to a shift in the resonant frequency. The prototype measurements show good agreement with the simulation results.

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A pentagonal patch-excited sectorized antenna (SA) suitable for 2.4-2.5 GHz localization systems was studied and developed. The integration of six patch-excited structures converges into a sectorized antenna called Hive5 that provides gain improvement compared to a patch antenna, maximum variation of 3 dB beam width over the radiation pattern and circular polarization (CP). This antenna is presented and analyzed taking into account the tap length and the flare angle. The proposed antenna in combination with a RF-Switch provides a cost effective solution for localization based on Wireless Sensor Networks (WSN) and will be used for implementing angle of arrival (AoA) techniques combined with RF fingerprinting techniques.