986 resultados para network block-device
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Power Systems (PS), have been affected by substantial penetration of Distributed Generation (DG) and the operation in competitive environments. The future PS will have to deal with large-scale integration of DG and other distributed energy resources (DER), such as storage means, and provide to market agents the means to ensure a flexible and secure operation. Virtual power players (VPP) can aggregate a diversity of players, namely generators and consumers, and a diversity of energy resources, including electricity generation based on several technologies, storage and demand response. This paper proposes an artificial neural network (ANN) based methodology to support VPP resource schedule. The trained network is able to achieve good schedule results requiring modest computational means. A real data test case is presented.
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Although it is always weak between RFID Tag and Terminal in focus of the security, there are no security skills in RFID Tag. Recently there are a lot of studying in order to protect it, but because it has some physical limitation of RFID, that is it should be low electric power and high speed, it is impossible to protect with the skills. At present, the methods of RFID security are using a security server, a security policy and security. One of them the most famous skill is the security module, then they has an authentication skill and an encryption skill. In this paper, we designed and implemented after modification original SEED into 8 Round and 64 bits for Tag.
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Combined tunable WDM converters based on SiC multilayer photonic active filters are analyzed. The operation combines the properties of active long-pass and short-pass wavelength filter sections into a capacitive active band-pass filter. The sensor element is a multilayered heterostructure produced by PE-CVD. The configuration includes two stacked SiC p-i-n structures sandwiched between two transparent contacts. Transfer function characteristics are studied both theoretically and experimentally. Results show that optical bias activated photonic device combines the demultiplexing operation with the simultaneous photodetection and self amplification of an optical signal acting the device as an integrated photonic filter in the visible range. Depending on the wavelength of the external background and irradiation side, the device acts either as a short- or a long-pass band filter or as a band-stop filter. The output waveform presents a nonlinear amplitude-dependent response to the wavelengths of the input channels. A numerical simulation and two building-blocks active circuit is presented and gives insight into the physics of the device.
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Glucose sensing is an issue with great interest in medical and biological applications. One possible approach to glucose detection takes advantage of measuring changes in fluorescence resonance energy transfer (FRET) between a fluorescent donor and an acceptor within a protein which undergoes glucose-induced changes in conformation. This demands the detection of fluorescent signals in the visible spectrum. In this paper we analyzed the emission spectrum obtained from fluorescent labels attached to a protein which changes its conformation in the presence of glucose using a commercial spectrofluorometer. Different glucose nanosensors were used to measure the output spectra with fluorescent signals located at the cyan and yellow bands of the spectrum. A new device is presented based on multilayered a-SiC:H heterostructures to detect identical transient visible signals. The transducer consists of a p-i'(a-SiC:H)-n/p-i(a-Si:H)-n heterostructure optimized for the detection of the fluorescence resonance energy transfer between fluorophores with excitation in the violet (400 nm) and emissions in the cyan (470 nm) and yellow (588 nm) range of the spectrum. Results show that the device photocurrent signal measured under reverse bias and using appropriate steady state optical bias, allows the separate detection of the cyan and yellow fluorescence signals. (C) 2013 Elsevier B.V. All rights reserved.
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Mestrado em Engenharia Informática
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Mestrado em Engenharia Electrotécnica e de Computadores
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The Bologna Process aimed to build a European Higher Education Area promoting student's mobility. The adoption of Bologna Declaration directives requires a self management distributed approach to deal with student's mobility, allowing frequent updates in institutions rules or legislation. This paper suggests a computational system architecture, which follows a social network design. A set of structured annotations is proposed in order to organize the user's information. For instance, when the user is a student its annotations are organized into an academic record. The academic record data is used to discover interests, namely mobility interests, among students that belongs the academic network. These ideas have been applied into a demonstrator that includes a mobility simulator to compare and show the student's academic evolution.
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In this paper we present results on the use of a semiconductor heterostructure based on a-SiC:H as a wavelength-division demultiplexer for the visible light spectrum. The proposed device is composed of two stacked p-i-n photodiodes with intrinsic absorber regions adjusted to short and long wavelength absorption and carrier collection. An optoelectronic characterisation of the device was performed in the visible spectrum. Demonstration of the device functionality for WDM applications was done with three different input channels covering the long, the medium and the short wavelengths in the visible range. The recovery of the input channels is explained using the photocurrent spectral dependence on the applied voltage. An electrical model of the WDM device is proposed and supported by the solution of the respective circuit equations. Short range optical communications constitute the major application field however other applications are foreseen. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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This paper presents the foundations of an Academic Social Network (ASN) focusing the Bologna Declaration and the Bologna Process (BP) mobility issues using ontological support. An ASN will permit students to share commons academic interests, preferences and mobility paths in the European Higher Education Space (EHES). The description of the conceptual support is ontology based allowing knowledge sharing and reuse. An approach is presented by merging Academic Ontology to Support the Bologna Mobility Process with Friend of a Friend ontology. The resulting ontology supports the student mobility profile in the ASN. The strategies to make available, in the network, knowledge about mobility issues, are presented including knowledge discovery and simulation approaches to cover student's mobility scenarios for BP.
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A pi'n/pin a-SiC:H voltage and optical bias controlled device is presented and its behavior as image and color sensor, optical amplifier and demux device is discussed. The design and the light source properties are correlated with the sensor output characteristics. Different readout techniques are used. When a low power monochromatic scanner readout the generated carriers the transducer recognizes a color pattern projected on it acting as a direct color and image sensor. Scan speeds up to 10(4) lines per second are achieved without degradation in the resolution. If the photocurrent generated by different monochromatic pulsed channels is readout directly, the information is demultiplexed. Results show that it is possible to decode the information from three simultaneous color channels without bit errors at bit rates per channel higher than 4000 bps. Finally, when triggered by light of appropriated wavelength, it can amplify or suppress the generated photocurrent working as an optical amplifier (C) 2009 Published by Elsevier Ltd.
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This paper is part of the results from the project "Implementation Strategies and Development of an Open and Distance Education System for the University of the Azores" funded by the European Social Fund. http://hdl.handle.net/10400.3/2327
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Mestrado em Engenharia Informática. Área de Especialização em Tecnologias do Conhecimento e Decisão.
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Thesis submitted in the fulfilment of the requirements for the Degree of Master in Electronic and Telecomunications Engineering
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Dissertação de natureza científica realizada para obtenção do grau de Mestre em Engenharia de Redes de Computadores e Multimédia
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Os serviços baseados em localização vieram dar um novo alento à criatividade dos programadores de aplicações móveis. A vulgarização de dispositivos com capacidades de localização integradas deu origem ao desenvolvimento de aplicações que gerem e apresentam informação baseada na posição do utilizador. Desde então, o mercado móvel tem assistido ao aparecimento de novas categorias de aplicações que tiram proveito desta capacidade. Entre elas, destaca-se a monitorização remota de dispositivos, que tem vindo a assumir uma importância crescente, tanto no sector particular como no sector empresarial. Esta dissertação começa por apresentar o estado da arte sobre os diferentes sistemas de posicionamento, categorizados pela sua eficácia em ambientes internos ou externos, assim como diferentes protocolos de comunicação em tempo quase-real. É também feita uma análise ao estado actual do mercado móvel. Actualmente o mercado possui diferentes plataformas móveis com características únicas que as fazem rivalizar entre si, com vista a expandirem a sua quota de mercado. É por isso elaborado um breve estudo sobre os sistemas operativos móveis mais relevantes da actualidade. É igualmente feita uma abordagem mais profunda à arquitectura da plataforma móvel da Apple - o iOS – que serviu de base ao desenvolvimento de uma solução optimizada para localização e monitorização de dispositivos móveis. A monitorização implica uma utilização intensiva de recursos energéticos e de largura de banda que os dispositivos móveis da actualidade não estão aptos a suportar. Dado o grande consumo energético do GPS face à precária autonomia destes dispositivos, é apresentado um estudo em que se expõem soluções que permitem gerir de forma optimizada a utilização do GPS. O elevado custo dos planos de dados facultados pelas operadoras móveis é também considerado, pelo que são exploradas soluções que visam minimizar a utilização de largura de banda. Deste trabalho, nasce a aplicação EyeGotcha, que para além de permitir localizar outros utilizadores de dispositivos móveis de forma optimizada, permite também monitorizar as suas acções baseando-se num conjunto de regras pré-definidas. Estas acções são reportadas às entidades monitoras, de modo automatizado e sob a forma de alertas. Visionando-se a comercialização da aplicação, é portanto apresentado um modelo de negócio que permite obter receitas capazes de cobrirem os custos de manutenção de serviços, aos quais o funcionamento da aplicação móvel está subjugado.