Browsing by Issue Date, starting with "2020-04"
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- Hispanidad, Lusitanidad e idea de ImperioPublication . Martinez Roda, Federico; Rezola, Maria InáciaLos conceptos Hispanidad y Lusitanidad estuvieron ligados a la idea de una España y de un Portugal más amplios que sus confines peninsulares. Ambos tuvieron cierta operatividad en sus respectivos países hasta el punto de configurar incluso una interpretación de pasado, sin embargo, no ocurrió lo mismo con la idea de Imperio. En la España de los finales años treinta y primeros cuarenta del siglo XX, fue una nueva formulación entre retórica y nostálgica, mientras que en Portugal la idea de Imperio se fundió con la de nación y tuvo decisivos efectos políticos.
- Optimisation of a plasmonic parallel waveguide sensor based on amorphous silicon compoundsPublication . Costa, João; Fantoni, Alessandro; Lourenço, Paulo; Vieira, ManuelaThis work reports the simulation of a plasmonic waveguide sensor working in the visible range based on amorphous silicon compounds. Typical plasmonic sensor interrogation schemes are based on scanning over the wavelength or the incident angle to search for the resonance condition. These solutions usually require expensive or bulky components, such as prisms, motor-driven rotation stages or tunable lasers. In this work we propose an amorphous silicon nitride waveguide structure consisting of an array of parallel surface plasmon interferometers of different lengths, each one comprising a thin layer of aluminium embedded into the waveguide. Using modal decomposition simulations, we show that the variation of the output power at the end of each waveguide array element provides a convenient interrogation scheme. By exploring amorphous silicon compounds that can be deposited by Pressure Enhanced Chemical Vapor Deposition (PECVD) at low temperatures, we aim to achieve a low-cost fabrication process that is compatible with backend CMOS processing and wavelengths in the visible range.
- O SPN e o SNI na encruzilhada do livro: António Ferro e o campo oficial da edição no Estado NovoPublication . Medeiros, NunoNo quadro do projecto de aglutinação orgânica da política de exaltação das virtudes do Estado Novo, a actividade dos seus serviços de propaganda, nomeadamente o Secretariado da Propaganda Nacional (SPN), depois renomeado Secretariado Nacional da Informação, Cultura Popular e Turismo (SNI), traduziu, sob a liderança do seu primeiro director, António Ferro, um dinamismo que não conhecerá par na relação do regime com o livro e o sector da edição. O acto fundador que criou o SPN em 1933 incumbiu o novo organismo do Estado de «integrar os portugueses no pensamento moral que deve dirigir a Nação», ficando aquele na dependência directa da Presidência do Conselho de Ministros, logo, de Salazar. Ferro baptizou a matriz filosófica da recém-criada instituição de «Política do Espírito», apontando um verdadeiro imperativo a consumar governativamente, imiscuindo no cadinho salazarista propaganda e política cultural. António Ferro gizou e assumiu um programa que aspirava a infundir no salazarismo «um ‘projecto cultural’, combinando habilmente recursos estéticos modernos com um programa nacionalista de ‘reinvenção da tradição’ que excedeu largamente as necessidades de propaganda interna e externa» do Estado Novo. Depois de um período de grande intensidade e concretizações, em 1944 o SPN passou a SNI, permanecendo até 1950 sob a tutela de Ferro, que se adaptou «à nova imagem de eficiência e racionalização que Salazar […] procurara instituir como novo modelo político».
- Indoor wayfinding using visible light communicationPublication . Vieira, Manuela; Vieira, Manuel Augusto; Louro, Paula; Fantoni, Alessandro; Vieira, PedroOptical wireless communication has been widely studied during the last years in short-range applications. This paper investigates the applicability of an intuitive wayfinding system in complex buildings using Visible Light Communication (VLC). Typical scenarios include finding places, like a particular shop or office, guiding users across different floors, through elevators and stairs. Data from the sender is encoded, modulated and converted into light signals emitted by the transmitters. Tetra-chromatic white sources are used providing a different data channel for each chip. At the receiver side, the modulated light signal, containing the ID and the 3D geographical position of the transmitter and wayfinding information, is received by SiC photodetector with light filtering and demultiplexing properties. Since lighting and wireless data communication is combined, each luminaire for downlink transmission become a single cell, in which the optical access point (AP) is located in the ceiling and the mobile users are scattered within the overlap discs of each cells underneath. The light signals emitted by the LEDs are interpreted directly by the receivers of the users positioned underneath. The effect of the location of the Aps is evaluated and a model for the different cellular networks is analyzed. Orthogonal topologies are tested, and a 3D localization design, demonstrated by a prototype implementation, is presented. Uplink transmission is implemented and the 3D best route to navigate through venue calculated. Buddy wayfinding services are also implemented. The results showed that the system make possible to determine the position of a mobile target inside the network, to infer the travel direction along the time and to interact with information received and to optimize the route towards a static or dynamic destination.
- Publicidade das marcas de saúde e beleza em Portugal: os apelos e os argumentos centrados nos valores da saúdePublication . Verissimo, Jorge; Medeiros, Carla; Rosário, João Ferreira do; Barros, João Avelino; David, Maria Alexandra Mendonça; Correia, Maria do RosárioNa sociedade marcada pela preocupação com a saúde e a beleza, e cuja publicidade reflete e transmite os valores sociais e culturais dominantes, desenvolvemos um estudo à publicidade a este tipo de produtos em Portugal de modo a avaliar as tendências.
- Do presencial… à distância! Alinhar a mudança para garantir qualidade do ensinoPublication . Coelho, André; Maia-Matos, Mário; Abreu, Renato; Ribeiro, Ricardo; Manteigas, VítorObjetivo: Criar questões relevantes e o ambiente adequado para a realização de testes à distância. Sumário: 1. Alinhamento construtivista. 2. Avaliação formativa e sumativa em EaD. 3. Boas práticas na avaliação de estudantes em EaD. 4. Boas práticas para testes online em EaD. 5. Como reduzir a oportunidade de fraude académica em EaD.
- Silicon nitride based devices: lithographic mask roughness mitigationPublication . Lourenço, Paulo; Fantoni, Alessandro; Costa, João; Vieira, ManuelaLithographic technology has been one of the main upholders to Moore's law in the semiconductor industry for the last decades. The underlying reason that enabled the evolution in semiconductor industry has been a steady silicon wafer printing cost, while being able to dramatically increase the number of nodes that can be printed per chip. Key developments in lithography such as wavelength decreasing, together with performance increase in lens and imaging technology, should be accounted for almost all the reduction of cost per function in integrated circuits technology. In this work, we will be presenting the simulation of two mitigation techniques for the impact of defects introduced by manufacturing processes. Namely, the lithographic mask limited resolution on the geometry of the representative device. These perturbations are a consequence of the lithographic mask limited resolution on the geometry of the representative device. For this purpose, the Beam Propagation and Finite Differences Time Domain methods will be used to simulate a multimode interference structure based on silicon nitride. The structure will be affected by previously mentioned perturbations and we expect results revealing a strong dependence between mask resolution, and imbalance and power loss. Two strategies will be followed concerning the mitigation of power loss and imbalance introduced by the limited resolution of lithographic mask: - Access waveguides tapering; - Adjustable power splitting ratios through the electro-optic effect. Through both strategies we aim to achieve an improvement on device’s performance but, in the latter are expected finer tuning capabilities, being enabled by dynamic compensation of power loss and imbalance when in a closed loop control architecture.
- VLC ready connected cars: trajectory redesign inside an intersectionPublication . Vieira, Manuel Augusto; Vieira, Manuela; Louro, Paula; Vieira, PedroThe redesign of the trajectories though complex, can be accomplished by the application of methods for navigation, guidance and combination of knowledge of road traffic control of vehicles. In this work the communication between the infrastructures and the vehicles, between vehicles and from the vehicles to the infrastructures is performed through Visible Light Communication (VLC) using the street lamps and the traffic signaling to broadcast the information. Vehicle headlamps and taillights are used to transmit data to other vehicles or infrastructures allowing digital safety and data privacy. Data is encoded, modulated and converted into light signals emitted by the transmitters. Tetra-chromatic white sources are used providing a different data channel for each chip. As receivers and decoders, SiC Wavelength Division Multiplexer (WDM) devices, with light filtering properties, are used. The primary objective is to control the arrival of vehicles to an intersection and schedule them to cross at times that minimize delays. A further objective is to allocate delays between left-turns and forward movements, moderating the speed and slot between vehicles travelling in these directions, maintaining a safe distance from one to another. Pedestrians and bicycles are incorporated. A Vehicleto-Everything (V2X) traffic scenario is stablished and bidirectional communication between the infrastructure and the vehicles is tested, using the VLC request/response concept. A phasing traffic flow is developed as a proof of concept. The experimental results confirm the cooperative VLC architecture showing that communication between connected cars is optimized using a request/response concept. An increase in the traffic throughput with least dependency on infrastructure is achieved.
- Implementing CNNs using a linear array of full mesh CGRAsPublication . Mário, Valter; Lopes, João D.; Véstias, Mário; De Sousa, JoseThis paper presents an implementation of a Convolutional Neural Network (CNN) algorithm using a linear array of full mesh dynamically and partially reconfigurable Coarse Grained Reconfigurable Arrays (CGRAs). Accelerating CNNs using GPUs and FPGAs is more common and there are few works that address the topic of CNN acceleration using CGRAs. Using CGRAs can bring size and power advantages compared to GPUs and FPGAs. The contribution of this paper is to study the performance of full mesh dynamically and partially reconfigurable CGRAs for CNN acceleration. The CGRA used is an improved version of the previously published Versat CGRA, adding multi CGRA core support and pre-silicon configurability. The results show that the proposed CGRA is as easy to program as the original full mesh Versat CGRA, and that its performance and power consumption scale linearly with the number of instances.
- Thin film refractive index and thicknessPublication . Lourenço, Paulo; Vieira, Manuela; Fantoni, AlessandroIntegrated optics are a contemporaneous reality in which thin-film technology and methods utilized in the development of integrated circuitry, are applied to both optical circuits and devices. This provides systems that show improved characteristics when compared to their electronic counterparts. Optical systems enable wider bandwidth operation, less power consumption, more immunity to interference and higher cost-efficiency. These features definitely represent a huge improvement in our daily lives when completely embedded in Information and Communications Technologies, replacing a large percentage of contemporaneous electronic based systems. The building blocks of these optical systems consist on waveguides and structures formed by deposited thin films. Two characteristics of utmost importance for these structures are the height and refractive index of the deposited film. In this work and by using a prism coupler, we will be presenting an optical setup and the experimental method that is used to determine both refractive index and thickness of the wave guiding structure.