Circuito de leitura digital para MEMS capacitivos

Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e Computadores

Digital literacy, technology and social inclusion: making sense of one-to-one computer programmes around the world

This book was produced in the scope of a research project entitled “Navigating with ‘Magalhães’: Study on the Impact of Digital Media in Schoolchildren”. This study was conducted between May 2010 and May 2013 at the Communication and Society Research Centre, University of Minho, Portugal and it was funded by the Portuguese Foundation for Science and Technology (PTDC/CCI-COM/101381/2008).

Foreword [to Digital literacy, technology and social inclusion: making sense of one-to-one computer programmes around the world]

(Excerto) In times past, learning to read, write and do arithmetic was to get on course to earn the “writ of emancipation” in society. These skills are still essential today, but are not enough to live in society. Reading and critically understanding the world we live in, with all its complexity, difficulties and challenges, require not only other skills (learning to search for and validate information, reading with new codes and grammar, etc) but, to a certain extent, also metaskills, matrixes and mechanisms that are transversal to the different and new literacies, are necessary. They are needed not just to interpret but equally to communicate and participate in the little worlds that make up our everyday activities as well as, in a broader sense, in the world of the polis, which today is a global world.

Introduction [to Digital literacy, technology and social inclusion: making sense of one-to-one computer programmes around the world]

This book was produced in the scope of a research project entitled “Navigating with ‘Magalhães’: Study on the Impact of Digital Media in Schoolchildren”. This study was conducted between May 2010 and May 2013 at the Communication and Society Research Centre, University of Minho, Portugal and it was funded by the Portuguese Foundation for Science and Technology (PTDC/CCI-COM/101381/2008). As we shall explain in more detail later in this book, the main objective of that research project was to analyse the impact of the Portuguese government programme named ´e-escolinha´ launched in 2008 within the Technological Plan for Education. This Plan responds to the principles of the Lisbon Strategy signed in 2000 and rereleased in the Spring European Council of 2005.

SOFHIA: a CAD environment to design digital control systems

"Series Title: IFIP - The International Federation for Information Processing, ISSN 1868-4238"

Multifunctional converter to interface renewable energy sources and electric vehicles with the power grid in smart grids context

This paper proposes a multifunctional converter to interface renewable energy sources (e.g., solar photovoltaic panels) and electric vehicles (EVs) with the power grid in smart grids context. This multifunctional converter allows deliver energy from the solar photovoltaic panels to an EV or to the power grid, and exchange energy in bidirectional mode between the EV and the power grid. Using this multifunctional converter are not required multiple conversion stages, as occurs with the traditional solutions, where are necessary two power converters to integrate the solar photovoltaic system in the power grid and also two power converters to integrate an off-board EV battery charger in the power grid (dc-dc and dc-ac power converters in both cases). Taking into account that the energy provided (or delivered) from the power grid in each moment is function of the EV operation mode and also of the energy produced from the solar photovoltaic system, it is possible to define operation strategies and control algorithms in order to increase the energy efficiency of the global system and to improve the power quality of the electrical system. The proposed multifunctional converter allows the operation in four distinct cases: (a) Transfer of energy from the solar photovoltaic system to the power grid; (b) Transfer of energy from the solar photovoltaic system and from the EV to the power grid; (c) Transfer of energy from the solar photovoltaic system to the EV or to the power grid; (d) Transfer of energy between the EV and the power grid. Along the paper are described the system architecture and the control algorithms, and are also presented some computational simulation results for the four aforementioned cases. It is also presented a comparative analysis between the traditional and the proposed solution in terms of operation efficiency and estimated cost of implementation.

Automatic visual detection of human behavior: a review from 2000 to 2014

Due to advances in information technology (e.g., digital video cameras, ubiquitous sensors), the automatic detection of human behaviors from video is a very recent research topic. In this paper, we perform a systematic and recent literature review on this topic, from 2000 to 2014, covering a selection of 193 papers that were searched from six major scientific publishers. The selected papers were classified into three main subjects: detection techniques, datasets and applications. The detection techniques were divided into four categories (initialization, tracking, pose estimation and recognition). The list of datasets includes eight examples (e.g., Hollywood action). Finally, several application areas were identified, including human detection, abnormal activity detection, action recognition, player modeling and pedestrian detection. Our analysis provides a road map to guide future research for designing automatic visual human behavior detection systems.

Gd2O3: Eu3+/PPO/POPOP/PS composites for digital imaging radiation detectors

Polymer based scintillator composites have been produced by combining polystyrene (PS) and Gd2O3:Eu3+ scintillator nanoparticles. Polystyrene has been used since it is a flexible and stable binder matrix, resistant to thermal and light deterioration and with suitable optical properties. Gd2O3:Eu3+ has been selected as scintillator material due to its wide band gap, high density and visible light yield. The optical, thermal and electrical characteristics of the composites were studied as a function of filler content, together with their performance as scintillator material. Additionally 1wt.% of 2,5 dipheniloxazol (PPO) and 0.01wt.% of (1,4-bis(2-(5-phenioxazolil))-benzol (POPOP) were introduced in the polymer matrix in order to strongly improve light yield, i.e. the measured intensity of the output visible radiation, under X-ray irradiation. Whereas increasing scintillator filler concentration (from 0.25wt.% to 7.5wt.%) increases scintillator light yield, decreases the optical transparency of the composite. The addition of PPO and POPOP, strongly increased the overall 2 transduction performance of the composite due to specific absorption and re-emission processes. It is thus shown that Gd2O3:Eu3+/PPO/POPOP/PS composites in 0.25 wt.% of scintillator content with fluorescence molecules is suitable for the development of innovate large area X-ray radiation detectors with huge demand from the industries.

Effect of the acoustic impedance in ultrasonic emitter transducers using digital modulations

In an underwater environment it is difficult to implement solutions for wireless communications. The existing technologies using electromagnetic waves or lasers are not very efficient due to the large attenuation in the aquatic environment. Ultrasound reveals a lower attenuation, and thus has been used in underwater long-distance communications. The much slower speed of acoustic propagation in water (about 1500 m/s) compared with that of electromagnetic and optical waves, is another limiting factor for efficient communication and networking. For high data-rates and real-time applications it is necessary to use frequencies in the MHz range, allowing communication distances of hundreds of meters with a delay of milliseconds. To achieve this goal, it is necessary to develop ultrasound transducers able to work at high frequencies and wideband, with suitable responses to digital modulations. This work shows how the acoustic impedance influences the performance of an ultrasonic emitter transducer when digital modulations are used and operating at frequencies between 100 kHz and 1 MHz. The study includes a Finite Element Method (FEM) and a MATLAB/Simulink simulation with an experimental validation to evaluate two types of piezoelectric materials: one based on ceramics (high acoustic impedance) with a resonance design and the other based in polymer (low acoustic impedance) designed to optimize the performance when digital modulations are used. The transducers performance for Binary Amplitude Shift Keying (BASK), On-Off Keying (OOK), Binary Phase Shift Keying (BPSK) and Binary Frequency Shift Keying (BFSK) modulations with a 1 MHz carrier at 125 kbps baud rate are compared.

Digital manipulatives as scaffolds for preschoolers’ language development

The study reported here aims at contributing to a deeper understanding of the educational possibilities offered by digital manipulatives in preschool contexts. It presents a study carried with a digital manipulative to enhance the development of lexical knowledge and language awareness, which are relevant language abilities for formal literacy learning. The study took place in a Portuguese preschool, with a class of 20 five-year-olds in collaboration with the teacher. The digital manipulative supported the construction of multiple fictional worlds, motivating children's verbal interactions, and the playing of words and sound games, thus contextualizing the learning of an extensive collection of vocabulary and language awareness abilities. The degree of engagement and involvement that the manipulative provided in supporting children’s imaginative play as well as the imitation, in their own play, of the playful pedagogical interventions that the teacher had designed, shows the importance of well- designed materials that support a child-centered learning model. As such, it sustains a discussion on the potential of digital manipulatives to enhance fundamental language development in the preschool years. Further, the study highlights the importance of multidisciplinary teams in the creation of innovative pedagogical materials.

Radio mobility in the digital era: interactivity, participation and content share possibilities in Iberian broadcasters

In the context of the scientific research into radio, recent years have encouraged many theories about the meaning of a post-radio (Oliveira & Portela, 2011), thus enlisting several parameters regarding the inclusion of contemporary radio in the digital and online environments. This digital migration has led to the development of mobile applications for radio, broadening the communicative potential of audiences (Aguado, Feijoo & Martínez, 2013), as well as promoting convergence of interactive content among listeners-users. Aware of this opportunity, the main broadcasters in Spain and Portugal have broadened their radiophonic scope to the mobile platform, especially geared towards smartphones through the development of mobile applications, commonly known as apps (Cerezo, 2010). As a symbol of a culture in permanent changing, smartphones not only provide greater easiness in terms of access and interaction, but also afford larger opportunities for disseminating content among audiences, a phenomenon that some studies have labelled as user distributed content (Villi, 2012). This article presents an exploratory analysis of the current policies of the main Spanish and Portuguese radio broadcasters regarding mobile applications, evaluating the different levels of interaction and participation in these platforms. This observation led to the conclusion, among other findings, that the mobile platform represents a supplementary channel for traditional FM radio, rather than a new medium with its own language and expression.

Sistema de aquisição e comunicação para sensores magnetoelétricos

Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e Computadores

Luto digital: plataformas para a gestão da herança digital

Dissertação de mestrado integrado em Engenharia e Gestão de Sistemas de Informação

As políticas tecnológicas para a educação e a literacia digital: o caso do programa governamental ‘e.escolinha’

Em 2008, o Governo português anunciou a iniciativa ‘e.escolinha’ que contemplou a distribuição de computadores ‘Magalhães’ aos alunos do 1º ciclo do ensino básico, durante três anos letivos consecutivos. Atualmente suspenso, o programa foi bandeira do XVII Governo Constitucional, liderado por José Sócrates, mas alvo de controvérsias por parte da oposição política e da comunidade escolar, sobretudo pela aparente tónica no acesso à tecnologia em vez de uma maior preocupação com a formação e as práticas pedagógicas. Ao abrigo do Plano Tecnológico da Educação, o ‘e.escolinha’ inseria-se numa política mais ampla para o desenvolvimento de uma economia competitiva e dinâmica, através das metas estabelecidas pela União Europeia na Estratégia de Lisboa 2000. A iniciativa foi apresentada ao país com objetivos ambiciosos, no que diz respeito às esperadas mudanças ao nível das práticas pedagógicas dos professores, do processo de aprendizagem das crianças e do sucesso escolar em geral. Porém, a face mais visível da política, embora possa compreender outros matizes, poderá ter ficado reduzida à questão do acesso, apostando pouco nas outras dimensões da literacia digital. Com base em entrevistas realizadas a atores-chave envolvidos no processo de conceção e implementação do ‘e.escolinha’, e nos documentos oficiais que enquadram o programa, o presente artigo pretende dar a conhecer a forma como decisores políticos e empresas enunciam e avaliam os objetivos desta iniciativa. Pretende-se, em particular, conhecer se partilham a ideia de uma deriva tecnológica desta medida governamental ou se entreveem, na mesma, objetivos de literacia digital. Este trabalho decorre do projeto de investigação “Navegando com o Magalhães: Estudo sobre o Impacto dos Media Digitais nas Crianças”, em curso no Centro de Estudos de Comunicação e Sociedade da Universidade do Minho, financiado pela Fundação para a Ciência e Tecnologia ((PTDC/CCI-COM/101381/2008) ) e co-financiado pelo FEDER (COMPETE: FCOMP-01-0124-FEDER-009056).

A comunicação em organizações virtuais: o paradigma digital

Dissertação de mestrado em Ciências da Comunicação (área de especialização em Publicidade e Relações Públicas)