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  • Pensamento Geométrico: Geometria não euclidiana no ensino secundário
    Publication . Gonçalves, Maria Teresa Serrão Sanches; Matos, José Manuel Leonardo de; Saraiva, Manuel Joaquim Félix da Silva
    Muitos anos dedicados à prática letiva foram determinantes para a decisão de levar a cabo esta investigação. Porque os conteúdos relativos à Geometria são de forma generalizada um problema para os alunos e um entrave ao seu sucesso escolar, tem todo o sentido centralizar a investigação na área da Didática da Matemática no tema Geometria. O objetivo desta investigação é o de averiguar como o conhecimento de outras geometrias (além da euclidiana) e a sua aplicação conduzem o pensamento geométrico dos alunos. Com o propósito bem definido de obter conclusões que possam contribuir de forma construtiva no domínio da didática da Matemática, e dar resposta a: (i) será importante, ou não, a apresentação e aplicação de outras geometrias (além da euclidiana) no ensino secundário com o objetivo de desenvolver capacidades geométricas? e (ii) de que modo o conhecimento e aplicação de outras geometrias influencia o pensamento geométrico nos alunos? Foram elaboradas propostas didáticas com um objetivo de estudo: “fazer emergir sinais” indiciadores de uma atividade intelectual, conducente à apropriação de significados geométricos, expressa através da linguagem. A um grupo de nove alunos do ensino secundário (alunos com idades compreendidas entre 15 e 18 anos), elementos do Clube de Matemática da escola que frequentam, foi proposto a realização de algumas tarefas investigativas. Estas tarefas foram selecionadas para potenciar o desenvolvimento do processo semiótico. A professora/investigadora conduziu as sessões fomentando a discussão e a comunicação segundo uma perspetiva dialética em que promoveu a evolução de sinais (analisados na linguagem) e orientou de forma a que estes fossem consistentes com os significados matemáticos definidos na intervenção didática. De todas as sessões foi feita a gravação áudio e todas essas gravações foram transcritas permitindo uma análise ao modo como os alunos se envolveram na realização das tarefas, à interação entre si e com o professor, aos sinais emergentes de quaisquer reações no grupo de trabalho, em particular aos emergentes das discussões coletivas e à linguagem utilizada. A análise dos dados recolhidos durante a realização das atividades pelos alunos teve em conta a mediação semiótica alicerçada na Teoria da Atividade. Cada verbalização ocorrida dentro da discussão coletiva foi classificada por um sinal. A partir dessa classificação analisou-se o estado evolutivo dos significados pessoais dos alunos em relação ao significado matemático, de acordo com os conceitos matemáticos que associámos a cada tarefa. Essa análise levou-nos a identificação de cadeias evolutivas dentro da discussão coletiva. Essas cadeias evolutivas foram sujeitas a uma análise mais detalhada e verificou-se que a apresentação e aplicação das GNE em tarefas com os alunos não teve um efeito inócuo e pode desenvolver capacidades geométricas e influenciar o pensamento geométrico dos alunos.
    2019-04Doctoral thesis Open access Show more
  • Performance Evaluation of Network Anomaly Detection Systems
    Publication . Fernandes Junior, Gilberto; Rodrigues, Joel José Puga Coelho
    Nowadays, there is a huge and growing concern about security in information and communication technology (ICT) among the scientific community because any attack or anomaly in the network can greatly affect many domains such as national security, private data storage, social welfare, economic issues, and so on. Therefore, the anomaly detection domain is a broad research area, and many different techniques and approaches for this purpose have emerged through the years. Attacks, problems, and internal failures when not detected early may badly harm an entire Network system. Thus, this thesis presents an autonomous profile-based anomaly detection system based on the statistical method Principal Component Analysis (PCADS-AD). This approach creates a network profile called Digital Signature of Network Segment using Flow Analysis (DSNSF) that denotes the predicted normal behavior of a network traffic activity through historical data analysis. That digital signature is used as a threshold for volume anomaly detection to detect disparities in the normal traffic trend. The proposed system uses seven traffic flow attributes: Bits, Packets and Number of Flows to detect problems, and Source and Destination IP addresses and Ports, to provides the network administrator necessary information to solve them. Via evaluation techniques, addition of a different anomaly detection approach, and comparisons to other methods performed in this thesis using real network traffic data, results showed good traffic prediction by the DSNSF and encouraging false alarm generation and detection accuracy on the detection schema. The observed results seek to contribute to the advance of the state of the art in methods and strategies for anomaly detection that aim to surpass some challenges that emerge from the constant growth in complexity, speed and size of today’s large scale networks, also providing high-value results for a better detection in real time.
    2019-04Doctoral thesis Open access Show more
  • A narração de si pelo outro: A incapacidade de dizer o amor no sentido beauvoiriano.
    Publication . Pereira, Ana Catarina
    Num texto escrito que se furta aos tradicionais padrões e metodologias académicas, ensaiamos uma leitura que viaja do romance O sangue dos outros, de Simone de Beauvoir, para uma reflexão sobre um dos temas centrais do livro: a incapacidade de declarar amor ao outro e de vivência plena de sentimentos íntimos. O tema, como reconheceremos, perpassa o século XX, encontrando expressão em diversos objectos artísticos, da literatura ao cinema, do teatro à dança, da música às artes plásticas. De uma perspectiva sociológica, estes anos de conflitos mundiais, de reposicionamentos políticos e de manifestações em prol de uma universalização dos direitos humanos, questionaram ou tornaram fugazes muitas das uniões matrimoniais, que foram deixando de poder basear-se em relações essencialmente económicas, morais ou religiosas. Face a profundas alterações em ideais e valores dominantes, o amor seria então revalorizado como o último dos compromissos.Não obstante, nas linhas essencialmente aporéticas que aqui apresentamos, não propomos leituras finais ou justificações últimas para a resistência a palavras que anunciem novas fases, vidas ou promessas mútuas. Partimos apenas de um romance que mimetiza uma realidade comum, propagada em várias formas de expressão artística da contemporaneidade.
    2019-04Journal article Open access Show more
  • Demand Response-Based Operation Model in Electricity Markets With High Wind Power Penetration
    Publication . Hajibandeh, Neda; Shafie-khah, Miadreza; Talari, Saber; Dehghan, Shahab; Amjady, Nima; Mariano, S.; Catalão, João
    The issue of climate change has received considerable attention in recent decades. Therefore, renewable energies and especially wind units have become a central point of attention. To cope with the uncertainties of wind power generation, resulting from the intermittent nature of this kind of energy, this paper proposes a Demand Response (DR) based operation approach. In other words, unlike the previous models in the literature that considered a supplementary role for the DR, this paper introduces the main role for the DR in the operation of future electricity markets. This approach focuses on a comprehensive modeling of the Demand Response Programs (DRPs) for the operational scheduling of electricity markets, considering the uncertainties of the generation of wind turbines, aiming at increasing the network security and decreasing the operation cost. The incorporation of market-based DRPs such as Demand Bidding (DB) and Ancillary Service Demand Response (ASDR) is also considered. Two novel quantitative indices are introduced to analyze the success of DRPs regarding efficiency and wind integration. Numerical results obtained on two IEEE test systems indicate the effectiveness of the proposed model.
    2019-04Journal article Restricted access Show more
  • Planos da cidade: Geografias do cinema de Palmas
    Publication . Silva, Sérgio Ricardo Soares Farias; Penafria, Manuela Maria Fernandes
    Desde o início da sua história, o cinema mantém uma relação intricada com as cidades. Territorialidades, paisagens e percursos urbanos coexistem tanto nos lugares “reais” como nas telas, o que nos conduz à perspectiva das Geografias de Cinema, campo no qual este trabalho se inscreve. Já não se trata apenas de questionar sobre as representações que a urbe recebe nos filmes, mas de investigar como os lugares imaginados por cineastas repercutem na identidade cultural dos lugares, ou seja, qual a capacidade do cinema em gerar experiência territorial. Para esta reflexão, o foco recai sobre as especificidades de Palmas, capital do estado brasileiro do Tocantins, e do audiovisual que lá se tem produzido. Por um lado, temos uma cidade nova, construída ex nihilo como índice de modernidade, marcada pelo personalismo político e com uma narrativa impregnada de oficialismo e muito arraigada midiaticamente. Por outro, encontramos um pequeno cinema, em condição periférica, com poucos recursos para produção e circulação. No confronto entre estas realidades, busca-se entender se os realizadores locais preservam suficiente independência para sonhar uma Palmas e debater uma história e uma identidade distintas daquelas predominantes, por exemplo, na imprensa hegemônica. Ainda que precise recorrer ao contexto urbanístico, político e cultural da cidade, a argumentação promovida parte fundamentalmente dos filmes. Para tanto, realiza-se a análise fílmica de onze obras diversas, tanto em termos de formato e gênero quanto em condições e época de produção. Recorre-se também a entrevistas com alguns dos cineastas estudados, o que resulta em material de fonte primária a auxiliar nas análises. Estas ações visam contribuir para uma historiografia ainda muito escassa do audiovisual local, de forma a lhe dar visibilidade e, portanto, existência na cartografia cinematográfica brasileira.
    2019-04Doctoral thesis Open access Show more
  • Essays on the economics of the energy mix diversification in the Transport Sector
    Publication . Neves, Sónia Almeida; Marques, António Manuel Cardoso; Fuinhas, José Alberto Serra Ferreira Rodrigues
    The analysis of the consequences of the diversification of the Transport Sector energy mix is the main focus of this thesis. As a sector highly powered by fossil fuels, the promotion of alternative energy sources such as electricity and renewable fuels has to be pursued to reduce the use of oil, and consequently cut greenhouse gases emissions. However, currently, the alternative sources are faced with several challenges. To address some of these challenges, this thesis performs four analyses organized into three main parts. In the first one, the interactions between both conventional and alternative transports’ energy sources, economic growth and carbon dioxide emissions have been examined. Two essays have been carried out in the first part, to achieve these objectives. The recent methods of Panel-Vector Autoregressive and the Autoregressive Distributed lag models have been applied. The main findings suggest that the electricity use in the transport sector only contributes to reducing GHG emissions if this electricity is coming from renewable sources. At the same time, the alternative energy sources could compromise the economic growth highlighting that their cost-effectiveness must be enlarged. With adequate policy supporting, the penetration of the electricity in transport sector could have a great potential in, for instance, storing renewable electricity, improving renewable electricity utilisation. For that, the deployment of electricity on the road transportation is required. These evidences have definitively motivated the second and third main parts of this thesis. They are focused on the main challenges that the electric mobility on road transportation is faced: the penetration of electric vehicles in the automotive market and the impact of these vehicles on the electricity system management and renewables integration. Thus, the second part of this thesis aims to analyse the driving factors of electric vehicles adoption. This analysis goes further by distinguishing the adoption drivers of 100% electric vehicles, also known as battery electric vehicles, and plug-in electric vehicles. The factors analysed include: political, social, economic, environmental, and technical. A Panel-Corrected Standard Errors (PCSE) estimator is used for European Union countries and the robustness of the results has been confirmed by employing a Seemingly Unrelated Regression (SUR) method. Actually, the main challenge for both 100% electric vehicles and plug-in electric vehicles adoption is the technological progress of the batteries. Furthermore, this analysis highlights that the policymaking should be focused on each type of vehicle technology instead of electric vehicles as a whole. In line with the findings of the first part of this thesis, countries with high endogenous potential should promote more 100% electric vehicles than plug-in electric vehicles to take advantage of the renewable electricity. While countries with low renewable potential should promote more plug-in electric vehicles. The policies supporting electric mobility have been effective in the 100% electric vehicles market share enlargement, but not for plug-in electric vehicles. With an appropriated policy support and technological development, the 100% electric vehicles could contribute to increasing the efficiency of the electricity system and renewables integration. These evidences constitute the main motivation for the third part of this thesis. Therefore, the main objective of the third part is to analyse the drivers of both peak electricity demand and renewables integration, providing special attention to the role played by battery electric vehicles to this equilibrium. Both Panel-Corrected Standard Errors and Driscoll-Kraay estimators have been applied for European Union countries. Different models’ specifications have been used to confirm the robustness of the results found. This part highlights that the deployment of the 100% electric vehicles has led to a decrease of the peak electricity demand, which is indeed a desirable effect. Still, it should deserve further attention since the deployment of the large amounts of battery electric vehicles could modify this effect. At the same time, the 100% electric vehicles have not contributed to renewables integration. The policies focused on demand side management have been effective in integrating renewables in contrast to their lack of success in reducing peak electricity demand. The policymakers should design demand side management efficient policies to reduce the peak load demand. The promotion of Demand Response measures, such as differentiated electricity tariffs in peak periods and out-off peak periods could be an efficient way to achieve it.
    2019-04Doctoral thesis Open access Show more
  • Hyaluronic acid functionalized nanoparticles loaded with IR780 and DOX for cancer chemo-photothermal therapy
    Publication . Alves, Cátia; Diogo, Duarte Miguel De Melo; Sousa, Ana Rita Lima; Costa, Elisabete; Correia, Ilidio
    IR780 is a near infrared (NIR) dye with a huge potential to be applied in cancer phototherapy and imaging. However, IR780 poor water solubility and acute cytotoxicity limit its direct use in cancer theragnostic. Herein, a novel Hyaluronic acid (HA)-based amphiphilic polymer was used, for the first time, in the preparation of polymeric nanoparticles (HPN) encapsulating IR780 aimed to be applied in breast cancer therapy. Furthermore, HPN co-encapsulating IR780 and Doxorubicin (DOX) were also produced in order to further enhance the therapeutic effectiveness of this nanoformulation. The results revealed that HPN were able to successfully encapsulate IR780 (IR-HPN) and the IR780-DOX combination (IR/DOX-HPN). Furthermore, the encapsulation of IR780 in HPN improved its absorption at 808 nm by about 2.2-fold, thereby enhancing its photothermal potential, as well as its cytocompatibility. The 2D in vitro cell uptake studies demonstrated that the nanostructures displayed a higher internalization by breast cancer cells than by normal cells. In addition, the assays performed in 3D in vitro models of breast cancer revealed that HPN can penetrate into spheroids. Furthermore, the 3D in vitro studies also demonstrated that the combined application of IR-HPN and NIR light was unable to induce cytotoxicity on spheroids. In contrast, IR/DOX-HPN produced a decrease on spheroids cells' viability, and their combination with NIR light induced an even stronger therapeutic effect, thus revealing the potential of these nanoparticles for cancer chemo-phototherapy.
    2019-04Journal article Restricted access Show more
  • Detecting Robotic Anomalies using RobotChain
    Publication . Lopes, Vasco; Alexandre, Luís
    Robotic events can provide notable amounts of information regarding a robot’s status, which can be extrapolated to detect productivity, anomalies, malfunctions and used for monitorization. However, when problems occur in sensitive environments like a factory, the logs of a machine may be discarded because they are susceptible to chances and malicious intents. In this paper we propose to use RobotChain for anomaly detection. RobotChain is a method to securely register robotic events, using a blockchain, which ensures that once an event gets registered on it, it’s secured and cannot be tampered with. We show how this system can be leveraged with the module for anomaly detection, that uses the information contained on the blockchain to detect anomalies on a UR3 robot.
    2019-04Conference object Open access Show more
  • Aplicação da Taxonomia SOLO na análise da qualidade da avaliação
    Publication . Pereira, Verónica Carla de Almeida Santos; Matos, José Manuel Leonardo de; Silva, César Augusto Teixeira Marques da
    JEAN PIAGET defendia que “a capacidade cognitiva humana nasce e desenvolve-se, não vem pronta.” Temos hoje consciência de que o ser humano evolui em consequência da sua interação sensorial com o mundo, construindo a sua intrincada relação de ações condicionadas pela perceção do que o rodeia e pela sua capacidade de criar e relacionar com o que apreende. O conhecimento resulta, assim, de um processo de aprendizagem complexo, variável de indivíduo para indivíduo, mas que pode ser compreendido, sistematizado e definido. BIGGS e COLLIS, partindo dos pressupostos gerais enunciados por PIAGET, elaboraram uma teoria, denominada Taxonomia SOLO, que nos fornece parâmetros para analisar e classificar os conteúdos de um processo de aprendizagem, através da descrição dos processos envolvidos na dialética pergunta/resposta, numa escala de dificuldade ou complexidade. A dialética pergunta/resposta é, na sua génese, a ferramenta essencial de um momento determinante do processo de ensino – a Avaliação. O nosso trabalho assenta essencialmente numa análise do processo de Avaliação, tendo por base o conjunto de provas de avaliação da disciplina de matemática num contexto determinado e num período de tempo concretamente definido, através da análise e classificação de questões sobre os diversos conteúdos avaliados. A investigação incidiu sobre os exames nacionais de Matemática do 12º ano de escolaridade, em ambas as fases de exame, entre 2006 e 2014. Como metodologia, seguimos os pressupostos da Taxonomia SOLO propostos por BIGGS e COLLIS, no modelo de categorização desenvolvido e adaptado por MÁRIO CEIA, a partir do qual seguimos uma matriz de classificação das questões que entendemos ajustada ao objeto da análise e fiel aos pressupostos de base. O nosso trabalho fornece uma análise exaustiva de um momento do processo de ensino enquanto processo de validação da metodologia proposta. Conscientemente, não aborda outras perspetivas fundamentais para uma análise global da qualidade de ensino e que não cabem no âmbito desta tese. Ainda assim, pelos resultados obtidos, podemos enunciar algumas propostas conclusivas quanto às evidências que resultam do estudo e que desde já se antecipam – o ensino da matemática é generalizante, o grau de exigência é cada vez maior e as médias finais na avaliação da disciplina tendiam para mais negativas.
    2019-04Doctoral thesis Open access Show more
  • Performance Evaluation of Smart Decision Support Systems on Healthcare
    Publication . Moreira, Mario Wedney de Lima; Rodrigues, Joel José Puga Coelho
    Medical activity requires responsibility not only from clinical knowledge and skill but also on the management of an enormous amount of information related to patient care. It is through proper treatment of information that experts can consistently build a healthy wellness policy. The primary objective for the development of decision support systems (DSSs) is to provide information to specialists when and where they are needed. These systems provide information, models, and data manipulation tools to help experts make better decisions in a variety of situations. Most of the challenges that smart DSSs face come from the great difficulty of dealing with large volumes of information, which is continuously generated by the most diverse types of devices and equipment, requiring high computational resources. This situation makes this type of system susceptible to not recovering information quickly for the decision making. As a result of this adversity, the information quality and the provision of an infrastructure capable of promoting the integration and articulation among different health information systems (HIS) become promising research topics in the field of electronic health (e-health) and that, for this same reason, are addressed in this research. The work described in this thesis is motivated by the need to propose novel approaches to deal with problems inherent to the acquisition, cleaning, integration, and aggregation of data obtained from different sources in e-health environments, as well as their analysis. To ensure the success of data integration and analysis in e-health environments, it is essential that machine-learning (ML) algorithms ensure system reliability. However, in this type of environment, it is not possible to guarantee a reliable scenario. This scenario makes intelligent SAD susceptible to predictive failures, which severely compromise overall system performance. On the other hand, systems can have their performance compromised due to the overload of information they can support. To solve some of these problems, this thesis presents several proposals and studies on the impact of ML algorithms in the monitoring and management of hypertensive disorders related to pregnancy of risk. The primary goals of the proposals presented in this thesis are to improve the overall performance of health information systems. In particular, ML-based methods are exploited to improve the prediction accuracy and optimize the use of monitoring device resources. It was demonstrated that the use of this type of strategy and methodology contributes to a significant increase in the performance of smart DSSs, not only concerning precision but also in the computational cost reduction used in the classification process. The observed results seek to contribute to the advance of state of the art in methods and strategies based on AI that aim to surpass some challenges that emerge from the integration and performance of the smart DSSs. With the use of algorithms based on AI, it is possible to quickly and automatically analyze a larger volume of complex data and focus on more accurate results, providing high-value predictions for a better decision making in real time and without human intervention.
    2019-04Doctoral thesis Open access Show more