1,388 research outputs found
Development of an e-portfolio social network using emerging web technologies
Dissertação de mestrado em Informatics EngineeringDigital portfolios (also known as e-Portfolios) can be described as digital collections of artifacts, being both a
product (a digital collection of artifacts) and a process (reflecting on those artifacts and what they represent). It
is an extension of the traditional Curriculum Vitae, which tells the educational and professional milestones of
someone, while the portfolio proves and qualifies them (e.g.: annually thousands of students finish a Master
degree on Informatics, but only one has built Vue, Twitter or Facebook – the Portfolio goes beyond the CV
milestones by specifying the person’s output throughout life and distinguishing them). e-Portfolios augment this
by introducing new digital representations and workflows, exposed to a community, being both a product and
a process. This approach can be useful for individual self-reflection, education or even job markets, where
companies seek talented individuals, because it expands the traditional CV concept and empowers individual
merit. There have been many studies, theories, and methodologies related with e-Portfolios, but transpositions
to web applications have been unsuccessful, untuitive and too complex (in opposition to the CV format, which
had success in various applications, for example LinkedIn).
This project aims to study new approaches and develop an exploratory web/mobile application of this method ology, by exploring the potential of social networks to promote them, augmented by emergent web technologies.
Its main output is the prototype of a new product (a social network of e-Portfolio) and its design decisions, with
new theoretical approaches applied to web development. By the end of this project, we will have idealized a web
infrastructure for interacting with networks of users, their skills, and communities seeking them.
The approach to the development of this platform will be to integrate emerging technologies like WebAssembly
and Rust in its development cycle and document our findings. At the end of this project, in addition to the
prototype of a new product, we hope to have contributed to the State of the Art of Web Engineering and to be
able to answer questions regarding new emerging web development ecosystems.Os portfólios digitais (também conhecidos como e-Portfolios) podem ser descritos como coleções digitais de
artefatos, sendo tanto um produto (uma coleção digital de artefatos) quanto um processo (refletindo sobre esses
artefatos e o que eles representam). É uma extensão do tradicional Curriculum Vitae, onde o primeiro conta os
marcos educacionais e profissionais de alguém, enquanto que o segundo, o Portfólio, comprova-os e qualifica-os
(e.g.: anualmente milhares de alunos concluem graduações em Informática, no entanto apenas um consebeu
o Vue, o Twitter ou o Facebook - o Portfólio vai além dos indicadores quantitativos do CV, especificando e
qualificando a produção da pessoa ao longo da vida e distinguindo-a). Os e-Portfolios expandem este conceito
com a introdução de novas representações digitais e fluxos de trabalho, expostos a uma comunidade, sendo
tanto um produto como um processo. Esta abordagem pode ser útil para a autorreflexão individual, educação ou
mesmo mercados de trabalho, onde as empresas procuram indivíduos talentosos, porque expande o conceito
tradicional de CV e potencializa o mérito individual. Existem muitos estudos, teorias e metodologias relacionadas
com os e-Portfolios, mas as transposições para aplicações web têm sido mal sucedidas, pouco intuitivas e muito
complexas (em oposição ao formato CV, que tem tido sucesso em várias aplicações, por exemplo no LinkedIn).
Este projeto visa estudar novas abordagens neste domínio e desenvolver uma aplicação exploratória web/mobile que melhor exprima os e-Portfolios, explorando o potencial das redes sociais para os promover em conjunto
com tecnologias web emergentes. As principais produções esperadadas deste trabalho são um protótipo de
um novo produto (uma rede social de e-Portfolio) e documentar novas abordagens teóricas aplicadas ao desenvolvimento web. No final deste projeto, teremos idealizado uma infraestrutura web para interagir com redes de
utilizadores, as suas competências e comunidades que os procurem.
A abordagem ao desenvolvimento desta plataforma será integrar tecnologias emergentes como WebAssembly e Rust no seu ciclo de desenvolvimento e documentar as nossas descobertas e decisões. No final deste
projeto, para além do protótipo de uma plataforma, esperamos ter contribuido para o Estado da Arte da Engenharia Web e responder a questões sobre novos ecossistemas emergentes de desenvolvimento web
Constraints-led approach and synergetic behaviour in volleyball performance
O objetivo desta tese foi investigar a Abordagem Baseada nos Constrangimentos (ABC)
e comportamento sinergético no voleibol. Enquadrados pela dinâmica ecológica
investigámos conceitos teóricos relacionados com o comportamento sinergético
individual e coletivo e aplicamos a ABC em equipas de voleibol. Inicialmente,
apresentámos uma revisão narrativa dos princípios da ABC e pedagogia não-linear
sugerindo dois exemplos para aplicação em treino. De seguida, produzimos dois artigos
de opinião sobre o papel das estruturas de biotensegridade no comportamento sinergético
individual e coletivo. Nos estudos experimentais implementámos a ABC para guiar os
atletas através das fases de “Search”, “Discover” e “Exploit”. Primeiro, numa equipa de
cadetes feminina manipulámos os constrangimentos da tarefa de forma a respeitar as
diferenças individuais e comparar a precisão no remate após o treino, assim como,
analisar a estratégia temporal na estrutura coordenativa da corrida e chamada de remate.
Os resultados mostram que respeitar as diferenças individuais promovem melhor
performance (i.e., na precisão do remate) e que congelar os graus de liberdade numa
componente da estrutura coordenativa da chamada foi a estratégia associada com mais
precisão no remate. De seguida, implementámos um estudo com jogadoras peritas para
comparar frequências de contacto na defesa entre o jogo formal, a estratégia tradicional
de defesa e a estratégia de coletivamente atender a variáveis especificadoras no decorrer
da jogada. Adicionalmente, medimos a sincronização da defesa em situações de sucesso
e insucesso defensivo. Resultados mostram que coletivamente atender a variáveis
especificadoras no decorrer da jogada promove maior frequência de contactos e que as
jogadas de sucesso defensivo estão associadas a alterações na sincronização no decorrer
da jogada. Por último, com jogadores jovens de elite comparámos os efeitos na
performance de ataque entre treinar de acordo com os princípios da ABC e com uma
abordagem tradicional. Também tivemos como objetivo predizer quais as variáveis
espácio-temporais que foram exploradas pelos jogadores nos ataques com sucesso.
Resultados mostram um aumento da performance com a ABC e que variabilidade na
chamada e consistência no ponto de contacto da bola aumenta a probabilidade de atacar
com sucesso.The aim of this thesis was to research the Constraints-led Approach (CLA) and synergetic
behaviour in volleyball performance. Grounded on ecological dynamics framework we
researched theoretically concepts related to individual and collective synergetic
behaviour and experimentally implemented the CLA with volleyball teams. First, we
presented a narrative review on the principles of CLA and nonlinear pedagogy providing
two practical examples to apply to the sub-phase of volleyball attack. Next, we advanced
a position statement and a novel hypothesis on the crucial role of biotensegrity structures
in individual and collective coordinative structurers (i.e., synergies). In the experimental
studies we implemented CLA to guide the performers trough the phases of “Search”,
“Discover” and “Exploit”. First, with a team of young female volleyball players we
manipulate task constraints to accommodate individual differences and compare spike
accuracy after training as well as understand time strategies in the coordinative structure
of the horizontal approach. Results show that accommodating individual differences
enhances performance (i.e., spike accuracy) and freezing degrees of freedom maintaining
high variability in a component of the coordinative structure of the horizontal approach
was the strategy of movement re-organization associated with higher spike accuracy.
Next, we implemented a study with expert female volleyball players to compare
frequencies of defensive ball contacts between real game, traditional defense strategy and
“online” attunement to specifying variables. Additionally, we measure group
synchronization in successful and unsuccessful defense situations. Results show that
collectively attuning to relevant information promotes significant higher frequencies of
defense ball contact than pre-determined strategies of action and successful defensive
plays are associated with “online” significant changes in group synchronization. Finally,
with young male elite volleyball players we aimed to compare the effects of training based
on CLA principles to a traditional approach on attack performance. Also, aimed to predict
what spatial temporal variables were exploited by the players to achieve successful
attacks. Results showed a significant improvement in attack performance for CLA, and
we found that variability at the end of the planting step and consistency at ball contact
increased the chances of a successful attack
Real time locating system based on active RFID
Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores (Telecomunicações). Universidade do Porto. Faculdade de Engenharia. 201
Characterization of molecular damage induced by UV photons and carbon ions on biomimetic heterostructures
The study of the effect of radiation on living tissues is a rather complex task to address mainly because they are made of a set of complex functional biological structures and interfaces. Particularly if one is looking for where damage is taking place in a first stage and what are the underlying reaction mechanisms. In this work a new approach is addressed to study the effect of radiation by making use of well identified molecular hetero-structures samples which mimic the biological environment. These were obtained by assembling onto a solid support deoxyribonucleic acid (DNA) and phospholipids together with a soft water-containing polyelectrolyte precursor in layered structures and by producing lipid layers at liquid/air interface with DNA as subphase. The effects of both ultraviolet (UV) radiation and carbon ions beams were systematically investigated in these heterostructures, namely damage on DNA by means vacuum ultraviolet (VUV), infrared (IR), X-Ray Photoelectron (XPS) and impedance spectroscopy. Experimental results revealed that UV affects furanose, PO2-, thymines, cytosines and adenines groups. The XPS spectrometry carried out on the samples allowed validate the VUV and IR results and to conclude that ionized phosphate groups, surrounded by the sodium counterions, congregate hydration water molecules which play a role of UV protection. The ac electrical conductivity measurements revealed that the DNA electrical conduction is arising from DNA chain electron hopping between base-pairs and phosphate groups, with the hopping distance equal to the distance between DNA base-pairs and is strongly dependent on UV radiation exposure, due loss of phosphate groups. Characterization of DNA samples exposed to a 4 keV C3+ ions beam revealed also carbon-oxygen bonds break, phosphate groups damage and formation of new species. Results from radiation induced damage carried out on biomimetic heterostructures having different compositions revealed that damage is dependent on sample composition, with respect to functional targeted groups and extent of damage. Conversely, LbL films of 1,2-dipalmitoyl-sn-Glycero-3-[Phospho-rac-(1-glycerol)] (Sodium Salt) (DPPG) liposomes, alternated with poly(allylamine hydrochloride) (PAH) revealed to be unaffected, even by prolonged UV irradiation exposure, in the absence of water molecules. However, DPPG molecules were damaged by the UV radiation in presence of water with cleavage of C-O, C=O and –PO2- bonds. Finally, the study of DNA interaction with the ionic lipids at liquid/air interfaces revealed that electrical charge of the lipid influences the interaction of phospholipid with DNA. In the presence of DNA in the subphase, the effects from UV irrladiation were seen to be smaller, which means that ionic products from biomolecules degradation stabilize the intact DPPG molecules. This mechanism may explain why UV irradiation does not cause immediate cell collapse, thus providing time for the cellular machinery to repair elements damaged by UV
Evaluation of fatigue performance at different temperatures
The fatigue performance of asphalt mixtures is used to predict pavement life to control the cracking in the asphalt layers. The design of an asphalt pavement is usually made for a specific temperature, what is intended to represent the pavement behaviour throughout a whole year. For damage analysis during a year, along which the pavement temperature constantly varies, it is necessary to calculate the fatigue performance of pavements at a wide range of temperatures. Thus, this paper presents the evaluation of the fatigue response of two asphalt mixtures, a conventional and an asphalt rubber mixture. Frequency sweep tests were also performed to evaluate the stiffness modulus. The fatigue test results showed that the fatigue life decreases when the test temperature decreases up to a certain value. After that value, the fatigue life increases when the test temperature decreases. To explain this phenomenon, this paper presents the preliminary tests carried out to measure the temperature inside the testing specimens to verify possible discrepancies between the climatic chamber temperature and the specimen temperature
Pequenos RNAs não codificantes em bactérias do complexo Burkholderia cepacia: contribuição para a sua identificação e caracterização do seu papel na virulência
Tese de mestrado. Biologia (Biologia Humana e Ambiente). Universidade de Lisboa, Faculdade de Ciências, 2011Nos últimos anos, um número crescente de trabalhos tem evidenciado que os pequenos RNAs reguladores não-codificantes (sRNAs) desempenham um papel basilar na regulação da expressão pós-transcricional de vários genes em procariontes. Entre esses genes, assumem particular importância aqueles cujos produtos constituem factores de virulência e de resposta a stresses vários. Os sRNAs permanecem praticamente desconhecidos no Complexo Burkholderia cepacia (Bcc). O Bcc compreende pelo menos dezassete espécies patogénicas oportunistas geneticamente próximas, capazes de causar infecções, particularmente graves em doentes com fibrose quística, em doentes imunocomprometidos e em doentes hospitalizados. O uso do nemátodo Caenorhabditis elegans como modelo de infecção permitiu identificar um mutante de B. cepacia IST408 cuja virulência foi severamente reduzida, devido à interrupção dum gene codificante para uma proteína 84% similar à chaperona de pequenos RNAs de Escherichia coli, a proteína Hfq. A conhecida interacção entre a proteína do Hfq2 e sRNAs potencia o interesse do uso desta proteína como ferramenta para o isolamento de sRNAs através de técnicas de co-purificação. Neste contexto, o presente trabalho contribuiu para a identificação e caracterização do papel de um sRNA, denominado mtvR, envolvido na virulência de Burkholderia cenocepacia J2315.Over the last years, increasing evidence has shown that small noncoding regulatory RNAs (sRNAs) play a critical role in the post-transcriptional regulation of gene expression in prokaryotes. Among genes recognized to be subject to post-transcriptional regulation, particular attention has been given to those encoding determinants of virulence and resistance to various stresses. The roles played by sRNAs remain unknown in bacteria of the Burkholderia cepacia complex (Bcc). The Bcc includes opportunistic pathogens that belong to at least seventeen closely related species, able to cause severe and often lethal infections, particularly among cystic fibrosis patients, immunocompromised patients and hospitalized patients. Previous work from the IST research team led to the identification of a gene encoding a protein 84% similar to the Escherichia coli RNA chaperone Hfq. In the present work we have exploited the known interaction between Hfq2 and sRNAs in co-purification experiments, envisaging the identification of sRNAs from Bcc. In this context, this program contributed to the identification and characterization of the sRNA mtvR. This sRNA plays a role in the virulence of Burkholderia cenocepacia J2315, as demonstrated by experiments using the nematode Caenorhabditis elegans as an infection model
Um novo método de dimensionamento de reforços de pavimentos flexíveis considerando a reflexão de fendas
No presente trabalho é proposto um método de dimensionamento de reforços de pavimentos flexíveis, considerando como critérios de ruína o aparecimento de fendas à superfície da camada de desgaste, resultantes da reflexão do fendilhamento existente nas camadas betuminosas do pavimento existente, bem como o fendilhamento por fadiga.
O método proposto baseia-se no dimensionamento estrutural corrente, acrescido duma verificação do critério de reflexão de fendas, tendo como base resultados laboratoriais de avaliação da reflexão de fendas em misturas betuminosas, realizados em deslocamento controlado e associados ao conceito de actividade das fendas após reforço
The Framework “Glacial and periglacial landforms and deposits” in the scope of the Portuguese Geological Heritage Inventory
“Geoformas, depósitos glaciários e periglaciários” é um dos contextos geológicos considerados no âmbito da inventariação em curso do património geológico em território nacional. Apesar da reduzida expressão geográfica que as geoformas, os depósitos glaciários e periglaciários têm em Portugal, é-lhes reconhecida importância científica, também por essa via e por resultarem de processos morfodinâmicos raros nas condições climáticas actualmente existentes em Portugal. Após uma avaliação de potenciais geossítios com base em critérios de valor científico, foram seleccionados dezasseis como possuindo relevância nacional.“Glacial and periglacial landforms and deposits” is one of the frameworks included in the
ongoing geological heritage national inventory. The scientific value of these features is connected with
the occurrence of relevant evidences of Quaternary glaciations in the higher mountains of the country
like erosion landforms (U shaped valleys, cirques), depositional landforms (moraines) and deposits
(subglacial tills). Sixteen geosites with national relevance were selected after a potential geosites
assessment focused in scientific criteria.Este trabalho é apoiado pela Fundação para a Ciência e a Tecnologia, através do financiamento
plurianual do CGUP e do projecto de investigação “Identificação, caracterização e conservação do
património geológico: uma estratégia de geoconservação para Portugal” (PTDC/CTEGEX/64966/2006).info:eu-repo/semantics/publishedVersio
The improvement of pavement performance using asphalt rubber hot mixes
The need of a better pavement performance has led researchers to develop new road
materials, mainly for the asphalt layers, where the modification of the asphalt is the
main example. This modification usually forces the use of polymers and fibers and,
more recently, the use of crumb rubber from ground tires, where the modified asphalt is
known as asphalt rubber. This asphalt rubber used in asphalt mixtures produces a
superior performance if compared to the asphalt mixtures with conventional asphalt.
The crumb rubber modification of the asphalts also presents a higher resistance to
climatic effects, compared to the other binders. Based on these assumptions, this paper
presents the results of the evaluation of mechanical properties, related to the pavement
performance, of asphalt rubber mixtures when compared to conventional mixtures. Two
types of aggregate were used (pebble and diorites) and two binders utilized (asphalt
rubber and conventional asphalt). The aging effect due to the asphalt mixture
production and compaction was taken into account. The materials performance was
evaluated through stiffness, fatigue and permanent deformation tests. Reflective
cracking performance was also predicted using a mechanistic-empirical method
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