2,714 research outputs found
COGNITO – The graphics and content delivery module
The poster presents the two main components for the graphics and content delivery module of COGNITO system. One Augmented reality player is presented as well as one editor of multimedia content to be used in the player (augmented information)
Who's got the power? Wage determination and its resilience in the Great Recession
Whereas wage inequality has risen markedly in most OECD countries in recent decades, it has fallen in several Southern European economies. To shed light on this phenomenon, we embed sectoral bargaining, which is common in Southern European economies, in a dynamic search and matching model. We estimate the model using comprehensive employer-employee data from Portugal for the last two decades and its data on collective bargaining agreements in different sectors, which allows us to assess the evolution of rent sharing. We find that since the mid-2000s, worker bargaining power has grown slightly at the bottom of the skill distribution while shrinking at the middle and top, contributing to the compression of the wage distribution. These changes, which persisted even during the Great Recession, increased the importance of sectoral bargaining in wage determination, weakened the relationship between wages and firm productivity, and reduced the assortative matching of workers to firms
Biomembranas de poliuretano produzidas por electrofiação para enxertos vasculares
Mestrado em Materiais e Dispositivos BiomédicosUm dos grandes desafios da engenharia de tecidos (TE) vasculares, prende-se com a pouca disponibilidade de tecidos vasculares autólogos para substituição de vasos sanguÃneos de pequeno diâmetro (<6 mm). Estudos demonstram que o poliuretano possui propriedades mecânicas adequadas para a utilização em vasos sanguÃneos de pequenos diâmetros. Trabalhos anteriores realçam as propriedades antibacterianas de compósitos compostos por PU e nanopartÃculas de oxido de zinco (nZnO).
O presente estudo teve como objetivo a produção de membranas compósitas de PU/ nZnO com recurso a electrofiação. Mais concretamente pretendia-se avaliar as propriedades antibacterianas e mecânicas dos compósitos, testando diferentes concentrações de nZnO.
Foram sintetizadas nanopartÃculas de óxido de zinco, através do método de precipitação quÃmica à temperatura ambiente, obtendo-se nano estruturas porosas. As membranas compósitas foram testadas contra E.coli e S.aureus evidenciando um bom comportamento antibacteriano, bem como uma relação do mesmo com a concentração de nZnO nas membranas. No que diz respeito aos ensaios mecânicos, as membranas mostraram boas propriedades.
Em conclusão, as nZnO podem ser adicionas ao PU formando uma membrana com propriedades antibacterianas e boas propriedades mecânicasOne of the great challenges of vascular tissue engineering (TE) is the lack of availability of autologous vascular tissues to replace small-diameter (<6 mm) blood vessels. Studies have shown that polyurethane has mechanical properties suitable for use in blood vessels of small diameters. Previous papers highlight the antibacterial properties of composites composed of PU and nanoparticles of zinc oxide (nZnO).
The present study had as objective the production of composite membranes of PU / nZnO with the use of electrofying. More specifically, it was intended to evaluate the antibacterial and mechanical properties of the composites by testing different concentrations of nZnO.
Nanoparticles of zinc oxide were synthesized through the chemical precipitation method at room temperature, obtaining nano porous structures. The composite membranes were tested against E. coli and S. aureus showing a good antibacterial behavior, as well as a relation thereof with the concentration of nZnO in the membranes. With regard to mechanical tests, the membranes showed good properties.
In conclusion, the nZnO can be added to the PU forming a membrane with antibacterial properties and good mechanical properties
Treatment of aqueous effluents contaminated with active pharmaceutical ingredients
"The need to significantly improve human living conditions led to a large
increase in the worldwide consumption of pharmaceutical drugs. Over the past
few years, the development of advanced analytical tools and investigations on
wastewater samples confirmed the presence of residual amounts of active
pharmaceutical ingredients (APIs) in wastewater treatment plants (WWTPs),
sewage treatment plants (STPs), groundwater and drinking water. Even at low
concentrations (ng.L-1 – μg.L-1), the regular contact and ingeston of APIs can lead
to deleterious effects towards living organisms. Numerous studies demonstrated
that APIs present in WWTPs are a matter of concern towards wildlife and public
health. Given the widespread occurance of these drugs in aquatic ecossystems
and their deleterious effects, the development of strategies able to mitigate their
introduction in the aquatic environment is of great importance.(...)"N/
Simultaneous multi-access in heterogeneous mobile networks
The exponential growth of the number of multihomed mobile devices is changing the way how we
connect to the Internet. Unfortunately, it is not yet easily possible to a multihomed device to be
simultaneously connected to the network through multiple links.
This work enhances the network access of multihomed devices. This enhancement is achieved by using
simultaneously all of the mobile devices interfaces, and by individually routing each data flow through
the most adequate technology. The proposed solution is only deployed at the network core and it does
not depend on the mobile devices, i.e., it’s transparent to the mobile devices. This work gives the
necessary tools to reuse the already deployed technologies like WiFi or 3G/LTE. Moreover, it is also
possible to extend the network by using femtocells which support multi access technologies. This work
is also integrated with IEEE 802.21 standard to improve the handover mechanisms in the network.
Additionally, we also propose an integration with a broker that can manage all the data flows individually.
The proposed solution improves the quality of service of the users while not overloading the operator
infrastructure. Evaluation results, obtained from the developed prototype, evidence that the overhead
for using the proposed solution is very small when compared to the advantages.O crescimento exponencial do número de equipamentos móveis com múltiplas tecnologias de acesso
à rede está a mudar a maneira como nos ligamos à Internet. Infelizmente, ainda não é possÃvel usar
simultaneamente todas as interfaces de rede de um equipamento móvel.
Este trabalho melhora o acesso à rede a partir de dispositivos móveis com múltiplas interfaces de rede.
Para alcançar esta melhoria todas as interfaces de rede dos dispositivos móveis podem ser usadas
simultaneamente, e os fluxos de tráfego são encaminhados individualmente através da tecnologia mais
conveniente. A solução proposta apenas é instalada na rede core, ou seja, é transparente para os
equipamentos móveis. Este trabalho desenvolveu as ferramentas necessárias para reutilizar as
tecnologias existentes que já estão disponÃveis em larga escala, como o WiFi ou o 3G/LTE. É também
possÃvel usar femto-Âcélulas com suporte a múltiplas tecnologias de acesso para expandir mais
rapidamente a rede. Este trabalho criou também uma integração com a norma IEEE 802.21 para
melhorar os processos de handover. Adicionalmente propomos a integração com um broker externo
para uma melhor gestão dos fluxos de tráfego.
A solução proposta melhora a qualidade de serviço dos utilizadores sem sobrecarregar a infra-Âestrutura
do operador. Os resultados obtidos a partir dos testes realizados ao protótipo desenvolvido mostram
que o impacto na performance ao usar esta solução é extremamente reduzido quando comparado com
as suas vantagens
ROAZ and ROAZ II Autonomous Surface Vehicle Design and Implementation
International Lifesaving Congress 2007, La Coruna, Spain, December, 2007The design and implementation of the ROAZ and
ROAZ II autonomous surface vehicles (ASV) is presented. These
systems were developed at Autonomous Systems Lab, ISEP/IPP –
Instituto Superior de Engenharia do Porto under a research
program in marine robotics. With multiple applications either in
river and estuarine environments or in the sea, the system
applications in search and rescue operations are addressed and
were taken in consideration for the overall system design.
Mechanical design issues are discussed. Hardware, software
and implementation status are described along with the control
and navigation system architecture. The real time vision
processing system is described and results are presented in
operational scenario
Measuring chromosome-end fusions in fission yeast
Dissertation presented to obtain the Ph.D degree in Molecular BiologyThe ends of eukaryotic chromosomes are protected from illegitimate
repair by structures called telomeres. These are comprised of specific DNA
repeats bound by a specialized protein complex. When telomere function is
compromised, chromosome ends fuse, generating chromosomal
abnormalities and genomic instability.(...
Métodos de análise da complexidade no problema de empacotamento de paletes do distribuidor
In the pallet loading problem, one of the main goals is to allocate the highest number of boxes as possible, to minimize empty spaces in the pallet. Those empty spaces are called trim-loss. If all boxes have a rectangular shape, which is the most common one, it is possible to pack them so that their faces are coincident with themselves. By doing that, the trim-loss can be minimized. Although loading a pallet may seem linear to most people, some customers impose restrictions that increase the complexity of the pallet loading. Due to that, to evaluate the complexity of a packed pallet, some metrics were created. They consist in an evaluation of a set of parameters that are inherent to the pallet loading process and affect its complexity. After analysing some of those constraints and loading methods enforced by some pickers in a real company, it was possible to obtain samples where the metrics were applied to learn which parameters add the most complexity in the pallet loading process. In the future, after knowing the relevancy of each parameter, the metrics can be used in pallet generation tools to learn how complex is the loading of a certain pallet and study new and easier ways to load the boxes that reduce the complexity of such process. Two statistical tests were then used to analyse the samples retrieved: the principal components analysis and the multiple linear regression. The first is used to combine multiple variables into a smaller set that represents the most relevant information, while the multiple linear regression uses the variables and respective observations to calculate a model that can predict the value of the complexity of a packed pallet in given circumstances. In the first one, it was learned that three principal components were extracted, but since the third one explained a small percentage of the total data variance, it was decided to retain only two components: the box quantities, which explains 41% of the total variance, followed by the box dimensions, explaining 28% of the total variance. The multiple linear regression revealed that the component representing the box quantities, which contains the Number of Box Types, Number of Column Piles, Number of Boxes, Time Spent Packing, and Percentage of Fragile Boxes variables is the component that mostly increase the complexity of pallet cargo arrangements. Although the model can predict the data that was obtained with an average accuracy, some of the coefficients ended up being small, those being related to the components Box Dimensions, which has the Number of Heavy Boxes, Average Box Weight, Average Maximum Width variables, and Height Between Pile and Worker and Number variables, meaning that they aren’t very significant towards evaluating the complexity of a pallet loading process. Using a multiple linear regression with the 9 variables showed that the variable who adds more complexity is the Number of Column Piles. Overall, the results obtained were acceptable, and showed that the variable that adds more complexity is the ones that the pickers see as adding more complexity, and also that the results of the multiple regression with the components match the one using the original variables. It is worth noting that this variable is subjective, meaning that one worker’s perception on the complexity may not match others’ perception. Despite having obtained only one variable being considered as statistically significant towards explaining the complexity in the pallet loading problem, it doesn’t mean it’s the only one that adds complexity.No problema de carregamento de paletes, um dos grandes objetivos é alocar o maior número de caixas possÃvel, visando minimizar espaços vazios conhecidos por trim-loss. Se todas as caixas possuÃrem um formato retangular, que é o formato mais comum, é possÃvel arrumá-las de forma que as suas faces fiquem encostadas entre si, minimizando assim o trim-loss. No entanto, apesar do empacotamento de caixas em paletes parecer linear para a maioria das pessoas, certos clientes impõem restrições que aumentam a complexidade do empacotamento. Como tal, para avaliar a complexidade de um arranjo de paletes, criaram-se métricas, que consistem na avaliação de um conjunto de parâmetros inerentes ao processo ou à s caracterÃsticas do carregamento de paletes que afetam a sua complexidade. Após analisar numa empresa real as restrições e os métodos de empacotamento usados pelos operadores, foi possÃvel obter amostras onde as métricas são aplicadas para tentar saber quais as mais relevantes no processo, para assim futuramente estas métricas serem aplicadas em ferramentas de geração de paletes para poder analisar os resultados obtidos e estudar maneiras onde estas sejam carregadas mais facilmente. Posteriormente, dois testes estatÃsticos foram aplicados aos dados recolhidos: uma análise de componentes principais e a regressão linear múltipla. O primeiro usa-se para combinar várias variáveis e formar um conjunto mais pequeno que represente a informação mais relevante, enquanto a regressão linear múltipla usa as variáveis e respetivas observações para calcular um modelo que consiga prever valores de complexidade do carregamento de paletes em quaisquer circunstâncias. No primeiro, verificou-se a existência de três componentes principais, mas dado que o terceiro componente explica uma percentagem da variância total dos dados pequena, decidiu-se extrair apenas dois componentes: as quantidades das caixas é o componente que explica maiores valores de variância nos dados (41%), seguido pelas dimensões das caixas, explicando 28% da variância total dos dados. A regressão linear múltipla revelou que o componente que representa as quantidades das caixas, que contém as variáveis Número de Tipos de Caixa, Número de Colunas, Número de Caixas, Tempo Despendido a Carregar Caixas e Percentagem de Caixas Frágeis, é aquele que faz crescer mais substancialmente a complexidade do carregamento de caixas em paletes. Com os vários testes, verificou-se que os componentes Dimensões das Caixas, que possui as variáveis Número de Caixas Pesadas Carregadas, Peso Médio das Caixas, Largura Máxima Média, e a diferença de alturas entre pilhas de caixas e o operador, não acrescentam muita significância na explicação da avaliação da complexidade no problema de carregamento de paletes. A regressão linear múltipla com as variáveis originais mostrou que o Número de Colunas é a variável que adiciona mais complexidade. Apesar do modelo obtido ter significância, quase todos os coeficientes obtidos acabaram por ser baixos e com valores Significância (sig.) acima de 0,05, não sendo essas variáveis relevantes no modelo. Valores baixos de Cronbach’s Alpha e R2 ajustado evidenciam a suscetibilidade da aparição destes valores. No geral, os resultados obtidos nesta dissertação foram satisfatórios, mas os coeficientes baixos da regressão linear múltipla não foram bons. O número de observações retido e o escalamento das variáveis são causas possÃveis para esta discrepância de valores ter acontecido. Vale a pena referir que a variável que avalia a complexidade é uma variável subjetiva, pelo que o que um picker considera como sendo complexo pode não corresponder ao que outros trabalhadores pensem. Apesar de, estatisticamente, apenas uma variável ter significância na explicação da complexidade, na realidade todas as variáveis têm alguma influência na complexidade do carregamento de caixas em paletes. No geral, a perceção dos trabalhadores tem semelhanças com aquilo que se obteve nos resultados das regressões lineares
Automatic cymbal classification
Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de
Lisboa para a obtenção do grau de Mestre em Engenharia InformáticaMost of the research on automatic music transcription is focused on the transcription of pitched instruments, like the guitar and the piano. Little attention has been given to unpitched instruments, such as the drum kit, which is a collection of unpitched instruments. Yet, over the last few years this type of instrument started to garner more attention, perhaps due to increasing popularity of the drum kit in the western music.
There has been work on automatic music transcription of the drum kit, especially the snare drum, bass drum, and hi-hat. Still, much work has to be done in order to achieve automatic music transcription of all unpitched instruments. An example of a type of unpitched instrument that has very particular acoustic characteristics and that has deserved almost no attention by the research community is the drum kit cymbals.
A drum kit contains several cymbals and usually these are treated as a single instrument or are totally disregarded by automatic music classificators of unpitched instruments. We propose to fill this gap and as such, the goal of this dissertation is automatic music classification of drum kit cymbal events, and the identification of which class of cymbals they belong to.
As stated, the majority of work developed on this area is mostly done with very different percussive instruments, like the snare drum, bass drum, and hi-hat. On the other hand, cymbals are very similar between them. Their geometry, type of alloys, spectral and sound traits shows us just that. Thus, the great achievement of this work is not only being able to correctly classify the different cymbals, but to be able to identify such similar instruments, which makes this task even harder
Um contributo do marketing sensorial para o marketing da experiência turÃstica rural
A importância dos cinco sentidos humanos – visão, audição, olfato, paladar e tato – no marketing de experiências turÃsticas positivas, únicas e memoráveis tem vindo a ser enfatizada no âmbito da investigação em turismo. Particularmente, a riqueza multissensorial e a vulnerabilidade dos recursos endógenos existentes nas áreas rurais, com caracterÃsticas divergentes do ambiente urbano e potenciadoras de atividades ligadas à natureza e aos ativos rurais, justificam um marketing da experiência turÃstica adequado ao desenvolvimento sustentável das áreas rurais. Considerando o contributo do marketing sensorial para o design de um ambiente potenciador de experiências turÃsticas desejáveis e para a segmentação de turistas, o presente trabalho pretende refletir sobre o papel dos cinco sentidos no marketing de experiências turÃsticas que reforcem o desenvolvimento sustentável dos destinos rurais
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