Enhanced PCA-based localization using depth maps with missing data

In this paper a new method for self-localization of mobile robots, based on a PCA positioning sensor to operate in unstructured environments, is proposed and experimentally validated. The proposed PCA extension is able to perform the eigenvectors computation from a set of signals corrupted by missing data. The sensor package considered in this work contains a 2D depth sensor pointed upwards to the ceiling, providing depth images with missing data. The positioning sensor obtained is then integrated in a Linear Parameter Varying mobile robot model to obtain a self-localization system, based on linear Kalman filters, with globally stable position error estimates. A study consisting in adding synthetic random corrupted data to the captured depth images revealed that this extended PCA technique is able to reconstruct the signals, with improved accuracy. The self-localization system obtained is assessed in unstructured environments and the methodologies are validated even in the case of varying illumination conditions.

The role of public policy in health care promotion: a comparative perspective

Comunicação apresentada na 17th International conference on Health Promotio Hospitals and Health Services em Hersonissis, Crete, Grécia de 6-8 de maio de 2009

O E-commerce e a internacionalização. O caso Bilua e-commerce

Relatório de Estágio apresentado ao Instituto de Contabilidade e Administração do Porto para a obtenção do grau de Mestre em Marketing Digital, sob orientação do Mestre Especialista António Silva Vieira

Application of the EcoBlock method to eco-design - electric hand dryers versus paper towels

Sustainable Construction, Materials and Practice, p. 426-432

Remuneration Structure Definition for Distributed Generation Units and Demand Response Participants Aggregation

The implementation of competitive electricity markets has changed the consumers’ and distributed generation position power systems operation. The use of distributed generation and the participation in demand response programs, namely in smart grids, bring several advantages for consumers, aggregators, and system operators. The present paper proposes a remuneration structure for aggregated distributed generation and demand response resources. A virtual power player aggregates all the resources. The resources are aggregated in a certain number of clusters, each one corresponding to a distinct tariff group, according to the economic impact of the resulting remuneration tariff. The determined tariffs are intended to be used for several months. The aggregator can define the periodicity of the tariffs definition. The case study in this paper includes 218 consumers, and 66 distributed generation units.

Sherlock Holmes: from paper to the screen

Dissertação de Mestrado apresentado ao Instituto de Contabilidade e Administração do Porto para a obtenção do grau de Mestre em Tradução e Interpretação Especializadas, sob orientação da doutora Clara Sarmento Esta versão não contém as críticas e sugestões dos elementos do júri

Bridging environmental conflicts with social metabolism : forestry expansion and socioeconomic change

Dissertação apresentada para obtenção do Grau de Doutor em Ciências do Ambiente, pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

Anti-phenolic glycolipid-I (PGL-I) determination using blood collection on filter paper in leprosy patients

The authors studied 70 leprosy patients and 20 normal individuals, comparing the traditional sera collection method and the finger prick blood with the conservation on filter paper for specific antibodies against the native phenolic glycolipid-I (PGL-I) from Mycobacterium leprae. The finger prick blood dried on filter paper was eluated in phosphate buffer saline (PBS) containing 0.5% gelatin. The classical method for native PGL-I was performed for these eluates, and compared with the antibody determination for sera. It was observed that there is a straight correlation comparing these two methods; although the titles found for the eluates were lower than those obtained for serology. This blood collection method could be useful for investigation of new leprosy cases in field, specially in contacts individuals.

The clothing industry as a globalized sector: implications for work organisation, quality of work and job content

The clothing sector in several countries is still seen, in many aspects as a traditional sector with some average characteristics, nevertheless is a very important sector in terms of labour market. Globalization and de-localization are having a strong impact in the organisation of work and in occupational careers. Very few companies are able to keep a position in the market without changes in organisation of work and workers, founding different ways to face this reality according to size, capital and position. We could find two main paths: one where companies outsource production to another territory, close and/ or dismissal the workers; other path, where companies up skilled their capacities. This paper will present some results from the European project WORKS – Work organisation and restructuring in the knowledge society (6th Framework Programme), focusing the Portuguese case studies in several clothing companies in a comparative analysis with some other European countrie

A utilidade da demonstração de fluxos de caixa na ótica dos Técnicos Oficiais de contas

O tema Fluxos de Caixa tem cada vez mais importância nas empresas e no relato financeiro das mesmas. Com a entrada em vigor do Sistema de Normalização Contabilística em 2010, tornou-se obrigatória a apresentação da Demonstração de Fluxos de Caixa nas Demonstrações Financeiras das empresas que adotem o regime geral. Segundo a Norma Contabilística e de Relato Financeiro 2 – Demonstração de Fluxos de Caixa, nos seus parágrafos 7 e 8, a Demonstração de Fluxos de Caixa “deve relatar os fluxos de caixa durante o período classificados por atividades operacionais, de investimento e de financiamento. A classificação por atividades proporciona informação que permite aos utentes determinar o impacto dessas atividades na posição financeira da entidade e nas quantias de caixa e seus equivalentes”. Possibilita a avaliação das empresas, a deteção de sinais de fragilidade e ajuda a decidir qual o melhor caminho a seguir. O objetivo central deste trabalho consiste em evidenciar a importância e utilidade da Demonstração de Fluxos de Caixa para os profissionais de contabilidade e para os utilizadores da informação financeira, na ótica dos Técnicos Oficiais de Contas, e será alcançado através de um questionário a este grupo de profissionais. Os resultados obtidos permitiram-nos aferir que os Técnicos Oficiais de Contas consideram esta Demonstração Financeira importante e atribuem-lhe a utilidade que efetivamente representa, isto é, consideram-na uma peça indispensável para a gestão de tesouraria como para a gestão operacional, financeira ou de investimentos de qualquer empresa. Contudo, na sua opinião, esta Demonstração é ainda pouco valorizada pelos utilizadores da informação financeira.

Análise e identificação do sinal de aceleração num pé

Com a massificação do uso da tecnologia no dia-a-dia, os sistemas de localização têm vindo a aumentar a sua popularidade, devido à grande diversidade de funcionalidades que proporcionam e aplicações a que se destinam. No entanto, a maior parte dos sistemas de posicionamento não funcionam adequadamente em ambientes indoor, impedindo o desenvolvimento de aplicações de localização nestes ambientes. Os acelerómetros são muito utilizados nos sistemas de localização inercial, pelas informações que fornecem acerca das acelerações sofridas por um corpo. Para tal, neste trabalho, recorrendo à análise do sinal de aceleração provindo de um acelerómetro, propõe-se uma técnica baseada na deteção de passos para que, em aplicações futuras, possa constituir-se como um recurso a utilizar para calcular a posição do utilizador dentro de um edifício. Neste sentido, este trabalho tem como objetivo contribuir para o desenvolvimento da análise e identificação do sinal de aceleração obtido num pé, por forma a determinar a duração de um passo e o número de passos dados. Para alcançar o objetivo de estudo foram analisados, com recurso ao Matlab, um conjunto de 12 dados de aceleração (para marcha normal, rápida e corrida) recolhidos por um sistema móvel (e provenientes de um acelerómetro). A partir deste estudo exploratório tornou-se possível apresentar um algoritmo baseado no método de deteção de pico e na utilização de filtros de mediana e Butterworth passa-baixo para a contagem de passos, que apresentou bons resultados. Por forma a validar as informações obtidas nesta fase, procedeu-se, seguidamente, à realização de um conjunto de testes experimentais a partir da recolha de 33 novos dados para a marcha e corrida. Identificaram-se o número de passos efetuados, o tempo médio de passo e da passada e a percentagem de erro como as variáveis em estudo. Obteve-se uma percentagem de erro igual a 1% para o total dos dados recolhidos de 20, 100, 500 e 1000 passos com a aplicação do método proposto para a contagem do passo. Não obstante as dificuldades observadas na análise dos sinais de aceleração relativos à corrida, o algoritmo proposto mostrou bom desempenho, conseguindo valores próximos aos esperados. Os resultados obtidos permitem afirmar que foi possível atingir-se o objetivo de estudo com sucesso. Sugere-se, no entanto, o desenvolvimento de futuras investigações de forma a alargar estes resultados em outras direções.

Development of paper-based color test-strip for drug detection in aquatic environment: Application to oxytetracycline

The wide use of antibiotics in aquaculture has led to the emergence of resistant microbial species. It should be avoided/minimized by controlling the amount of drug employed in fish farming. For this purpose, the present work proposes test-strip papers aiming at the detection/semi-quantitative determination of organic drugs by visual comparison of color changes, in a similar analytical procedure to that of pH monitoring by universal pH paper. This is done by establishing suitable chemical changes upon cellulose, attributing the paper the ability to react with the organic drug and to produce a color change. Quantitative data is also enabled by taking a picture and applying a suitable mathematical treatment to the color coordinates given by the HSL system used by windows. As proof of concept, this approach was applied to oxytetracycline (OXY), one of the antibiotics frequently used in aquaculture. A bottom-up modification of paper was established, starting by the reaction of the glucose moieties on the paper with 3-triethoxysilylpropylamine (APTES). The so-formed amine layer allowed binding to a metal ion by coordination chemistry, while the metal ion reacted after with the drug to produce a colored compound. The most suitable metals to carry out such modification were selected by bulk studies, and the several stages of the paper modification were optimized to produce an intense color change against the concentration of the drug. The paper strips were applied to the analysis of spiked environmental water, allowing a quantitative determination for OXY concentrations as low as 30 ng/mL. In general, this work provided a simple, method to screen and discriminate tetracycline drugs, in aquaculture, being a promising tool for local, quick and cheap monitoring of drugs.

New modified electrochemical conductive paper support for BSA detection

Chemical sensors and biosensors are widely used to detect various kinds of protein target biomolecules. Molecularly Imprinted Polymers (MIPs) have raised great interest in this area, because these act as antibody-like recognition materials, with high affinity to the template molecule. Compared to natural antibodies, these are also of lower cost and higher stability. There are different types of supports used to carry MIP materials, mostly of these made of gold, favourably assembled on a Screen Printed Electrode (SPE) strategy. For this work a new kind of support for the sensing layer was developed: conductive paper. This support was made by modifying first cellulose paper with paraffin wax (to make it waterproof), and casting a carbon-ink on it afterwards, to turn it conductive. The SPAM approach previously reported in1 was employed herein to assemble to MIP sensing material on the conductive paper. The selected charged monomers were (vinylbenzyl) trimethlammonium chloride (positive charge) or vinylbenzoic acid (negative charge), used to generate binding positions with single-type charge (positive or negative). The non-specific binding area of the MIP layer was assembled by chronoamperometry-assisted polymerization (at 1 V, for 60, 120 or 180 seconds) of vinylbenzoate, cross-linked with ethylene glycol vinyl ether. The BSA biomolecules lying within the polymeric matrix were removed by Proteinase K action. All preparation stages of the MIP assembly were followed by FTIR, Raman spectroscopy and, electrochemical analysis. In general, the best results were obtained for longer polymerization times and positively charged binding sites (which was consistent with a negatively-charged protein under physiological pH, as BSA). Linear responses against BSA concentration ranged from 0.005 to 100 mg/mL, in PBS buffer standard solutions. The sensor was further calibrated in standard solutions that were prepared in synthetic or real urine, and the analytical response became more sensitive and stable. Compared to the literature, the detection capability of the developed device is better than most of the reported electrodes. Overall, the simplicity, low cost and good analytical performance of the BSA SPE device, prepared with positively charged binding positions, seems a suitable approach for practical application in clinical context. Further studies with real samples are required, as well as gathering with electronic-supporting devices to allow on-site readings.

Analysis of Two Arms Working in Cooperation

This paper analyzes the performance of two cooperative robot manipulators. In order to capture the working performancewe formulated several performance indices that measure the manipulability, the effort reduction and the equilibrium between the two robots. In this perspective the proposed indices we determined the optimal values for the system parameters. Furthermore, it is studied the implementation of fractional-order algorithms in the position/force control of two cooperative robotic manipulators holding an object.