Fog Computing

Everything that is not a computer, in the traditional sense, is being connected to the Internet. These devices are also referred to as the Internet of Things and they are pressuring the current network infrastructure. Not all devices are intensive data producers and part of them can be used beyond their original intent by sharing their computational resources. The combination of those two factors can be used either to perform insight over the data closer where is originated or extend into new services by making available computational resources, but not exclusively, at the edge of the network. Fog computing is a new computational paradigm that provides those devices a new form of cloud at a closer distance where IoT and other devices with connectivity capabilities can offload computation. In this dissertation, we have explored the fog computing paradigm, and also comparing with other paradigms, namely cloud, and edge computing. Then, we propose a novel architecture that can be used to form or be part of this new paradigm. The implementation was tested on two types of applications. The first application had the main objective of demonstrating the correctness of the implementation while the other application, had the goal of validating the characteristics of fog computing.Tudo o que não é um computador, no sentido tradicional, está sendo conectado à Internet. Esses dispositivos também são chamados de Internet das Coisas e estão pressionando a infraestrutura de rede atual. Nem todos os dispositivos são produtores intensivos de dados e parte deles pode ser usada além de sua intenção original, compartilhando seus recursos computacionais. A combinação desses dois fatores pode ser usada para realizar processamento dos dados mais próximos de onde são originados ou estender para a criação de novos serviços, disponibilizando recursos computacionais periféricos à rede. Fog computing é um novo paradigma computacional que fornece a esses dispositivos uma nova forma de nuvem a uma distância mais próxima, onde “Things” e outros dispositivos com recursos de conectividade possam delegar processamento. Nesta dissertação, exploramos fog computing e também comparamos com outros paradigmas, nomeadamente cloud e edge computing. Em seguida, propomos uma nova arquitetura que pode ser usada para formar ou fazer parte desse novo paradigma. A implementação foi testada em dois tipos de aplicativos. A primeira aplicação teve o objetivo principal de demonstrar a correção da implementação, enquanto a outra aplicação, teve como objetivo validar as características de fog computing

Automatic histogram threshold using fuzzy measures

In this paper, an automatic histogram threshold approach based on a fuzziness measure is presented. This work is an improvement of an existing method. Using fuzzy logic concepts, the problems involved in finding the minimum of a criterion function are avoided. Similarity between gray levels is the key to find an optimal threshold. Two initial regions of gray levels, located at the boundaries of the histogram, are defined. Then, using an index of fuzziness, a similarity process is started to find the threshold point. A significant contrast between objects and background is assumed. Previous histogram equalization is used in small contrast images. No prior knowledge of the image is required.info:eu-repo/semantics/publishedVersio

Hierarchical fuzzy logic based approach for object tracking

In this paper a novel tracking approach based on fuzzy concepts is introduced. A methodology for both single and multiple object tracking is presented. The aim of this methodology is to use these concepts as a tool to, while maintaining the needed accuracy, reduce the complexity usually involved in object tracking problems. Several dynamic fuzzy sets are constructed according to both kinematic and non-kinematic properties that distinguish the object to be tracked. Meanwhile kinematic related fuzzy sets model the object's motion pattern, the non-kinematic fuzzy sets model the object's appearance. The tracking task is performed through the fusion of these fuzzy models by means of an inference engine. This way, object detection and matching steps are performed exclusively using inference rules on fuzzy sets. In the multiple object methodology, each object is associated with a confidence degree and a hierarchical implementation is performed based on that confidence degree.info:eu-repo/semantics/publishedVersio

Uma plataforma de hospedagem baseada na Web para máquinas pedagógicas

Dificuldades na implantação multi-plataforma e utilização pedagógica das máquinas virtuais podem ter um impacto prejudicial no sucesso de um curso de cons- trução de compiladores. Este artigo apresenta um curso de construção de compiladores de suporte de plataforma, que aborda essa questão. A plataforma proposta é baseada na web, onde máquinas virtuais são acessadas remotamente através de um navegador e pela utilização adequada dos serviços na web. Além disso, ambas as versões de linha de comando e interface gráfica de usuário são suportadas. Além de portabilidade e problemas de manutenção, uma característica interessante do projeto de arquitetura é a sua capacidade de integrar facilmente novas máquinas virtuais. Como prova conceitual, vamos mostrar alguns resultados preliminares sobre a integração de duas máquinas virtuais muito diferentes, que são utilizadas em cursos de constru- ção de compiladores, em universidades portuguesas

Espumas de poliuretano funcionais derivadas de subprodutos industriais

Doutoramento em Engenharia QuímicaConsiderando a dependência da indústria de espumas de poliuretano (PUFs) de recursos fósseis, é necessário encontrar alternativas, substituindo os recursos derivados do petróleo, por recursos renováveis. Além disso, materiais funcionais ecológicos com maior valor acrescentado são cada vez mais necessários. A presente tese aborda estas necessidades explorando a utilização de glicerol não refinado (CG), um subproduto da indústria de biodiesel, como poliol na produção de PUFs. Devido à variabilidade da composição química do CG, o efeito da sua composição nas propriedades das PUFs foi estudado, tendo-se verificado que os ácidos gordos e ésteres metílicos poderão atuar como tensoactivos, homogeneizando a estrutura celular das espumas, baixando assim a sua densidade e condutividade térmica. Seguidamente, foi estudado o efeito dos principais componentes das formulações usadas na produção de espumas sobre as respetivas propriedades utilizando o planeamento de experiências (DoE). Este estudo permitiu verificar que que a densidade e a condutividade térmica das espumas estão relacionadas com as quantidades de agente de expansão e tensoactivo, enquanto que as propriedades mecânicas dependem das quantidades de isocianato e de catalisador. No sentido de preparar novos materiais funcionais e ecológicos com maior valor acrescentado, foram desenvolvidas formulações com o objetivo de melhorar o conforto térmico e a eficiência energética, reduzir a flamabilidade e melhorar o isolamento sonoro das PUFs. Através da adição de materiais de mudança de fase (PCMs) e grafite expansível (EG) não se conseguiu obter melhorias ao nível do conforto térmico das espumas, mas a adição de 5% de EG melhorou consideravelmente as suas propriedades de reação ao fogo. Verificou-se também que as espumas derivadas de CG apresentam boas propriedades de absorção sonora, podendo estas ser melhoradas para baixas frequências pela adição de outro poliol renovável derivado de borras de café. Por fim, foi ainda desenvolvido um método de reciclagem de PUFs, em que o produto obtido foi utilizado com sucesso como substituinte parcial do CG na produção de espumas.In view of the dependence of the polyurethane foams (PUFs) industry on fossil resources, there is a need to find alternatives such as the replacement of petrol derived resources by those from renewable resources. Additionally eco-friendly functional materials with higher added value are ever more in demand. The present project, addresses these needs by exploring the use of crude glycerol (CG), a byproduct of biodiesel industry as the polyol component in the production of PUFs. As the chemical composition of CG is variable, the effect of CG composition on PUFs properties was studied and it was observed that fatty acids and methyl esters can act as surfactants, improving the homogeneity of the cellular structure of the foams and subsequently decreasing their density and their thermal conductivity. Next, the effect of the main components used in PUFs formulations on their properties was studied using the design of experiments (DOE) tool. The results obtained confirmed that the density and thermal conductivity of the foams are related with the blowing agent and surfactant content, while the mechanical properties are associated with the isocyanate and catalyst content. As regards the preparation of new functional and ecological materials with higher added value, formulations have been developed aiming at materials for enhanced thermal comfort and energy efficiency, improved reaction to fire and better sound insulation. The addition of phase change materials (PCMs) and expanded graphite (EG) did not bring improvements regarding the thermal comfort, but the addition of 5% of EG improved the reaction of the foams to fire significantly. Furthermore the CG derived foams presented good sound absorption properties, which can be improved for lower frequencies by the addition of another renewable polyol derived from the liquefaction of coffee grounds. Finally, method for recycling of PUFs was developed and the product obtained was used as a partial substituent of GC in the production of foam

The "missing link": a 4-day period transiting exoplanet around OGLE-TR-111

We report the discovery of a transiting hot Jupiter around OGLE-TR-111, from our radial velocity follow-up of OGLE transiting candidates in Carina. The planet has a mass of 0.53 +- 0.11 M_J and a radius of 1.0 +0.13-0.06 R_J. Three transiting exoplanets have already been found among OGLE candidates, all with periods near 1.5 days. The planet presented here, with P=4.0 days, is the first exoplanet detected by transits with the characteristics of a "normal" hot Jupiter, as found in abundance by radial velocity surveys The radius of OGLE-TR-111b and the scarcity of hot Jupiters detected among OGLE transit candidates tend to indicate that the case of HD209458b, with a radius of 1.4 R_J, is exceptional, with most hot Jupiters being smaller.Comment: 4 pages, 4 figures, to be published in A&A Letter

Waist-to-height ratio is independently related to whole and central body fat, regardless of the waist circumference measurement protocol, in non-alcoholic fatty liver disease patients

This is the peer reviewed version of the following article: Pimenta N.M., Cortez-Pinto H., Melo X., Silva-Nunes J., Sardinha L.B. & Santa-Clara H. (2017) Waist-to-height ratio is independently related to whole and central body fat, regardless of the waist circumference measurement protocol, in non-alcoholic fatty liver disease patients. J Hum Nutr Diet. 30, 185–192, which has been published in final form atdoi: 10.1111/jhn.12410. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.Background: Waist-to-height ratio (WHtR) has been reported as a prefer-able risk related body fat (BF) marker, although no standardised waistcircumference measurement protocol (WCmp) has been proposed. Thepresent study aimed to investigate whether the use of a different WCmpaffects the strength of relationship between WHtR and both whole andcentral BF in non-alcoholic fatty liver disease (NAFLD) patients.Methods: BF was assessed with dual energy X-ray absorptiometry (DXA) in28 NAFLD patients [19 males, mean (SD) 51 (13) years and nine females,47 (13) years]. All subjects also underwent anthropometric evaluationincluding height and waist circumference (WC) measurement using fourdifferent WCmp (WC1, minimal waist; WC2, iliac crest; WC3, mid-distancebetween iliac crest and lowest rib; WC4, at the umbilicus) and WHtR wascalculated using each WC measurements (WHtR1, WHtR2, WHtR3 andWHtR4, respectively). Partial correlations were conducted to assess the rela-tion of WHtR and DXA assessed BF.Results: All WHtR were particularly correlated with central BF, includingabdominal BF (r = 0.80, r = 0.84, r = 0.84 and r = 0.78, respectively, forWHtR1, WHtR2, WHtR3 and WHtR4) and central abdominal BF (r = 0.72,r = 0.77, r = 0.76 and r = 0.71, respectively, for WHtR1, WHtR2, WHtR3and WHtR4), after controlling for age, sex and body mass index. There wereno differences between the correlation coefficients obtained between allstudied WHtR and each whole and central BF variable.Conclusions: Waist-to-height ratio was found a suitable BF marker in thepresent sample of NAFLD patients and the strength of the relationshipbetween WHtR and both whole and central BF was not altered by usingdifferent WCmp in the present sample of NAFLD patients.FUNDING SOURCES The first author of this paper was supported by a research grant (PhD scholarship) from the Foundation for Science and Technology (FCT), Ministry of Education and Science of Portugal (grant: SFRH/ BD/ 70515/ 2010). The present study was funded by: the Centre for the Study of Human Performance, Portuguese Foundation for Science and Technology, Lisbon, Portugal.info:eu-repo/semantics/publishedVersio

Comparison of RNA extraction methods from biofilm samples of Staphylococcus epidermidis

<p>Abstract</p> <p>Background</p> <p>Microbial biofilms are communities of bacteria adhered to a surface and surrounded by an extracellular polymeric matrix. Biofilms have been associated with increased antibiotic resistance and tolerance to the immune system. <it>Staphylococcus epidermidis </it>is the major bacterial species found in biofilm-related infections on indwelling medical devices. Obtaining high quality mRNA from biofilms is crucial to validate the transcriptional measurements associated with the switching to the biofilm mode of growth. Therefore, we selected three commercially available RNA extraction kits with distinct characteristics, including those using silica membrane or organic extraction methods, and enzymatic or mechanical cell lysis, and evaluated the RNA quality obtained from two distinct <it>S. epidermidis </it>bacterial biofilms.</p> <p>Results</p> <p>RNA extracted using the different kits was evaluated for quantity, purity, integrity, and functionally. All kits were able to extract intact and functional total RNA from the biofilms generated from each <it>S. epidermidis </it>strain. The results demonstrated that the kit based on mechanical lysis and organic extraction (FastRNA^®Pro Blue) was the only one that was able to isolate pure and large quantities of RNA. Normalized expression of the <it>icaA </it>virulence gene showed that RNA extracted with PureLink™ had a significant lower concentration of <it>icaA </it>mRNA transcripts than the other kits tested.</p> <p>Conclusions</p> <p>When working with complex samples, such as biofilms, that contain a high content extracellular polysaccharide and proteins, special care should be taken when selecting the appropriate RNA extraction system, in order to obtain accurate, reproducible, and biologically significant results. Among the RNA extraction kits tested, FastRNA^®Pro Blue was the best option for both <it>S. epidermidis </it>biofilms used.</p

New insights on biofilm antimicrobial strategies

Over the last few decades, the study of microbial biofilms has been gaining interest among the scientific community [...]info:eu-repo/semantics/publishedVersio