Observação e modelação do comportamento dinâmico do viaduto do Corgo: utilização integrada de modelos de identificação modal e modelos de elementos finitos de barra

Trabalho Final de Mestrado elaborado no Laboratório Nacional de Engenharia Civil (LNEC) para a obtenção do grau de Mestre em Engenharia Civil pelo Instituto Superior de Engenharia de Lisboa no âmbito do protocolo de Cooperação entre o ISEL e o LNECNa presente dissertação, analisam-se os resultados obtidos em ensaios de vibração ambiente realizados no viaduto do Corgo. Os registos de acelerações medidos foram analisados através de técnicas de processamento de sinal e foram utilizados modelos de identificação modal baseados na técnica de decomposição no domínio da frequência, com vista à identificação dos principais parâmetros modais da referida estrutura. Mostra-se que, instrumentando apenas a secção central do tabuleiro, é possível obter resultados com interesse para a calibração dos modelos numéricos. Para tal, foi desenvolvido em MATLAB o programa DynBridges 1.0 (EF barra 3D) para cálculo dinâmico do viaduto. Os modos de vibração calculados são representados com base em animações 3D, assim como as oscilações da secção instrumentada. O comportamento dinâmico do viaduto foi também estudado com o programa Ansys. As configurações modais identificadas são comparadas com as obtidas com os dois programas referidos.Abstract: In this dissertation, the data from ambient vibration tests, performed on the Corgo viaduct, are analysed. The records of the measured accelerations were analysed by signal processing techniques and modal identification methods, based on frequency domain decomposition, are used in order to get the main modal parameters of the referred structure. It is shown t hat by instrumenting only the deck's middle section, it is possible to obtain interesting results for the calibration of numerical models. The program DynBridges 1.0 (EF 3D bar) was developed in MATLAB, to perform the dynamic calculation of the viaduct. The modal configurations are represented by 3D animations as well as the oscillations of the instrumented section. The dynamic behavior of the viaduct was also studied with the ANSYS program. The identified modal configurations are compared with those obtained with both programs

Effects of Ballroom dancing in older adults: systematic review

The combination of scientific progress and improvement of public health status, housing and working conditions has led to a decrease in birth and death rates and an increase of the average life expectancy. As a result the world’s population is aging (NIS – “Projections of resident population from 2012 to 2060.”). This scenario urged the need to promote a healthy and active aging among the population through physical activity programs, for example cardiorespiratory, neuromotor, flexibility and endurance exercises. (Garber, et al. 2011). Ballroom dancing is an activity that combines cardiorespiratory, endurance, balance, coordination and flexibility training activities. Systematic revision is a very accurate way of summarising data and determining the methodologic quality of various research articles. Here we present the first systematic review of studies that investigated the effects of ballroom dancing on aging population. To assess the effectiveness of ballroom dancing in promoting healthy aging in the elderly. We searched 6 databases (Scielo, PEDro, Lilacs, PubMed, SportDiscus and Medline) for published research on the topic of ballroom dancing in the elderly using a selection of keywords: Dance, Ballroom, Elderly, Older adults, Age, Dança, Danças de Salão, Idoso e Sénior. The studies were selected according to the inclusion criterions and the quality and the strength of the evidence reported were assessed. Specifically, the methodological quality was assessed using the Physiotherapy Evidence Database (PEDro) and the strength of the evidence using an evidence synthesis grading system (Van Tulder, et al. 1997). Four articles were evaluated according to the PEDro scale, which obtained a mean score of 4.75, i.e. a low methodological quality. The papers showed improvements in terms of balance (3 of 4 articles analysed), strength, overall fitness, cognitive function, autonomy or gait speed. This systematic review showed, although with limited evidence, that ballroom dancing promotes the improvement of several variables such as balance, overall physical condition and gait. It is clear that the effects of Ballroom Dancing as a promoter of healthy aging, although a very promising area of research given the current status of the developed world’s population, is still in its infancy

Integrated tool for the acoustic assessment and monitoring of marine activities and operations

Peer ReviewedPostprint (author’s final draft

Nutri-Score: uma ferramenta de saúde pública para melhorar os hábitos alimentares da população portuguesa

This article intends to help filling the existing gap in guidance for the implementation of FOP labelling systems.4 As such, the following sections present the growing evidence on the impact of the Nutri-Score labelling scheme in promoting healthier eating behaviours and informs health professionals, as well as decision makers, on the way forward.info:eu-repo/semantics/publishedVersio

Consensus in high performance computing

Dissertação de mestrado integrado em Informatics EngineeringFor a long time, developers and scientists designed consensus solutions that sacrificed thread scalability or load balance to decrease the latency. The appearance of networking and memory with microseconds requests reshaped how high-throughput consensus solutions are designed today. Today’s protocols must be multi-threaded to scale and seize the high hardware-level parallelism available. Moreover, their focus should be on not overloading the system instead of decreasing the latency. In the last decade, storage devices underwent an enormous development in their performance. The NVMe devices bought the request’s latency of solid-state devices to the microseconds range. Additionally, the software available to manage and operate these devices kept up with the hardware development. Libraries such as the Storage Performance Tool Kit (SPDK) appeared to ease the development of high-performance storage applications. In this context, this work aimed to answer a fundamental question: can NVMe Devices and SPDK improve the existing consensus-related work? This dissertation describes a solution for the distributed consensus problem that combines Disk Paxos (a consensus algorithm that relies upon writing and reading in a network of storage devices to achieve a distributed agreement) with NVMe Devices and SPDK. We conceived this solution using C++ and conducted a performance evaluation that, in the end, compared our solution with LibPaxos. Our findings describe the issues and benefits of the usage of these technologies to solve consensus. With our approach, we increase the understanding of the potential of these new technologies in enabling better solutions for the consensus problem in the future.Durante bastante tempo, as abordagens adotadas para resolver o consenso distribuído sacrificavam a escalabilidade do número de “threads” ou o balanceamento da carga com o objetivo de diminuir a latência da solução. O aparecimento de redes e latências de memória, com pedidos na ordem dos microssegundos, alterou a forma como os algoritmos de alto desempenho são desenhos, hoje em dia. Os protocolos atuais têm de ser “multithreaded” para conseguirem escalar e aproveitar o elevado paralelismo existente do hardware disponível. Para além disso, o foco dos protocolos deve residir em evitar a sobrecarga do sistema e não na redução da latência. Na última década, houve um grande desenvolvimento nos dispositivos de armazenamento. Os discos “NVMe” introduziram latências na gama dos microssegundos aumentando significativamente o desempenho dos discos de armazenamento. Adicionalmente, o “software” disponível, para gerir e operar sobre estes dispositivos, também acompanhou o seu desenvolvimento. Bibliotecas, como o “Storage Performance Tool Kit (SPDK)”, apareceram para facilitar o desenvolvimento de aplicações de armazenamento de alto desempenho. Neste contexto, este trabalho teve, como principal objetivo, responder à seguinte questão: Podem os dispositivos NVMe e o SPDK melhorar o trabalho existente sobre o consenso distribuído? Esta dissertação descreve uma solução para o consenso distribuído que combina o Disk Paxos, um algoritmo que resolve o consenso distribuído, através de leituras e escritas numa rede partilhada de discos, com os dispositivos NVMe e a biblioteca SPDK. Esta solução foi desenvolvida em C++ e foi realizada uma análise de desempenho que, na sua fase final, compara a mesma com outra solução existente, o LibPaxos. A análise desenvolvida descreve os problemas e os benefícios de usar estas tecnologias para resolver o problema de consenso distribuído. Com esta abordagem, foi possível explorar e descobrir o potencial que as tecnologias usadas têm para possibilitar o desenvolvimento de melhores soluções no futuro

Transimpedance amplifier for early detection of breast cancer

Breast cancer is the most common type of cancer worldwide. The effectiveness of its treatment depends on early stage detection, as well as on the accuracy of its diagnosis. Recently, diagnosis techniques have been submitted to relevant breakthroughs with the upcoming of Magnetic Resonance Imaging, Ultrasound Sonograms and Positron Emission Tomography (PET) scans, among others. The work presented here is focused on studying the application of a PET system to a Positron Emission Mammography (PEM) system. A PET/PEM system works under the principle that a scintillating crystal will detect a gamma-ray pulse, originated at the cancerous cells, converting it into a correspondent visible light pulse. The latter must then be converted into an electrical current pulse by means of a Photo- -Sensitive Device (PSD). After the PSD there must be a Transimpedance Amplifier (TIA) in order to convert the current pulse into a suitable output voltage, in a time period lower than 40 ns. In this Thesis, the PSD considered is a Silicon Photo-Multiplier (SiPM). The usage of this recently developed type of PSD is impracticable with the conventional TIA topologies, as it will be proven. Therefore, the usage of the Regulated Common-Gate (RCG) topology will be studied in the design of the amplifier. There will be also presented two RCG variations, comprising a noise response improvement and differential operation of the circuit. The mentioned topology will also be tested in a Radio-Frequency front-end, showing the versatility of the RCG. A study comprising a low-voltage self-biasing feedback TIA will also be shown. The proposed circuits will be simulated with standard CMOS technology (UMC 130 nm), using a 1.2 V power supply. A power consumption of 0.34 mW with a signal-to-noise ratio of 43 dB was achieved

Initial Coin Offering (ICOs) : determinants of successful Initial Coin Offering (ICOs)

O objetivo desta dissertação é identificar as determinantes que influenciam o sucesso de uma Initial Coin Offering (ICO). Especificamente, este trabalho investiga diferentes abordagens usadas para lançar com sucesso uma Initial Coin Offering (ICO) e identifica os seus determinantes. Uma amostra de 206 white papers de Initial Coin Offering foi examinada para detetar se as divulgações de algumas características específicas aumentam a probabilidade das ICOs serem bem-sucedidas. O conteúdo do white paper, a classificação do site icobench e a plataforma Ethereum aumentaram a qualidade da informação e a probabilidade de sucesso das ICOs. Resultados semelhantes foram encontrados quando os ICOs são Smart contracts. Além disso, descobriu-se que o local onde as ICOs são lançadas determina o montante de dinheiro arrecadado, bem como o lançamento de um projeto ICOs em um país paraíso fiscal afeta positivamente o sucesso da ICO.The aim of this dissertation is to identify the determinants that lead Initial Coin Offering (ICO) to success. Specifically, this work investigates different approaches used to launch successful Initial Coin Offering (ICO) and identify its determinants. A sample of 206 Initial Coin Offerings white papers has been examined to detect if the disclosure of some specific characteristics increases the probability of successful ICOs. Both length of the white papers, rating of Icobench website and Ethereum platform have been found to increase the quality of information and probability of successful ICOs. Similar results have been found when ICOs are smart contracts. Moreover, the location where ICOs are launched has been found to determine the amount of money raised, and the launch of ICOs project in a tax haven country positively affects ICO success