Browsing by Issue Date, starting with "2020-03"
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- Seismic Vulnerability Assessment of Existing Reinforced Concrete Buildings in Urban CentersPublication . Ferreira, Tiago Miguel; Rodrigues, Hugo; Vicente, RomeuDespite the recent advances in the analysis of the seismic performance of reinforced concrete structures, the assessment of large building inventories aimed at defining and prioritizing structural retrofitting strategies is still a technically challenging task. This paper aims to contribute to bridging this gap by presenting a simplified methodology for assessing the seismic vulnerability of reinforced concrete buildings, which is then applied to a group of 91 buildings affected by recent earthquakes with different macroseismic intensities. The presented methodology is based on the evaluation of eight parameters associated with different factors that affect the seismic response of the building, namely its structural features, foundation conditions, and position within the urban mesh. The formulation of each parameter and the relative weight attributed to each one of them were defined on the basis of post-earthquake damage observation and expert opinion. After defined, the proposed methodology is applied to Faro city center. Based on the results obtained, a cost benefit analysis is made considering a strengthening solution to the buildings with soft-story irregularity.
- O Estigma na Esquizofrenia: Atitude dos Profissionais da Saúde MentalPublication . Vidal-Barrantes, Francisco-JavierO objetivo desta investigação: analisar quais as atitudes dos médicos psiquiatras, enfermeiros e auxiliares de ação médica, junto das pessoas diagnosticadas com esquizofrenia e o impacto que estas atitudes poderão ter nas suas intervenções. A amostra é constituída por 95 profissionais de saúde mental de algumas casas de saúde e instituições hospitalares públicas e privadas de Portugal: 25 médicos psiquiatras (26.3%), 30 enfermeiros (31.6%) e 40 auxiliares de ação médica (42,1%), que responderam voluntariamente a dois questionários: Questionário Sociodemográfico e Questionário de Atribuição AQ-27. Os resultados indicam que dentre os 9 domínios do Questionário de Atribuição AQ-27, os de Responsabilidade e Irritação apresentaram os valores estatísticos mais baixos. Os de Ajuda, Coação e Pena apresentaram os valores estatísticos mais elevados. O género dos profissionais, assim como o tempo de serviço dos mesmos na instituição, não determinaram diferenças estatisticamente significativas nos diferentes domínios. Os profissionais que lidam com utentes crónicos apresentam valores superiores de Irritação, Medo e Evitamento comparativamente com aqueles que trabalham diretamente com pessoas com uma doença mental em estado agudo e crónico. As diferenças nas habilitações académicas entre os profissionais, a utilização do diagnóstico psiquiátrico, assim como o modelo de intervenção de atenção sanitário atual, entre outros, poderão explicar estes resultados.
- Afonso Lopes Vieira: a sementeira para a infância e juventude – textos esquecidosPublication . Nobre, CristinaAfonso Lopes Vieira foi dos primeiros escritores portugueses a publicar textos especificamente destinados ao público infantil e juvenil, tanto poéticos como dramáticos ou adaptações de clássicos, e até experiências no domínio cinematográfico. Destacam-se as obras: ANIMAIS NOSSOS AMIGOS (1911); HINO A CAMÕES (1911); BARTOLOMEU MARINHEIRO (1912); CANTO INFANTIL (1912); AUTO DA BARCA DO INFERNO (PARODIA INFANTIL) (1917); O AFILHADO DE SANTO ANTÓNIO (1928); “A Cigarra e a Formiga. Fábula mentirosa. Fábula verdadeira” (1935); O CONTO DE AMADIZ DE PORTUGAL PARA OS RAPAZES PORTUGUESES (1938);
- Mild cognitive impairment in older adults: Analysis of some factorsPublication . Dixe, Maria dos Anjos; Braúna, Mônica; Camacho, Timóteo; Couto, Filipa; Apóstolo, JoãoMild cognitive decline is a feared aspect of aging associated with frailty experienced by individuals.
- Strategy to improve the mechanical properties of bioabsorbable materials based on chitosan for orthopedic fixation applicationsPublication . Figueiredo, Lígia; Fonseca, Rita; Pinto, Luís F. V.; Ferreira, Frederico Castelo; Almeida, Amélia; Rodrigues, AlexandraBioabsorbable polymeric fixation devices have been used as an alternative to metallic implants in orthopedics,preventing the stress shielding effect and avoiding a second surgery for implant removal. However,several problems are still associated with current bioabsorbable implants, including the limited mechanical stiffness and strength, and the adverse tissue reactions generated. To minimize or even eliminate the problems associated with these implants, strategies have been developed to synthesize new implant materials based on chitosan. To overcome the brittle behavior of most 3D chitosan-based structures, glycerol and sorbitol were blended to chitosan and the effect of these plasticizers in the produced specimens was analyzed by flexural tests, Berkovich tests, scanning electron microscopy (SEM) and micro-CT analyzes. The improvement of the mechanical properties was also tested by adding ceramics, namely hydroxyapatite powder and biphasic mixtures of hydroxyapatite (HA) and beta-tricalcium phosphate (β-TCP). In the plasticizers group, the best combination of the measured properties was obtained for chitosan with 10% glycerol (flexural strength of 53.8 MPa and indentation hardness of 19.4 kgf/mm2), while in the ceramics group the best mechanical behavior was obtained for chitosan with 10% HAþβ-TCP powder (flexural strength of 67.5 MPa and indentation hardness 28.2 kgf/mm2). All the tested material compositions were dense and homogeneous, fundamental condition for a good implant performance. These are encouraging results, which support the continued development of chitosan-based materials for orthopedic fixation applications.
- Satellite‐Terrestrial Channel Characterization in High‐Speed Railway Environment at 22.6 GHzPublication . Ma, Lei; Guan, Ke; Yan, Dong; He, Danping; Leonor, Nuno R.; Ai, Bo; Kim, JunhyeongThe integration of satellite and terrestrial communication systems plays a vital role in the fifth-generation mobile communication system (5G) for the ubiquitous coverage, reliable service, and flexible networking. Moreover, the millimeter wave (mmWave) communication with large bandwidth is a key enabler for 5G intelligent rail transportation. In this paper, the satellite-terrestrial channel at 22.6 GHz is characterized for a typical high-speed railway (HSR) environment. The three-dimensional model of the railway scenario is reconstructed and imported into the Cloud Ray-Tracing (CloudRT) simulation platform. Based on extensive ray-tracing simulations, the channel for the terrestrial HSR system and the satellite-terrestrial system with two weather conditions are characterized, and the interference between them are evaluated. The results of this paper can help for the design and evaluation for the satellite-terrestrial communication system enabling future intelligent rail transportation.
- Analysis of Radiowave Propagation in Forest Media Using the Parabolic EquationPublication . Ramos, Glaucio L.; Pereira, Paulo T.; Leonor, Nuno; Caldeirinha, Rafael F. S.This paper presents preliminary results about path loss prediction in vegetation using the parabolic equation technique. The trees were modelled in a flat and a triangular format and their effect in the path loss was analysed. A real measurement scenario with trees was also modelled and compared with the PE simulation. The use of the parabolic equation method to study the path loss attenuation in forest environments seems to be very promise.
- Skin lesion classification enhancement using border-line features – The melanoma vs nevus problemPublication . Pereira, Pedro M. M.; Fonseca-Pinto, Rui; Paiva, Rui Pedro; Assuncao, Pedro A. A.; Tavora, Luis M. N.; Thomaz, Lucas A.; Faria, Sergio M. M.Machine learning algorithms are progressively assuming an important role as a computational tool to support clinical diagnosis, namely in the classification of pigmented skin lesions. The current classification methods commonly rely on features derived from shape, colour, or texture, obtained after image segmentation, but these do not always guarantee the best results. To improve the classification accuracy, this work proposes to further exploit the border-line characteristics of the lesion segmentation mask, by combining gradients with local binary patterns (LBP). In the proposed method, these border-line features are used together with the conventional ones to enhance the performance of skin lesion classification algorithms. When the new features are combined with the classical ones, the experimental results show higher accuracy, which impacts positively the overall performance of the classification algorithms. As the medical image datasets usually present large class imbalance, which results in low sensitivity for the classifiers, the border-line features have a positive impact on this classification metric, as evidenced by the experimental results. Both the features’ usefulness and their impact are assessed in regard to the classification results, which in turn are statistically tested for completeness, using three different classifiers and two medical image datasets.
- A Practical Deconvolution Antenna Method to Retrieve Scattering Profile in Complex Random Media - A Vegetation Case Study at 28 GHzPublication . Leonor, Nuno; Fernandes, Telmo; Caldeirinha, RafaelThis paper presents a method to improve the extraction the Radiative Energy Transfer (RET) theory input parameters for application in vegetation attenuation modeling. The input parameters for this model, which are extracted from specific measurement data, are normally influenced by the radiation pattern of the receiver antenna. A new method to improve the accuracy of the scattering function parameters obtained from measurements is presented. This method is based on the prior analysis of the antenna's radiation pattern distortion while measuring the scattering function, allowing the development of calibration curves, to correct the distorted propagation parameters. The proposed method was tested with measurements conducted inside an anechoic chamber, using real small indoor trees, mimicking a forest scenario using various different receiver antennas at 28 GHz, and the model accuracy improvement was assessed at various vegetation depths.
- Sustainable tourism and the circular economy: A theoretical overviewPublication . Costa, Berta; Rodrigues, Susana; Moreno, PilarThe concept of sustainable tourism has become one of the most noteworthy topics among academics and practitioners and a hallmark in tourism discourse. During the last decades, tourism has developed into one of the largest socio-economic activities, and thus driving economic growth that most supports to the countries’ GDP (Gross Domestic Product). The world economic paradigm, and consequently the tourism industry, is configured according to the linear model of production and consumption, in which goods are discarded after usage, resulting in massive waste. Furthermore, the degrading impact of tourism, along with the assumption that natural resources are abounding, and that environment has unlimited means to absorb waste, need to be addressed without delay. Considering these premises, the principle of sustainable tourism arose with the objective of minimizing the negative effects of tourism related activities. From this standpoint, circular economy emerges as a solution, as it harmonizes economic development with the sustainable use of natural resources, and also enables the tourism industry to become more sustainable. The purpose of this article is to outline the conceptual dimensions of sustainable tourism and circular economy, and also scrutinize how these two constructs have evolved over the past decades and their correlation. A broad literature review was conducted, in order to draw attention to the constituent elements brought to discussion.