1,781 research outputs found

    Qualificação da iluminação natural em interiores: aplicação das redes neurais artificiais e 3DSkyView

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    Environmental comfort in public school buildings is not often seen as a project requirement, due to the difficulty in considering all comfort-related architectural variables at once. This paper focuses on the level of illuminance in classrooms, by defining the importance and the relationship among visual comfort variables. The research method consisted of the observation of the users’ behaviour under different conditions of illuminance levels in the environment. Two methodological tools have been applied: the 3DSkyView extension, which was used for determining sky view factors, and artificial neural networks, which were applied for modelling the relationships between variables. The results indicate that students are used to develop tasks, either under too high, or under too low illuminance levels. The sky view factor (SVF) has presented the highest relevance for visual comfort among all variables investigated, assuming an importance level of 21% in May and 37,1% in November.O conforto ambiental em arquitetura de escolas públicas não é considerado sistematicamente requisito de projeto, sendo um dos obstáculos a impossibilidade de maximizar todas as variáveis do conforto simultaneamente. Este artigo analisa o nível de iluminância de sala de aula, definindo a importância e as relações entre as variáveis do conforto luminoso. O método de pesquisa consiste em uma análise através da observação comportamental e medições dos níveis de iluminância no ambiente. Faz-se uso de duas ferramentas metodológicas: a extensão 3DSkyView, como forma de obter a variável Fator de Visão do Céu (fator de forma), e as Redes Neurais Artificiais, como ferramenta de modelagem das relações entre as variáveis levantadas. Os resultados mostraram que os estudantes estão habituados a realizar tarefas com valores de iluminância baixos ou altos demais. A variável fator de visão do céu (FVC) apresentou os maiores valores de importância para o conforto visual, sendo 21% para o mês de maio e 37,1% para o mês de novembro

    Fator de visão do céu e intensidade de ilhas de calor na escala do pedestre

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    A falta de ferramentas disponíveis para a tomada de decisões no planejamento urbano baseado nas interações entre clima e cidade é um desafio para o arquiteto e para o urbanista. Apesar da existência de alguns modelos destinados a esse fim, as limitações para sua aplicação dificultam ainda mais o quadro. Procurando gerar informações que colaborem com essa área, este artigo tem por objetivo avaliar o papel do fator de visão do céu na intensidade de ilhas de calor em um bairro residencial. Primeiro, foram feitas caracterizações da área de estudo e determinação da geometria urbana, utilizando-se como unidade geométrica o fator de visão do céu. Foram selecionados pontos de referência e realizadas medições de temperatura do ar em cânions urbanos. A partir de dados disponibilizados pela estação meteorológica localizada em área rural, foram feitas comparações entre os pontos e a área rural, gerando dados de intensidade das ilhas de calor. Através da identificação das tendências térmicas da área, os dados de máxima intensidade da ilha noturna em cada ponto serviram de base para a comparação com um modelo empírico. Propôs-se uma equação de correção, e dados reais de pesquisas anteriores foram comparados com dados simulados pela nova equação. Os resultados indicam que a temperatura urbana noturna varia de acordo com a faixa de fator de visão do céu considerada

    Cyclists' noise exposure in a Brazilian medium-sized city

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    This study aimed to assess cyclists' exposure to noise in a medium-sized Brazilian city. Mobile sensors were used to conduct noise measurements in streets with and without dedicated cycling infrastructures. The method can be summarized in the following procedures: i) characterization of the study area; ii) data collection and validation; iii) calculation of exposure indicators; and iv) comparison and representation of the results on maps. Two strategies were adopted for the analysis, namely, spatial data aggregation and temporal data aggregation. Thus, measurements were initially organized in 1,200 nodes distributed along the paths. The results indicate that bicycle riders in Sao Carlos may be exposed, in some routes, to a high proportion of high noise-level segments. In the two routes selected for this study, the cyclist was exposed to noise levels above the adopted threshold (> 75dBA) in 33.2% and 18.9% of the nodes. Also, the possibility of simultaneously working with two related indicators has broadened the classification criteria of the route segments regarding noise exposure

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

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    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

    Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

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    A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV

    Search for supersymmetry in events with one lepton and multiple jets in proton-proton collisions at root s=13 TeV

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    Measurement of the azimuthal anisotropy of Y(1S) and Y(2S) mesons in PbPb collisions at root s(NN)=5.02 TeV

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    The second-order Fourier coefficients (v(2)) characterizing the azimuthal distributions of Y(1S) and Y(2S) mesons produced in PbPb collisions at root s(NN) = 5.02 TeV are studied. The Y mesons are reconstructed in their dimuon decay channel, as measured by the CMS detector. The collected data set corresponds to an integrated luminosity of 1.7 nb(-1). The scalar product method is used to extract the v2 coefficients of the azimuthal distributions. Results are reported for the rapidity range vertical bar y vertical bar < 2.4, in the transverse momentum interval 0 < pT < 50 GeV/c, and in three centrality ranges of 10-30%, 30-50% and 50-90%. In contrast to the J/psi mesons, the measured v(2) values for the Y mesons are found to be consistent with zero. (C) 2021 The Author(s). Published by Elsevier B.V.Peer reviewe

    Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

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    Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (μ̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ¯ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ¯ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),μ̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| &lt; 0.03 at 95% confidence level. [Figure not available: see fulltext.

    Search for anomalous couplings in boosted WW/WZ -> l nu q(q)over-bar production in proton-proton collisions at root s=8TeV

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    Measurement of the top quark mass using charged particles in pp collisions at root s=8 TeV

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