229 research outputs found

    Comparative Evaluation of Data-Driven Approaches to Develop an Engine Surrogate Model for NOx Engine-Out Emissions under Steady-State and Transient Conditions

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    In this paper, a methodology based on data-driven models is developed to predict the NOx emissions of an internal combustion engine using, as inputs, a set of ECU channels representing the main engine actuations. Several regressors derived from the machine learning and deep learning algorithms are tested and compared in terms of prediction accuracy and computational efficiency to assess the most suitable for the aim of this work. Six Real Driving Emission (RDE) cycles performed at the roll bench were used for the model training, while another two RDE cycles and a steady-state map of NOx emissions were used to test the model under dynamic and stationary conditions, respectively. The models considered include Polynomial Regressor (PR), Support Vector Regressor (SVR), Random Forest Regressor (RF), Light Gradient Boosting Regressor (LightGBR) and Feed-Forward Neural Network (ANN). Ensemble methods such as Random Forest and LightGBR proved to have similar performances in terms of prediction accuracy, with LightGBR requiring a much lower training time. Afterwards, LightGBR predictions are compared with experimental NOx measurements in steady-state conditions and during two RDE cycles. Coefficient of determination (R2), normalized root mean squared error (nRMSE) and mean average percentage error (MAPE) are the main metrics used. The NOx emissions predicted by the LightGBR show good coherence with the experimental test set, both with the steady-state NOx map (R2 = 0.91 and MAPE = 6.42%) and with the RDE cycles (R2 = 0.95 and nRMSE = 0.04)

    THE IMPLICATIONS OF A NORTH AMERICAN FREE TRADE AREA FOR AGRICULTURE

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    This is one of two papers commissioned by the International Agricultural Trade Research Consortium on various aspects related to the agricultural sector of a prospective North American Free Trade Agreement. The companion paper to this one has been prepared by a working group chaired by Thomas Grennes, North Carolina State University. To minimize duplication with the Grennes paper, this paper has given greater attention to the general trade policy issues raised by a NAFTA, institutional factors, additional commodity detail in cereals, fruit and vegetables, and the relevance of other regional trade agreements such as the Canada-U.S. Trade Agreement. This work has also benefitted from an earlier report and its annexes, prepared for the Fraser Institute, under the direction of Tim Josling.International Relations/Trade,

    Efeitos de fungos termófilos sobre a madeira de Eucalyptus saligna: III. a população fúngica.

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    Este é um trabalho complementar a uma série de estudos com fungos termófilos, em madeira de eucalipto. Seu objetivo foi determinar a ação de uma população de fungos termófilos sobre a madeira e a celulose, obtida com cavacos de madeira de Eucalyptus saligna. Amostras de cavacos secos ao ar foram esterilizados por autoclavagem. Após a inoculação, os cavacos foram incubados, por 30 dias, a 30, 40 e 50oC. O inóculo foi preparado com uma amostra de 20 g de cavacos naturalmente contaminados com os fungos: Aspergillus sp., Dactylomyces thermophilus, Penicillium bacillisporum, Rhizomucor sp., Sporotrichum sp. e Thermoascus aurantiacus. Os cavacos foram analisados quanto aos teores de holocelulose, lignina e extrativos. Preparou-se, também, celulose não branqueada com os cavacos dos tratamentos e analisou-se o rendimento bruto da celulose. A análise dos resultados mostrou que os teores de holocelulose e lignina permaneceram inalterados revelando que os fungos não degradam celulose ou lignina. A diminuição nos teores de extrativos começaram a ser detectados a 40 e 50oC, exceção feita aos açúcares livres em etanol. O maior decréscimo ocorreu a 50oC. O decréscimo no teor foi observado na fração solúvel em etanol-tolueno (19,3%), em diclorometano (7,1%) e em água quente (4%); com extrativos totais e açúcares livres em etanol, o decréscimo foi de 8,6% e 4,8%, respectivamente. A análise da produção de celulose não branqueada verificou-se uma relação direta entre produção e a temperatura de incubação. Cavacos não inoculados e os inoculados/incubados a 30oC produziram 50,8% de celulose, enquanto que os incubados a 40 e 50oC produziram 52 e 53,1%, respectivamente

    Adaptação transcultural e validação da Hamilton Early Warning Score para o Brasil

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    Objetivo: Adaptar transculturalmente e validar, para a língua portuguesa, a Hamilton Early Warning Score para detectar a deterioração clínica em serviços de emergência.Método: Estudo metodológico compreendendo as etapas de tradução, síntese, retrotradução, comitê de especialistas (n=13), pré-teste, envio e análise das propriedades de medidas em uma amostra composta por 188 pacientes. Comparou-se a Canadian Acute Scale Triage com a Hamilton Early Warning Score. Foram utilizados o Coeficiente Kappa Ponderado, Coeficiente de Correlação Intraclasse e de Pearson, Regressão Logística Binária e a Área Sob a Curva Receiver Operating Characteristic para a análise dos dados.Resultados: A Hamilton Early Warning Score apresentou confiabilidade excelente, ou seja, α=0,924 (p<0,001). A validade de construto identificou correlação forte e negativa r=-0,75 e a preditiva apresentou um odds ratio de 1,63, IC 95% (1,358-1,918) (p<0,001).Conclusão: A Hamilton Early Warning Score em português é válida e confiável para reconhecer pacientes em condição de deterioração clínica em serviços de emergência. Palavras-chave: Estudo de validação. Alerta rápido. Deterioração clínica. Serviços médicos de emergência. Comparação transcultural. Segurança do paciente

    Electronics design of the RPC system for the OPERA muon spectrometer

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    The present document describes the front-end electronics of the RPC system that instruments the magnet muon spectrometer of the OPERA experiment. The main task of the OPERA spectrometer is to provide particle tracking information for muon identification and simplify the matching between the Precision Trackers. As no trigger has been foreseen for the experiment, the spectrometer electronics must be self-triggered with single-plane readout capability. Moreover, precision time information must be added within each event frame for off-line reconstruction. The read-out electronics is made of three different stages: the Front-End Boards (FEBs) system, the Controller Boards (CBs) system and the Trigger Boards(TBs) system. The FEB system provides discrimination of the strip incoming signals; a FAST-OR output of the input signals is also available for trigger plane signal generation. FEB signals are acquired by the CB system that provides the zero suppression and manages the communication to the DAQ and Slow Control. A Trigger Board allows to operate in both self-trigger mode (the FEB’s FAST-OR signal starts the plane acquisition) or in external-trigger mode (different conditions can be set on the FAST-OR signals generated from different planes)

    Performance of Long Modules of Silicon Microstrip Detectors

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    This note describes the performance of modules assembled with up to twelve silicon microstrip detectors. These modules were built for the instrumented Silicon Target (STAR) that has been installed in the NOMAD spectrometer. Laboratory and test beam results are compared with model predictions. For a module of nine detectors, test beam results indicate a signal--to--noise ratio of 19, a hit finding efficiency of 99.8\% and a spatial resolution of 6.0 μ\mum. Laboratory measurements indicate that modules of twelve detectors exhibit a signal--to--noise ratio of the order of 16
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