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[ACM Press the 3rd International Conference - Tetouan, Morocco (2018.10.10-2018.10.11)] Proceedings of the 3rd International Conference on Smart City Applications - SCA '18 - Empirical models for estimating the global solar radiation based on air temperature and sunshine duration
摘要： This work aims to develop and validate empirical models for estimating global solar radiation at site of Alhoceima based on the meteorological data measured during the period 2010-2017. The empirical models studied in this paper are broken down into two categories: the first category consist of linear and nonlinear regression which relates the monthly average daily global solar radiation to the sunshine duration, such as: the model of Angstr?m-Prescott, the cubic, quadratic model (Ogleman et al.), exponential (Almorox), logarithmic and power model. The second category consists of mathematical models calculating the monthly average daily global solar radiation based on the air temperature. And finally this study proposed model wish is based on sunshine duration and gives the best results for the city of Alhoceima. Statistical evaluation of the performance and accuracy of the models on the basis of The Root Mean Square Error (RMSE), Mean Bias Error MBE and R2 coefficient of determination, showed that all calibrated models estimates very well the monthly average daily global radiation. However the proposed model is more accurate with smaller errors and the best coefficient of determination.
关键词： air temperature,empirical model,sunshine duration,Daily global solar radiation,estimating global solar radiation
更新于2025-09-23 15:23:52
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Monte Carlo based model for diffuse reflectance from turbid media for the diagnosis of epithelial dysplasia
摘要： Diffuse reflectance from biological tissue has been widely used in diagnostic oncology for characterizing biochemical and morphological changes in epithelial tissue. However, computational complexity and time consumption involved in the extraction of absorption and scattering properties of tissues from diffuse reflectance reduce its potentiality for the effective diagnosis in a clinical setup. In this regard, a simple and accurate empirical equation for diffuse reflectance from a turbid medium was developed. A diffuse reflectance lookup table was generated using Monte Carlo simulations of all the optical properties typical of soft tissues in the visible and near infrared region of the spectrum for a semi-infinite medium. The generated lookup table was used to extract an empirical equation for diffuse reflectance using the surface fitting method. The proposed equation was tested with simulations and tissue phantom validation studies. The accuracy of the proposed empirical equation is tenfold higher than the diffusion approximation method. The uniqueness of the present method lies in its reliability even at extremities.
关键词： turbid medium,empirical model,Monte Carlo,epithelial dysplasia,diffuse reflectance
更新于2025-09-23 15:23:52
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The rational and effective design of nonfullerene acceptors guided by a semi-empirical model for an organic solar cell with an efficiency over 15%
摘要： Although much progress has been made for organic photovoltaics (OPVs), the active layer material design is generally based on a trial and error approach. It is still a challenge to rationally design active layer materials to further improve OPV performance. Herein, guided by a semi-empirical model we have proposed, two new small molecule acceptors, named F-2F and FO-2F, have been designed and synthesized based on an acceptor F-H. With difluoro substituted end group, F-2F shows red-shifted absorption than F-H, but still far from the range required in the semi-empirical model. Thus, with a subtle molecular optimization by inserting oxygen atom into the backbone of F-2F, FO-2F has been designed, which exhibits much red-shifted absorption, close to the preferred absorption range of the semi-empirical model. Blending with donor polymer PM6, OPV device based on FO-2F achieved an impressive PCE of 15.05% with a Voc of 0.878 V, a Jsc of 22.26 mA cm-2 and a notable FF of 0.77. Both the Voc and Jsc are among the predicted range of the model. These results render molecule FO-2F a new acceptor example which could demonstrates over 15% PCE only observed almost entirely for Y6 series.
关键词： acceptor,semi-empirical model,nonfullerene,A-D-A,organic solar cell
更新于2025-09-23 15:19:57
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[IEEE 2018 7th International Conference on Agro-geoinformatics (Agro-geoinformatics) - Hangzhou (2018.8.6-2018.8.9)] 2018 7th International Conference on Agro-geoinformatics (Agro-geoinformatics) - Research on Empirical Model and Gap Rate Model for Estimating Rice Leaf Area Index Based on UAV HD Digital Images
摘要： The Leaf Area Index (LAI), as an important plant characteristic parameter, is of great significance for the monitoring of vegetation growth and the estimation of surface vegetation productivity. Rice is one of the world's major food crops, timely and accurate measurement of rice LAI can provide scientific information on agriculture. The remote sensing system of UAV is characterized by its cost-effective and real-time data acquisition. The method of estimating LAI by remote sensing technology has great advantages over traditional methods and has gradually become a frontier method for agricultural research. At present, the commonly used LAI inversion methods are empirical model method and physical model method. The former is not accurate because not all of the spectral information is used. The latter cannot directly calculate the analytical solution because of the complicated model and many input parameters. The main purpose of this paper is to obtain high-definition digital images of different varieties of rice using low-altitude drones, and to analyze the feasibility of estimating the LAI of rice canopy by empirical model method and porosity model method, and analyze the difference and estimation process between them. There are problems.
关键词： Leaf Area Index(LAI),Remote sensing,Empirical model,Unmanned Aerial Vehicle(UAV),Rice,Gap rate model
更新于2025-09-11 14:15:04
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[IEEE 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Atlanta, GA, USA (2017.10.21-2017.10.28)] 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Detector response function of a HPGe detector to photon energies between 200 keV and 1.5 MeV for Gamma-ray nondestructive assay instrument
摘要： A semi-empirical detector response function (DRF) model of HPGe detector was proposed to fit gamma-ray nondestructive assay transmission spectra. The model for each single peak contained a step function, a Gaussian function, and an exponential tail function. The Gaussian standard deviation obtained by electronic noise and Fano factor, so our DRF only had 4 parameters and they were obtained by the weighted nonlinear least-squares fitting method. In the application, 152Eu spectra were obtained by using the 30%, 50%, 70% HPGe detector, and fitted by the established DRF model. Reduced chi- square values were at the interval of 0.039-0.202. Its validity that the model had good versatility, can be applicable to different detection efficiency of HPGe detectors.
关键词： gamma-ray nondestructive assay,HPGe detector,semi-empirical model,detector response function
更新于2025-09-04 15:30:14
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Dependence of Modulation Transfer Function on Electric Field Intensity of Photo conductor and Mobility-lifetime Product of Carriers in Polycrystalline Mercuric Iodide Based Flat Panel X-Ray Detectors: A Quantitative Approach and Error Analysis
摘要： In this Paper, a simplified mathematical model for Modulation Transfer Function (MTF) of Polycrystalline Mercuric Iodide based flat panel x-ray detector is applied on three different published prototypes of Polycrystalline Mercuric Iodide. Our aim was to fit the curves generated by simulation of MTF model with the curves acquired from experimental data. The mobility-lifetime product for the best curve fitting was examined for each prototype. Percentage of fitting error has been estimated for each prototype. Finally, average absolute error has been calculated for all the incorporated prototypes. This study can be further extended to develop a generic empirical model for the Modulation Transfer Function of polycrystalline mercuric iodide based flat panel x-ray detectors.
关键词： Modulation Transfer Function,Mobility-Lifetime Product,Average Absolute Error,Error Analysis,Empirical Model,Electric Field Intensity
更新于2025-09-04 15:30:14