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Animal models of pulmonary hypertension due to left heart disease 被引量:1
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作者 Shao-Fei Liu Yi Yan 《Animal Models and Experimental Medicine》 CSCD 2022年第3期197-206,共10页
Pulmonary hypertension due to left heart disease(PH-LHD) is regarded as the most prevalent form of pulmonary hypertension(PH). Indeed, PH is an independent risk factor and predicts adverse prognosis for patients with ... Pulmonary hypertension due to left heart disease(PH-LHD) is regarded as the most prevalent form of pulmonary hypertension(PH). Indeed, PH is an independent risk factor and predicts adverse prognosis for patients with left heart disease(LHD). Clinically, there are no drugs or treatments that directly address PH-LHD, and treatment of LHD alone will not also ameliorate PH. To target the underlying physiopathological alterations of PH-LHD and to develop novel therapeutic approaches for this population, animal models that simulate the pathophysiology of PH-LHD are required. There are several available models for PH-LHD that have been successfully employed in rodents or large animals by artificially provoking an elevated pressure load on the left heart, which by transduction elicits an escalated pressure in pulmonary artery. In addition, metabolic derangement combined with aortic banding or vascular endothelial growth factor receptor antagonist is also currently applied to reproduce the phenotype of PH-LHD. As of today, none of the animal models exactly recapitulates the condition of patients with PH-LHD. Nevertheless, the selection of an appropriate animal model is essential in basic and translational studies of PH-LHD. Therefore, this review will summarize the characteristics of each PH-LHD animal model and discuss the advantages and limitations of the different models. 展开更多
关键词 animal model l eft ventricular failure metabolic syndrome pulmonary hypertension due to left heart disease pulmonary vascular remodeling
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Biomass-Based Rice (Oryza sativa L.) Aboveground Architectural Parameter Models 被引量:11
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作者 CAO Hong-xin LIU Yan +11 位作者 LIU Yong-xia Jim Scott Hanan YUE Yan-bin ZHU Da-wei LU Jian-fei SUN Jin-ying SHI Chun-lin GE Dao-kuo WEI Xiu-fang YAO An-qing TIAN Ping-ping BAO Tai-lin 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2012年第10期1621-1632,共12页
To quantify the relationships between rice plant architecture parameters and the corresponding organ biomass, and to research on functional structural plant models of rice plant, this paper presented a biomass-based m... To quantify the relationships between rice plant architecture parameters and the corresponding organ biomass, and to research on functional structural plant models of rice plant, this paper presented a biomass-based model of aboveground architectural parameters of rice (Oryza sativa L.) in the young seedling stage, designed to explain effects of cultivars and environmental conditions on rice aboveground morphogenesis at the individual leaf level. Various model variables, including biomass of blade and blade length, were parameterized for rice based on data derived from an outdoor experiment with rice cv. Liangyou 108, 86You 8, Nanjing 43, and Yangdao 6. The organ dimensions of rice aboveground were modelled taking corresponding organ biomass as an independent variable. Various variables in rice showed marked consistency in observation and simulation, suggesting possibilities for a general rice architectural model in the young seedling stage. Our descriptive model was suitable for our objective. However, they can set the stage for connection to physiological model via biomass and development of functional structural rice models (FSRM), and start with the localized production and partitioning of assimilates as affected by abiotic growth factors. The finding of biomass-based rice architectural parameter models also can be used in morphological models of blade, sheath, and tiller of the other stages in rice life. 展开更多
关键词 BIOMASS plant architectural parameter model rice (Oryza sativa l.)
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Genetic variation of height growth rhythm between clones of Larix kaempferi × L. gmelini based on logistic models 被引量:1
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作者 Chunming Li Hui Xia +4 位作者 Hui Bai Hongmei Wang Yajuan Xing Xiyang Zhao Xiaomei Sun 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第5期1387-1394,共8页
Fifty-three larch interspecific hybrid clones(Larix kaempferi × L.gmelini) and their parent clones were used for growth curve analysis of height variations.The growth curves of the 55 clones were 'S'-shaped a... Fifty-three larch interspecific hybrid clones(Larix kaempferi × L.gmelini) and their parent clones were used for growth curve analysis of height variations.The growth curves of the 55 clones were 'S'-shaped and 36 exhibited similar curves as the male parent.The coefficients of the logistic models were higher than 0.943,indicating that our results were effective in the simulation of the growth curves.ANOVA analysis showed significant differences in height of different clones (P/0.01).Average date of maximum height growth was Day 173,and average duration of rapid growth lasted for 50 days.Annual average increase in height was 9.7cm d^(-1) and daily average increase was 0.2 cm.The ratio of GR to the total annual increase in height ranged from 51.2 to 68.8%,with the average being 59.8%.There was a positive correlation between k values and plant heights which benefited from the evaluation of early plant height.There was also a positive correlation between GR(growth stage),GD(plant height) and annual increase in height.These results are informative to the evaluation of the elite clone selection and provide a theoretical basis for breeding and management. 展开更多
关键词 larix kaempferi ×l. gmelini Hybrid clones logistic modeling Plant height variation
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Adjustment of Mathematical Models and the Quality of Drying the Pulped Coffee at Different Air Conditions 被引量:1
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作者 Paulo Carteri Coradi Reni Saath +1 位作者 Carlos Henrique Reinato Flavio Meira Borem 《Journal of Agricultural Science and Technology(B)》 2019年第1期38-48,共11页
The aim of the study was to describe the drying kinetics of washed coffee (Coffea arabica L.) and evaluate the best mathematical model to fit the experimental drying data conducted with different air humidity (40%, 50... The aim of the study was to describe the drying kinetics of washed coffee (Coffea arabica L.) and evaluate the best mathematical model to fit the experimental drying data conducted with different air humidity (40%, 50% and 60%), temperatures (23, 40 and 60 °C) and the quality of the coffee. The cherries coffee were separated and standardized in the processes of washing, mechanical and manual separation. Then, approx. 85 kg of coffee cherries were pulped and taken directly to the yard. The washed coffee was completed dried in a mechanical dryer and yard. The results showed that the different conditions of the ambient air significantly influenced the processes of drying. The water content of the hygroscopic equilibrium of pulped coffee is directly proportional to the water activity and relative humidity (RH), decreasing with increasing temperature, for the same value of equilibrium. The Oswin model was best represented by the hygroscopicity of the pulped coffee, while the Midilli model shows the best fit to describe the drying curves of the washed coffee. The effective diffusion coefficient increases with increasing temperature of the drying air and reducing of RH, being described by the Arrhenius equation. Electrical conductivity, potassium leaching, total titratable acidity and grease acidity increase with increasing drying temperature regardless of the type of processing. Reducing sugars, total sugars and the sensorial quality was negatively affected with increasing drying temperature regardless of the type of processing. The drying at 60 °C/40% RH negatively affected the coffee quality. 展开更多
关键词 COFFEA arabica l. drying MATHEMATICAl MODElING pulped coffee.
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Effects of rotation and gravity on an electro-magneto-thermoelastic medium with diffusion and voids by using the Lord-Shulman and dual-phase-lag models 被引量:3
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作者 S.M.ABO-DAHAB A.M.ABD-ALLA A.A.KILANY 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2019年第8期1135-1154,共20页
The effects of rotation and gravity on an electro-magneto-thermoelastic medium with diffusion and voids in a generalized thermoplastic half-space are studied by using the Lord-Shulman (L-S) model and the dual-phase-la... The effects of rotation and gravity on an electro-magneto-thermoelastic medium with diffusion and voids in a generalized thermoplastic half-space are studied by using the Lord-Shulman (L-S) model and the dual-phase-lag (DPL) model. The analytical solutions for the displacements, stresses, temperature, diffusion concentration, and volume fraction field with different values of the magnetic field, the rotation, the gravity, and the initial stress are obtained and portrayed graphically. The results indicate that the effects of gravity, rotation, voids, diffusion, initial stress, and electromagnetic field are very pronounced on the physical properties of the material. 展开更多
关键词 electromagnetic field GRAVITY field ROTATION initial stress voids DIFFUSION normal mode analysis lord-Shulman (l-S) model dual-phase-lag (DPl) model
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Quantitative Assessment of Remotely Sensed Global Surface Models Using Various Land Classes Produced from Landsat Data in Istanbul
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作者 Naci YASTIKLI Umut G SEFERCIK Fatih ESIRTGEN 《Chinese Geographical Science》 SCIE CSCD 2014年第3期307-316,共10页
Digital elevation model (DEM) is the most popular product for three-dimensional (3D) digital representation of bare Earth surface and can be produced by many techniques with different characteristics and ground sa... Digital elevation model (DEM) is the most popular product for three-dimensional (3D) digital representation of bare Earth surface and can be produced by many techniques with different characteristics and ground sampling distances (GSD). Space-borne opti- cal and synthetic aperture radar (SAR) imaging are two of the most preferred and modern techniques for DEM generation. Using them, global DEMs that cover almost entire Earth are produced with low cost and time saving processing. In this study, we aimed to assess the Satellite pour robservation de la Terre-5 (SPOT-5), High Resolution Stereoscopic (HRS), the Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER), and the Shuttle Radar Topography Mission (SRTM) C-band global DEMs, produced with space-borne optical and SAR imaging. For the assessment, a reference DEM derived from 1 : 1000 scaled digital photogrammetric maps was used. The study is performed in 100 km2 study area in Istanbul including various land classes such as open land, forest, built-up land, scrub and rough terrain obtained from Landsat data. The analyses were realized considering three vertical accuracy types as fundamental, supplemental, and consolidated, defined by national digital elevation program (NDEP) of USA. The results showed that, vertical accuracy of SRTM C-band DEM is better than optical models in all three accuracy types despite having the largest grid spacing. The result of SPOT-5 HRS DEM is very close by SRTM and superior in comparison with ASTER models. 展开更多
关键词 digital elevation model (DEM) quantitative assessment Satellite pour l'observation de la Terre (SPOT) AdvancedSpace-borne Thermal Emission and Reflection Radiometer (ASTER) Shuttle Radar Topography Mission (SRTM)
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Improvement of Bare Soil Semi-Empirical Radar Backscattering Models (Oh and Dubois) with SAR Multi-Spectral Satellite Data (X-, C- and L-Bands)
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作者 Rémy Fieuzal Frédéric Baup 《Advances in Remote Sensing》 2016年第4期296-314,共20页
The objective of this study is to improve the performance of semi-empirical radar backscatter models, which are mainly used in microwave remote sensing (Oh 1992, Oh 2004 and Dubois). The study is based on satellite an... The objective of this study is to improve the performance of semi-empirical radar backscatter models, which are mainly used in microwave remote sensing (Oh 1992, Oh 2004 and Dubois). The study is based on satellite and ground data collected on bare soil surfaces during the Multispectral Crop Monitoring experimental campaign of the CESBIO laboratory in 2010 over an agricultural region in southwestern France. The dataset covers a wide range of soil (viewing top soil moisture, surface roughness and texture) and satellite (at different frequencies: X-, C- and L-bands, and different incidence angles: 24.3° to 53.3°) configurations. The proposed methodology consists in identifying and correcting the residues of the models, depending on the surface properties (roughness, moisture, texture) and/or sensor characteristics (frequency, incidence angle). Finally, one model has been retained for each frequency domain. Results show that the enhancements of the models significantly increase the simulation performances. The coefficient of correlation increases of 23% in mean and the simulation errors (RMSE) are reduced to below 2 dB (at the X and C-bands) and to 1 dB at the L-band, compared to the initial models. At the X- and C-bands, the best performances of the modified models are provided by Dubois, whereas Oh 2004 is more suitable for the L-band (r is equal to 0.69, 0.65 and 0.85). Moreover, the modified models of Oh 1992 and 2004 and Dubois, developed in this study, offer a wider domain of validity than the initial formalism and increase the capabilities of retrieving the backscattering signal in view of applications of such approaches to stronglycontrasted agricultural surface states. 展开更多
关键词 Semi-Empirical Backscatters Model Oh Model Dubois Model Multi-Frequency (X- C- l-Band) Microwave TerraSAR-X Radarsat-2 Alos-PAlSAR
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Asymptotics of the“Minimum L_1-Norm”Estimates in Nonparametric Regression Models
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作者 Shi Pei-De Cheng Ping Institute of Systems Science Academia Sinica Beijing,100080 China 《Acta Mathematica Sinica,English Series》 SCIE CSCD 1994年第3期276-288,共13页
Consider the nonparametric regression model Y=go(T)+u,where Y is real-valued, u is a random error,T ranges over a nondegenerate compact interval,say[0,1],and go(·)is an unknown regression function,which is m... Consider the nonparametric regression model Y=go(T)+u,where Y is real-valued, u is a random error,T ranges over a nondegenerate compact interval,say[0,1],and go(·)is an unknown regression function,which is m(m≥0)times continuously differentiable and its ruth derivative,g<sub>0</sub><sup>(m)</sup>,satisfies a H■lder condition of order γ(m +γ】1/2).A piecewise polynomial L<sub>1</sub>- norm estimator of go is proposed.Under some regularity conditions including that the random errors are independent but not necessarily have a common distribution,it is proved that the rates of convergence of the piecewise polynomial L<sub>1</sub>-norm estimator are o(n<sup>-2(m+γ)+1/m+γ-1/δ</sup>almost surely and o(n<sup>-2(m+γ)+1/m+γ-δ</sup>)in probability,which can arbitrarily approach the optimal rates of convergence for nonparametric regression,where δ is any number in (0, min((m+γ-1/2)/3,γ)). 展开更多
关键词 Estimates in Nonparametric Regression models Minimum l1-Norm
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Convergence Rate of the L-N Estimator in Poisson-Gamma Models
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作者 Na Xia Zhong-zhan Zhang Zhi-liang Ying 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2006年第4期639-654,共16页
We focus on in this paper the convergence rate of the L-N estimators for the fixed effect β in Poisson-Gamma models which are typical hierarchical generalised linear models(HGLMs). Under the proper assumptions on r... We focus on in this paper the convergence rate of the L-N estimators for the fixed effect β in Poisson-Gamma models which are typical hierarchical generalised linear models(HGLMs). Under the proper assumptions on response variables and some smoothing conditions, we obtain the strong consistency and the convergence rate of the L-N estimator based on the combination of L-N and quasi-likelihood. 展开更多
关键词 H-likelihood l-N estimators Poisson-Gamma models strong consistency random effect
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L波段差分干涉SAR卫星严格回归轨道优化设计方法
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作者 李楠 温俊健 +3 位作者 刘艳阳 凌惠祥 魏春 陈筠力 《测绘学报》 EI CSCD 北大核心 2024年第10期1873-1880,共8页
相比于传统SAR卫星应用方向,我国第一代L波段差分干涉SAR卫星主要用于实现全球精准地表形变测量。为了达到重轨差分干涉优于5 cm的形变测量指标,首先需要解决卫星空间基准轨道高精度回归的工程难题。对此,本文提出一种严格回归轨道优化... 相比于传统SAR卫星应用方向,我国第一代L波段差分干涉SAR卫星主要用于实现全球精准地表形变测量。为了达到重轨差分干涉优于5 cm的形变测量指标,首先需要解决卫星空间基准轨道高精度回归的工程难题。对此,本文提出一种严格回归轨道优化设计方法,通过地球重力场阶数需求分析建立卫星高阶动力学模型,将J4摄动下修正的太阳同步回归轨道参数作为优化算法初值,以卫星WGS-84坐标系位置、速度回归精度满足收敛阈值为目标,利用启发式多目标进化算法开展轨道参数寻优。仿真试验表明,寻优结果回归精度可达厘米级,优于既定工程指标,并且本文方法有效性和正确性已经过L波段差分干涉SAR卫星在轨验证。 展开更多
关键词 严格回归轨道 合成孔径雷达差分干涉 高阶重力场 优化轨道设计 l波段差分干涉SAR卫星
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基于R-L分数阶定义的CCM Flyback变换器建模与分析
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作者 王硕禾 符屹男 +2 位作者 常宇健 杨鹏 李倩 《太阳能学报》 EI CAS CSCD 北大核心 2024年第6期217-225,共9页
针对电容电感都为分数阶这一事实,利用分数阶微积分R-L定义和状态空间平均法,对工作在电感电流连续模式(CCM)下的分数阶Flyback变换器进行建模与分析。推导CCM分数阶Flyback变换器的静态工作点和小信号传递函数以及变换器工作在CCM模式... 针对电容电感都为分数阶这一事实,利用分数阶微积分R-L定义和状态空间平均法,对工作在电感电流连续模式(CCM)下的分数阶Flyback变换器进行建模与分析。推导CCM分数阶Flyback变换器的静态工作点和小信号传递函数以及变换器工作在CCM模式下的条件。其次,讨论Caputo模型与R-L导数模型的区别,得出在R-L分数阶定义下直流静态工作点不仅与占空比相关,而且还与电感和电容的阶数以及负载有关。最后,在PSIM中搭建R-L分数阶CCM Flyback变换器电路模型,得到不同分数阶电感电容阶数下分数阶Flyback变换器输出电压和电感电流的仿真波形,通过仿真结果与理论计算结果对比,验证所建模型的正确性,得出分数阶电感电容的阶数会影响闭环控制器的设计和分数阶模型能更加精确地描述Flyback变换器的工作特性。 展开更多
关键词 DC-DC变换器 电力电子 仿真平台 R-l定义 分数阶建模
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盐湖大气环境下316 L仪表管点蚀深度预测研究
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作者 骆正山 刘月 《中国安全生产科学技术》 CAS CSCD 北大核心 2024年第6期105-110,共6页
为提高316 L仪表管在盐湖大气环境下点蚀深度的预测精度,采用变阶平均弱化缓冲算子、积分背景值和新陈代谢对分数阶累加灰色模型FGM(1,1,r)进行改进,首先通过改进Tent混沌映射、莱维飞行和区间自适应反向学习策略提高黏菌算法(SMA)的寻... 为提高316 L仪表管在盐湖大气环境下点蚀深度的预测精度,采用变阶平均弱化缓冲算子、积分背景值和新陈代谢对分数阶累加灰色模型FGM(1,1,r)进行改进,首先通过改进Tent混沌映射、莱维飞行和区间自适应反向学习策略提高黏菌算法(SMA)的寻优能力和收敛速度,随后利用改进黏菌算法(ISMA)对FGM(1,1,r,ρ)中的参数r和ρ进行寻优,最后构建仪表管ISMA-FGM(1,1,r,ρ)点蚀深度预测模型。研究结果表明:经优化的新模型比原模型误差更小、拟合度更高,在仪表管点蚀深度预测方面具有更好的性能。研究结果可为仪表管道系统的完整性评价和风险预警提供参考。 展开更多
关键词 盐湖大气环境 316 l仪表管 点蚀深度 改进黏菌算法(ISMA) FGM(1 1 r)模型
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Multi-objective PID control for non-Gaussian stochastic distribution system based on two-step intelligent models 被引量:3
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作者 YI Yang ZHANG TianPing GUO Lei 《Science in China(Series F)》 2009年第10期1754-1765,共12页
A new method for controlling the shape of the conditional output probability density function (PDF) for general nonlinear dynamic stochastic systems is proposed based on B-spline neural network (NN) model and T-S ... A new method for controlling the shape of the conditional output probability density function (PDF) for general nonlinear dynamic stochastic systems is proposed based on B-spline neural network (NN) model and T-S fuzzy model. Applying NN approximation to the measured PDFs, we transform the concerned problem into the tracking of given weights. Meanwhile, the complex multi-delay T-S fuzzy model with exogenous disturbances, parametric uncertainties and state constraints is used to represent the nonlinear weight dynamics. Moreover, instead of the non-convex design algorithms and PI control, the improved convex linear matrix inequality (LMI) algorithms and the generalized PID controller are proposed such that the multiple control objectives including stability, robustness, tracking performance and state constraint can be guaranteed simultaneously. Simulations are performed to demonstrate the efficiency of the proposed approach. 展开更多
关键词 probability density function non-Gaussian stochastic systems PID controller B-spline NN l1 performance index T-S fuzzy model
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ASYMPTOTIC NORMALITY OF MINIMUML_1-NORM ESTIMATES IN LINEAR MODELS 被引量:2
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作者 陈希孺 白志东 +1 位作者 赵林城 吴月华 《Science China Mathematics》 SCIE 1990年第11期1311-1328,共18页
Consider the standard linear model where x_x,x_2… are assumed to be the known p-vectors, β the unknown p-vector of regression coefficients, and e_1, e_2, …the independent random error sequence, each having a median... Consider the standard linear model where x_x,x_2… are assumed to be the known p-vectors, β the unknown p-vector of regression coefficients, and e_1, e_2, …the independent random error sequence, each having a median zero. Define the minimum L_1norm estimator as,the solution of the minimization problem inf It is proved in this paper that is asymptotically normal under very weak conditions. In particular, the condition imposed on {xi} is exactly the same which ensures the asymptotic normality of least-squares estimate: 展开更多
关键词 linear model minimum l_1-norm estimate asymptotic normality.
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Robust goodness-of-fit tests for AR(p) models based on L_1-norm fitting
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作者 蒋建成 郑忠国 《Science China Mathematics》 SCIE 1999年第4期337-346,共10页
A robustified residual autocorrelation is defined based on L1-regression. Under very general conditions, the asymptotic distribution of the robust residual autocorrelation is obtained. A robustified portmanteau statis... A robustified residual autocorrelation is defined based on L1-regression. Under very general conditions, the asymptotic distribution of the robust residual autocorrelation is obtained. A robustified portmanteau statistic is then constructed which can be used in checking the goodness-of-fit of AR(p) models when using L1-norm fitting. Empirical results show that L1-norm estimators and the proposed portmanteau statistic are robust against outliers, error distributions, and accuracy for a given finite sample. 展开更多
关键词 l1-regression model diagnostic CHECKING ROBUST residual AUTOCORRElATION time series.
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Supervised topic models with weighted words:multi-label document classification 被引量:1
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作者 Yue-peng ZOU Ji-hong OUYANG Xi-ming LI 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2018年第4期513-523,共11页
Supervised topic modeling algorithms have been successfully applied to multi-label document classification tasks.Representative models include labeled latent Dirichlet allocation(L-LDA)and dependency-LDA.However,these... Supervised topic modeling algorithms have been successfully applied to multi-label document classification tasks.Representative models include labeled latent Dirichlet allocation(L-LDA)and dependency-LDA.However,these models neglect the class frequency information of words(i.e.,the number of classes where a word has occurred in the training data),which is significant for classification.To address this,we propose a method,namely the class frequency weight(CF-weight),to weight words by considering the class frequency knowledge.This CF-weight is based on the intuition that a word with higher(lower)class frequency will be less(more)discriminative.In this study,the CF-weight is used to improve L-LDA and dependency-LDA.A number of experiments have been conducted on real-world multi-label datasets.Experimental results demonstrate that CF-weight based algorithms are competitive with the existing supervised topic models. 展开更多
关键词 Supervised topic model Multi-label classification Class frequency labeled latent Dirichlet allocation (l-lDA) Dependency-lDA
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基于自由曲面和L-system的红掌生长模型
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作者 邹一波 褚诗贤 +1 位作者 葛艳 陈明 《湖南农业大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第1期85-90,共6页
针对红掌花卉生长可视化中参数难以确定的问题进行研究,提出推导控制点的方法,建立红掌器官模型:采用Bezier曲线结合扫描成型的方法来构造叶柄模型,采用双三次NURBS曲线对佛焰苞进行建模;运用红掌的相关表型数据拟合生长函数,提出基于... 针对红掌花卉生长可视化中参数难以确定的问题进行研究,提出推导控制点的方法,建立红掌器官模型:采用Bezier曲线结合扫描成型的方法来构造叶柄模型,采用双三次NURBS曲线对佛焰苞进行建模;运用红掌的相关表型数据拟合生长函数,提出基于红掌生长规律的微分L-system,可有效模拟红掌的拓扑结构和生长过程;通过虚拟器官表示红掌器官的几何属性,降低微分L-system的复杂度。试验验证提出的方法对红掌各项生长指标拟合度可达0.89以上,并可对每个生长阶段的红掌进行模拟,能有效地对红掌的生长过程进行建模。 展开更多
关键词 红掌 自由曲面建模 l-SYSTEM 生长函数 虚拟器官
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Understanding of tribocorrosion and corrosion characteristics of304L stainless steel in hot concentrated nitric acid solution
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作者 LIU Zheng ZHANG Lian-min +3 位作者 LIU Chen-chen TAN Ke-di MA Ai-li ZHENG Yu-gui 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第10期3657-3673,共17页
Spent fuel reprocessing plays a pivotal role in achieving efficient recycling of nuclear fuel.Among thedifferent forms of failure encountered in spent fuel reprocessing,tribocorrosion stands out as a critical concern.... Spent fuel reprocessing plays a pivotal role in achieving efficient recycling of nuclear fuel.Among thedifferent forms of failure encountered in spent fuel reprocessing,tribocorrosion stands out as a critical concern.Herein,the tribocorrosion behavior,as well as the corrosion behavior,of 304L stainless steel(SS)in high-temperatureconcentrated nitric acid was investigated.The results indicated that 304L SS formed a thin(1.54 nm)and stable passivefilm on the surface,imparting high resistance to nitric acid corrosion.Meanwhile,it was found that the synergistic effectbetween corrosion and wear accounted for a high total tribocorrosion weight loss of over 85%,implying the dominantrole of the synergistic effect in the tribocorrosion process.Furthermore,the wear of 304L SS in deionized water revealedboth abrasive and adhesive wear characterizations,whereas the tribocorrosion in nitric acid only exhibited abrasive wearfeature.Eventually,the tribocorrosion and corrosion models of 304L SS in hot concentrated nitric acid were proposedbased on the comprehensive experimental findings. 展开更多
关键词 304l stainless steel TRIBOCORROSION CORROSION hot nitric acid mechanism model
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基于肠道菌群-LPS/TLR4通路探讨野菊花提取物对“过食膏粱厚味”致高尿酸血症大鼠的作用
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作者 焦琳 庞敏霞 +5 位作者 董英杰 苏洁 俞静静 颜美秋 陈素红 吕圭源 《浙江中医药大学学报》 CAS 2024年第8期915-928,共14页
[目的]研究野菊花提取物(Chrysanthemi Indici Flos extract,CYM.E)对“过食膏粱厚味”致高尿酸血症(hyperuricemia,HUA)大鼠的治疗作用及机制。[方法]将64只大鼠随机分为正常对照组,模型对照组,别嘌醇10 mg·kg^(-1)组,苯溴马隆5 m... [目的]研究野菊花提取物(Chrysanthemi Indici Flos extract,CYM.E)对“过食膏粱厚味”致高尿酸血症(hyperuricemia,HUA)大鼠的治疗作用及机制。[方法]将64只大鼠随机分为正常对照组,模型对照组,别嘌醇10 mg·kg^(-1)组,苯溴马隆5 mg·kg^(-1)组,CYM.E15、30、60、90 mg·kg^(-1)组,每组8只。除正常对照组外,其余各组均灌胃脂肪乳剂,建立拟人“过食膏粱厚味”致HUA大鼠模型。实验期间测定血清尿酸(uric acid,UA)、总胆固醇(total cholesterol,TC)、甘油三酯(triglyceride,TG)、高密度脂蛋白胆固醇(high density lipoprotein cholesterol,HDL-c)和低密度脂蛋白胆固醇(low density lipoprotein cholesterol,LDL-c)水平;酶联免疫吸附测定(enzyme linked immunosorbent assay,ELISA)法测定血清白细胞介素-6(interleukin-6,IL-6)、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)和血浆脂多糖(lipopolysaccharide,LPS)水平;实时荧光定量聚合酶链式反应(Real-time quantitative polymerase chain reaction,qRT-PCR)法测定小肠中TNF-α、Toll样受体4(Toll like receptor 4,TLR4)的mRNA表达;免疫印迹法检测小肠中TLR4蛋白表达;应用16S rDNA测序技术,对肠道菌群进行操作分类单元(operational taxonomic units,OTU)分类,选择合适的OTU进行结构分析、LEfSe差异贡献分析等。[结果]CYM.E能显著降低模型大鼠血清UA、TC、LDL-c、IL-6和TNF-α水平;显著降低血浆LPS水平;同时显著下调小肠组织TNF-αmRNA、TLR4 mRNA表达和TLR4蛋白表达,改善肠道的微炎症状态;增加乳酸杆菌、双歧杆菌的丰度与种类,降低拟杆菌、大肠杆菌的丰度与种类。[结论]CYM.E具有降低血清UA水平、调节血脂、减低炎症损伤、减少LPS释放等作用,可能通过调节肠道微生态发挥作用。 展开更多
关键词 高尿酸血症 脂肪乳剂 野菊花 动物模型 脂代谢 微炎症 肠道微生态 lPS/TlR4
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Spatial patterns of the Brusselator model with asymmetric Lévy diffusion
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作者 Hongwei Yin Shangtao Yang +2 位作者 Xiaoqing Wen Haohua Wang Shufen Yang 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第11期129-136,共8页
The formation of spatial patterns is an important issue in reaction–diffusion systems.Previous studies have mainly focused on the spatial patterns in reaction–diffusion models equipped with symmetric diffusion(such ... The formation of spatial patterns is an important issue in reaction–diffusion systems.Previous studies have mainly focused on the spatial patterns in reaction–diffusion models equipped with symmetric diffusion(such as normal or fractional Laplace diffusion),namely,assuming that spatial environments of the systems are homogeneous.However,the complexity and heterogeneity of spatial environments of biochemical reactions in vivo can lead to asymmetric diffusion of reactants.Naturally,there arises an open question of how the asymmetric diffusion affects dynamical behaviors of biochemical reaction systems.To answer this,we build a general asymmetric L´evy diffusion model based on the theory of a continuous time random walk.In addition,we investigate the two-species Brusselator model with asymmetric L´evy diffusion,and obtain a general condition for the formation of Turing and wave patterns.More interestingly,we find that even though the Brusselator model with symmetric diffusion cannot produce steady spatial patterns for some parameters,the asymmetry of L´evy diffusion for this model can produce wave patterns.This is different from the previous result that wave instability requires at least a three-species model.In addition,the asymmetry of L´evy diffusion can significantly affect the amplitude and frequency of the spatial patterns.Our results enrich our knowledge of the mechanisms of pattern formation. 展开更多
关键词 asymmetric lévy diffusion Turing and wave patterns Brusselator model
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