期刊文献+
共找到428篇文章
< 1 2 22 >
每页显示 20 50 100
Correlation Analysis of Fiscal Revenue and Housing Sales Price Based on Multiple Linear Regression Model
1
作者 Wei Zheng Xinyi Li +1 位作者 Nanxing Guan Kun Zhang 《数学计算(中英文版)》 2020年第1期3-12,共10页
This paper selects seven indicators of financial revenue and housing sales price in recent 19 years in China,and uses SPSS and Excel to carry out descriptive statistics,independent sample t-test,correlation analysis a... This paper selects seven indicators of financial revenue and housing sales price in recent 19 years in China,and uses SPSS and Excel to carry out descriptive statistics,independent sample t-test,correlation analysis and regression analysis to comprehensively study the correlation between financial revenue and housing sales price in China,and establishes the relationship between financial revenue and housing sales price When the average selling price of commercial housing increases by one unit,the fiscal revenue will increase by 27.855 points. 展开更多
关键词 Financial Revenue Housing Sales Price Correlation analysis Multiple linear regression model
下载PDF
Empirical Likelihood Diagnosis of Modal Linear Regression Models
2
作者 Shuling Wang Lin Zheng Jiangtao Dai 《Journal of Applied Mathematics and Physics》 2014年第10期948-952,共5页
In this paper, we investigate the empirical likelihood diagnosis of modal linear regression models. The empirical likelihood ratio function based on modal regression estimation method for the regression coefficient is... In this paper, we investigate the empirical likelihood diagnosis of modal linear regression models. The empirical likelihood ratio function based on modal regression estimation method for the regression coefficient is introduced. First, the estimation equation based on empirical likelihood method is established. Then, some diagnostic statistics are proposed. At last, we also examine the performance of proposed method for finite sample sizes through simulation study. 展开更多
关键词 MODAL linear regression model Empirical LIKELIHOOD OUTLIERS Influence analysis
下载PDF
Robust Linear Regression Models:Use of a Stable Distribution for the Response Data
3
作者 Jorge A.Achcar Angela Achcar Edson Zangiacomi Martinez 《Open Journal of Statistics》 2013年第6期409-416,共8页
In this paper, we study some robustness aspects of linear regression models of the presence of outliers or discordant observations considering the use of stable distributions for the response in place of the usual nor... In this paper, we study some robustness aspects of linear regression models of the presence of outliers or discordant observations considering the use of stable distributions for the response in place of the usual normality assumption. It is well known that, in general, there is no closed form for the probability density function of stable distributions. However, under a Bayesian approach, the use of a latent or auxiliary random variable gives some simplification to obtain any posterior distribution when related to stable distributions. To show the usefulness of the computational aspects, the methodology is applied to two examples: one is related to a standard linear regression model with an explanatory variable and the other is related to a simulated data set assuming a 23 factorial experiment. Posterior summaries of interest are obtained using MCMC (Markov Chain Monte Carlo) methods and the OpenBugs software. 展开更多
关键词 Stable Distribution Bayesian analysis linear regression models MCMC Methods OpenBugs Software
下载PDF
Rainfall Estimation using Image Processing and Regression Model on DWR Rainfall Product for Delhi-NCR Region 被引量:1
4
作者 Kuldeep Srivastava Ashish Nigam 《Journal of Atmospheric Science Research》 2020年第1期9-15,共7页
Observed rainfall is a very essential parameter for the analysis of rainfall,day to day weather forecast and its validation.The observed rainfall data is only available from five observatories of IMD;while no rainfall... Observed rainfall is a very essential parameter for the analysis of rainfall,day to day weather forecast and its validation.The observed rainfall data is only available from five observatories of IMD;while no rainfall data is available at various important locations in and around Delhi-NCR.However,the 24-hour rainfall data observed by Doppler Weather Radar(DWR)for entire Delhi and surrounding region(up to 150 km)is readily available in a pictorial form.In this paper,efforts have been made to derive/estimate the rainfall at desired locations using DWR hydrological products.Firstly,the rainfall at desired locations has been estimated from the precipitation accumulation product(PAC)of the DWR using image processing in Python language.After this,a linear regression model using the least square method has been developed in R language.Estimated and observed rainfall data of year 2018(July,August and September)was used to train the model.After this,the model was tested on rainfall data of year 2019(July,August and September)and validated.With the use of linear regression model,the error in mean rainfall estimation reduced by 46.58% and the error in max rainfall estimation reduced by 84.53% for the year 2019.The error in mean rainfall estimation reduced by 81.36% and the error in max rainfall estimation reduced by 33.81%for the year 2018.Thus,the rainfall can be estimated with a fair degree of accuracy at desired locations within the range of the Doppler Weather Radar using the radar rainfall products and the developed linear regression model. 展开更多
关键词 Rainfall estimation Rainfall analysis Doppler Weather Radar Precipitation Accumulation Product Image processing linear regression model
下载PDF
A Recursive Binary Tree Model for the Analysis of the Response to Antiretroviral Therapy of HIV Infected Adults in Burkina Faso
5
作者 Simon Tiendrébéogo Séni Kouanda +1 位作者 Blaise Somé Simplice Dossou-Gbeté 《Open Journal of Statistics》 2019年第6期643-656,共14页
In this paper we aim to analyse temporal variation of CD4 cell counts for HIV-infected individuals under antiretroviral therapy by using statistical methods. This is achieved by resorting to recursive binary regressio... In this paper we aim to analyse temporal variation of CD4 cell counts for HIV-infected individuals under antiretroviral therapy by using statistical methods. This is achieved by resorting to recursive binary regression tree approach [1]?[2]. This approach has made it possible to highlight the existence of several segments of the population of interest described by the interactions between the predictive covariates of the response to the treatment regimen. 展开更多
关键词 model-Based CONDITIONAL regression Tree CD4 Cell COUNT Prediction linear Mixed model Stability analysis ANTIRETROVIRAL Therapy
下载PDF
Inference Procedures on the Generalized Poisson Distribution from Multiple Samples: Comparisons with Nonparametric Models for Analysis of Covariance (ANCOVA) of Count Data
6
作者 Maha Al-Eid Mohamed M. Shoukri 《Open Journal of Statistics》 2021年第3期420-436,共17页
Count data that exhibit over dispersion (variance of counts is larger than its mean) are commonly analyzed using discrete distributions such as negative binomial, Poisson inverse Gaussian and other models. The Poisson... Count data that exhibit over dispersion (variance of counts is larger than its mean) are commonly analyzed using discrete distributions such as negative binomial, Poisson inverse Gaussian and other models. The Poisson is characterized by the equality of mean and variance whereas the Negative Binomial and the Poisson inverse Gaussian have variance larger than the mean and therefore are more appropriate to model over-dispersed count data. As an alternative to these two models, we shall use the generalized Poisson distribution for group comparisons in the presence of multiple covariates. This problem is known as the ANCOVA and is solved for continuous data. Our objectives were to develop ANCOVA using the generalized Poisson distribution, and compare its goodness of fit to that of the nonparametric Generalized Additive Models. We used real life data to show that the model performs quite satisfactorily when compared to the nonparametric Generalized Additive Models. 展开更多
关键词 Count regression Over Dispersion Generalized linear models analysis of Covariance Generalized Additive models
下载PDF
Analysis of Alkaline Foam to Water Temperature Model
7
作者 Zhen Xu Lihong Zhao Kai Tan 《World Journal of Engineering and Technology》 2016年第3期433-436,共4页
Factors affecting bath water temperature model include the shape and size of a bath, people’s gesture, volume, individual temperature adaptation as well as body movement in the bath. In addition, the bathroom space, ... Factors affecting bath water temperature model include the shape and size of a bath, people’s gesture, volume, individual temperature adaptation as well as body movement in the bath. In addition, the bathroom space, ambient temperature and bath materials will also affect changes of the water temperature to a certain extent. In this paper, the cooling function and linear regression method are used and the MATLAB software is also used to simulate the model of water temperature, alkaline bath foams that obtained can accelerate changes in water temperature. 展开更多
关键词 Water Temperature model Cooling Function linear regression analysis
下载PDF
Regression analysis and its application to oil and gas exploration:A case study of hydrocarbon loss recovery and porosity prediction,China
8
作者 Yang Li Xiaoguang Li +3 位作者 Mingyu Guo Chang Chen Pengbo Ni Zijian Huang 《Energy Geoscience》 EI 2024年第4期240-252,共13页
In oil and gas exploration,elucidating the complex interdependencies among geological variables is paramount.Our study introduces the application of sophisticated regression analysis method at the forefront,aiming not... In oil and gas exploration,elucidating the complex interdependencies among geological variables is paramount.Our study introduces the application of sophisticated regression analysis method at the forefront,aiming not just at predicting geophysical logging curve values but also innovatively mitigate hydrocarbon depletion observed in geochemical logging.Through a rigorous assessment,we explore the efficacy of eight regression models,bifurcated into linear and nonlinear groups,to accommodate the multifaceted nature of geological datasets.Our linear model suite encompasses the Standard Equation,Ridge Regression,Least Absolute Shrinkage and Selection Operator,and Elastic Net,each presenting distinct advantages.The Standard Equation serves as a foundational benchmark,whereas Ridge Regression implements penalty terms to counteract overfitting,thus bolstering model robustness in the presence of multicollinearity.The Least Absolute Shrinkage and Selection Operator for variable selection functions to streamline models,enhancing their interpretability,while Elastic Net amalgamates the merits of Ridge Regression and Least Absolute Shrinkage and Selection Operator,offering a harmonized solution to model complexity and comprehensibility.On the nonlinear front,Gradient Descent,Kernel Ridge Regression,Support Vector Regression,and Piecewise Function-Fitting methods introduce innovative approaches.Gradient Descent assures computational efficiency in optimizing solutions,Kernel Ridge Regression leverages the kernel trick to navigate nonlinear patterns,and Support Vector Regression is proficient in forecasting extremities,pivotal for exploration risk assessment.The Piecewise Function-Fitting approach,tailored for geological data,facilitates adaptable modeling of variable interrelations,accommodating abrupt data trend shifts.Our analysis identifies Ridge Regression,particularly when augmented by Piecewise Function-Fitting,as superior in recouping hydrocarbon losses,and underscoring its utility in resource quantification refinement.Meanwhile,Kernel Ridge Regression emerges as a noteworthy strategy in ameliorating porosity-logging curve prediction for well A,evidencing its aptness for intricate geological structures.This research attests to the scientific ascendancy and broad-spectrum relevance of these regression techniques over conventional methods while heralding new horizons for their deployment in the oil and gas sector.The insights garnered from these advanced modeling strategies are set to transform geological and engineering practices in hydrocarbon prediction,evaluation,and recovery. 展开更多
关键词 regression analysis Oil and gas exploration Multiple linear regression model Nonlinear regression model Hydrocarbon loss recovery Porosity prediction
下载PDF
Biomass estimation of Shorea robusta with principal component analysis of satellite data
9
作者 Nilanchal Patel Arnab Majumdar 《Journal of Forestry Research》 SCIE CAS CSCD 2010年第4期469-474,524,共7页
Spatio-temporal assessment of the above ground biomass (AGB) is a cumbersome task due to the difficulties associated with the measurement of different tree parameters such as girth at breast height and height of tre... Spatio-temporal assessment of the above ground biomass (AGB) is a cumbersome task due to the difficulties associated with the measurement of different tree parameters such as girth at breast height and height of trees. The present research was conducted in the campus of Birla Institute of Technology, Mesra, Ranchi, India, which is predomi- nantly covered by Sal (Shorea robusta C. F. Gaertn). Two methods of regression analysis was employed to determine the potential of remote sensing parameters with the AGB measured in the field such as linear regression analysis between the AGB and the individual bands, principal components (PCs) of the bands, vegetation indices (VI), and the PCs of the VIs respectively and multiple linear regression (MLR) analysis be- tween the AGB and all the variables in each category of data. From the linear regression analysis, it was found that only the NDVI exhibited regression coefficient value above 0.80 with the remaining parameters showing very low values. On the other hand, the MLR based analysis revealed significantly improved results as evidenced by the occurrence of very high correlation coefficient values of greater than 0.90 determined between the computed AGB from the MLR equations and field-estimated AGB thereby ascertaining their superiority in providing reliable estimates of AGB. The highest correlation coefficient of 0.99 is found with the MLR involving PCs of VIs. 展开更多
关键词 above ground biomass spectral response modeling vegetation indices principal component analysis linear and multiple regression analysis.
下载PDF
Function-on-Partially Linear Functional Additive Models
10
作者 Jinyou Huang Shuang Chen 《Journal of Applied Mathematics and Physics》 2020年第1期1-9,共9页
We consider a functional partially linear additive model that predicts a functional response by a scalar predictor and functional predictors. The B-spline and eigenbasis least squares estimator for both the parametric... We consider a functional partially linear additive model that predicts a functional response by a scalar predictor and functional predictors. The B-spline and eigenbasis least squares estimator for both the parametric and the nonparametric components proposed. In the final of this paper, as a result, we got the variance decomposition of the model and establish the asymptotic convergence rate for estimator. 展开更多
关键词 FUNCTIONAL Data analysis FUNCTIONAL Principal COMPONENT analysis PARTIAL linear regression models Penalized B-SPLINES Variance model
下载PDF
Functional Analysis of Chemometric Data
11
作者 Ana M. Aguilera Manuel Escabias +1 位作者 Mariano J. Valderrama M. Carmen Aguilera-Morillo 《Open Journal of Statistics》 2013年第5期334-343,共10页
The objective of this paper is to present a review of different calibration and classification methods for functional data in the context of chemometric applications. In chemometric, it is usual to measure certain par... The objective of this paper is to present a review of different calibration and classification methods for functional data in the context of chemometric applications. In chemometric, it is usual to measure certain parameters in terms of a set of spectrometric curves that are observed in a finite set of points (functional data). Although the predictor variable is clearly functional, this problem is usually solved by using multivariate calibration techniques that consider it as a finite set of variables associated with the observed points (wavelengths or times). But these explicative variables are highly correlated and it is therefore more informative to reconstruct first the true functional form of the predictor curves. Although it has been published in several articles related to the implementation of functional data analysis techniques in chemometric, their power to solve real problems is not yet well known. Because of this the extension of multivariate calibration techniques (linear regression, principal component regression and partial least squares) and classification methods (linear discriminant analysis and logistic regression) to the functional domain and some relevant chemometric applications are reviewed in this paper. 展开更多
关键词 FUNCTIONAL Data analysis B-SPLINES FUNCTIONAL Principal Component regression FUNCTIONAL Partial Least SQUARES FUNCTIONAL LOGIT models FUNCTIONAL linear DISCRIMINANT analysis Spectroscopy NIR Spectra
下载PDF
基于一元线性回归模型的供水网络中水表读数虚高问题研究 被引量:1
12
作者 韩义秀 《浙江工贸职业技术学院学报》 2024年第1期70-73,84,共5页
为了定量研究供水网络中总表漏水程度和分表读数虚高程度,根据水量平衡分析法的原理,结合大数据分析技术,建立了一元线性回归方程,回归常数代表总表漏水量程度,回归系数代表分表读数虚高程度。通过针对2021年某高校供水管网的实证研究表... 为了定量研究供水网络中总表漏水程度和分表读数虚高程度,根据水量平衡分析法的原理,结合大数据分析技术,建立了一元线性回归方程,回归常数代表总表漏水量程度,回归系数代表分表读数虚高程度。通过针对2021年某高校供水管网的实证研究表明,总表日均漏水量为15.5958吨,分表读数虚高率为1.07%。该方法对供水管网漏损率的精准评估等问题的解决提供了新的思路和方法。 展开更多
关键词 供水网络 水量平衡分析法 一元线性回归模型 漏水量 虚高
下载PDF
考虑异质交通流的随机参数优化速度跟驰模型
13
作者 潘义勇 全勇俊 管星宇 《深圳大学学报(理工版)》 CAS CSCD 北大核心 2024年第4期415-422,共8页
为分析交通流异质性对车辆跟驰行为的影响,基于随机参数线性回归方法改进优化速度函数.根据分位数回归对交通流速度-密度数据进行分类,对每个类别数据进行随机参数线性回归,并得到不同类别的改进优化速度函数与假设检验结果,结合改进的... 为分析交通流异质性对车辆跟驰行为的影响,基于随机参数线性回归方法改进优化速度函数.根据分位数回归对交通流速度-密度数据进行分类,对每个类别数据进行随机参数线性回归,并得到不同类别的改进优化速度函数与假设检验结果,结合改进的优化速度函数和全速度差跟驰模型建立随机优化速度跟驰模型,利用傅里叶变化理论对跟驰模型进行稳定性分析,并搭建环形车道仿真平台对跟驰模型进行数值实验.结果表明,分类处理后的随机参数模型误差较未分类降低28%;随机参数跟驰车队的速度值随着0.5分位点车辆的增多而增大;随机参数跟驰模型车队较固定参数跟驰模型车队更能反映交通流异质性对车队的影响.建立的模型能够提高仿真维度,真实反映交通流的复杂运行状况. 展开更多
关键词 交通工程 交通流理论 分位数回归 随机参数线性回归 优化速度函数 跟驰模型 稳定性分析
下载PDF
基于可见/近红外光谱和函数型线性回归模型的成熟期苹果可溶性固形物含量预测
14
作者 黄华 刘亚 +4 位作者 马毅航 向思函 何佳宁 王诗婷 郭俊先 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2024年第7期1905-1912,共8页
可溶性固形物含量(SSC)是反映苹果品质和成熟度的重要指标,能够用于苹果品质分析和成熟度预测。以新疆阿克苏冰糖心红富士苹果为研究对象,从果实膨大定形期至完熟期,以3d等间隔周期采摘样本,采集其380~1110nm的可见/近红外光谱,测定其S... 可溶性固形物含量(SSC)是反映苹果品质和成熟度的重要指标,能够用于苹果品质分析和成熟度预测。以新疆阿克苏冰糖心红富士苹果为研究对象,从果实膨大定形期至完熟期,以3d等间隔周期采摘样本,采集其380~1110nm的可见/近红外光谱,测定其SSC,共552个样品。然后,利用基函数平滑方法将采集的可见/近红外光谱离散数据转化为光谱曲线,即函数型数据,并以可见/近红外光谱曲线、一阶导曲线、二阶导曲线为函数型解释变量,SSC为标量响应变量,分别建立函数型线性回归模型。为了验证和分析模型的性能,根据原始光谱离散数据,经过移动平滑、一阶导和二阶导预处理后,分别建立偏最小二乘回归(PLSR)、核支持向量机(KSVM)、随机森林(RF)、梯度提升树(GBM)和深度神经网络(DeepNN)。结果表明,在建立的18个模型中,针对训练集,PLSR-dNIR模型、KSVM-dNIR模型、RF-dNIR模型、GBM-dNIR模型和Deep NN-d2NIR模型都优于FunLR-NIR模型、FunLR-dNIR模型、FunLR-d2NIR模型,且Deep NN-dNIR模型最优(r_(c)=0.9996,R_(c)^(2)=0.9986,RMSEC=0.0740,RPDC=27.4366);针对测试集,FunLR-NIR模型、FunLR-dNIR模型、FunLR-d2NIR模型均优于其他所有模型,且FunLR-NIR模型最优(r_(v)=0.9534,R_(v)^(2)=0.9077,RMSEV=0.5856,RPDV=3.3017)。综合训练集和测试集的结果来看,核支持向量机模型、随机森林模型、梯度提升树模型和深度神经网络模型容易过拟合,而函数型线性回归模型具有更好的普适性。此外,从三个函数型线性回归模型(FunLR-NIR模型、FunLR-dNIR模型、FunLR-d2NIR模型)的预测效果看,模型均具有良好的鲁棒性和较高的预测精度。试验结果表明,结合可见/近红外光谱技术与函数型数据分析构建的函数型线性回归模型,可成功、有效地实现成熟期苹果的可溶性固形物含量预测。 展开更多
关键词 苹果 可溶性固形物含量 可见/近红外光谱 函数型数据分析 函数型线性回归模型
下载PDF
渤海海域井壁取心裂解烃S_(2)烃类损失恢复回归分析
15
作者 李阳 郭明宇 +3 位作者 倪鹏勃 李鸿儒 符强 黄子舰 《录井工程》 2024年第2期49-56,共8页
地化录井受工程、地质条件及人为因素的影响,往往造成岩石样品从井底到地表的烃类损失,不能很好地反映地下储层的真实含油气信息,因此需要一种合理准确的方法进行烃类损失恢复。针对渤海海域不同地区不同层位的岩屑值(自变量)与壁心值(... 地化录井受工程、地质条件及人为因素的影响,往往造成岩石样品从井底到地表的烃类损失,不能很好地反映地下储层的真实含油气信息,因此需要一种合理准确的方法进行烃类损失恢复。针对渤海海域不同地区不同层位的岩屑值(自变量)与壁心值(因变量)之间的关系,基于最小二乘法、梯度下降法及其衍生算法,以多元线性回归和非线性回归两种方式来拟合研究区井壁取心数据。多元线性回归模型可使用标准方程法、岭回归、LASSO(Least Absolute Shrinkage and Selection Operator)及弹性网进行回归拟合,非线性回归模型可使用梯度下降法和分段函数的拟合方法。对不同回归分析方法进行分析对比可知,岭回归在计算线性关系的烃类损失方面具有较好的效果,决定系数r^(2)均超过0.7;基于岭回归分段函数拟合和非线性回归模型y=x/(b+kx)适合非线性烃类损失恢复。与传统的烃类损失恢复方法相比,使用量化的方式对研究区烃类进行恢复,更加科学全面,具有广泛的应用前景。 展开更多
关键词 烃类损失恢复 裂解烃 回归分析 多元线性回归模型 非线性回归模型 井壁取心
下载PDF
早胜牛母牛体重与体尺性状相关回归分析
16
作者 陈长博 路平乐 +5 位作者 苏涛龙 狄亚鹏 高永权 杨永慧 杨雅楠 赵生国 《黑龙江畜牧兽医》 CAS 北大核心 2024年第8期31-36,共6页
为了阐明不同月龄早胜牛母牛体重与体尺指标之间的关系,以建立不同月龄早胜牛的体重估测模型,试验分别测定了12月龄(233头)、18月龄(514头)和24月龄(797头)共1544头早胜牛母牛的体重(Y)、体高(X_(1))、体斜长(X_(2))、胸围(X_(3))和管围... 为了阐明不同月龄早胜牛母牛体重与体尺指标之间的关系,以建立不同月龄早胜牛的体重估测模型,试验分别测定了12月龄(233头)、18月龄(514头)和24月龄(797头)共1544头早胜牛母牛的体重(Y)、体高(X_(1))、体斜长(X_(2))、胸围(X_(3))和管围(X_(4))指标,并进行了相关分析、通径分析和逐步回归分析。结果表明:12,18,24月龄早胜牛母牛体重与体尺指标均呈极显著正相关(P<0.01),其中均与胸围的相关性最高,相关系数分别为0.947,0.848,0.908;12,18,24月龄早胜牛母牛体尺指标间均呈极显著正相关(P<0.01);12,18,24月龄早胜牛母牛体尺指标对体重的直接影响由大到小均依次为胸围(0.677,0.409,0.574)、体斜长(0.188,0.394,0.378)、体高(0.134,0.255,0.048)和管围(0.057,-0.015,-0.009);12月龄早胜牛母牛体斜长对体重的间接影响最大,胸围对体重的间接影响最小;18,24月龄早胜牛母牛体高对体重的间接影响最大,管围对体重的间接影响最小;建立了12,18,24月龄早胜牛母牛体重预测多元线性回归模型,分别为Y=93.023+0.717X_(1)+0.229X_(2)+0.171X_(3)+0.285X_(4)、Y=107.257+0.652X_(1)+0.571X_(2)+0.448X_(3)、Y=-245.280+2.430X_(1)+1.519X_(2)+0.182X_(3),3个模型的R2分别为0.925,0.872,0.880,拟合度较高。说明可通过测定早胜牛母牛胸围、体斜长和体高指标,利用上述不同月龄的体重回归模型估测其体重。 展开更多
关键词 早胜牛母牛 体重 体尺 相关性分析 线性回归 体重估测模型
下载PDF
河南荥阳市耕地土壤重金属分布特征及来源解析 被引量:3
17
作者 张妍 赵新雷 +1 位作者 冯雪珍 郭亚娇 《岩矿测试》 CAS CSCD 北大核心 2024年第2期330-343,共14页
耕地质量关系着人民生活,而重金属是影响耕地质量的重要因素之一。根据全国土壤污染状况调查显示,中国耕地环境状况不容乐观,对耕地的重金属调查分析迫在眉睫。但仅简单地对重金属含量水平及来源类型进行判断已不足以为区域土壤重金属... 耕地质量关系着人民生活,而重金属是影响耕地质量的重要因素之一。根据全国土壤污染状况调查显示,中国耕地环境状况不容乐观,对耕地的重金属调查分析迫在眉睫。但仅简单地对重金属含量水平及来源类型进行判断已不足以为区域土壤重金属污染治理提供支持,而通过对各类污染源贡献率的定量计算,不仅可以明确农田土壤重金属分布特征,同时可判别污染源类别及来源,从而识别优先控制的污染元素,为重金属污染精准管控提供关键信息。本文采集河南荥阳市耕地表层土壤样品(0~20cm),应用电感耦合等离子体质谱和发射光谱法(ICP-MS/OES)、原子荧光光谱法(AFS)及离子选择电极法(IES)对As、Cd、Cr、Cu、Hg、Ni、Pb、Zn等8种重金属进行测试和p H分析;利用多元统计、绝对因子分析-多元线性回归(APCS-MLR)受体模型探讨研究区8种重金属污染含量空间分布特征及来源,利用富集因子和地累积指数开展土壤污染评价。结果表明:(1)耕地土壤中重金属含量整体偏高。除Cr外,其他元素为郑州市土壤背景值的1.04~1.40倍,其中Cd的累积效应较明显。(2)研究区重金属高值区主要分布于荥阳市城区周边。(3)基于富集因子法、相关性分析、主成分分析及APCS-MLR源解析结果显示,研究区重金属主要有三个来源:自然源对Ni、As、Cu、Cr的贡献率分别为98%、94%、80%及63%;工业源对Cd的贡献率为78%;其他源则主要是农业化肥源、燃煤源的混合源,对Cr、Pb、Hg的贡献率分别为37%、35%及33%。(4)地累积指数表明,研究区各重金属以无污染为主,而Cd超标率最高,其中度、中-重度污染、重度污染样点数分别为19个、5个及3个,并存在1个极重度污染样点。综上,Cd在研究区耕地中富集较明显,为潜在的主要污染元素;工业源、自然源、农业化肥源及燃煤源是重金属的主要来源,表明人类活动已对研究区耕地产生影响,需采取措施避免该影响进一步加剧。 展开更多
关键词 耕地土壤重金属 来源解析 绝对因子分析-多元线性回归(APCS-MLR)受体模型 风险评价 荥阳
下载PDF
纸张抗张强度相关因素的数学统计分析方法
18
作者 杨艳琦 姚杰 《造纸科学与技术》 2024年第6期21-23,共3页
为实现对纸张抗张强度的自动化检测,提高纸张产品的生产质量和生产效率,对造纸企业实际生产数据实施标准化预处理,并通过灰色关联度算法对纸张抗张强度与其他因素之间的相关性进行分析。在此基础上,采用线性回归模型对灰色关联度算法进... 为实现对纸张抗张强度的自动化检测,提高纸张产品的生产质量和生产效率,对造纸企业实际生产数据实施标准化预处理,并通过灰色关联度算法对纸张抗张强度与其他因素之间的相关性进行分析。在此基础上,采用线性回归模型对灰色关联度算法进行求解。为验证该模型的有效性,通过拟合优度指标对模型进行验证,发现该模型相较于Xgboost-SVM、Lasso回归以及逐步回归等模型,体现出了更加理想的拟合效果。最终得到检测厚度、检测定量、喂料泵电流等15个与纸张抗张强度高度相关的影响因素,可用于指导现场工作人员对纸张抗张强度的合理化控制,具有一定的应用价值。 展开更多
关键词 制浆造纸工艺 影响因素分析 线性回归模型 相关度统计
下载PDF
胜利矿区煤炭粉尘污染时空变化特征
19
作者 霍江润 李晶 +2 位作者 王党朝 王科雯 闫萧萧 《煤炭学报》 EI CAS CSCD 北大核心 2024年第8期3522-3534,共13页
露天煤矿开采产生的煤炭粉尘对矿区及周边大气、植被、土壤和居住环境造成影响,但煤炭粉尘污染程度、污染范围量化及其长时序趋势变化等相关研究滞后。提出了煤炭粉尘最大影响范围和持续影响范围概念,基于Google Earth Engine平台和2006... 露天煤矿开采产生的煤炭粉尘对矿区及周边大气、植被、土壤和居住环境造成影响,但煤炭粉尘污染程度、污染范围量化及其长时序趋势变化等相关研究滞后。提出了煤炭粉尘最大影响范围和持续影响范围概念,基于Google Earth Engine平台和2006—2021年Landsat TM/ETM^(+)/OLI影像,反演增强型煤炭粉尘指数(Enhanced Coal Dust Index,ECDI)和煤炭粉尘污染程度,综合运用线性回归和叠置分析方法,揭示了胜利矿区开采过程中煤炭粉尘的时序变化及空间差异特征。结果表明:①煤炭粉尘污染年际变化可分为严重期(2006—2009年)、改善期(2010—2013年)和稳定期(2014—2021年),与开采生命周期基本一致,且随开采时间的推进呈现先强后减弱的变化趋势;②2019—2021年春季和夏季煤炭粉尘污染程度普遍偏高,季相变化在相对无污染区、轻度污染区和中度污染区相对明显;③煤炭粉尘持续影响范围的总体识别精度为92.67%(kappa系数为0.85),随着原煤产量的递增,常年持续和最大影响范围不断缩小,下降幅度分别为43%和80%,年内持续影响范围空间分布保持基本稳定,年内最大影响范围下降;④2006—2021年相对无污染区面积净增191.69 km^(2)(62.70%),严重污染区面积净减4.59 km^(2)(19.74%),煤炭粉尘污染程度呈下降、上升趋势的面积分别占矿区面积的52.11%和4.07%。2021年相对无污染区和轻度污染区面积达矿区总面积的91.91%(约601.13 km^(2))。 展开更多
关键词 Google Earth Engine 煤炭粉尘污染 时空变化 像元二分模型 线性回归分析
下载PDF
核泄漏事故风险评估中的概率分析及预测
20
作者 何博文 关群 《合肥工业大学学报(自然科学版)》 CAS 北大核心 2024年第2期161-168,共8页
文章利用逻辑回归模型(logistic regression model,LRM)、线性判别模型(linear discriminant model,LDM)和支持向量机(support vector machine,SVM)3种统计模型,从核反应堆的内部和外部因素2个方面评估其在核泄漏事故中所体现的相关安... 文章利用逻辑回归模型(logistic regression model,LRM)、线性判别模型(linear discriminant model,LDM)和支持向量机(support vector machine,SVM)3种统计模型,从核反应堆的内部和外部因素2个方面评估其在核泄漏事故中所体现的相关安全性能。针对每种模型,利用数理统计理论探究核反应堆相关影响因素与其发生核泄漏事故的概率。研究发现核反应堆外部因素有主导内部因素的趋势并在整个核泄漏事故风险中占有举足轻重的地位。文章提供的模型分析与预测结果可为核反应堆工程师及其相关决策者在核反应堆的选址、设计及建设运营等方面提供参考。 展开更多
关键词 核泄漏 风险评估 概率分析 逻辑回归模型(LRM) 线性判别模型(LDM) 支持向量机(SVM)
下载PDF
上一页 1 2 22 下一页 到第
使用帮助 返回顶部