共查询到20条相似文献，搜索用时 22 毫秒
1.
A statistical study of the dependence between various critical fusion temperatures of a certain kind ofcoal and its chemical components is carried out.As well as using classical dependence techniques(multiple,stepwise and PLS regression,principal components,canonical correlation,etc.)together withthe corresponding inference on the parameters of interest,non-parametric regression and bootstrapinference are also performed. 相似文献
2.
A new regression method for non-linear near-infrared spectroscopic data is proposed.The technique isbased on a model which is linear in the principal components and simple functions(squares and products)of them.Added variable plots are used to determine which squares and products to incorporate into themodel.The regression coefficients are estimated by a Stein estimate which shrinks towards the estimatedetermined by the first several principal components and the selected non-linear terms.The technique isnot computationally intensive and is appropriate for routine predictions of chemical concentrations.Themethod is tested on three data sets and in all cases gives more accurate predictions than does linearprincipal components regression. 相似文献
3.
SIJMEN DE JONG 《地理学报(英文版)》1993,(6)
PLS1 regression is generally viewed as lying in between PCR and OLS regression.Proof is given thatthe coefficient of determination,R~2,for a PLS multivariate calibration model is at least as high as thatfor a PCR model with the same number of components.It appears that PLS can be linked to acorrelation-weighted polynomial regression of a constant response on the eigenvalues of the covariancematrix of the predictor variables. 相似文献
4.
A partial susceptibility approach to analysing the magnetic properties of environmental materials: a case study 总被引：2，自引：0，他引：2
An approach to expressing the magnetic properties of environmental materials in terms of the contributions of the magnetic susceptibilities of specific magnetic components is reported. The approach links the partial susceptibilities of discrete particles, domains or mineral fractions with the concentration-dependent parameters by means of multiple linear regression methods. The case study, using the Liverpool street dust data set, demonstrates that the technique is able to model the contributions of the main magnetic components satisfactorily. Several factors may have a significant impact on the regression results. These include the validity of the linear proportional relationships between partial susceptibilities and the relevant concentration-dependent parameters, the adequacy of the variable selection procedure and the regression model, and the suitability of certain magnetic parameters. 相似文献
5.
QUADRATIC PLS REGRESSION 总被引：2，自引：0，他引：2
AGNAR HSKULDSSON 《地理学报(英文版)》1992,(6)
We treat here an extension of linear PLS regression to include regression on quadratic PLS components.The quadratic regression can be viewed as a natural extension of linear PLS regression to quadratic PLSaccording to the H-principle of mathematical modelling.The numerical implementation is treated indetail.It is shown that this approach can be used for models with large numbers of variables.Somemodelling strategies are discussed depending on the purpose of the modelling.Applications of thisapproach are treated. 相似文献
6.
傅氏变换在短序列确定海平面变化趋势中的应用 总被引：9，自引：0，他引：9
由一元线性回归分析的正则方程计算表明，在验潮记录较短的客观条件下，高尖扰动对确定海平面变化趋势的影响是显著的，其中影响最显著的高频带是ｆ≥０．０２０８ｃｐｍ，即对应周期Ｔ小于４年的高频扰动。要从短序列中确定海平面的变化趋势，必须消除周期泪地４年的高频扰动的影响。 相似文献
7.
Using the biogeocenoses of taiga geosystems as an example, we employed the method of correlation analysis and the technique
for analyzing the main components to demonstrate that a relative altitude is a complex indicator of serialness of landscape-level
geosystems, reflecting not only the particular geographical signatures but also a certain system of conjugation of the portions
of landscape and the force of spatial and typological connections that causes the concrete facies to deviate from zonal normal.
Complex indicators: the main components, and the correlation and regression coefficients, were used to reveal a functional
correlation of the sets of BGC attributes between themselves and with a relative altitude of the location. 相似文献
8.
Image analysis as a method to quantify sediment components 总被引：1，自引：0，他引：1
Varved lake sediments, with their annual to seasonal resolution, have a high potential for inferring past environmental and climatic conditions. To fully utilize the information present in varved records, high-resolution analyses, which often are time-consuming and difficult to perform, are desirable. The investigation reported here aims at (i) developing image analysis as a method for estimating annual accumulation rates of sediment components such as minerogenic matter, organic matter and biogenic silica, and (ii) assessing the relative importance of these components for changes in varve thickness. Image analysis was used to digitize the grey-scale variations and to measure the varve thickness of 540 varves (476-1015 AD) from Lake Kassjön in northern Sweden. From the 35 cm long digitized sediment sequence, 108 consecutive five-year samples were cut out quantitatively, and relationships between grey-scale variations and sediment dry mass and individual sediment components were assessed. There is a strong correlation between corrected grey-scale (i.e. the product of grey-scale and varve thickness) and the dry mass accumulation rate (r = 0.90, p < 0.001). With a stepwise multiple regression a significant model (R2 = 0.81) between corrected grey-scale and the accumulation rates of minerogenic matter (r = 0.90, p < 0.001) and biogenic silica (r 0.26, p < 0.012) was obtained. Considering the minor contribution and weak significance of biogenic silica, image analysis can be used as a fast and non-destructive method to infer past annual accumulation rates of dry mass and minerogenic matter in Kassibn. The model of the relationship between changes in varve thickness, and water content and accumulation rates of sediment components has little predictive power (R2 = 0.45). The result shows that the varve thickness in Kassjön, at least during the period 476-1015 AD, is not determined by a single sediment component but partly depends on interactions between the major sediment components. 相似文献
9.
Principal components analysis of fracture trace and sinkhole characteristics near 33 wells drawing water from the Ocala aquifer identified three hydrogeologically significant components. Multiple regression analysis using these components as independent variables showed that the flow of water to a well bore is influenced in order of importance by (1) proximity to a zone of high secondary permeability; (2) average aquifer transmissivity near the well; and (3) degree of cavity development in the closest zone of high secondary permeability. 相似文献
10.
景区依托型旅游村与核心景区耦合发展研究 总被引：3，自引：0，他引：3
旅游村作为新型乡村旅游地,是国家乡村旅游＂百千万工程＂中最基础的组成部分。从景区依托型旅游村的视角出发,选取黄山山岔村与黄山风景区作为案例地,运用多元回归分析方法,对两者之间耦合发展进行研究。结果显示：（1）黄山风景区发展大力提升了山岔村社会经济文化水平;（2）黄山风景区发展对村落环境影响较小;（3）黄山风景区发展对村落社区参与有影响,但并不显著。从景区与村落的发展特征出发,较为系统地揭示景区依托型旅游村与核心景区耦合发展的内在动力源于位差潜势、催化潜势、管理潜势和多稳定潜势,这些形成了景村耦合发展的演化机制。在此基础上,提出了景村耦合发展的4条途径。 相似文献
11.
《The Professional geographer》2013,65(4):324-328
Principal components analysis of fracture trace and sinkhole characteristics near 33 wells drawing water from the Ocala aquifer identified three hydrogeologically significant components. Multiple regression analysis using these components as independent variables showed that the flow of water to a well bore is influenced in order of importance by (1) proximity to a zone of high secondary permeability; (2) average aquifer transmissivity near the well; and (3) degree of cavity development in the closest zone of high secondary permeability. 相似文献
12.
珠江口伶仃洋海平面变化趋势研究 总被引：4，自引：2，他引：2
根据珠江口伶仃洋三灶,赤湾,香港三个站的验潮记录,应用傅氏变换方法对月均潮序列先做离散傅氏变换,并将周期小于４ａ的波动幅设为零,再进行反傅氏变换,以消除小于４ａ的周期波动对确定海平面变化趋势的影响,最后由低通序列一元线性回归分析确定穆江口各站的海平面变化趋势。 相似文献
13.
Yang Qingshu Luo Xianlin 《地理科学》1999,19(3):2
Tidal
gauge records are collected from three tidal stations in Lingdingyang Estuary. Fourier
transform and inverse fourier transform are used to eliminate the components that periods
are less than 4a from monthly mean time series. The secular trends of sea level are
determined by means of linear regression of low-passed time series. The empirical
orthogonal function (EOF) is used to analyse the spatial and temperal characteristics of
sea level change in Lingdingyang Estuary. The average rate of sea level change in
Lingdingyang Estuary, which is estimated by the time series of the main mode, is 0.89
mm/a. 相似文献
14.
Biomass equations for shrub species of Tamaulipan thornscrub of North-eastern Mexico 总被引：1，自引：0，他引：1
J. Nvar E. Mndez A. Njera J. Graciano V. Dale B. Parresol 《Journal of Arid Environments》2004,59(4):269
Nine additive allometric equations for computing above-ground, standing biomass were developed for the plant community and for each of 18 single species typical of the Tamaulipan thornscrub of north-eastern Mexico. Equations developed using additive procedures in seemingly unrelated linear regression provided statistical efficiency in total biomass estimates at the scales of both individual species and at the plant community. A single equation for each species improves efficiency in biomass estimates by 12.5% in contrast to using a single equation for the plant community. Therefore, additive equations developed in seemingly unrelated linear regression of parameter estimation are recommended to compute biomass components and total biomass for the species described. 相似文献
15.
青海湖环湖地区草地植被生物量遥感监测模型 总被引：57，自引：0，他引：57
利用青海湖环湖地区2000年陆地卫星TM遥感图像数据和同期野外实测的34处样方产草量数据,分析了遥感植被指数与草地植被生物量之间的相关关系,进而分别建立了遥感植被指数与草地植被生物量的一元线性回归模型和非线性回归模型。研究表明,遥感植被指数与草地生物量之间存在较好的相关性,但不同遥感植被指数与草地植被生物量相关性程度存在一定差别。此外,所建遥感植被指数与草地植被生物量的非线性回归模型在拟合精度上优于一元线性回归模型,且由三次方程得到的非线性回归模型最适用于监测青海湖环湖地区的草地植被生物量。 相似文献
16.
A. Müller 《Geophysical Journal International》2000,142(1):257-269
Error estimates from statistical regression analysis are often obviously too small, leading to doubts about the given equations, the statistical method itself and finally, with resignation, to the conclusion that mathematical equations and reality never agree. However, for magnetotelluric data we have found an almost perfect fit between observed scattering and predicted confidence limits of regression coefficients after accounting for a systematic error—the bias.
Different methods to compensate for bias in magnetotelluric impedance estimation have been described using additional data from a reference station. However, sufficiently accurate reference data are often not available. A new method has been developed that enables bias compensation without additional data. For the new method we derive a linear relationship between the effect of bias and an expression depending on the data fit. From this we extrapolate the solution for the unbiased impedance. The new method assumes a special model of uncorrelated noise as well as an approximation for the structure of the impedance tensor. From each pair of components of the unrotated impedance tensor corresponding to the same output channel, one of the pair can be compensated if its magnitude is large compared to that of the other.
The method has been successfully applied in many cases. We claim that the solution is closer to the true impedance than any solution based on the selection of events. It gives a measure of the partitioning of noise between the electric and magnetic channels.
We applied the method to measurements from the North Anatolian Fault Zone (Turkey) and from the Merapi volcano (Central Java) in the period range 10–2500 s. Different instrumentation was used for the two sets of measurements, but in both cases we used fluxgate magnetometers to measure the magnetic variations. 相似文献
Different methods to compensate for bias in magnetotelluric impedance estimation have been described using additional data from a reference station. However, sufficiently accurate reference data are often not available. A new method has been developed that enables bias compensation without additional data. For the new method we derive a linear relationship between the effect of bias and an expression depending on the data fit. From this we extrapolate the solution for the unbiased impedance. The new method assumes a special model of uncorrelated noise as well as an approximation for the structure of the impedance tensor. From each pair of components of the unrotated impedance tensor corresponding to the same output channel, one of the pair can be compensated if its magnitude is large compared to that of the other.
The method has been successfully applied in many cases. We claim that the solution is closer to the true impedance than any solution based on the selection of events. It gives a measure of the partitioning of noise between the electric and magnetic channels.
We applied the method to measurements from the North Anatolian Fault Zone (Turkey) and from the Merapi volcano (Central Java) in the period range 10–2500 s. Different instrumentation was used for the two sets of measurements, but in both cases we used fluxgate magnetometers to measure the magnetic variations. 相似文献
17.
Zhenhong Du Sensen Wu Mei-Po Kwan Chuanrong Zhang Feng Zhang Renyi Liu 《International journal of geographical information science》2018,32(10):1927-1947
Spatiotemporal kriging (STK) is recognized as a fundamental space-time prediction method in geo-statistics. Spatiotemporal regression kriging (STRK), which combines space-time regression with STK of the regression residuals, is widely used in various fields, due to its ability to take into account both the external covariate information and spatiotemporal autocorrelation in the sample data. To handle the spatiotemporal non-stationary relationship in the trend component of STRK, this paper extends conventional STRK to incorporate it with an improved geographically and temporally weighted regression (I-GTWR) model. A new geo-statistical model, named geographically and temporally weighted regression spatiotemporal kriging (GTWR-STK), is proposed based on the decomposition of deterministic trend and stochastic residual components. To assess the efficacy of our method, a case study of chlorophyll-a (Chl-a) prediction in the coastal areas of Zhejiang, China, for the years 2002 to 2015 was carried out. The results show that the presented method generated reliable results that outperform the GTWR, geographically and temporally weighted regression kriging (GTWR-K) and spatiotemporal ordinary kriging (STOK) models. In addition, employing the optimal spatiotemporal distance obtained by I-GTWR calibration to fit the spatiotemporal variograms of residual mapping is confirmed to be feasible, and it considerably simplifies the residual estimation of STK interpolation. 相似文献
18.
基于GIS的定位观测数据空间化 总被引：20，自引：3，他引：17
属性数据空间化是当前GIS领域的前沿问题之一。在对中国624个气象站多年平均气温数据空间化过程中,通过使用30秒分辨率的数字高程数据,把气温分解为受经纬度、海拔高度影响的规律性成分和受其它因素影响的非规律性成分两部分,并分别用多元回归和反距离权重内插方法对二者实施空间化,最后将空间化结果进行合成得到基于栅格的中国多年平均气温分布数据。该数据既能反映气温在空间上的宏观变化,又能反映气温在局部地区的微观变化。该方法可供其它类型观测数据空间化、特别是在观测站点稀疏的情况下参考和借鉴。 相似文献
19.
20.
基于环境设计预防犯罪理论（CPTED）和社会失序理论,利用2012年10―12月在广州门禁小区进行的大规模入户调查数据,采用多层次回归模型从社区内部环境角度对广州门禁小区家庭的入室盗窃受害情况及其发生的环境机理进行研究。通过5个多层次回归模型的对比分析发现：家庭被盗情况主要受到家庭的住房特征和人口特征的影响,小区变量对家庭变量有非常重要的调节作用。住房特征、公共空间使用率、家庭人口特征和小区的正式控制机构失效度对家庭是否被盗有着非常显著的影响;环境形象和人口流动性、小区开放度和功能混合度通过对家庭特征的间接影响而影响家庭的被盗情况。 相似文献