检索结果-南通市图书馆

Comparison of the local pivotal method and systematic sampling for national forest inventories

Forest Ecosystems 2020年第4期7卷 716-732页

作者： Minna Räty Mikko Kuronen Mari Myllymäki Annika Kangas Kai Mäkisara Juha Heikkinen Natural Resources Institute Finland(Luke) PO Box 2FI-00791 HelsinkiFinland. Natural Resources Institute Finland(Luke) Yliopistokatu 6FI-80100 JoensuuFinland

Background:The local pivotal method(LPM)utilizing auxiliary data in sample selection has recently been proposed as a sampling method for national forest inventories(NFIs).Its performance compared to simple random sampling(SRS)and LPM with geographical coordinates has produced promising results in simulation *** this simulation study we compared all these sampling methods to systematic *** LPM samples were selected solely using the coordinates(LPMxy)or,in addition to that,auxiliary remote sensing-based forest variables(RS variables).We utilized field measurement data(NFI-field)and Multi-Source NFI(MS-NFI)maps as target data,and independent MS-NFI maps as auxiliary *** designs were compared using relative efficiency(RE);a ratio of mean squared errors of the reference sampling design against the studied *** a method in NFI also requires a proven estimator for the ***,three different variance estimators were evaluated against the empirical variance of replications:1)an estimator corresponding to SRS;2)a Grafström-Schelin estimator repurposed for LPM;and 3)a Matérn estimator applied in the Finnish NFI for systematic sampling ***:The LPMxy was nearly comparable with the systematic design for the most target *** REs of the LPM designs utilizing auxiliary data compared to the systematic design varied between 0.74–1.18,according to the studied target *** SRS estimator for variance was expectedly the most biased and conservative ***,the Grafström-Schelin estimator gave overestimates in the case of *** the RS variables were utilized as auxiliary data,the Grafström-Schelin estimates tended to underestimate the empirical *** systematic sampling the Matérn and Grafström-Schelin estimators performed for practical purposes ***:LPM optimized for a specific variable tended to be more efficient than systematic sampling,but all of the considered LPM designs were

关键词： auxiliary data Bias Local pivotal method Matérn estimator National forest inventory Sampling efficiency Simple random sampling Spatially balanced sampling Systematic sampling Variance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Optimality of Solution with Numerical Investigation for Coronavirus Epidemic Model

引用

Computers, Materials & Continua 2021年第5期67卷 1713-1728页

作者： Naveed Shahid Dumitru Baleanu Nauman Ahmed Tahira Sumbal Shaikh Ali Raza Muhammad Sajid Iqbal Muhammad Rafiq Muhammad Aziz-ur Rehman Department of Mathematics and Statistics The University of LahoreLahorePakistan Department of Mathematics University of Management and TechnologyLahorePakistan Department of Mathematics Cankaya UniversityBalgatAnkara06530Turkey Department of Medical Research China Medical University HospitalChina Medical UniversityTaichungTaiwanChina Institute of Space Sciences Magurele-BucharestRomania Department of Mathematics Lahore College for Women UniversityLahorePakistan Department of Mathematics National College of Business Administration and Economics LahorePakistan Department of Mathematics Faculty of SciencesUniversity of Central PunjabLahorePakistan

The novel coronavirus disease,coined as COVID-19,is a murderous and infectious disease initiated from Wuhan,*** killer disease has taken a large number of lives around the world and its dynamics could not be controlled so *** this article,the spatio-temporal compartmental epidemic model of the novel disease with advection and diffusion process is projected and *** counteract these types of diseases or restrict their spread,mankind depends upon mathematical modeling and medicine to reduce,alleviate,and anticipate the behavior of disease *** existence and uniqueness of the solution for the proposed system are ***,the solution to the considered system is made possible in a well-known functions *** this purpose,a Banach space of function is chosen and the solutions are optimized in the closed and convex subset of the *** essential explicit estimates for the solutions are investigated for the associated auxiliary *** numerical solution and its analysis are the crux of this ***,the consistency,stability,and positivity are the indispensable and core properties of the compartmental models that a numerical design must *** this end,a nonstandard finite difference numerical scheme is developed to find the numerical solutions which preserve the structural properties of the continuous *** M-matrix theory is applied to prove the positivity of the *** results for the consistency and stability of the design are also presented in this *** plausibility of the projected scheme is indicated by an appropriate *** simulations are also exhibited to conclude the results.

关键词： Spatio-temporal advection diffusion explicit estimates auxiliary data M-matrix

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Improved Prediction and Reduction of Sampling Density for Soil Salinity by Different Geostatistical Methods

引用

Agricultural Sciences in China 2007年第7期6卷 832-841页

作者： LI Yan SHI Zhou WU Ci-fang LI Hong-yi LI Feng Institute of Land Science and Property Management College of Southeast Land Management Zhejiang University Hangzhou 310029 P. R. China Institute of Agricultural Remote Sensing and Information Technology Application College of Environmental and Resource Sciencea Zhejiang University Hangzhou 310029 P.R. China Department of Environmental Engineering Zhejiang University Hangzhou 310029 P.R. China

The spatial estimation for soil properties was improved and sampling intensities also decreased in terms of incorporated auxiliary data. In this study, kriging and two interpolation methods were proven well to estimate auxiliary variables： cokriging and regression-kriging, and using the salinity data from the first two stages as auxiliary variables, the methods both improved the interpolation of soil salinity in coastal saline land. The prediction accuracy of the three methods was observed under different sampling density of the target variable by comparison with another group of 80 validation sample points, from which the root-mean-square error （RMSE） and correlation coefficient （r） between the predicted and measured values were calculated. The results showed, with the help of auxiliary data, whatever the sample size of the target variable may be, cokriging and regression-kriging performed better than ordinary kriging. Moreover, regression-kriging produced on average more accurate predictions than cokriging. Compared with the kriging results, cokriging improved the estimations by reducing RMSE from 23.3 to 29% and increasing r from 16.6 to 25.5%, regression-kriging improved the estimations by reducing RMSE from 25 to 41.5% and increasing r from 16.8 to 27.2%. Therefore, regression-kriging shows promise for improved prediction for soil salinity and reduction of soil sampling intensity considerably while maintaining high prediction accuracy. Moreover, in regression-kriging, the regression model can have any form, such as generalized linear models, non-linear models or tree-based models, which provide a possibility to include more ancillary variables.

关键词： auxiliary data prediction precision sampling density soil salinity kriging

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：