1st0pt在沉降预测中的应用研究   总被引：1，自引：1，他引：0  

吴清海 《测绘科学》2009,34(4)

预测方法有多种,找一种操作简单的方法较难。本文利用综合优化软件包1 st0pt,选用几种预测模型,通过对实测数据进行拟合,得出各种预测方法的计算模型,再利用最小二乘法原理,以预测绝对误差平方和最小为目标,给每种预测模型赋予不同的权重,组成规划方程,求出权重数列并组成新的预测模型,再对建筑物进行预测,将得到较好的预测结果。  相似文献   

一种非监督快速端元提取方法     

陈伟  余旭初  刘伟  杨国鹏 《测绘科学》2009,34(5)

正交子空间投影(OSP)方法广泛用于目标与背景的分离之中,对于高光谱影像,OSP可用于目标提取和混合像元分解,但缺点是需要端元的先验知识。针对这一问题,本文基于OSP的原理提出了一种非监督快速端元提取方法。实验使用模拟高光谱数据和由OM ISⅠ获取的真实高光谱数据,结果精度令人满意,证明了本文算法进行端元自动提取的可行性。  相似文献   

改进的单纯形法及其在非线性参数估计中的应用   总被引：3，自引：0，他引：3       下载免费PDF全文

李春风  许承权  蒲文利 《海洋测绘》2009,29(6):14-16

采用了改进的单纯形法,该算法利用遗传算法的变异操作来增强单纯形法的全局搜索能力,既兼顾了全局收敛性,又具有高效的局部搜索能力。并通过实例验证了该算法的优越性,以及应用于测量上的非线性最小二乘估计的可行性。  相似文献   

关于最小二乘问题近似解误差估计的进一步分析     

刘新国  张宏伟 《中国海洋大学学报(自然科学版)》2009,39(5)

Brezinski等人给出了最小二乘问题近似解的一族误差估计。该误差估计含有1个实参数。本文的贡献有3个方面:其一是给出了1种参数选择策略;其二是对该族误差估计的性质做出进一步分析;其三是分析了应用于Tikhonov正则化时应注意的一些问题。  相似文献   

Estimating sagebrush cover in semi-arid environments using Landsat Thematic Mapper data     

Ramesh Sivanpillai  Steven D. Prager  Thomas O. Storey 《International Journal of Applied Earth Observation and Geoinformation》2009

Sagebrush ecosystems of the western US provide important habitat for several ungulate and vertebrate species. As a consequence of energy development, these ecosystems in Wyoming have been subjected to a variety of anthropogenic disturbances. Land managers require methodology that will allow them to consistently catalog sagebrush ecosystems and evaluate potential impact of proposed anthropogenic activities. This study addresses the utility of remotely sensed and ancillary geospatial data to estimate sagebrush cover using ordinal logistic regression. We demonstrate statistically significant prediction of ordinal sagebrush cover categories using spectral (χ² = 113; p < 0.0001) and transformed indices (χ² = 117; p < 0.0001). Both Landsat spectral bands (c-value = 0.88) and transformed indices (c-value = 0.89) can distinguish sites with closed, moderate and open cover sagebrush cover categories from no cover. The techniques described in this study can be used for estimating categories of sagebrush cover in arid ecosystems.  相似文献   

半参数估计与LS估计的有效性比较   总被引：1，自引：1，他引：0  

吴友平  彭军还  鲁铁定 《测绘科学》2009,34(1)

建立半参数回归模型,将系统误差加入,推导出了模型正则化矩阵时参数平差的计算方法,并用直接法得到了参数、非参数的估计量,在MSE准则下与最小二乘估值(简称LS估值)进行比较,证明了半参数估值的有效性。  相似文献   

Comparing spatially varying coefficient models: a case study examining violent crime rates and their relationships to alcohol outlets and illegal drug arrests   总被引：3，自引：2，他引：1  

David C. Wheeler  Lance A. Waller 《Journal of Geographical Systems》2009,11(1):1-22

In this paper, we compare and contrast a Bayesian spatially varying coefficient process (SVCP) model with a geographically weighted regression (GWR) model for the estimation of the potentially spatially varying regression effects of alcohol outlets and illegal drug activity on violent crime in Houston, Texas. In addition, we focus on the inherent coefficient shrinkage properties of the Bayesian SVCP model as a way to address increased coefficient variance that follows from collinearity in GWR models. We outline the advantages of the Bayesian model in terms of reducing inflated coefficient variance, enhanced model flexibility, and more formal measuring of model uncertainty for prediction. We find spatially varying effects for alcohol outlets and drug violations, but the amount of variation depends on the type of model used. For the Bayesian model, this variation is controllable through the amount of prior influence placed on the variance of the coefficients. For example, the spatial pattern of coefficients is similar for the GWR and Bayesian models when a relatively large prior variance is used in the Bayesian model.   相似文献   

局部最优估计的参数求解方法   总被引：1，自引：1，他引：0  

李保平  蔡华  孙涛  王毅 《测绘信息与工程》2009,34(3)

结合了飞行器轨道拟合的实际问题,介绍了在约束条件下基于局部最优估计的参数求解,阐述了其经验和方法。  相似文献   

最短独立闭合环与附合路线的快速搜索方法     

游为  范东明  付淑娟 《测绘科学》2009,34(4)

提出了一种间接平差误差方程转化为条件平差条件方程的快速且易实现自动化的方法,同时采用矩阵分析理论,通过对条件方程进行特殊的矩阵分块及变换,自动搜索出水准网或GPS网的最短独立闭合环与附合路线,并自动解算出闭合差。上述方法有别于传统的图论理论,不依赖于任何信息文件,算法简单,自动化程度高。  相似文献   

半参数模型统计诊断与粗差检验(英文)     

丁士俊  张松林  姜卫平  王守春 《地球空间信息科学学报》2009,12(4):296-302

This paper systematically studies the statistical diagnosis and hypothesis testing for the semiparametric linear regression model according to the theories and methods of the statistical diagnosis and hypothesis testing for parametric regression model.Several diagnostic measures and the methods for gross error testing are derived.Especially,the global and local influence analysis of the gross error on the parameter X and the nonparameter s are discussed in detail;at the same time,the paper proves that the d...  相似文献