尺度参数的Lp估计与精度评定   总被引：3，自引：0，他引：3  

周世健  陈永奇  邓康伟 《测绘学报》1998,27(4):300-307

根据定位参数与尺度参数的联合Ｍ估计,导出了尺度参数的Ｌｐ估计;当ｐ＝２时,与最小二乘估计一致,观测数据服从正态分布时,为最优无偏估计;由于尺度参数Ｌｐ估计的影响函数为无界函数,估计不具抗差性,但把残差Ｗｉｎｓｏｒ化,作者得到了尺度参数的抗差Ｌｐ估计;依据定位参数的协方差阵,可进行Ｌｐ估计的精度评定。这些结果对于Ｌｐ估计的研究和应用具有一定的参考价值。  相似文献   

GIS叠置后同名线元的方差估计     

戴洪磊  徐泮林  卢秀山 《武汉大学学报(信息科学版)》1998,(1)

将等精度同名点元的方差估计结果扩展到非等精度情况,由此导出了叠置输出图中同名线元上任意点处任意方向的位差估计通用公式和线要素总长度的方差估计公式。  相似文献   

Robust Kalman filter for rank deficient observation models   总被引：14，自引：0，他引：14  

K. R. Koch  Y. Yang 《Journal of Geodesy》1998,72(7-8):436-441

A robust Kalman filter is derived for rank deficient observation models. The datum for the Kalman filter is introduced at the zero epoch by the choice of a generalized inverse. The robust filter is obtained by Bayesian statistics and by applying a robust M-estimate. Outliers are not only looked for in the observations but also in the updated parameters. The ability of the robust Kalman filter to detect outliers is demonstrated by an example. Received: 8 November 1996 / Accepted: 11 February 1998  相似文献   

Statistical estimation of corner frequency and its application to seismic event-identification     

G.R. Dargahi-Noubary 《Soil Dynamics and Earthquake Engineering》1998,17(5):297-309

A statistical method is proposed for estimation of the corner frequency. It is based on inference for a stochastic model whose short-term behavior resembles the established source time functions. Properties of the estimates are investigated and some numerical examples are presented. A discussion concerning earthquake–explosion discrimination and the way corner frequency can be related to the rate of zero-crossings is also included. The paper is concluded with some numerical examples.  相似文献   

江淮地震区的地震活动性研究   总被引：3，自引：0，他引：3  

王Zhen  刘红桂 《地震》1998,18(4):410-416

江淮地震区是以５－６级地震为主的中强地震活动区,其地震活动存在百年尺度和数十年尺准周期性,中强地震活动存在东移和逆时针迁移二种运动,１９９０年以来本区与华北及华南地区的交界带地震活跃。根据以上分析贝斯估计、地震复发的条件概率预测、下世纪初可能发生６级左右地震,位置估计在本区东部的南黄海海域,苏、皖交界也有发生中等以上地震的可能。  相似文献   

Earthquake damage and loss estimation with Geographic Information System   总被引：1，自引：0，他引：1  

YONG CHEN GE PING LI QI FU CHEN LING CHEN MIN FENG LI Center for Analysis  Prediction  China Seismological Bureau  Beijing  China 《地震学报(英文版)》1998,11(6):751-758

ＩｎｔｒｏｄｕｃｔｉｏｎＡｓｅｓｉｎｇｔｈｅｐｏｔｅｎｔｉａｌｅａｒｔｈｑｕａｋｅｄａｍａｇｅａｎｄｌｏｓｉｎａｒｅｇｉｏｎｉｓｉｍｐｏｒｔａｎｔｆｏｒｍａｎｙａｓｐｅｃｔｓ,ｓｕｃｈａｓｒｉｓｋｍｉｔｉｇａｔｉｏｎ,ｒｅｓｏｕｒｃｅｓａｌｏｃａｔ...  相似文献   

Kalman filtering in groundwater flow modelling: problems and prospects     

U. Eigbe  M. B. Beck  H. S. Wheater  F. Hirano 《Stochastic Environmental Research and Risk Assessment (SERRA)》1998,12(1):15-32

The popularity of applying filtering theory in the environmental and hydrological sciences passed its first climax in the 1970s. Like so many other new mathematical methods it was simply the fashion at the time. The study of groundwater systems was not immune to this fashion, but neither was it by any means a prominent area of application. The spatial-temporal characteristics of groundwater flow are customarily described by analytical or, more frequently, numerical, physics-based models. Consequently, the state-space representations associated with filtering must be of a high order, with an immediately apparent computational over-burden. And therein lies part of the reason for the but modest interest there has been in applying Kalman filtering to groundwater systems, as reviewed critically in this paper. Filtering theory may be used to address a variety of problems, such as: state estimation and reconstruction, parameter estimation (including the study of uncertainty and its propagation), combined state-parameter estimation, input estimation, estimation of the variance-covariance properties of stochastic disturbances, the design of observation networks, and the analysis of parameter identifiability. A large proportion of previous studies has dealt with the problem of parameter estimation in one form or another. This may well not remain the focus of attention in the future. Instead, filtering theory may find wider application in the context of data assimilation, that is, in reconstructing fields of flow and the migration of sub-surface contaminant plumes from relatively sparse observations. Received: October 27, 1997  相似文献   

Variogram Fitting by Generalized Least Squares Using an Explicit Formula for the Covariance Structure   总被引：4，自引：0，他引：4  

Marc G. Genton 《Mathematical Geology》1998,30(4):323-345

In the context of spatial statistics, the classical variogram estimator proposed by Matheron can be written as a quadratic form of the observations. If data are Gaussian with constant mean, then the correlation between the classical variogram estimator at two different lags is a function of the spatial design matrix and the variance matrix. When data are independent with unidimensional and regular support, an explicit formula for this correlation is available. The same is true for a multidimensional and regular support as can be shown by using Kronecker products of matrices. As variogram fitting is a crucial stage for correct spatial prediction, it is proposed to use a generalized least squares method with an explicit formula for the covariance structure (GLSE). A good approximation of the covariance structure is achieved by taking account of the explicit formula for the correlation in the independent situation. Simulations are carried out with several types of underlying variograms, as well as with outliers in the data. Results show that this technique (GLSE), combined with a robust estimator of the variogram, improves the fit significantly.  相似文献   

海洋初级生产力遥感与GIS评估模型研究   总被引：9，自引：1，他引：8  

李国胜  邵宇宾 《地理学报》1998,53(6):546-553

本文探讨了利用遥感和地理信息系统技术获取海洋初级生产力的基本原理和方法。根据表层海水叶绿素遥感信息反演模型。介绍了三种基于表层海水中叶绿素浓度的海洋初级生产力算法。根据这三种算法,利用ＧＩＳ建模技术,推导了具有空间特征的海洋初级生产力的ＧＩＳ理论估算模型,以及这种模型的求解方法。  相似文献   

氮类污染物在土壤中迁移转化规律试验研究   总被引：17，自引：2，他引：17       下载免费PDF全文

王超 《水科学进展》1997,8(2):176-182

在分析氮物质迁移过程的基础上,借助于土柱物理模型试验装置,试验研究了氮类污染物在土壤中迁移转化规律,得到了NH₄+-N、NO₃--N在土柱内的时空变化过程。在分析实测资料后,建立了考虑氮的迁移和转化的数学模型。根据实测资料和数学模型的数值解,运用最优化技术率定模型参数,参数验证结果与独立的实测值吻合良好。  相似文献