共查询到20条相似文献，搜索用时 705 毫秒
1.
AlexanderVKsendzuk 《地球空间信息科学学报》2002,5(1):22-27
This paper describes the stochastic model of the scattered electromagnetic field.Unlike common-used functional-determined models the proposed is characterised by amplitude/phase fluctuation of the received signal. This paper derives the statistical characteristic of the input signal and describes algorithm for its estimation in post-processing and real-time processing modes.Achieved characteristics allow the mapping and estimation of the surface models more accurate,moreover,such processing increase space resolution of synthetic aperture radar. 相似文献
2.
In this paper,the structure of systematic and random errors in marine survey net are discussed in detail and the adjustment method for observations of marine survey net is studied,in which the rank-defect haracteristic is discovered first up to now.On the basis of the survey-line systematic error model,the formulae of the rank-defect adjustment model are deduced according to modern adjustment theory.An examle of calculations with really observed data is carried out to demonstrate the efficiency of this adjustment model.Moreover,it is proved that the semi-systematic error correction method used at present in marine gravimetry in China is a special case of the adjustment model presented in this paper. 相似文献
3.
Optimization of land use structure consists of economic and social and ecological optimization.Applying the minds of system engineering and principles of ecology,this paper presents such thoughts:the optimal forest-coverage rate calculated according to the reality of a district is set as main standard of ecological rationality in the district;through considering the value of ecosystem services of the land with GREEN equivalent(mainly cultivated land and grassland)and based on the rule GREEN equivalent,this paper introduces the area conversion between woodland and cultivated land ,also between woodland and grassland;this paper establishes a multi-dimension controlling model of optimization of land use structure,In addition,a multiobjective linear programming model for optimization of land use structure is designed.In the end,this paper tests and verifies this theory of ecological optimization,taking Qionghai city in Hainan Province as an example. 相似文献
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This paper aims at multiscale representation of urban GIS,presenting a model to dynamically generalize the building on the basis of Delaunay triangulation model.Considering the constraints of position accuracy,statistical area balance and orthogonal characteristics in building cluster generalization,this paper gives a progressive algorithm of building cluster aggregation,including conflict detection (where),object(who) displacement,and geometrical combination operation(how).The algorithm has been realized in an interactive generalization system and some experiment illustrations are provided. 相似文献
5.
YU Zhiwen 《地球空间信息科学学报》2003,6(1):62-65
This paper puts forward a new conception:model warebouse,analyzes the reason why model warehouse appears and introduces the characteristics and architecture of model warehouse.last,this paper points out that model warehouse is an important part of WebGIS. 相似文献
6.
A distributed hypermap model for internet gis 总被引：4，自引：0，他引：4
The rapid development of Internet technology makes it possible to integrate GIS with the Internet,forming Internet GIS.Internet GIS is based on a distributed client/server architecture and TCP/IP & IIOP.When constructing and designing Internet GIS,we face the problem of how to express information units of Internet GIS.In order to solve this problem,this paper presents a distributed hypermap model for Internet GIS.This model provides a solution to organize and manage Internet GIS information units.It also illustrates relations between two information units and in an internal information unit both on clients and servers.On the basis of this model,the paper contributes to the expressions of hypermap relations and hypermap operations.The usage of this model is shown in the implementation of a prototype system. 相似文献
7.
ZHANGJin GONGJianya 《地球空间信息科学学报》2002,5(1):37-43
This paper discusses the features and relevant theories of GIS spatial data model based on hypergraph,etc.The integrated concept model based on hypergraph and object-oriented model(HOOM) is proposed by the authors.The principal contribution of this paper is that we study the K-section and other theories of hypergraph.An application example using HOOM is given at the end of the paper. 相似文献
8.
WUXiaofang CAIZhongliang WUGuofeng DUQingyun 《地球空间信息科学学报》2003,6(4):27-31
Through analyzing the principle of data sharing in the database system, this paper discusses the principle and method for integrating and sharing GIS data by data engine, introduces a way to achieve the high integration and sharing of GIS data on the basis of VCT in VC , and provides the method for uniting VCT into RDBMS in order to implement a spatial database with object-oriented data model. 相似文献
9.
ZHU XinyanGONG JianyaZHANG XiaodongXIONG Hanjiang ZHU Xinyan Professor National Laboratory for Information Engineering in Surveying Mapping Remote Sensing WTUSM Luoyu Road Wuhan China 《地球空间信息科学学报》1999,2(1):49-54
Spatial data, including geometrical data, attribute data, image data and DEM data, are huge in volume and relations among them are complex. How to effectively organize and manage those data is an important problem in GIS. Several problems about space data organization and management in GeoStar which is a basic GIS software made in China are discussed in this paper. The paper emphasizes on object model of spatial vector, data organization, data management and how to realize the goal, and the like. 相似文献
10.
On the basis of simplification of the Planck function in a low temperature range, this paper revises the practical split-window algorithm and presents a method for retrieving snow surface temperature （Ts） based on MODIS data in the middle-latitude region. The application of this method in Qinghai Lake region reveals that it is feasible for the retrieval of Ts. Results of correlation analysis indicate that there was strong negative relationship between Ts and altitude. By analyzing three typical areas in which land cover was relatively homogenous, this paper discusses the relationship between Ts and normalized difference snow index （NDSI） and then presents a new concept named ＂NDSI-Ts space＂. 相似文献
11.
This paper investigates the mathematic features of non-linear models and discusses the processing way of non-linear factors which contributes to the non-linearity of a non-linear model. On the basis of the error definition, this paper puts forward a new adjustment criterion, SGPE. Last, this paper investigates the solution of a non-linear regression model in the non-linear model space and makes the comparison between the estimated values in non-linear model space and those in linear model space. 相似文献
12.
非线性半参数模型在GPS系统误差处理中的应用 总被引：7，自引：1，他引：6
本文总结了当前测量界对系统误差的处理方法,提出了用非线性半参数核估计来处理GPS双差定位中系统误差的方法,即用非线性半参数模型中的非参数分量表达双差模型中残余的系统误差。最后通过算例检验了此方法对于提取GPS双差定位中残余的系统误差的有效性。 相似文献
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The non-linear 2D symmetric helmert transformation : An exact non-linear least-squares solution 总被引：1，自引：1，他引：0
Peter J. G. Teunissen 《Journal of Geodesy》1988,62(1):1-16
In this paper a particular class of non-linear least-squares problems for which it is possible to take advantage of the special
structure of the non-linear model, is discussed. The non-linear models are of the ruled-type (Teunisson, 1985a). The proposed solution strategy is applied to the2D non-linear Symmetric Helmert transformation which is defined in the paper. An exact non-linear least-squares solution, using
a rotational invariant covariance structure is given. 相似文献
16.
Manfred M. Fischer 《Journal of Geographical Systems》2002,4(3):287-299
In this paper we view learning as an unconstrained non-linear minimization problem in which the objective function is defined
by the negative log-likelihood function and the search space by the parameter space of an origin constrained product unit
neural spatial interaction model. We consider Alopex based global search, as opposed to local search based upon backpropagation
of gradient descents, each in combination with the bootstrapping pairs approach to solve the maximum likelihood learning problem.
Interregional telecommunication traffic flow data from Austria are used as test bed for comparing the performance of the two
learning procedures. The study illustrates the superiority of Alopex based global search, measured in terms of Kullback and
Leibler's information criterion.
Received: December 2001 / Accepted: August 2002
The author gratefully thanks Martin Reismann (Department of Economic Geography & Geoinformatics) for his valuable research
assistance. 相似文献
17.
YAO Yibin 《地球空间信息科学学报》2007,10(4):240-244
With the daily SINEX files of the IGS, the time series of IGS stations are obtained using an independently developed software under generalized network adjustment models with coordinate patterns. From ... 相似文献
18.
T. Saito 《Journal of Geodesy》1973,47(4):367-395
In this paper the author constructs general algorithms for the non-linear least squares of condition equations and shows the
procedure of their application for the settlement of the problem of unfavorable condition equations in the adjustment of a
quadrilateral. 相似文献
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随机变量非线性变换统计性质的高精度逼近算法 总被引：1，自引：0，他引：1
应用扩展卡尔曼滤波对非线性系统进行状态估计时 ,要对系统的动力方程进行线性化 ,这就为状态的估计带来一定的误差。本文首先对非线性变换的函数进行级数展开 ,获得了随机变量经非线性变换后的真实均值和协方差表达式 ,并得到一阶线性化的均值和协方差 ,然后提出了一种精度更高的变换算法用以逼近非线性变换后的真实均值和协方差 ,理论分析和数值试验都表明新算法不仅具有更高的精度 ,而且更容易实现 相似文献