基于网络的煤田地质资料信息管理系统的设计与开发   总被引：1，自引：0，他引：1  

黄佩  曹代勇 《中国煤田地质》2007,19(1):78-80

煤田地质资料是地质信息资源的载体，传统的资料管理模式已不能满足当代数字化和信息化社会的发展需求。利用SqlServer数据库，在ASP．net技术的支持下，借助MapXtreme2004平台，建立了青海省煤田地质资料信息管理系统。该系统采用B／S结构，实现了煤田地质资料的属性和图形的联合查询，以及各种类型的资料在Web浏览器中查阅。  相似文献   

对建设水文数据仓库的初步研究     

章树安  吴礼福  艾萍 《水文》2007,27(1):17-21

本文根据目前对水文信息的应用需求,提出了建设水文数据仓库的必要性。对数据仓库及相关技术作了简要介绍,结合水文数据实际状况和应用主题,提出了建设水文数据仓库的数据组织、基本体系结构和建设步骤等相关内容。  相似文献   

数据挖掘技术在水文预报中的应用及水文预报发展趋势研究   总被引：2，自引：1，他引：2  

张弛  王本德  李伟 《水文》2007,27(2):74-77,85

数据挖掘作为知识发现过程中的重要步骤,是从大型数据库中提取未知的、有价值的和可操作性的关系、模式和趋势用于决策支持的过程。我国目前在防洪领域存在着大量水文数据,如何充分有效地利用各种智能算法对这些数据进行分析与挖掘,以形成相应的水文预报模型进行准确的水文预报是防洪决策支持系统完善和发展的重要方面。本文首先全面地介绍数据挖掘的功能分类及以数据挖掘为基础的水文预报体系,然后对数据挖掘技术在水文预报中的应用进行了探讨和研究。  相似文献   

直流激电测深二维反演的若干问题研究     

刘海飞  阮百尧  吕玉增 《物探与化探》2007,31(1):47-50,54

目前,激电数据的二维反演主要针对高密度激电数据,而对于常规的激电测深则很少涉及.据此,针对常规激电测深二维反演所涉及到的一些技术难点进行探讨.在正演过程中,根据实测数据实现有限元网格自动剖分,并采用双网格系统,用相邻节点电导率双线性连续进行有限元模拟,并对模拟的误差进行校正.在反演过程中,利用互换原理和Broyden的方法计算偏导数矩阵;采用与奇异值分解算法精度相当的共轭梯度算法求解偏导数矩阵方程.最后通过对模拟数据和实测数据进行反演试算,验证本计算方法是可行的.  相似文献   

International Association of Geoanalysts' Protocol for the Certification of Geological and Environmental Reference Materials: A Supplement     

Jean S. Kane  Philip J. Potts  Thomas Meisel  Michael Wiedenbeck 《Geostandards and Geoanalytical Research》2007,31(3):285-288

The International Association of Geoanalysts (IAG) published a protocol for the certification of reference materials in close accord with the International Organisation for Standardisation (ISO) guidelines (Kane et al. 2003). This article supplements that protocol, providing additional discussion of best approaches for pre-selecting laboratories for participation in certification projects. This discussion also makes a distinction between inter-laboratory certifications, where n = 15 is the general standard, and expert laboratory certifications, where a much smaller number of laboratories will be deemed qualified to provide data of the quality needed for certification.  相似文献   

Kriging Regionalized Positive Variables Revisited: Sample Space and Scale Considerations   总被引：1，自引：0，他引：1  

Raimon Tolosana-Delgado  Vera Pawlowsky-Glahn 《Mathematical Geology》2007,39(6):529-558

Frequently, regionalized positive variables are treated by preliminarily applying a logarithm, and kriging estimates are back-transformed using classical formulae for the expectation of a lognormal random variable. This practice has several problems (lack of robustness, non-optimal confidence intervals, etc.), particularly when estimating block averages. Therefore, many practitioners take exponentials of the kriging estimates, although the final estimations are deemed as non-optimal. Another approach arises when the nature of the sample space and the scale of the data are considered. Since these concepts can be suitably captured by an Euclidean space structure, we may define an optimal kriging estimator for positive variables, with all properties analogous to those of linear geostatistical techniques, even for the estimation of block averages. In this particular case, no assumption on preservation of lognormality is needed. From a practical point of view, the proposed method coincides with the median estimator and offers theoretical ground to this extended practice. Thus, existing software and routines remain fully applicable.  相似文献   

A Comparison between a Modified Counter Propagation Network and an Extended Self-Organizing Map in Remotely Sensed Data Classification     

Yongliang Chen  Micha I. Pazner  Wei Wu 《Mathematical Geology》2007,39(6):559-574

A modified counter propagation network model and an extended self-organizing map model have the same three-layer network architecture while employing slightly different learning rules. Their network architecture comprises an input layer, a Kohonen layer and an output layer. The neurons between two neighboring layers are fully connected and the neighboring neurons within the Kohonen layer also have neighborhood connections. The modified counter propagation network model employs the Kohonen algorithm to train the Kohonen layer while using the Widrow–Hoff rule to train the output layer. However, the extended self-organizing map model applies a modified Kohonen’s learning rule to train both the Kohonen layer and the output layer. This paper compares the performances of these two models in supervised classification of remotely sensed data. The training results show that compared to the extended self-organizing map model, the modified counter propagation model has faster learning speed but larger output errors. The classification results indicate that the extended self-organizing map model has a faster classification speed and a much higher classification precision than the modified counter propagation model.  相似文献   

遥感监测水质参数的方法概述     

王旭楠  陈圣波  吕航  谭瑶  乔小利 《吉林大学学报(地球科学版)》2007,(Z1)

介绍了内陆湖泊水质遥感监测的特点及遥感监测水质的机理;总结了国内外近年来用于内陆湖泊水质参数反演的3种常用方法:经验模型、半经验法和机理模型法,并分析了3种模型的优缺点;讨论了目前遥感在水质监测应用中存在的问题和未来该领域研究的重点。  相似文献   

UKF滤波算法在数据同化中的应用          下载免费PDF全文

黄春林  李新 《热带气象学报》2007,23(6):617-622

介绍了一种新的数据同化算法（UKF，Unscented Kalman Filter），该算法不需要计算伴随矩阵，就能够解决模式的非线性问题。以Lorenz系统为例，进行了数据同化的数值试验。结果表明：基于UKF的同化方案与背景场的初始值无关，它能有效地抑制状态变量误差的增长，同化结果精度高。  相似文献   

THE EFFECTS OF BOGUS TYPHOON AND OBSERVED OCEANIC DATA ON THE ABILITY OF T_(213)L_(31) TO PREDICT TC TRACK     

麻素红  王建捷  万丰 《热带气象学报(英文版)》2007,13(2):149-152

The abilities of typhoon (TC) track prediction by a medium-range forecast model T213L31 at National Meteorological Center are analyzed and its ability to improve its TC forecasts is discussed. The results show that about 57% of the TCs could be predicted by T213L31 but the initial position errors are large.The 43% area without the prediction of TC tracks is concentrated between 13°N and 20°N and east of 120°E and lack of conventional observation data is the main reason for the absence of TC prediction in this area.The adding of bogus TC could improve the ability of TC track prediction when there is no TC vortex in the analysis field, but could only have positive effects on the short-range TC track prediction when there is TC vortex in the T213L31 analysis field.  相似文献