参数带椭球约束平差算法的应用     

肖兆兵  宋迎春  谢雪梅 《大地测量与地球动力学》2018,38(9):964-967

针对实际工程应用中遇到的参数带有范围约束的情形,提出带椭球约束的平差算法,并给出其具体模型和解算步骤。数值模拟实验和病态测边网数据计算表明,在处理病态问题时,最小二乘平差（least-squares,LS）已不适用,而与岭估计、奇异值分解法（singular value decomposition,SVD）以及不等式约束相比,本文算法精度更高。  相似文献   

大獭蛤软体部营养成分的分析与评价   总被引：1，自引：0，他引：1  

潘英  秦小明  潘红平 《广东海洋大学学报》2007,27(3):78-81

对大獭蛤(Lutraria maxima)软体部进行营养成分分析,并对其营养价值进行综合评定。结果表明,大獭蛤软体部粗蛋白含量为81.20%,干物质中水解氨基酸总量为83.50%,其中必需氨基酸为30.22%,占氨基酸总量的36.19%;氨基酸中6种呈味氨基酸含量丰富,占氨基酸总量的53.81%;大獭蛤软体部第一限制氨基酸为亮氨酸;矿物质含量丰富。可见,大獭蛤软体部营养价值高,呈味特性良好。  相似文献   

海洋磁力测量中多站地磁日变改正基值归算   总被引：2，自引：0，他引：2       下载免费PDF全文

卞光浪  刘雁春  翟国君  边刚  于波 《海洋测绘》2009,29(6):5-8

海洋磁力测量多站日变改正时,为了减小磁场水平差异的影响,需要进行地磁日变基值归算。分析了地磁日变化时空分布特点,研究了地磁日变基值对多站地磁日变改正时磁测的影响,提出了多站地磁日变基值归算方法。经地磁日变同步观测数据验证表明：一定空间范围内,各站地磁日变数据日平均值基本上呈同步变化,利用此方法归算得到的分站地磁日变基值稳定。  相似文献   

Singular value decomposition and cluster analysis as regression diagnostics tools for geodetic applications     

Markus Vennebusch  Axel Nothnagel  Hansjörg Kutterer 《Journal of Geodesy》2009,83(9):877-891

It is well known that high-leverage observations significantly affect the estimation of parameters. In geodetic literature, mainly redundancy numbers are used for the detection of single high-leverage observations or of single redundant observations. In this paper a further objective method for the detection of groups of important and less important (and thus redundant) observations is developed. In addition, the parameters which are predominantly affected by these groups of observations are identified. This method thus complements other diagnostics tools, such as, e.g., multiple row diagnostics methods as described in statistical literature (see, e.g., Belsley et al. in Regression diagnostics: identifying influential data and sources of collinearity. Wiley, New York, 1980). The method proposed in this paper is based on geometric aspects of adjustment theory and uses the singular value decomposition of the design matrix of an adjustment problem together with cluster analysis methods for regression diagnostics. It can be applied to any geodetic adjustment problem and can be used for the detection of (groups of) observations that significantly affect the estimated parameters or that are of negligible impact. One of the advantages of the proposed method is the improvement of the reliability of observation plans and thus the reduction of the impact of individual observations (and outliers) on the estimated parameters. This is of particular importance for the very long baseline interferometry technique which serves as an application example of the regression diagnostics tool.  相似文献   

不规则边界场地中方格法土方工程量的计算   总被引：1，自引：0，他引：1  

郭红霞 《北京测绘》2009,(1)

结合方格法计算土方工程量的全过程,介绍了一种不同于传统教材的确定高程权的方法。采用该方法,比较好地解决了不规则边界场地采用方格法计算土方量的难题,对该方法的实际应用具有指导意义。  相似文献   

基于语义相似度的海量遥感图像可视化研究     

林艳  朱建军 《测绘科学》2009,34(6)

针对海量遥感图像如何有效的传达分类结果以实现有效的可视化问题,本文按照分类的语义标注结果的相似度并运用现有的信息可视化技术来实现图像的可视化。首先采用了贝叶斯网络学习的方法进行图像的自动分类标注,然后利用基于图像布局的多维标度算法(Multi-dimensional Scale)以及无需降维的Value and Relation(VaR)技术实现可视化。实验表明本文的方法能够填补图像低层视觉特征和高层语义之间鸿沟,对大量的图像在一个视图内进行有效的浏览,而不造成图像的混乱,并能实现高层次的图像分析。实验的可视化结果是十分有效的。  相似文献   

以生态-经济为导向的江苏省土地开发适宜性分区   总被引：11，自引：4，他引：7  

陈雯  孙伟  段学军  陈江龙 《地理科学》2007,27(3):312-317

随着城市化和工业化进程的加快,经济发达地区大量的农业及生态保护用地被侵占,开发可持续性受到威胁。从协调经济、人口、资源、环境相互关系出发,空间开发强调因地制宜,即让开发成本低、资源环境容量大的地区承担高强度的工业化和城市化等社会经济活动;而让生态价值高、开发难度大的区域承担农业和生态维护功能。土地开发适宜性分区,以生态-经济为导向,借鉴已有区划方法,采用要素层-关系层-逻辑层-应用层的技术路线,评价适宜各单元的开发强度,划分开发与保护空间。将这一方法运用于江苏省的案例研究之中,以县和省辖市市区为基本评价单元,通过选择自然生态与经济社会两方面的指标,综合分析生态和经济重要性指数,将江苏全省划分为优先开发区域、适度开发区域、适度保护区域、优先保护区域和灰色区域等五大类型区。这一结果可以作为引导空间开发秩序、实施区域建设空间管制的重要依据。  相似文献   

步云山自然保护区生态功能价值研究   总被引：4，自引：4，他引：0  

于航  董德明  陶磊  王宪恩  于连生  阎振元  孔令锦  于新 《地理科学》2007,27(4):593-596

以可持续发展为目标,以生态学原理为标准,通过对保护区涵养水量、森林价值以及生态足迹三方面的研究和计算,系统分析了步云山自然保护区的生态功能,指出保护区在规划过程中存在的问题,提出相应解决办法的依据。  相似文献   

基于遥感影像的城市森林分类提取及生态价值估算研究   总被引：2，自引：1，他引：1  

柳晶辉  邵芸  黄初冬 《地理与地理信息科学》2007,23(4):33-36

以北京通州新城区城市森林为研究对象,提出一种基于信息论的决策树分类方法,以提取Aster遥感影像中城市森林平面量,改善传统分类方法仅利用影像光谱特征信息的不足,高分辨率影像和地面调查数据验证显示其分类精度达84.6%.结合分类影像图,引入城市森林生态价值评估模型(CITYgreen模型)估算出通州新城区森林的生态价值约为598.87万美元.研究表明,该方法适合大面积区域的城市森林分类提取及其生态价值估算.  相似文献   

Stress‐dependent hardening and failure surfaces of dry sand     

W. Ehlers  O. Avci 《国际地质力学数值与分析法杂志》2013,37(8):787-809

During several triaxial compression experiments on plastic hardening, softening, and failure properties of dense sand specimens, it was found on various stress paths that the size of the failure surface was not constant. Instead, it changed depending on the current state of hydrostatic pressure. This finding is in contrast to the standard opinion consisting of the fact that the failure surface remains constant, once it has been reached during an experiment or in situ. In general, the behaviour of cohesionless granular‐material‐like sand is somehow characterised in between fluid and solid, where the solid behaviour results from the angle of internal friction and the confining pressure. Although the friction angle is an intrinsic material property, the confining pressure varies with the boundary conditions, thus defining different solid properties like plastic hardening, softening, and also failure. Based on our findings, it was the goal of the present contribution to introduce an improved setting for the plastic strain hardening and softening behaviour including the newly found yield properties at the limit state. For the identification of the material parameters, a complete triaxial experimental analysis of the tested sand is given. The overall elasto‐plasticity concept is validated by numerical computations of several laboratory foundation‐ and slope‐failure experiments. The performance of the proposed approach is compared with the standard concept of a constant failure surface, where the corresponding yield surfaces are understood as contours of equivalent plastic work or plastic strain. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献