BOC调制信号多径误差分析

针对导航信号的多径误差分析,在多径误差包络曲线分析方法基础上提出了多径误差包络期望分析方法。与包络曲线分析方法相比,包络期望分析方法能够定量分析导航信号多径误差。基于包络期望分析方法,对同码速率的二进制偏移载波(BOC)调制导航信号与二进制相位控键(BPSK)调制导航信号的多径误差进行了对比分析。结果表明,BOC调制导航信号具有更小的典型多径误差。     

半参数模型统计诊断与粗差检验(英文)

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...     

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针对     

散乱数据插值的HASM方法

本文运用高精度曲面建模(HASM)方法,研究了空间散乱数据插值算法,并以陕西咸阳彬县大佛寺煤矿区的实测数据为案例,使用交叉统计检验方法比较分析HASM方法与地理信息系统(GIS)领域中常用传统插值方法的空间插值结果。结果表明,HASM方法具有较高的精度。本文还分析了传统常用插值方法的一些统计结果,得出一些结论,这些结论对于使用常用传统GIS空间插值方法的研究者有很好的参考作用。     

由ERS-1波形重构确定我国近海平均海平面

近海岸区域平均海面高在大地测量学、物理海洋学以及地球物理学研究中具有非常重要的意义.受各种条件的制约和限制,目前卫星测高技术主要应用于深海区域,在近海区域尤其是海岸线附近区域的应用几乎为空白.本文根据ERS-1测高卫星回波波形特征,采用五参数线性模型,由最小二乘拟合方法,对近海区域尤其是靠近海岸线附近的ERS-1测高波形数据进行波形重构.比较波形重构前、后解算平均海面高,表明波形重构技术不仅明显改善了解算近海海面高的精度,而且增加了近海测高海平面的分辨率,并使卫星测高有效观测延伸至海岸线附近.随后,本文利用波形重构后海面高数据构造了近海多年平均海平面,并对我国近海海平面特征进行了初步分析.     

全球化背景下的南京港城关联发展效应分析

运用灰色关联分析法,通过计算港城关联发展的均值关联度,对近10年南京港城关联发展效应进行了定量测度。研究结果表明:南京港城关联发展效应总体上比较显著,但具有明显的阶段性,其中: 1990年到1994年,港城关联发展效应呈弱化状态,1994年到1998年呈强化态势,1998年以后则呈现明显的弱化趋势。城市产业结构的变动、港口功能的演变、周围港口的激烈竞争以及港口管理体制和国际贸易的发展是导致上述动态特征的成因机制。     

面向多分辨率DEM的河网相似性测度与分析

河网是地形结构的核心要素,能够有效地反映DEM对地表形态的刻画能力.实现不同分辨率条件下DEM河网相似性测度对DEM地形综合、DEM质量评估及DEM不确定性分析等研究具有重要意义.基于此,本文以黄土高原典型样区为研究区,基于5 m高精度DEM建立的多分辨率DEM数据集,构建了地形特征自适应的DEM河网自动提取方法,建立...     

Explicit integration of a porosity‐dependent hydro‐mechanical model for unsaturated soils

An adaptive substepping explicit integration scheme is developed for a porosity‐dependent hydro‐mechanical model for unsaturated soils. The model is referred to as the modified σ –Θ model in this paper, which features the employment of the subloading surface plasticity and the stress–saturation approach. On numerical aspects, convex/nonconvex subloading surfaces in the σ –Θ space may result in incorrect loading–unloading decisions during the integration. A new loading–unloading decision method is developed here to solve the problem and then embedded into the explicit integration scheme for the modified σ –Θ model. In addition, to enhance the accuracy of the explicit integration, local errors from both hydraulic and mechanical components are included in the error control for each substep. A drift correction method is also developed to ensure the state point lies on the subloading surface in the σ –Θ space within a set error level. The performance of the loading–unloading decision method for the modified σ –Θ model is discussed through comparing it with the conventional loading–unloading decision method. The importance of involving the hydraulic component in the error control is also demonstrated. The accuracy and efficiency of the proposed adaptive substepping explicit integration scheme for the modified p–Θ model are also studied via several numerical examples. Copyright © 2016 John Wiley & Sons, Ltd.     

A generalized conditional intensity measure approach and holistic ground‐motion selection

A generalized conditional intensity measure (GCIM) approach is proposed for use in the holistic selection of ground motions for any form of seismic response analysis. The essence of the method is the construction of the multivariate distribution of any set of ground‐motion intensity measures conditioned on the occurrence of a specific ground‐motion intensity measure (commonly obtained from probabilistic seismic hazard analysis). The approach therefore allows any number of ground‐motion intensity measures identified as important in a particular seismic response problem to be considered. A holistic method of ground‐motion selection is also proposed based on the statistical comparison, for each intensity measure, of the empirical distribution of the ground‐motion suite with the ‘target’ GCIM distribution. A simple procedure to estimate the magnitude of potential bias in the results of seismic response analyses when the ground‐motion suite does not conform to the GCIM distribution is also demonstrated. The combination of these three features of the approach make it entirely holistic in that: any level of complexity in ground‐motion selection for any seismic response analysis can be exercised; users explicitly understand the simplifications made in the selected suite of ground motions; and an approximate estimate of any bias associated with such simplifications is obtained. Copyright © 2010 John Wiley & Sons, Ltd.     

原始数据误差对放样点精度影响的探讨

本文在文献[3]的基础上,进一步探讨了工程测量中原始数据误差对放样点精度影响的问题。首先,讨论了施工控制网中原始数据误差存在的形式、特点以及它们对放样点精度影响的传播规律,并建立了关于相对放样点位精度的矩阵公式。在此基础上,对现有的几种常用放样方法中原始数据误差的影响进行了分析和计算。结果表明,在施工放样测量工作中,应该密切注视原始数据误差的影响,并对此问题提出一些合理的建议。