GPS RTK技术在城镇地籍二调中的应用

针对GPS RTK精度能否满足二调城镇地籍控制测量要求的问题,本文结合某镇二调地籍控制测量项目,利用以GPS RTK技术为主、全站仪技术为辅的方法来加密图根控制点,通过对RTK测量成果的内符合与外符合精度分析,实践证明GPS RTK技术应用于二调地籍图根控制测量可行。     

摄影测量与遥感学科发展现状与趋势

近年来,随着多种新型传感器和遥感平台的出现与成熟,遥感数据获取的能力得到了显著地增强,也为遥感数据的处理与应用带来了新的机遇与挑战。利用多传感器集成与各种影像、点云等数据之间的融合技术,能够有效地提高遥感数据的精度与可靠性,已成为摄影测量与遥感领域的重要发展趋势。本文分别从摄影测量和遥感两个方面对本领域的最新研究进展进行论述。其中摄影测量部分主要对各种新型传感器与平台的发展与应用进行探讨,其中包括：无人机系统、高分辨率遥感卫星、航空数码相机、机载与地面激光雷达系统以及移动测图系统,同时也对数字摄影测量处理平台、激光点云与光学影像的融合等技术进行深入分析。遥感部分则从基础物理与建模、合成孔径雷达、高光谱遥感、分类与变化检测算法等角度进行阐述。在文章的最后,对摄影测量与遥感整个学科的发展前景进行了展望。     

Electric load evaluation and forecast based on the elliptic orbit algorithmic model

Electric load forecast analysis has become increasingly important for the industry. Climate factors are the ones of key factors influencing the load demand. The sun is vital for attributing climate change as the earth is moving (revolution, rotation) in its elliptical orbit around the sun. The paper introduces an elliptic orbit algorithmic model for yearly and daily electric load movement analysis. In the proposed model, electric load movement as a time series is mapped to the polar coordinates to build the algorithmic model that the angular coordinate represents time, and the radial coordinate donates its corresponding electric load. The built model with its elliptical orbit is used for load movement analysis. The proposed approach is applied to yearly load movement evaluation and forecast for State Gird Corporation of China (SG) and its five branches in 2006, and daily load movement evaluation and forecast for one daily load of Shanghai Grid. The experiments yield results agreeing well with their actual loads. The results indicate workability of the proposed.     

信息化背景下提高《测量学》教学质量的几点思考

针对目前测量学教学中面临的一些问题，对新的技术背景下，如何提高测量学课程的教学质量提出了一些看法。     

利用卫星激光测高数据对星载SAR干涉测量DEM进行倾斜改正的研究

InSAR与ICEsat测高技术作为极具潜力的两项对地观测技术,各有其特点,利用卫星激光测高数据对星载SAR干涉测量DEM进行倾斜改正具有十分重要的意义,为提取无控制特殊困难地区大范围DEM提供了一种全新的方法。本文介绍了InSAR与ICEsat激光测高两种技术的特点及互补性;分析了利用ICEsat测高数据改正InSAR数据本身难以消除的误差的可行性;并以南极Grove山大范围DEM的提取为例,证实了其优越性。     

基于文化框架的随机粒子群优化算法

提出了随机粒子群优化算法(rPSO),并将其与标准PSO纳入到文化算法(CA)框架中,建立了基于文化框架的随机粒子群优化算法(CA-rPSO)。该算法以rPSO作为信念空间的进化算法,以PSO作为群体空间的进化算法,形成了两者独立并行进化的"双演化双促进"机制。选取5个测试函数进行了仿真实验分析并与其他算法进行了比较,结果表明CA-rPSO的寻优性能得到显著提高,且算法简单、易于实现。     

利用总体最小二乘估计AR模型参数及其在变形监测中的应用

本文在简单介绍ARMA（p,q）模型识别方法的基础上,推导了ARMA（p,q）模型向AR（p1）模型转换的方法。然后介绍了最小二乘法（LS）在AR模型参数估计中的应用,并指出了该方法的缺陷：在进行参数的估计时,只考虑了当期观测值的误差而并没有顾及系数矩阵的误差。在此基础上,将整体最小二乘（TLS）法引入到AR模型的参数求解中,详细介绍了TLS的解算方法。最后通过对具体工程实例的变形监测数据的分析,验证了采用了TLS法对AR模型参数估计及预报的可行性,并且比LS法具有更高的精度。     

Effect of chemical interaction on barenblatt crack profiles in brittle solids

A self-consistent solution for continuum-slit Barenblatt cracks with interactive chemistry is presented. Environmental species entering the crack mouth are limited in their transport along the ever-narrowing interface by molecular size restrictions. The ensuing cohesion zone behind the tip consists of three regions: an extended far region of weak solid-fluid-solid attraction; a small intermediate region of strong solid-fluid-solid repulsion; and an exclusionary near-tip intrinsic region of strong solid-solid attraction. To facilitate an analytical solution of the equations for the crack-opening displacements, the cohesion stresses are taken to be uniformly distributed within each of these zones. The magnitudes of these stresses are expressed in terms of the intersurface energies that define equilibrium crack states, for virgin and healed interfaces. Illustrative calculations of the crack profiles are given for the well-documented mica-water system. It is shown that the penetrating species cause a significant local bulge in the repulsion region, consistent with Thomson's picture of a molecular wedge.     

On the computation of integral properties of objects

This paper discusses computationally efficient methods for evaluating engineering properties of objects on computers. These methods use existing solid modeling techniques that lend themselves to mass property evaluations. An overall review of the quasidisjoint representation methods used for the approximate evaluation of integral properties of solid models is given. These methods of representation are typically used by analysis packages in the calculation of volume, surface area, center of gravity, mass, moment of inertia, etc. The methods are identical to approximate solid modeling techniques whose implementation involves the subdivision of space into subdomains. Finally, the method of cell decomposition is used for the determination of integral properties of solids modeled by a Constructive Solid Geometry (CSG) technique. The method suggested is very practical for microcomputer implementation. Sample numerical results are finally shown to compare the approximated results with the exact values.