GPS高程拟合的方式及可靠性分析

在范围不大的区域中，高程异常具有一定的几何相关性，GPS高程拟合就是利用这一原理，求解正常高。在解析法求解过程中，首先用最小二乘法确定拟合数学模型的系数，在此基础上计算出待测点的高程异常值。通过实例验证：GPS高程拟合的精度主要取决于GPS大地高的精度、重合点正常高的精度、重合点的分布及拟模型的选择。一般在重合点数量充足且分布均匀的情况下，GPS高程拟合的精度可达到四等水准网的精度要求。     

Monitoring of Over Cutting Area and Lubrication Distribution in a Large Slurry Pipe Jacking Operation

Slurry pipe jacking was firmly established as a special method for the non-disruptive construction of the underground pipelines of sewage systems. Pipe jacking, in its traditional form, has occasionally been used for short railways, roads, rivers, and other projects. Basically the system involves the pushing or thrusting of concrete pipes into the ground by a number of jacks. In slurry pipe jacking, during the pushing process, mud slurry and lubricant are injected into the face and the over cutting area that is between the concrete pipes and the surrounding soil. Next, the slurry fills voids and the soil stabilizes due to the created slurry cake around the pipes. Fillings also reduce the jacking force or thrust during operation. When the drivage and pushing processes are finished, a mortar injection into the over cutting area is carried out in order to maintain permanent stability of the surrounding soil and the over cutting area. Successful lubrication around the pipes is extremely important in a large diameter slurry pipe jacking operation. Control of lubrication and gaps between pipes and soil can prevent hazards such as surface settlement and increases in thrust. Also, to find voids around the pipes after the jacking process, in order to inject mortar for permanent stabilizing, an investigation around the pipes is necessary. To meet these aims, this paper is concerned with the utilization of known methods such as the GPR (Ground Penetrating Radar) system and borehole camera to maintain control of the over cutting area and lubricant distribution around the pipes during a site investigation. From this point of view, experiments were carried out during a tunnel construction using one of the largest cases of slurry pipe jacking in Fujisawa city, Japan. The advantages and disadvantages of each system were clarified during the tests.     

圆形标志中心子像素定位方法的研究与实现

采用回光反射材料制作圆形回光反射标志，经摄影后得到标志的“准二值影像”；对标志的椭圆影像进行亚像素边缘提取，经最小二乘椭圆拟合后得到标志中心的子像素级位置。试验表明，可以达到0．02像素的定位精度。     

台风活动对副热带高压位置和强度的影响

利用一个浅水模式，实施了6组时间积分为4－5个模式日的试验，研究了台风对副热带高压中心位置及强度的影响。结果表明：台风和副热带高压的相互作用可以使高压中心位置西移,强度增加。据此讨论了台风活动和西北地区东部干旱之间统计联系的可能机制。     

A non-linear stress-stiffness model for geomaterials at small to intermediate strains

A double exponential fitting model (DEFM) capable of expressing the non-linear stress-stiffness relationship of geomaterials has been proposed by Shibuya et al. (1997). The model comprises two material constants; the elastic stiffness at very small strains and the strength, together with other free parameters to determine the complete stress-stiffness relationship. In this paper, the capability of the original function used for DEFM in simulating the tangent stiffness-stress relationship of geomaterials is first discussed. Second, the methods for determining the free model parameters, as well as its conversion to obtain a stress-strain relationship are proposed. The applicability of DEFM to predicting non-linear stress-stiffness relationship is examined in detail in a total of forty-nine fitting cases of compression test data on sedimentary rock, artificial soft rock and soft clay. It is found that the DEFM is effective in expressing the non-linear stress-stiffness relationship of various kinds of geomaterials at small to intermediate strains, say less than 0.5%. The superiority of this model compared to other fitting models currently in use is also demonstrated in some of the fitting cases.     

Statistic forecast of typhoons going over the Chinese coasts

According to the measured data of typhoons going over the Chinese coasts in 1949-2002, a statistic relative equation showing the relation between the central atmospheric pressure of typhoons in a certain region at a certain period of time and their accumulation of frequency is established, and the concept of recurrence interval of typhoons is put forward, which is of actual significance for typhoon disaster reduction along the coastal area.     

地图投影的最小二乘二元多项式拟合的误差估计

探讨了在地图投影的最小二乘二元多项式拟合中参考点的分布对拟合误差的影响,提出了一种基于矩阵的秩亏的方法来判断参考点是否在指定次数的二元多项式空间的代数曲线上,并导出在极小范数最小二乘意义下的拟合多项式的误差估计式,公式表明拟合误差和参考点的最小二乘误差无关。     

印度洋春、夏季海温对西藏高原夏季降水的影响

利用NCEP提供的1950—1997年全球月平均海表面温度场资料，首先通过EOF分解得到不同季节印度洋海温场空间分布特征，并在此基础上使用合成分析、相关分析和SVD分解等多种方法讨论了印度洋前期和同期海温异常与西藏高原夏季降水变化的关系。寻找出影响高原夏季降水的关键海区，目的为高原夏季早涝预测提供参考依据。     

泰山顶部近地层风的方差与谱分析

风在速度与方向上的不稳定性可引发结构振动并可导致损坏。山顶风较少受局地作用影响, 流场较稳定，作为典型风况对山顶风湍流脉动情形进行的观测和分析，对于研究建筑结构风载振动情形有着重要意义。在不同风况下对泰山气象站近地层风的风速和风向进行了同时、逐秒测记，所得样本经检验符合正态分布。计算表明，风向样本方差显著大于风速样本方差。绘制了各风速、风向样本自、互谱密度曲线图。谱图显示诸样本具有红噪声序列特征，不同样本自、互谱密度曲线具有相近形状，而以风速自谱曲线吻合程度最好，谱密度曲线在周期为4秒及2秒处有峰值。此后的研究应结合记录仪器的改进增加采样频率，对周期为2秒以下谱曲线作进一步分析。     

关于O3层垂直剖面遥感的逆转曲线的数学拟合模式

逆转遥感是当前获得大气O₃层垂直剖面资料的重要方法之一，而逆转曲线的质量对遥感结果的精度至关重要．本文在最小二乘法的基础上，结合逆转曲线的特征，加以适当处理，建立了逆转曲线的拟合数学模式．其性能良好，对研究O₃层垂直剖面的长期演变趋势具有重要意义．