几种粗差估值方法的比较

基于均值漂移模型,重点讨论粗差估值的计算问题,给出了观测值统计相关时数据探测法(data snooping)的粗差估值公式。探讨数据探测法粗差估值与粗差的同时定位与定值法(LEGE)、拟准检定法(QUAD)、部分最小二乘法(PLS)的粗差估值之间的关系,证明当观测值统计相关时,部分最小二乘法和QUAD法在粗差估值的计算上具有等价性,与数据探测法和LEGE法都不一致。当观测值统计独立且不等权时,QUAD法、PLS法和数据探测法具有等价性,与LEGE法在粗差估值上不同;当观测值统计独立且等权时,4种方法在粗差估值计算上具有等价性。最后通过算例验证了结论。     

道路网多特征匹配优化算法

同名道路匹配技术是道路数据集成、更新和融合的重要前提。道路网匹配在智能交通(intelligent transportation system,ITS)与位置服务(location-based service,LBS)等方面具有重要的研究价值和应用意义。本文提出了一种道路网多特征匹配优化算法:首先从形状、距离、语义3方面分别设计了基于面积累积的形状差、综合中值Hausdorff距离和全局加权属性项距离3种相似性度量,以更准确地描述道路待匹配对之间的特征差异;然后通过SVM对相似性特征样本集训练,以构建道路网回归匹配模型;最后利用此模型对未知匹配结果道路待匹配对进行匹配结果预测。大量试验结果表明,本文算法对非线性偏差明显的道路网数据能够实现较高的匹配准确率和召回率,能有效地用于包含多重匹配关系的道路网匹配。     

PM2.5浓度插值中不同空间插值方法对比

针对不同插值方法对于重点大气颗粒物污染源PM_(2.5)大区域内整体分布情况的插值效果和精度存在差异性的问题,该文以石家庄市赵县100个点的PM_(2.5)的数据作为样本点,利用反距离权重法、普通克里格插值法和协同克里格插值法,分别进行PM_(2.5)浓度的空间插值。利用研究区内另外20个PM_(2.5)的数据点进行插值精度的检验。研究结果表明:协同克里格插值的精度最高,但可视化效果不如其他两种方法。     

波浪水槽中非线性浅水波传播特性与模拟

通过建立解析解、进行数值模拟和物理实验，研究了波浪水槽中非线性浅水波浪传播特性，给出了数值模拟中对应造波板做正弦运动的二阶入射边界条件。数值模拟采用高阶Boussinesq方程。实验结果、数值结果和解析解进行对比，并讨论了解析解的适用范围、高次谐波的产生及三波相互作用问题。     

Monthly Variation of Sea-Air Temperature Differences in the Korean Coast

Monthly variations of sensible heat, latent heat and momentum fluxes and the modification of sea temperature to air temperature were examined at four coastal stations—Sokcho, Kangnung, Ulsan and Chungmu in the path of the East Korea Warm Current from the year of 1981 to 1990, which was one of main migration routes of Japanese common squid. The difference between monthly averaged sea surface and air temperatures at the 10 m height above the sea surface mainly became negative values from April through August, while they had positive ones from September through March. Monthly variability of the temperature differences is significant in both summer and winter, while it is generally small in spring and fall. Negative values of sensible heat fluxes, which indicated a heat gain by the sea through heat conduction across the air-sea interface were found at the four coastal stations from April to August. Minimum values of sensible heat fluxes at Sokcho, Kangnung and Chungmu were in June, except for Ulsan in August. To the contrary, positive sensible heat flux implying a heat loss from sea toward atmosphere occurred from October to February with a maximum in December. Latent heat fluxes due to condensation of moist air over sea surface had small magnitudes from April to August and those due to evaporation of water particles from the sea surface into the lower atmosphere had relatively large magnitudes from October to March. Minimum values of latent heat fluxes also occurred in June except for August in Ulsan. Momentum flux was small from June to August under weak wind in summer, but it was large from December to February under strong wind in winter. Regression equations between sea surface temperature and air temperature at the 10 m height above the sea surface had very high correlation coefficients from 0.92-0.98, except for 0.78-0.84 of Ulsan, which was partially affected by upwelling of cool water from the bottom into the sea surface. Similar to the sea surface, correlation coefficients were over 0.83-0.97 except for 0.70-0.79 for Ulsan at the 10 m depth of sea and were over 0.70-0.95 except for 0.59-0.82 for Ulsan at the 20 m depth.     

Deep Penetration of Spudcan Foundation into Double Layered Soils

The spudcan foundation has been widely used in offshore engineering for jack-up figs. However, “punch through”failure often occurs where a stronger soil layer overlays a softer soil layer. In this study, spudcan penetration into double layered soils is investigated numerically. The soil profde is set up as a stronger soil layer overlaying a softer soil layer,with the soil strength ratio ( bottom soil strength / top soil strength) varied from 0.1 to 1.0 ( 1 means uniform soil). The bearing bohaviour is discussed and the beating capacity factors are given for various cases involving different layer thicknesses and different strength ratios of the two clay layers. The development of the plastic zones and the effect of soil selfweight on the beating capacity are also discussed. From this study, it is found that, when a spudcan is distant from the soil layer boundary, the spudean can be analysed with single soil layer data. However, when a spudcan becomes closer to the soil boundary layer, the influence of the lower soft soil layer is significant, and the beating capacity of the spudean decreases. The critical distance is an indication of the occurrence of “punch through” failure. The critical distance between the spudcan and the layer boundary is larger for a rough spudean than the one for a smooth one, and the critical distance decreases with increasing soil strength ratio. The depth of cavity formed during initial spudcan penetration depends on the top layer soil strength, soil strength ratio and unit soil self-weight, and the cavity affects the spudcan beating behaviour as well.     

切向流速探头简介

切向流速探测器是海洋湍流探测中基本的和必要的工具。该探测器可用压电陶瓷双金属片作其传感器。本文介绍了一种目前国际上常用的切向流速探头的结构、制作方法、工作原理、测定其灵敏度的装置、步骤以及在用回归法拟合实验曲线求灵敏度时所用的回归方程。文中还证明了多年来一些海洋学家所采用的拟合函数并非是最佳的。     

Wave reflection from vertical breakwater with porous structure

This paper presents numerical solutions for the wave reflection from submerged porous structures in front of the impermeable vertical breakwater. A new time-dependent mild-slope equation involves the parameters of the porous medium including the porosity, the friction factor and the inertia coefficient, etc. is derived for solving the boundary value problem. A comprehensive comparison between the present model and the existing analytical solution for the case of simple rectangular geometries of the submerged structure is performed first. Then, more complicated cases such as the inclined and trapezoidal submerged porous structures in front of the vertical breakwater with sloping bottom are considered. This study also examines the effects of the permeable properties and the geometric configurations of the porous structure to the wave reflection. It is found that the submerged porous structure with trapezoidal shape has more efficiency to reduce the wave reflection than that of triangular shape. The numerical results show that the minimum wave reflection is occurred when the breakwater is located at the intermediate water depth.     

测度链上微分方程的进展

综述测度链上微分方程理论的基本概念及其最新进展，包括作者的研究集体所做的工作，也提出一些值得进一步研究的课题。     

On hydraulic falls of two-layer flow

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