重力数据处理中几种断裂构造识别方法的组合应用

为了提高使用重力数据推断断裂构造的有效性,先以"田"字形小子域滤波法突出重力梯级带异常,再分别联合水平总梯度模、解析信号振幅及水平方向导数进行二次处理.通过理论模型试验,比较单方法及不同组合方法的处理效果,并将组合方法应用到金羊盆地实测重力数据的处理中,推断研究区的断裂构造格架.与地震剖面划分的断裂进行比对,证明了利用组合方法划分断裂构造的有效性.研究结果表明,已有断裂构造识别方法的组合应用能够更清晰地刻画地质体的边界,在应用重力数据推断断裂构造方面具有非常好的实用性.     

用GPS和VLBI数据检测固体地球的体积和形状变化

本文利用2003年GPS和VLBI组合的站坐标、站速度及它们的误差估计,采用Delaunay算法生成的三角形来逼近地形表面,研究了地球的表面积、体积及它们的变化趋势,并利用板块运动模型插值方法得到的全球分布均匀的台站对检测方法进行了检核.结果表明,实测的和插值后的数据给出的结论是一致的,即若以赤道为界,北半球在压缩,南半球在膨胀;若以0°～180°经线为界,东半球处于挤压变形中,西半球处于扩张变形中;若以90°～270°经线为界,包含太平洋的半球处于压缩状态,而包含大西洋的半球则处于扩张变形中.这种变形证明地球仍处于非对称变形中.根据GPS和VLBI组合的数据解算的体积变化率达到 -15937×1012?m3·a-1,相当于地球半径每年大约缩短3～4 mm,表明地球整体上处于压缩变形中.     

A simple experimental method to regain the mechanical behavior of naturally structured marine clays

Quantitative laboratory studies on the structural behavior of natural intact marine clays require a large number of identical natural samples leading to an expensive and challenging task. This study proposes a simple method to reconstruct an artificial structured marine clay as the state of its natural intact clay at both macro and micro levels. For this purpose, the Shanghai marine clay is selected and mixed with low cement contents (1–6%). The clay-cement slurry is mixed in a container with the ice-covered sides at a low temperature about 0 ± 2 °C to postpone the hydration reactions until consolidation began. The purpose of adding cement is to generate the inter-particle bonding and structure in reconstituted samples. Initially, the reconstituted samples are consolidated under the in situ stress of 98 kPa and then under the pre-consolidation pressure of 50 kPa. Mechanical characteristics such as compression index, yield stress, unconfined compression strength, shear strength ratio, and the stress paths from triaxial tests are compared with natural intact clay accordingly. Scanning electron microscope and mercury intrusion porosimetry analyses are also performed to analyze the microstructure of clays for comparison. Furthermore, the proposed method is also examined by using natural intact marine clays of different locations and characteristics.     

改进的参数统计机载雷达点云滤波方法

针对基于高程的偏度参数统计的LiDAR数据滤波对地形起伏城区滤波适应性不强的弱点,文章对该方法进行了改进,提出基于二次曲面高程残差的偏度参数统计法的LiDAR数据滤波。实验结果表明改进的方法不仅延续了参数统计法无需阈值的优势,而且对城区滤波更具适应性、合理性和稳定性,能够明显提高滤波精度。     

Experimentation of structured light and stereo vision for underwater 3D reconstruction

Current research on underwater 3D imaging methods is mainly addressing long range applications like seafloor mapping or surveys of archeological sites and shipwrecks. Recently, there is an increasing need for more accessible and precise close-range 3D acquisition technologies in some application fields like, for example, monitoring the growth of coral reefs or reconstructing underwater archaeological pieces that in most cases cannot be recovered from the seabed. This paper presents the first results of a research project that aims to investigate the possibility of using active optical techniques for the whole-field 3D reconstructions in an underwater environment. In this work we have tested an optical technique, frequently used for in air acquisition, based on the projection of structured lighting patterns acquired by a stereo vision system. We describe the experimental setup used for the underwater tests, which were conducted in a water tank with different turbidity conditions. The tests have evidenced that the quality of 3D reconstruction is acceptable even with high turbidity values, despite the heavy presence of scattering and absorption effects.     

Fast algorithm for maneuvering target detection in SAR imagery based on gridding and fusion of texture features

Designing detection algorithms with high efficiency for Synthetic Aperture Radar(SAR) imagery is essential for the operator SAR Automatic Target Recognition(ATR) system.This work abandons the detection strategy of visiting every pixel in SAR imagery as done in many traditional detection algorithms,and introduces the gridding and fusion idea of different texture fea-tures to realize fast target detection.It first grids the original SAR imagery,yielding a set of grids to be classified into clutter grids and target grids,and then calculates the texture features in each grid.By fusing the calculation results,the target grids containing potential maneuvering targets are determined.The dual threshold segmentation technique is imposed on target grids to obtain the regions of interest.The fused texture features,including local statistics features and Gray-Level Co-occurrence Matrix(GLCM),are investigated.The efficiency and superiority of our proposed algorithm were tested and verified by comparing with existing fast de-tection algorithms using real SAR data.The results obtained from the experiments indicate the promising practical application val-ue of our study.     

菲涅耳体地震层析成像分辨率研究

层析成像分辨率的研究,不仅可以帮助分析层析方法的反演能力,评价层析反演的效果,还可以帮助指导层析参数设置,优化观测系统设计等.本文对比研究了前人提出的两种菲涅耳体层析成像分辨率的计算方法,并针对其存在的问题进行了优化.文中通过对二维理论模型的定量计算,总结了菲涅耳体地震层析成像分辨率的一些规律,并将其与射线层析的分辨率...     

Structuring decision-making for ecosystem-based management

Ecosystem-based management (EBM) has been widely accepted as the new paradigm to manage marine ecosystems. Although various efforts have been made to define key components, guidelines, and principles, in support of its implementation, there is still a gap between theory and practice. To implement EBM, managers require a decision-making framework in which the values of constituents, objectives and performance measures are consistent and used to evaluate and choose between alternatives. Structured decision-making (SDM) is a systematic approach that can contribute to develop this framework for EBM. SDM was used for the on-going EBM process on the west coast of Vancouver Island, British Columbia, Canada. This case study provides insights into how SDM can be implemented for EBM, as well as some challenges and opportunities encountered during the process.     

Google Earth在道路工程前期规划设计中的应用研究

Google Earth数据具备免费、直观、时效性强等特点,在道路工程设计中具有巨大的应用前景。本文以乌拉泊饮水源保护工程吐乌大高速公路段项目为例,提取项目区Google Earth最新卫星影像图和高程点数据,通过ArcGIS地统计学工具和Sufer克里金差值法进行项目区前期设计分析,获得最优路线和蓄水池的设置点,从而使前期项目设计节约劳动时间,降低劳动强度,提高工作效率。具有较强的实用性和可操作性。     

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