石英Ti/Ge-P:基于机器学习的矿床类型判别新图解SCIEI北大核心CSCD

石英的微量元素记录了石英生长的物理化学条件。通过微量元素对石英原岩进行分类的研究历史已久,经典工作是在以微量元素为坐标轴的图解上绘制各类型石英的分布范围,以区分石英类型。经典图解包括Rusk(2012)提出用于区分三种矿床类型石英的Al-Ti二元图解,和Schr9n et al.(1988)提出的用于判别不同岩浆岩类型石英的Ti-Al-Ge三元图解。越来越多的研究表明,上述图解不能满足对更多石英类型进行分类的需求,同时也出现与部分已知产状类型的石英微量元素判别相矛盾的情况。随着石英原位微区测试方法的成熟,高精度石英微量元素数据逐渐丰富为系统开展机器学习提供了大数据基础,为石英微量元素研究提供了新的角度和可能性。本研究运用机器学习分类方法对石英微量元素进行精确数学分析,提出Ti/Ge-P图解为石英成因研究提出新的地球化学指标。本文同时测试了六种经典机器学习分类算法,提高Ti/Ge-P图解在石英成因分类研究上的精度。此Ti/Ge-P图解适用于多种矿床研究,包括但不局限于斑岩型矿床、矽卡岩型矿床、浅成低温热液型矿床、卡林型矿床以及造山型矿床中的石英。这项工作是大数据技术与机器学习技术在地球化学研究中的积极探索。     

一种基于MapGIS区明码文件的快速分类赋色方法

通过分析MapGIS区明码文件结构,提出一种利用Excel的VLOOKUP函数,批量修改明码文件区颜色参数,并结合VBA编程语言快速实现区块分类赋色的方法。文中方法能够较好地解决MapGIS拓扑重建随机赋色的问题,在一定程度上既简化了图件分类符号化的步骤,又保证了图形数据的正确性。     

云计算环境下空间索引构建研究

空间数据索引对于空间数据管理和分析具有重要作用,与数据处理速度和效率密切相关。随着人类社会进入大数据时代,遥感矢量数据具备了大数据的特点,传统的空间索引构建方法无法有效满足矢量大数据处理的需求,为此引入云计算环境来进行空间索引构建,目的是提高空间索引构建速度。首先,对常见的空间索引及现阶段云计算环境下基于MapReduce模型的空间数据管理进行了综述;然后以云计算环境下R树索引构建为例,对云计算环境下空间索引的构建进行了研究;最后,通过实验验证,证明了云计算环境下空间索引构建的速度与单机索引构建相比,加速比为28~40倍;在相同云环境下,网格索引构建速度最快,R+索引构建速度相对较慢。     

地形图分发格式转换及保密探讨

介绍了矢量地形图转换成栅格地形图的一般工作流程,阐述了利用Auto CAD图形处理软件和Adobe.Acrobat.Professional软件实现数据转换的快捷方法及具体步骤,还对地形图为什么要保密、如何解决地形图保密与实际应用之间的矛盾进行了阐述。     

两江新区东部区域地形图投影变形处理方法

两江新区东部区域位于重庆市独立坐标中东带结合部,无论采用重庆市独立坐标系中带还是东带,每千米边长高斯投影长度变形都在1．0～4．0 cm之间,超出规范规定。本文研究并确定控制两江新区投影变形的最终方案,建立了两江新区工程坐标系与重庆市独立坐标系的坐标转换关系,提出并编程实现了DXF格式地形图的坐标转换方法。     

鄂尔多斯盆地中—晚侏罗世构造事件的沉积响应

中—晚侏罗世是东亚大地构造发展的重要转折时期,鄂尔多斯盆地周缘构造带记录了强烈的陆内多向挤压变形,其发生的动力学背景与古太平洋、西伯利亚、特提斯同时向东亚大陆汇聚产生的远程效应有关。鄂尔多斯盆地侏罗纪沉积记录了该期构造事件的发生、发展过程:(1)自早侏罗世富县期至晚侏罗世芬芳河期,鄂尔多斯盆地岩相古地理演化经历了河流-冲积扇、湖泊-沼泽、河流-三角洲和冲积扇,中侏罗统直罗组底部砾岩发育时期为湖进序列向湖退序列转换的关键时期;(2)Qm-F-Lt图解中,中侏罗统延安组砂岩投点落入了稳定克拉通范围,中侏罗统直罗组和安定组的投点落入了石英再造山旋回范围内,预示着中侏罗世直罗期,鄂尔多斯盆地周缘构造活动性迅速增强;(3)中侏罗统安定组内部发育了一套全区可以稳定对比的泥晶碳酸盐岩,生物化石发育,该套泥晶碳酸盐岩上下地层的颜色由早期的灰绿色突变为紫红色,古盐度突然升高,预示着古气候环境突变,构造活动更为强烈;(4)根据盆地内热流体的记录及相邻区碎屑锆石年龄谱特征,中晚侏罗世构造事件发生的起始、强烈活动时限分别为168.0 Ma和161.0 Ma。     

脉冲耦合神经网络支持下的网络Voronoi图构建

针对网络Voronoi图中点与点之间通过实际路径距离而非传统欧式距离相连,在实际应用中较平面Voronoi图更加合理,该文提出了一种基于改进脉冲耦合神经网络的网络Voronoi图构建算法。借助模型的自动波发放及并行处理特性,较好地实现了基于路网的网络空间剖分,顾及了道路网及其点群自身属性对其服务范围的影响。实验表明,该算法实现了点群网络Voronoi图的构建,最短路径思想的引入使得构建的网络Voronoi图符合Voronoi图基本特征,可以用来表示点群的服务范围,不仅如此,算法的并行特性保证了算法的高效率。     

A model of submarine channel-levee evolution based on channel trajectories: Implications for stratigraphic architecture

Channel-levee systems are frequently interpreted as having a long history of cut-and-fill by channel-shaped features of different scales. Results from a simple geometric model based on a centerline migration algorithm combined with a vertical channel trajectory show that an incising-to-aggrading trajectory of a single channel can produce realistic morphologies similar to systems observed on the seafloor and subsurface, including features such as a basal erosional surface, coeval inner and outer levees, internal erosional boundaries, and terraces draped by inner levee deposits. Channel migration results in composite erosional surfaces that are distinct from topographic surfaces, and their formation does not require larger than usual erosional flows. Many submarine channels interpreted as underfit were probably carved by flows similar to the ones that eroded and deposited the entire channel system. We suggest that the features of most submarine channel-levee systems do not require large temporal variations in flow magnitude but can be explained by a simpler model whereby incision, migration and aggradation of a single channel form over time results in an apparently complex system.     

Numerical Simulation of a Torrential Rain Event in the Northeast of Huaihe Basin. Part I: Model Verification and Analysis of MCSs

A torrential rain event accompanying Typhoon Prapiroon occurred in 2000, with 24-h rainfall amount reaching 800mm near the typhoon center. This event is simulated by the nonhydrostatic mesoscale model ARPS (V5.2), with thriple one-way nested-grids. Grid spacings of 45, 15, and 5 km are chosen for the three nested domains. The corresponding grid sizes are 75×75, 140×140, and 180×180, respectively. The NCEP/NCAR reanalysis data, radar echoes, and GMS-5 satellite images are assimilated with the ARPS model initially using a 3-D data assimilation system--ADAS. The simple ice phase scheme and the Kain-Fritsch cumulus parameterization scheme are used. There are 35 layers in the vertical, with a vertical grid spacing of about 625 m. The integration is performed up to 48 h from 0800 BT 29 to 0800 BT 31 August 2000. Compared with radar echoes, GMS-5 satellite images, and intensive surface observations, the results show that the heavy rain area down between the 500-hPa trough and the subtropical high in the left-front of Prapiroon is well simulated by the model ARPS, and the simulated rainfall centers are consistent with observations. A comparison of the radar echoes with these retrieved from the simulated hydrometeors reveals that there are meso-β scale convective systems that exhibit distinctive characteristics, and there are four convective belts converging in the vicinity of Xiangshui, where the maximum rainfall is observed. A further comparision of skew T-lgp diagrams from simulated and observed data demonstrates significant instability in this torrential rain process. The persistent vertical wind shear provides kinetic energy for the development of the MCSs, hence promoting the baroclinic development of convective cells, and the concentration of heavy rain at the specific location. The consistency between model results and observations encourages a further study of the torrential rain event using the simulation data.     

基于ObjectARX的图形接口和数据提取方法

在对AutoCAD图形数据库的结构、组成进行分析的基础上,基于AutoCAD 2002绘图平台,运用VisualC++编译环境结合ObjectARX开发工具,研究了创建图形实体、设置图层、图线与线型比例等接口函数的方法,为CAD软件的开发奠定了基础;并结合DXF接口方法,实现了图形数据信息的自动提取,为图形的自动生成和空间分析提供基础数据。该成果已用于公路与铁路选线设计部门,极大地提高了设计效率,取得良好经济效益。