A qualitative and quantitative evaluation of experimental model catchment evolution

Due to the geological time scales required for observation of catchment evolution, surrogates or analogues of field data are necessary to understand long‐term processes. To investigate long‐term catchment behaviour, two experimental model catchments that developed without rigid boundaries under controlled conditions are examined and a qualitative and quantitative analysis of their evolution is presented. Qualitatively, the experimental catchments have the visual appearance of field scale data. Observation demonstrates that changes in catchment shape and network form are conservative. Quantitative analysis suggests that the catchments reach an equilibrium form while a reduction in the channel network occurs. While the catchments are laboratory scale models, the results provide insights into field scale behaviour. Copyright © 2003 John Wiley & Sons, Ltd.     

东营城区高精度三维地震采集方法研究

根据东营城区内建筑物较多，环境干扰较大，地下构造复杂，断裂非常发育，目的层埋藏深，资料信噪比较低的特点，以地震老资料和钻井资料为基础，建立地震地质模型，利用射线追踪技术选取合适的观测系统参数。充分利用卫星数字地图，没计了灵活多变的观测系统，采用可控震源与炸药震源配合使用方法，及时对城区内地下面元的覆盖次数、方位角和炮检距的分布进行质量监控，利用现场处理系统对资料进行及时分析，提高了地震资料品质。所获得的东营城区高精度三维地震采集资料显示，其浅中层分辨率和中深层信噪比都有了明显改善，取得了良好的地质效果。     

The diurnal and seasonal characteristics of urban heat island variation in Beijing city and surrounding areas and impact factors based on remote sensing satellite data

Based on the land surface temperature (LST), the land cover classification map,vegetation coverage, and surface evapotranspiration derived from EOS-MODIS satellite data, and by the use of GIS spatial analytic technique and multivariate statistical analysis method, the urban heat island (UHI) spatial distribution of the diurnal and seasonal variabilities and its driving forces are studied in Beijing city and surrounding areas in 2001. The relationships among UHI distribution and landcover categories, topographic factor, vegetation greenness, and surface evapotranspiration are analyzed. The results indicate that: (i) The significant UHI occur in Beijing city areas in the four seasons due to high heat capacity and multi-reflection of compression building, as well as with special topographic features of its three sides surrounded by mountains,especially in the summer. The UHI spatial distribution is corresponding with the urban geometry structure profile. The LST difference is approximately 4-6℃ between Beijing city and suburb areas, comparatively is 8- 10℃ between Beijing city area and outer suburb area in northwestern regions. (ii) The UHI distribution and intensity in daytime are different from nighttime in Beijing city area, the nighttime UHI is obvious. However, in the daytime, the significant UHI mainly appears in the summer, the autumn takes second place, and the UHI in the winter and the spring seem not obvious. The surface evapotranspiration in suburb areas is larger than that in urban areas in the summer, and high latent heat exchange is evident, which leads to LST difference between city area and suburb area. (iii) The reflection of surface landcover categories is sensitive to the UHI, the correlation between vegetation greenness and UHI shows obviously negative.The scatterplot shows that there is the negative correlation between NDVI and LST (R2 = 0.6481).The results demonstrate that the vegetation greenness is an important factor for reducing the UHI,and large-scale construction of greenbelts can considerably reduce the UHI effect.     

林州市生态农业可持续发展浅论

生态农业是实施农业可持续发展的关键,文章用系统研究方法,从林州市生态农业可持续发展基础条件,现存问题入手,对生态农业可持续发展与对策进行了探讨。     

论数字城市工程及其技术体系

分析了数字城市的内涵,基于数字工程思想,总结了数字城市的工程结构与技术体系,进而阐述了数字城市的意义与建设策略。     

一种基于DCT变换的盲水印检测算法

提出了一种基于DCT变换的盲图像水印算法。实验表明,该算法对典型攻击具有较好的鲁棒性。     

矿山三维地质模型及数字化仿真

针对传统的地质建模中数据源的复杂性及工程、地质现象差异等困难,该文提出多元、多方法集成和多层次干预的建模思路,采用三维激光扫描技术构建矿山整体三维模型。依托ArcGIS桌面系统、GoCAD、Flac3D等软件模拟滑坡动态、岩层分布等信息。通过空间分析和数值模拟揭示其潜在信息和规律,有效地实现了数据库、三维模型、数值模拟的一致性,为数字矿山开发、建设提供一条新思路。     

基于云计算的智慧唐山时空信息平台数据库构建

随着云计算技术的不断发展,大数据与信息化时代的优势越来越突出,应用越来越广泛。时空信息平台作为智慧城市建设的重要内容,管理海量基础地理信息数据,是智慧城市建设的基础。因此,海量数据的管理成为时空信息平台设计的关键。以智慧唐山建设为例,结合云计算技术,探讨时空信息平台数据库的构建,针对云平台基础地理信息数据体系、云平台数据库体系架构以及云平台数据库管理系统等方面进行设计,明确基于云计算时空信息平台数据库建设内容,探讨适用于智慧城市建设的时空信息云平台解决方案。     

某数字城市实景影像数据采集方案设计

随着测绘科技、计算机及网络技术的飞速发展,完全基于4D数据构建的数字城市已不能适应信息时代对于属性信息"准、全、新"的要求。可量测立体影像和360°全景影像数据将原来地理信息数据由4D上升到5D,弥补了4D数据的缺憾。本文主要介绍了这两种数据外业采集和内业处理的方法和过程,对未来数字城市建设数据采集方法的改进有一定的参考价值。     

基于Skyline的三维数字城市建设项目的设计与研究

在分析数字城市建设现状及其存在的问题基础上,提出了三维数字城市建设项目的设计思想和技术路线,对系统的开发结构和系统功能模块设计进行了详细的描述,最后阐述了所涉及的关键技术、系统的应用情况和与国内外同类技术的综合比较。