南昌地震台数字水位与模拟水位观测对比研究

对南昌台数字水位与模拟水位的观测资料进行了对比研究。发现它们的动态变化是一致的。数据的相关性良好，虽然数字水位在记录连续水震波方面逊于模拟水位，但综合分析，数字化仪器的信息量大，快捷，优于模拟水位，完全可以取代模拟水位。     

数字观测仪器的防雷击设置

本文介绍了辽阳地震台对供电系统，信号电缆及通讯线路等设施防雷电结构的设置及效果。     

“数字油田”的理论与实践

石油天然气工业是我国的支柱能源产业 ,具有行业涉及专业多、建设投资大、研究主体是隐藏在地下巨大的流动矿资源、数据是第一财富等特点。石油天然气工业的信息化意义重大 ,该文结合作者的“数字油田”实践 ,给出了“数字油田”的理论技术、设计方法和实现路线     

论“数字城市”及其三维再现关键技术

“数字城市”是以计算机技术、多媒体技术和大规模存储技术为基础 ,以宽带网络为纽带 ,运用 3S技术、遥测、仿真—虚拟技术等对城市进行多分辨率、多尺度、多时空和多种类的三维描述。通过“数字城市”技术可以将现代城市的信息收集、整理、归纳起来 ,并按照地理坐标建立完整的空间数据模型 ,经过网络联结使每个人都能快速、完整、形象地了解城市的过去、现状和未来。目前国内外“数字城市”研究基本上是停留在软硬环境建设方面 ,至多处于研究的初期阶段 ,并没有在“数字城市”研究方面取得实质性的进展。本文主要探讨我国实现“数字城市”的关键技术 ,诸如 :数字城市空间基础设施、多种GIS系统集成模型研究、 3D GIS、三维城市规划、城市仿真与虚拟现实技术、数字城市支持下的数字社区等等。     

An algorithm to aid varve counting and measurement from thin-sections

An algorithm has been implemented to count and measure laminations from digital images of petrographic thin-sections. Boundaries and limits of laminations are first marked manually using imaging software. These marks are then exported to a workable format output file. Using the output file, the algorithm extracts the relevant information for lamination counts and thickness measurements along one or more parallel vertical lines. Compared to manual counts, the use of the algorithm improves the accuracy of measurements and speeds up the process. The method requires tools commonly available in most laboratories, i.e., a digital camera or a flat bed scanner with transparency capability and a desktop computer with 64 MB of RAM. From the algorithm, two utilities are implemented in Visual Basic for Applications and Fortran to be used on both Apple Macintosh and a PC-compatible, with Adobe^® Photoshop^®.     

自动赋初值的LSB-Snake模型的道路半自动提取方法研究

LSB-Snake模型是一个半自动提取线状地物的有效方法,但是在提取道路时需要人工输入道路特征（与背景相比道路的亮暗、宽度）作为初始值,在初始种子点稀少的时候不够稳健,且降低了LSB-Snake模型的效率。因此,本文提出了自动赋初值的LSB-Snake模型,采用自适应模板匹配方法为LSB-Snake模型提供初始特征,同时在初始种子点的基础上自动生成可靠、密集的点,共同作为LSB-Snake模型的种子点参与道路提取。对IKONOS和QuickBird进行道路提取的试验证明：在给定同样数目的初始种子点的情况下,提出的自动赋初值LSB-Snake模型比LSB-Snake模型更加稳健;由于无需人工输入道路特征,自动化程度更高;在道路附近地物阴影、遮挡较多的情况下,抗干扰能力更强。     

绝对值极小平差法的研究

在实际观测误差中,有时存在少量的粗差.此时,最小二乘法的平差结果往往会受到严重歪曲和影响,而绝对值极小平差法同最小二乘法相比较,有较好的抗粗差能力.本文主要介绍了绝对值极小平差法所采用的数学模型、解的不唯一性以及该方法在抗粗差能力方面同最小二乘法的比较结果.     

公路路基沉降灰色预测方法之探讨

根据公路路基沉降规律和GM(1,1)模型单调指数变化的特性,提出了对原始数列进行分析,合理选择GM(1,1)模型或灰色Verhulst模型。若原始数列处于快速沉降阶段,宜选用GM(1,1)模型;若原始数列处于沉降饱和阶段,宜选用灰色Verhulst模型,并用数学方法证明了灰色Verhulst模型的合理性。     

数字图书馆的公共性反思

本文在把握数字图书馆的基本特征前提下,运用公共性理论分析研究数字图书馆的公共性,通过分析数字图书馆的公共性特征及影响因素,发现许多非技术性的因素影响数字图书馆的进程,甚至违背了数字图书馆的服务宗旨,理想与现实之间存在着很大差距。     

Spatial distribution and geomorphology of lunette dunes on the High Plains of Western Kansas: implications for geoarchaeological and paleoenvironmental research

The High Plains are a vast, low relief landscape that contains thousands of upland-embedded depressional playa wetlands. Lunettes are isolated dunes that form from prolonged periods of aeolian deposition along the downwind margin of some larger playas. Playa-lunette systems are important landscape elements that have the potential to preserve high-resolution records of past environments, and several archeological sites have been associated with playa-lunette systems throughout the High Plains. While a comprehensive playa wetland geospatial database has been developed for the High Plains, lunettes have only been mapped for the Southern High Plains of Texas and New Mexico. The purpose of this research was to map and characterize the geomorphology of all lunettes associated with playas in the High Plains and bordering regions of western Kansas. Results indicate 129 lunettes are associated with 104 playas in Kansas. All lunettes are associated with playas larger than 5 ha, and about 10% of these larger playas have a lunette. Lunette height ranges from approximately 1.5–12 m, with a median height of 3 m. Most lunettes (60%) are in Finney, Gray, Lane, and Scott counties, which have broad, flat uplands with few major drainages upwind of playas and lunettes.