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971.
Cadastral Information System (CIS) is designed for the office automation of cadastral management. With the development of the market economics in China, cadastral management is facing many new problems. The most crucial one is the temporal problem in cadastral management. That is, CIS must consider both spatial data and temporal data. This paper reviews the situation of the current CIS and provides a method to manage the spatiotemporal data of CIS, and takes the CIS for Guangdong Province as an example to explain how to realize it in practice.  相似文献   
972.
Recent technical advances in remote sensing data capture and spatial resolution lead to a widening gap between increasing data availability on the one hand and insufficient methodology for semi-automated image data processing and interpretation on the other hand. At the interface of GIS and remote sensing, object-based image analysis methodologies are one possible approach to close this gap. With this, methods from either side are integrated to use both the capabilities of information extraction from image data and the power to perform spatial analysis on derived polygon data. However, dealing with image objects from various sources and in different scales implies combining data with inconsistent boundaries. A landscape interpretation support tool (LIST) is introduced which seeks to investigate and quantify spatial relationships among image objects stemming from different sources by using the concept of spatial coincidence. Moreover, considering different categories of object fate, LIST enables a change categorization for each polygon of a time series of classifications. The application of LIST is illustrated by two case-studies, using Landsat TM and ETM as well as CIR aerial photographs: the first showing how the tool is used to perform object quantification and change analysis; the latter demonstrating how superior aggregation capabilities of the human brain can be combined with the fine spatial segmentation and classification. Possible fields of application are identified and limitations of the approach are discussed.  相似文献   
973.
网站群可以实现分散资源的有效整合,代表了我国电子政务的发展趋势。由于缺乏统一规划,使得网站构建技术不同、信息格式不统一,导致网站群站点间信息难以共享,形成"信息孤岛"现象。为了提高网站群应用及管理水平,提出了一种基于元数据的技术架构,从数据层和业务层阐述了网站群信息共享解决方案,既满足系统扩展性的同时又有效解决信息整合与交互问题,实现了网站群站点间信息共享。  相似文献   
974.
Abstract

Flood frequency analysis based on a set of systematic data and a set of historical floods is applied to several Mediterranean catchments. After identification and collection of data on historical floods, several hydraulic models were constructed to account for geomorphological changes. Recent and historical rating curves were constructed and applied to reconstruct flood discharge series, together with their uncertainty. This uncertainty stems from two types of error: (a) random errors related to the water-level readings; and (b) systematic errors related to over- or under-estimation of the rating curve. A Bayesian frequency analysis is performed to take both sources of uncertainty into account. It is shown that the uncertainty affecting discharges should be carefully evaluated and taken into account in the flood frequency analysis, as it can increase the quantiles confidence interval. The quantiles are found to be consistent with those obtained with empirical methods, for two out of four of the catchments.

Citation Neppel, L., Renard, B., Lang, M., Ayral, P.-A., Coeur, D., Gaume, E., Jacob, N., Payrastre, O., Pobanz, K. & Vinet, F. (2010) Flood frequency analysis using historical data: accounting for random and systematic errors. Hydrol. Sci. J. 55(2), 192–208.  相似文献   
975.
实验使用hiTAIL-PCR(high-efficiency thermal asymmetric interlaced PCR,高效热不对称交错PCR)方法,从海单胞菌Marinomonas sp. BSi20584中克隆β-半乳糖苷酶基因。从GenBank注册的已知β-半乳糖苷酶氨基酸序列出发,设计引物克隆编码β-半乳糖苷酶保守片段的DAN序列;根据Marinomonas sp. BSi20584天然酶N端氨基酸残基测序结果,设计上游引物,保守DNA片段5’端设计下游引物,克隆N端到保守序列之间的DNA片段;将所得的2个DNA片段拼接并命名拼接后的片段为nbs。根据hiTAIL-PCR方法设计引物,染色体步移克隆nbs上下游片段,拼接上下游片段得到全长序列,设计引物扩增全长片段并测序。本文成功克隆了Marinomonas sp. BSi20584菌株β-半乳糖苷酶的编码基因,全长1 971 bp,NCBI比对表明其编码产物为GH-42家族的一个新成员。  相似文献   
976.
基于一种新颖的液体悬浮式长周期、超低频检测技术,避免电磁信号可能产生的一切干扰,由此研制地震前驱波检测装置及分析软件.提取前驱波信号与实际地震进行比对分析,结果表明,利用该装置及分析软件,对于记录前驱波和地震预测研究较以往有新的收获.  相似文献   
977.
A fiber-section model based Timoshenko beam element is proposed in this study that is founded on the nonlinear analysis of frame elements considering axial,flexural,and shear deformations.This model is achieved using a shear-bending interdependent formulation(SBIF).The shape function of the element is derived from the exact solution of the homogeneous form of the equilibrium equation for the Timoshenko deformation hypothesis.The proposed element is free from shear-locking.The sectional fiber model is constituted with a multi-axial plasticity material model,which is used to simulate the coupled shear-axial nonlinear behavior of each fiber.By imposing deformation compatibility conditions among the fibers,the sectional and elemental resisting forces are calculated.Since the SBIF shape functions are interactive with the shear-corrector factor for different shapes of sections,an iterative procedure is introduced in the nonlinear state determination of the proposed Timoshenko element.In addition,the proposed model tackles the geometric nonlinear problem by adopting a corotational coordinate transformation approach.The derivation procedure of the corotational algorithm of the SBIF Timoshenko element for nonlinear geometrical analysis is presented.Numerical examples confirm that the SBIF Timoshenko element with a fiber-section model has the same accuracy and robustness as the flexibility-based formulation.Finally,the SBIF Timoshenko element is extended and demonstratedin a three-dimensional numerical example.  相似文献   
978.
The Minqin Basin is at the lower reach of the Shiyang River of Gansu province in northwest China. Dramatic decline in groundwater level has resulted from over-abstraction of groundwater since the late 1950s to satisfy increasing irrigation and other demands. Severe water shortage led to environmental degradation. To better understand the spatial–temporal variation of groundwater levels and to evaluate the groundwater resources in the region, a three-dimensional regional groundwater flow model was built and calibrated under transient condition. The MODFLOW program was used and the research area was discretized as a square network with cell size of 400 × 400 m. The model showed that the aquifer was under destructive stress, with a groundwater resource deficit of 260 million cubic meters per year (Mm3/year) on average. Since the inflow of surface water from the upstream basin has declined to about 100–150 Mm3/year in recent decades, the irrigation return flow had become the main recharge and accounted for 60.6% of total recharge; meanwhile, abstraction by pumping wells took 99.2% from the total groundwater discharge.  相似文献   
979.
分析了山东省1:1万基础地理信息数据库更新现状,阐述了1:1万基础地理信息数据库及时更新的作业方法、主要更新内容、技术路线,提出了及时更新质量保证体系及质量控制方法,从基础资料的获取与收集,变化要素属性信息的分析确定,矢量要素采集、更新的精度,矢量要素采集的方向,矢量要素采集、更新的完整性,矢量要素采集、更新的现势性,属性项赋值的正确、完整性,更新后要素的逻辑一致性等几个方面,阐述了生产作业中需要注意的环节,分析了产生质量问题的原因,并结合实际工作经验,提出了保障产品质量的几点建议。  相似文献   
980.
社会生态系统(Social-ecological system,SES)是人与自然紧密联系的复杂适应系统,了解其组分、结构和成因是探究系统机理及规律的基础。选取高黎贡山东坡不同海拔的3个自然村,基于SPOT-5卫星影像和实地斑块调查结果,分析村域社会生态系统(Village SES,V-SES)景观组分构成;通过7个景观格局指数的计算结果,分析V-SES空间结构。在比较不同海拔V-SES景观组分和空间结构异同的基础上,结合自然环境参数和社会经济数据,分析导致V-SES差异的成因。结果显示:3个V-SES均为高度依赖于种植业的典型农耕社会生态系统,但其组分构成存在明显差异,低海拔的芒晃村系统组分最单一,而中海拔的芒岗村组分类型最丰富;其空间结构的差异则表现在景观形状复杂性、空间格局和景观连接性等方面,且均呈现出高海拔的汉龙村和中海拔的芒岗村位于两端、低海拔的芒晃居于二者之间的态势。导致V-SES差异的成因,既有气候条件和地形地貌等自然因素,也有人口压力、市场需求和外部政策等社会经济因素,还有系统内部人与自然交互作用的原因。  相似文献   
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