Probabilistic analysis of strip footings based on enhanced Kriging metamodeling

Two advanced Kriging metamodeling techniques were used to compute the failure probability of geotechnical structures involving spatially varying soil properties. These methods are based on a Kriging metamodel combined with a global sensitivity analysis that is called in literature Global Sensitivity Analysis-enhanced Surrogate (GSAS) modeling for reliability analysis. The GSAS methodology may be used in combination with either the Monte Carlo simulation (MCS) or importance sampling (IS) method. The resulting Kriging metamodeling techniques are called GSAS-MCS or GSAS-IS. The objective of these techniques is to reduce the number of calls of the mechanical model as compared with the classical Kriging-based metamodeling techniques (called AK-MCS and AK-IS) combining Kriging with MCS or IS. The soil uncertain parameters were assumed as non-Gaussian random fields. EOLE methodology was used to discretize these random fields. The mechanical models were based on numerical simulations. Some probabilistic numerical results are presented and discussed.     

Stochastic dynamic response of dam–reservoir–foundation systems to spatially varying earthquake ground motions

In this paper, stochastic dynamic responses of dam–reservoir–foundation systems subjected to spatially varying earthquake ground motions are investigated using the displacement-based fluid finite elements. For this purpose, variable-number-node two-dimensional (2D) fluid finite elements based on the Lagrangian approach is programmed in FORTRAN language and incorporated into a computer program SVEM, which is used for stochastic dynamic analysis of solid systems subjected to spatially varying earthquake ground motion. The spatially varying earthquake ground motion model includes incoherence, wave-passage and site-response effects. The incoherence effect is examined by considering the Harichandran and Vanmarcke coherency model. The effect of the wave passage is investigated by using various wave velocities. Homogeneous medium and firm soil types are selected for considering the site-response effect where the foundation supports are constructed. The Sar?yar concrete gravity dam, constructed in Turkey is selected for numerical example. The ground motion is described by filtered white noise and applied to each support point of the 2D finite element model of the dam–reservoir–foundation system. The record of Kocaeli earthquake in 1999 is used in the analyses. Displacements, stresses and hydrodynamic pressures occurring on the upstream face of the dam are calculated for four cases. It is concluded that spatially varying earthquake ground motions have important effects on the stochastic dynamic response of dam–reservoir–foundation systems.     

ArcGIS离线编辑在日常地籍变更中的应用

针对日常地籍变更频繁、零散、时限要求较高的特点,利用ArcGIS平台的版本机制,采用离线编辑的方式对地籍数据库的矢量图形数据更新进行设计,开发了适用于区、县级地籍数据日常变更的功能模块,提高了变更效率,很好地保障了地籍数据的现势性。     

地籍管理信息系统中空间信息更新的改进方法研究

空间信息的更新是地籍管理信息系统中一项重要内容。通过外业采集的宗地界址点的坐标,计算并检核实测界址点和计算机量测点之间的点位误差,更新增加的界址点信息,该更新方案具有操作简便,更新工作量小等优点,但更新后的点位精度低、更新后宗地面积与外业实测面积差值较大。针对该问题,本文提出了地籍空间信息更新的改进方案,合理采集外业数据,适当增加多余观测值,确定更为精确的坐标转换参数,在不改变原有工作模式的前提下,提高更新的界址点的点位精度,缩小计算机量取面积和实测宗地面积的差值。对于区域地块、零星地类的信息更新,改进方案是一种实用的更新方法。     

城乡一体化地籍管理信息系统建设及其成果应用研究

地籍工作是土地管理的基础,构建城乡一体化地籍管理制度是地籍管理工作的发展方向。本文在分析城乡一体化地籍管理数据模型的基础上,给出了城乡一体化地籍管理信息系统的架构设计和功能设计,并提出三维地籍管理信息系统的建设思路。在系统建设过程中,紧扣地籍成果的社会化应用,探讨了地籍成果为税务、法院、农业等部门提供共享和数据服务的方式。最后,提出以城乡一体化地籍管理信息系统为基础,融合房屋、草地、林地、海域等其他不动产登记信息,为推动建立不动产登记信息管理基础平台提供技术思路。     

LCR-G型重力仪仪器参数的时变特征

采用区域适定法对LCR－G型重力仪的仪器参数进行适时标定。对标定结果的分析表明：（1）区域适定法标定结果与基线标定结果精度相当；（2）重力仪的线性项参数呈现随时间的趋势性下降和非线性。采用区域适定解校正后的线性项参数处理区域重力网的观测资料，不仅能有效地削弱系统误差，而且可提高重力仪检测地震信息的能力。     

农村集体土地使用权地籍调查探讨

为了加强农村集体土地产权制度建设,深化农村土地利用制度改革,就要开展农村集体土地确权登记发证工作。地籍调查是农村集体土地使用权登记发证的基础工作,目的是运用先进的数字化技术,采取权属调查、地籍测量与数据入库等程序建立完善的地籍信息化管理制度,为农村集体土地使用权发证提供数字基础和技术支持。     

A space-time varying graph for modelling places and events in a network

Modelling topological relationships between places and events is challenging especially because these relationships are dynamic, and their evolutionary analysis relies on the explanatory power of representing their interactions across different temporal resolutions. In this paper, we introduce the Space-Time Varying Graph (STVG) based on the whole graph approach that combines directed and bipartite subgraphs with a time-tree for representing the complex interaction between places and events across time. We demonstrate how the proposed STVG can be exploited to identify and extract evolutionary patterns of traffic accidents using graph metrics, ad-hoc graph queries and clustering algorithms. The results reveal evolutionary patterns that uncover the places with high incidence of accidents over different time resolutions, reveal the main reasons why the traffic accidents have occurred, and disclose evolving communities of densely connected traffic accidents over time.     

基于时态GIS的地籍数据存储管理方法研究

面对现代地籍数据管理的需求,传统的静态GIS因其未考虑时间变化的因素而不能对地籍数据进行追根溯源的分析,而时态GIS可以很好的解决这一不足。文章对时态GIS进行了深入的研究,引入时空数据模型来管理地籍数据,并采用STER模型对数据库的设计进行了探讨。     

航空摄影测量在地籍测量中的应用研究

航空摄影测量技术应用于地籍测量中具有工艺流程自动化程度高、工作量大幅度减少、成图周期短、生产成本低、测绘成果精度好等特点,能够完成城乡大比例尺地籍测量任务,在现代城乡建设规划领域备受青睐。用航空摄影测量方法能否实测大比例尺地籍图,其界址点精度如何?针对这一问题,本文详细介绍了航空摄影测量技术应用于地籍测量中的理论与方法,对这种方法进行了探索与研究,并结合辽宁省兴城市用航测方法测绘地籍图的生产实际,认真研究了其中存在的问题。重点介绍了利用航空摄影测量技术进行地籍测量的作业流程,并针对工艺流程中的精度规范问题进行讨论研究,分析影响作业效率和作业精度的原因,最后对航空摄影测量技术在地籍中的应用进行总结,并提出设想,展望在城市中的发展。