共查询到20条相似文献，搜索用时 796 毫秒
1.
结合GIS(geographic information systems,地理信息系统)的空间数据处理能力,将潘家铮法从二维扩展到三维,提出一个基于栅格柱体单元的库岸滑坡滑速计算方法。建立了基于栅格柱体单元的三维滑坡滑速计算分析模型,给出了模型参数在GIS中的空间计算表达式。其次,通过对计算模型进行受力分析,结合牛顿运动定律,选取了沿滑体滑动方向和垂直方向来建立动力平衡方程,从而求解三维滑坡滑速。在GIS中开发出一个三维滑坡滑速计算扩展模块,并通过实例与潘家铮法所得结果进行对比。结果表明,该方法比潘家铮法计算的最大速度结果大15.2%,比启动加速度结果大32.8%,比达到最大速度的滑动时间短1 s。 相似文献
2.
3.
Computational power poses heavy limitations to the achievable problem size for Kriging. In separate research lines, Kriging algorithms based on FFT, the separability of certain covariance functions, and low-rank representations of covariance functions have been investigated, all three leading to drastic speedup factors. The current study combines these ideas, and so combines the individual speedup factors of all ideas. This way, we reduce the mathematics behind Kriging to a computational complexity of only $\mathcal{O}(dL^{*} \log L^{*})$ , where L ? is the number of points along the longest edge of the involved lattice of estimation points, and d is the physical dimensionality of the lattice. For separable (factorized) covariance functions, the results are exact, and nonseparable covariance functions can be approximated well through sums of separable components. Only outputting the final estimate as an explicit map causes computational costs of $\mathcal{O}(n)$ , where n is the number of estimation points. In illustrative numerical test cases, we achieve speedup factors up to 108 (eight orders of magnitude), and we can treat problem sizes of up to 15 trillion and two quadrillion estimation points for Kriging and spatial design, respectively, within seconds on a contemporary desktop computer. The current study assumes second-order stationarity and simple Kriging on a regular, equispaced lattice, without working with restricted neighborhoods. Extensions to many other cases are straightforward. 相似文献
4.
This paper describes an implementation of a highly scalable parallel computational facility with high speedup efficiency using relatively low-cost hardware, which consists of a cluster of desktop personal computers (PCs) connected via a 10-Gigabit Ethernet. Two-levels of parallelization were implemented. Communication between different PCs was achieved using message passing interface (MPI) protocol. Domain decomposition was automated and based on element numbering. Domain continuity was assured largely by re-numbering the elements using a “front squasher” code prior to decomposition. Within each PC, the shared memory parallelization was implemented using either the open-multiprocessing (OpenMP) or the MPI protocol. Analysis of three different problems with number of degrees-of-freedom ranging from about 129,000 to about 2,260,000 shows a speedup efficiency generally above 70%. Super-linear speedup was achieved in several of the cases examined in this study, with the hybrid MPI-OpenMP approach generally performing better compared to the pure MPI method for parallelization. The results demonstrate the feasibility of acquiring a parallel computing facility with relatively modest outlay that is within the reach of consulting or engineering offices. 相似文献
5.
Fadi Chaaban Hanan Darwishe Barbara Louche Yvonne Battiau-Queney Eric Masson Jamal El Khattabi Erick Carlier 《Environmental Earth Sciences》2012,65(1):183-193
The use of geographic information system (GIS) minimizes the effort and improves the efficiency of numerical models. The GIS
provides a platform for high capacity collection, management, manipulation, analysis, modeling and display of spatial data.
The conceptual model is created using GIS objects including points, arcs and polygons so that it can accurately represent
real world condition. According to the research problem, the geographical model is based on Hypergraph Based Data Structure
method, and a conceptual data model has been created from which a physical data model was elaborated in ArcGIS9.3 platform.
The groundwater modeling system (GMS) provides a powerful tool for hydrodynamics modeling and it is able to solve complex
problems such as the groundwater flow and seawater intrusion. The sand-dune system of Hardelot-Plage (North of France) suffers
from a lack of well-developed foredune. This problem is linked to the almost constant saturation of beach sand which is the
potential source of dune nourishment. In the south of Hardelot, the coastline is slowly, but constantly retreating. To remedy
this situation, a coupling between a GIS and GMS was adopted, in order to find the possible scenarios which could lower the
piezometric surface in the concerned area and allow dune nourishment again. The GMS used supports the Modflow-2000 code. A
direct approach to designing Modflow finite difference model is tedious and less intuitive, specifically for complex boundary
and initial conditions. Therefore, a Modflow model can be developed either using a grid or conceptual model approach. The
preparation of input data modeling is tedious and takes a long time. The model created in GMS was calibrated against the historical
and observed water level data for 1995–2006. Then a hydrodispersive model (MT3d code in GMS) was launched for evaluating sea-water
intrusion. The model was run to generate groundwater and salt concentration scenario during pumping tests. 相似文献
6.
图元重叠和压盖是GIS数据中经常遇到的现象,针对MAPGIS 6.x平台系统所提供的查询方式由于频繁地逐个图元提问,而不能满足用户快速查询的需要。这里首次提出了图元列表查询技术来解决叠盖图元的查询问题,并给出了它的实现流程,讨论了关键实现技巧。图元列表查询不仅可在列表中直观地列出用户指定位置处所有叠盖图元的基本信息,还可进一步详细查询各个图元的信息(属性信息、图形参数信息),查询快速、操作简便。最后用实例证明了该技术的实用性。 相似文献
7.
结合GIS（地理信息系统）的空间分析能力和滑动面正应力分布假定模型,建立了基于栅格单元的三维边坡极限平衡模型,提出了基于GIS的边坡稳定性计算方法。该方法首先建立了基于栅格柱体单元的三维边坡稳定性分析模型,给出了模型参数在GIS中的空间表达式;其次,在极限平衡条件下,推导出滑体在GIS中的3个力平衡方程式和1个力矩平衡方程式,形成了用于求解三维安全系数的方程组;最后,基于摩尔-库仑强度准则,以及滑动面正应力分布的假定,求解三维安全系数。同时利用COM（组件对象模型）技术开发出一个基于GIS的三维边坡稳定性分析扩展模块,该模块可实现复杂的算法计算以及多种组合荷载下的稳定性计算,并通过算例验证了该模块的正确性和便利性。 相似文献
8.
空间三维滑坡敏感性分区工具及其应用 总被引：1，自引：0，他引：1
对于滑坡敏感性分区目前有三种方法:定性法、统计法和基于岩土定量模型的确定性方法。定性法基于对滑坡敏感性或灾害评估的人为判断;统计法用一个来源于结合了权重因子的预测函数或指标;而确定性法,或者说是物理定量模型法以质量、能量和动量守恒定律为基础。二维确定性模型广泛用于土木工程设计,而无限边坡模型(一维)也用于滑坡灾害分区的确定性模型。文中提出了一个新的基于GIS(地理信息系统)的滑坡敏感性分区系统,这个系统可用于从复杂地形中确认可能的危险三维(3-D)滑坡体。所有与滑坡相关的空间数据(矢量或栅格数据)都被集成到这个系统中。通过把研究区域划分为边坡单元并假定初始滑动面是椭球的下半部分,并使用Monte Carlo随机搜索法,三维滑坡稳定性分析中的三维最危险滑面是三维安全系数最小的地方。使用近似方法假定有效凝聚力、有效摩擦角和三维安全系数服从正态分布,可以计算出滑坡失稳概率。3DSlopeGIS是一个计算机程序,它内嵌了GIS Developer kit(ArcObjects of ESRI)来实现GIS空间分析功能和有效的数据管理。应用此工具可以解决所有的三维边坡空间数据解问题。通过使用空间分析、数据管理和GIS的可视化功能来处理复杂的边坡数据,三维边坡稳定性问题很容易用一个友好的可视化图形界面来解决。将3DSlopeGIS系统应用到3个滑坡敏感性分区的实例中:第一个是一个城市规划项目,第二个是预测以往滑坡灾害对临近区域可能的影响,第三个则是沿着国家主干道的滑坡分区。基于足够次数的Monte Carlo模拟法,可以确认可能的最危险滑坡体。这在以往的传统边坡稳定性分析中是不可能的。 相似文献
9.
Prioritization of disaster risk was carried out for a community in Toronto, Canada. Geographic information systems (GIS) were used for spatial analysis, including spatial overlays and clipping for extracting spatial and attribute information related to people’s vulnerability, critical infrastructure and landuse. In order to determine disaster risk, the overall community vulnerability was evaluated by combining social, economic, physical and environmental vulnerabilities. This paper uses the propane explosion incident as the case in point to demonstrate the methodology and procedure used to evaluate risk using GIS techniques. City of Toronto spatial data have been integrated with the study area to gather landuse information, identify risk zones based on the propane storage facility location and evaluate risks. Statistics Canada 2006 census data have been used for area demographics and people’s social and economic status. Vulnerability indicators were determined based on the GIS-derived spatial and attribute data for the hazard and evacuation zones followed by a quantitative spatial risk estimation and ranking. The methodology of this study, based on the risk evaluation and prioritization conducted, can be applied to future decision making in effective landuse planning and the development of risk management strategies. 相似文献
10.
A new numerical method to solve the system of equations describing two phase flow in a Hele-Shaw cell is presented. It combines
a mixed finite element method, the method of subtraction of the singularity and a front tracking grid in a single computational
strategy. This choice of discretization techniques is well motivated by the difficulties present in the system of equations
and the physics of the problem. The new method was tested against analytical solutions and also by solving the Saffman–Taylor
viscous fingering problem for finite and infinite mobility ratios. In both cases convergence under mesh refinement is achieved
for the fingers developed from an initial sinusoidal interface. Finger splitting is observed for low values of the surface
tension and high mobility ratio. Different explanations, based in our results, are provided for this phenomenon.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
11.
网络在城市地理信息系统的构建过程中越来越重要, 信息资源正从单纯的自供自给的封闭模式发展成为内部数据加外部数据模式.在研究网格计算、空间元数据、开放网格服务体系及互操作等技术基础上, 利用Wrapper/ Mediator方法给出基于开放网格服务体系(open grid service architecture, OGSA) 城市空间信息共享技术的总体架构.该框架解决了多源系统间的互操作问题, 为城市地理信息系统建设中空间数据共享提供一种全新的理论指导. 相似文献
12.
在分析水生态空间基础理论的基础上,以东辽河流域为例,以GIS技术为关键的数据处理平台,分析了流域地表水生态空间的演化分异。东辽河流域单位流域面积河流系统所提供的水生态空间为204.08mm,是流域多年平均降水量的39.83%;流域多年平均次坡面水生态空间为97.35mm,是坡面系统生态需水的19.48%,是流域河流系统水生态空间的47.70%。流域河流系统水生态空间和坡面系统水生态空间均具有明显的地域分异特征;全流域水生态空间形成了以河渠网为中心的高值分布网和以湖库为中心的高值分布"岛"。 相似文献
13.
This paper addresses the problem of explicit fractured media modelling in an operational case. On one side, realistic fracture models are mainly used for research purposes in order to investigate better the flow behaviour impacted by the complex multi-scale fracture network. Often, a very fine grid and hence an increased computation time are needed. On the other hand, an operational fractured reservoir is still generally modelled using an implicit fracture media representation. The upscaled petrophysical properties and dual media are defined on a coarse grid to limit the computational time of dynamic simulation. The challenge of this work is to demonstrate that an explicit fracture modelling is not reserved only for the research domain, but can be applied to an operational case study. The static model is constructed using a multiple point statistics approach in order to represent complex interaction patterns of fractures and faults observed at the analogue outcrop. The dynamic behaviour is simulated based on this spatial fracture network representation. 相似文献
14.
结合国内水资源与环境管理信息系统的前沿及面临的问题,着重从系统目的分析、结构设计和功能实现三个方面来论述西南岩溶地区水资源信息系统的构建。系统数据库由空间数据库和属性数据库两大部分组成。系统的功能主要包括:数据更新修订功能、信息资料查询功能、空间分析功能和绘图打印功能。 相似文献
16.
从数字高程数据(DEM)中自动提取自然水系及汇水盆地,并在GIS平台中表示出来,是开展基于GIS的区域水资源勘查与评价研究工作的基础,具有重要的实际意义。这里提出了一种根据自然水系自动提取结果,圈定各级水系汇水盆地,并将其表示成GIS中矢量图形数据的算法。该算法包括以下四个进程:①以水流方向数据和自然水系的分级标识数据为依据,将同一级别每一条水系汇水盆地内的栅格自动识别出来;②根据不同水系汇水盆地栅格的标识数据,自动搜索汇水盆地的边界栅格;③确定不同水系汇水盆地的分界线,并计算分界线上各个节点的X-Y坐标;④建立不同水系汇水盆地空间实体的拓扑关系,生成GIS可以识别的矢量图形数据。用我国东天山地区的DEM数据进行了算法的试验研究,实验结果表明,该算法是可行的。 相似文献
17.
基于空间信息网格（SIG）的矿产资源评价 总被引：2，自引：0，他引：2
随着GIS的普及和深化,空间信息的大数据量、高复杂性和难共享的问题对其研究和应用提出了新的挑战.空间信息网格(Spatial Information Grid,SIG)作为创新性的网络空间信息基础设施和技术体系,为解决这些问题提供了新的契机.本文在给出SIG基本定义和基本特征的基础上,就如何实现基于SIG的矿产资源评价进行了有益的探索和实践,并取得了很好的效果,为矿产资源评价提供了新的方法和思路. 相似文献
18.
Development of a GIS-based monitoring and management system for underground coal mining safety 总被引：2，自引：0，他引：2
Seda alap Mahmut Onur Karsl&#x;olu Nuray Demirel 《International Journal of Coal Geology》2009,80(2):105-112
Coal mine safety is of paramount concern to mining industry. Mine accidents have various causes and consequences including catastrophic failure of mine, substantial economic losses and most notably loss of lives. Therefore, any initiative in mine monitoring is of vital importance for progressing safety surveillance and maintenance.This paper presents the development of a geographic information system (GIS)-based monitoring and management system for underground mine safety in three levels as constructive safety, surveillance and maintenance, and emergency. The developed model integrates the database design and management to the monitoring system implementation which encompasses query and analysis operations with the help of web and desktop applications. Interactive object-oriented graphical user interfaces (GUIs) were developed to visualize information about the entities gathered from the model and also to provide analysis operations based on the graphical representations and demonstrations using data tables and map objects.The research methodology essentially encompasses five main stages: (i) designing a conceptual database model; (ii) development of a logical model in terms of entity-relationship (ER) diagrams; (iii) development of a physical model based on physical constraints and requirements; (iv) development of GUIs and implementation of the developed model, analysis and queries; (v) verification and validation of the created model for Ömerler underground coal mine in Turkey. The proposed system is expected to be an efficient tool for improving and maintaining healthy standards in underground coal mines which can possibly be extended to a national GIS infrastructure. 相似文献
19.
北京市土壤污染预警系统的设计与开发 总被引：10，自引：0，他引：10
针对日益严重的土壤污染问题,必须采用快速高效的方法对污染进行现状分析和预测警报,GIS技术正是解决问题的好办法。依据ESRI公司地理信息系统软件ArcView GIS的原理和方法,以北京市地球化学和重金属元素分布数据为基础,设计开发了北京市土壤污染预警系统。对其结构和功能做了详细介绍,对数据库的建立、界面的设计以及和其他应用程序的结合等技术方法进行了分析和探索。该系统具备数据管理、查询、分析预测、制图制表等功能,界面友好、形象、方便、易于操作和维护。系统的建立为北京市土地使用、防治土壤污染提供高效、科学的 相似文献