燃气管网地理信息系统的应用

GIS以数据库方式管理系统,将图形数据和属性数据统一进行存储、处理和分析。建立为燃气管网维护、规划、管线设计、管道施工和竣工资料、抢修决策及相关属性数据查询的空间信息库,使用者可以方便地进行查询统计、运行调度及档案管理。介绍了燃气管网GIS系统组成、功能及应用情况,同时介绍了GIS建设及运行过程中应该注意的事项。     

给水管网中细菌总数快速预测模型的建立与应用

对选定实际给水管网的水质进行了长期监测,研究了水质与细菌总数的相关关系,分析确定了与细菌总数相关性较高且易于测定的水温、自由余氯、总余氯、浊度及UV254等5项指标.应用多元线性回归分析建立了实际给水管网中细菌总数的快速预测模型.经验证,该模型预测的准确度为64.55%,能够用于实际给水管网中细菌总数的快速预测,可为保障供水管网水质微生物学指标的安全提供快速、可靠的技术支持.     

不同GIS平台下供水管网数据转换的研究

通过对MapGIS供水管网数据和ArcGIS Geodatabase数据模型的分析,提出了一种将MapGIS供水管网数据转换到ArcGIS平台的方法。该方法通过对图形数据和属性数据的统一处理,及对ArcGIS几何网络构建中捕捉容限和要素级别的合理设置,使得管网数据的转换准确、操作简捷。应用实例表明,经该方法转换得到的ArcGIS管网数据与原管网数据完全一致。     

某城镇供水管网污染源反追踪模型构建及求解过程

城市供水管网中突发外源性污染物入侵事故时,可以根据供水管网的属性数据和水质监测数据来反演推求污染物侵入的地点、时间和速度。结合南方某城镇供水管网案例,构建污染源模拟-优化反向追踪的数学模型,并利用粒子群-蚁群融合算法进行求解。结果表明,粒子群-蚁群融合算法可提高求解模型的准确率和计算效率,结果表现出较好的稳定性。针对该案例提出了一套供水管网外源性突发污染事故下的污染源定位方案,在随机选取的15个模拟污染事故中,模型输出结果准确率达到92. 0%,10 min内求解模型的准确率为64. 7%。     

基于地理信息系统的供热系统设计

随着我国国家建设的不断推进和供热企业的快速发展,在供热管网中引入地理信息系统对于供热企业来说具有重要的意义.本文结合龙口热力公司的实际情况建立一个基于地理信息系统的供热系统.该系统可以将文字信息与图形描述结合起来.建立空间地理数据和相关属性数据的共同检索和相关查询系统,具有数据管理、地图管理、管网设备与运行管理、系统决策管理和系统管理等五大功能,实现了供热管理的科学化和自动化.     

基于ArcEngine的城市地下管网信息系统的建设研究

结合城市地下管网系统的特点和需求,综合分析了基于ArcEngine的城市地下管网信息系统的建设方案,以及实现空间数据、属性数据的一体化存储,探讨了城市地下管网信息系统建设的关键技术,并针对城市地下管网信息系统进行了总体框架设计、数据层设计和功能设计。     

基于变态相似理论的供水管网试验模型研究

建立供水管网试验模型的目的是便于研究真实城市供水管网中管流的水力特性和水质情况.根据管流的变态相似理论,推导了供水管网原型和试验模型之间的各种相似关系,分析鲻并确定了承压管网符合欧拉相似定律.依据管网的简化原则,对区域复杂的管网进行简化,得到能够建立试验模型的管网结构,提出了构建供水管网试验模型的具体方法和步骤,确定了试验模型的变态率和具体参数.应用EPANET软件模拟管网运行情况,对比管网试验模型和原型的运行检测数据,证明模型和原型的管道流量、流速指标能够很好地满足相似关系,表明此模拟方法准确可靠.     

基于WebGIS的地下管网在线编辑系统的实现

为实现基于Web GIS对地下管网数据进行动态更新,并对数据的拓扑关系进行维护,建立了基于元数据面向实体的管网模型并提出了基于客户端缓存的要素捕捉方法。专业管网元数据与管网GIS模型相结合,元数据用于描述各专业管网的特性,管网GIS模型存储空间要素和空间拓扑,管网模型用关系型数据库进行存储,客户端通过标准服务接口对数据进行维护,结合要素捕捉提高编辑的准确性。通过建立实例系统对研究成果进行了验证,实现了对数据进行快速有效的更改和处理。     

基于GIS(地理信息系统)的SWMM模型在城市雨水管网优化改造中的应用研究

文章应用GIS(地理信息系统)对四川省简州新城开发区进行了设计要素的快速分析处理和收集,并快速构建SWMM模型。通过对简州新城管网模型的分析,总结内涝产生的原因,重新改造管网,并与改造之前对比,实践证明,以GIS和SWMM为基础的数字化模拟方法相较于以往的方法更直观高效,能够有效辅助设计、城市规划和管网优化改造,且具有预见性,可以在设计中推广应用。     

SimHydraulics/Simscape在供热管网水力分析中的应用

供热管网水力计算手工分析过程非常繁琐.SimHydraulics/Simscape作为专业的水力仿真辅助分析软件工具包可通过模型化图形输入、输出方式构建应用系统模型进行分析计算,从而简化过程实现动态仿真.该工具集具有建模直观、编辑方便、计算分析快速准确、交互性能强大等优点.尤其适用于对现有管网进行校核计算和模拟调节以及水力器件的性能仿真.     

Monitoring tunnel deformations by means of multi-epoch dispersed 3D LiDAR point clouds: An improved approach

Monitoring tunnel deformations is a crucial task when evaluating tunnel stability and safety. This task requires an accurate and high-resolution spatial technique to precisely capture the meticulous anomalies on a tunnel surface. As a response, the light detection and ranging (LiDAR) technique, which collects detailed spatial data in a fast and automatic manner, was recently proposed by Han et al. (2013) for monitoring the deformation of a 2D tunnel profile. Although the proposed approach successfully uses this modern spatial technique in tunnel analysis, the benefits of the 3D LiDAR technique have not been fully exposed. This study improved the technique as a real 3D approach. The associated uncertainties can be reduced by avoiding the 3D to 2D profile projection step. The minimum-distance projection (MDP) was then estimated using directly the 3D dispersed point clouds so that any deformation signal (point displacement) along the entire tunnel surface can be immediately identified. Furthermore, a rigorous covariance propagation approach was introduced to provide explicit quality indications on the obtained solution. The results of simulation tests and a real case study of a highway tunnel showed that the spatial implications of the 3D LiDAR technique can be fully explored by implementing the improved approach. Consequently, a more accurate and comprehensive solution for monitoring tunnel deformations can be achieved.     

Transformation of a 4D product and process model to generate motion of mobile cranes

Modeling and visualization of motion of mobile cranes enable project engineers to identify possible spatial conflicts related to cranes prior to actual operation on job sites and hence, could minimize hazardous conditions and delays associated with spatial conflicts. Current tools for visualizing equipment motion in three dimensions (3D) and across time have limitations due to their reliance on users in modeling a sequence of movement of each piece of equipment experientially and manually. This paper presents an approach for automatically generating motions of mobile cranes to support conflict detection. This approach builds on and extends existing approaches in product and process modeling and visualization of construction operations. It takes a product and process model that contains building design and schedule information of a specific project together with specifications of cranes and construction methods utilized by the project as input. The crane specifications and construction methods constitute project-independent information that describes how cranes should be operated during the execution of activities. The output of the approach is a transformed product and process model that incorporates a set of operations and motions of cranes, which can be used for identifying spatial conflicts associated with crane operations. Validation studies show that the developed approach can be used to model different types of mobile cranes and generate their motion during operations, which enables detection of spatial conflicts related to cranes.     

The Role of Geographical Information Systems in Urban Hydrological Modelling

'Geographical information systems'(GIS) technology holds considerable benefits to urban hydrology because of the spatial nature of catchment analysis. The availability of a spatio-temporal database of catchment characteristics can eliminate the adoption of simplifying assumptions, which reduce the quality of a research study. This research study was undertaken to demonstrate the need for accurate spatial and temporal accounting of land-use in an urbanizing catchment. The definition of the extent of GIS use, the approach to its integration into a study, and spatial database development, are crucial for eventual success.     

Reliability approach to slope stability analysis with spatially correlated soilproperties

A reliability approach to a slope stability analysis, considering spatially correlated soil properties, is used to systematically evaluate the various sources of uncertainty that arise in these types of problems. Measurement errors and bias that often occur during soil investigations are now incorporated into the probabilistic model of soil properties in addition to the spatial variability and the effects of spatial averaging. The results of the analysis show that the unconditional approach, which considers spatial variability, but does not account for measurement-related uncertainties, can yield unconservative results because of an unrealistically large variance reduction. In contrast, the results obtained from the unconditional approach, which does consider spatial variability and measurement-related uncertainties, as well as those from the conditional approach, lead to significantly lower probabilities of failure that are much less sensitive to the scales of fluctuation.     

Urban sustainability in developing countries’ megacities: modelling and predicting future urban growth in Lagos

In the first part of the paper urban sustainability issues in African countries are considered with a focus on urban growth. The need for urban management tools that are able to provide prospective scenarios is addressed. Urban simulations can represent a useful approach to an understanding of the consequences of current planning policies or their incompleteness. Simulations of future urban growth are usually quite difficult without tools that embrace the complexity of the urban system. The second part of this paper describes an urban growth simulation for the city of Lagos in Nigeria using a dynamic spatial model prototype. We propose a bottom-up approach, integrating land-use factors with a dynamic approach for modelling future urban land-use scenarios. The model for Lagos was calibrated and tested using measured time-series data on land-use, through a set of spatial metrics and Kappa (κ) coefficients. Afterwards, a twenty-year simulation was run until 2020. The simulation results are realistic and relatively accurate, confirming the effectiveness of the proposed model. This work was performed in the framework of the European Commission’s MOLAND project.     

基于点云技术的乡村景观遗产空间信息记录与可视化方法研究

点云技术为提升乡村景观遗产保护方法带来了重要机遇。从乡村景观的遗产价值保护出发,以识别乡村景观空间模式为目标,探索如何运用点云技术定量化记录和表现乡村景观的空间信息。以贵州安顺鲍家屯古村落为研究案例,全面集成数字近景摄影测量技术、激光雷达技术和点云可视化技术,构建了一套多尺度的空间信息数字化采集、处理和分析方法,能够快速、精确、全面地记录和表现乡村景观的空间特征,为识别其空间模式提供数据基础,也为遗产保护和发展提供新的视角和工具。     

An Agent-Based Modeling approach for sustainable urban planning from land use and public transit perspectives

Urbanism is a challenging topic in the world, which has resulted in several land-use and transportation issues in urban environments. To address these issues, urban planners follow integrated planning approaches that are more compatible with sustainable development objectives. Transit-Oriented Development (TOD) is widely recognized as one of the most feasible and comprehensive sustainable planning approaches. In this research, a three-step TOD-based method was developed for sustainable urban planning in the central region of Tehran. First, a measurable index was developed to assess public transit infrastructure (PTI) and TOD levels in the study area. At the second step, which was the focus of the research, an Agent-Based Modeling (ABM) approach was used to make a balance between TOD and PTI levels. ABM is a bottom-up approach that can solve spatial problems and can be integrated with top-down policies and spatial analysis tools. Finally, the performance of the model was evaluated by conducting several statistical, visual and empirical assessments using Tehran municipality's reference data. These assessments confirmed the efficiency and feasibility of the model.     

σ-convergence in the presence of spatial effects

Abstract.  This paper explores the implications that spatial effects can hold for the application of measures of σ -convergence. The bias of a common indicator of σ -convergence is examined for a family of spatial process models including: [a] spatial lag, [b] spatial error, and [c] spatial moving average. We show that the measure of σ -convergence is sensitive to a number of distinct influences including global dispersion, spatial dependence, and a variety of forms of spatial heterogeneity. We suggest a decomposition of the convergence indicator into two components: one reflecting global dispersion, and one reflecting the influence of spatial effects. We then illustrate this approach with a case study of the U.S. states over the 1929–2000 period.     

“框景”的表现与意义——以徽州古民居为例

框景是中国传统的空间造景手法。徽州古民居中的"框景",是将门、窗、柱梁结构、天井等构成框格,对自然环境进行裁剪划分,以获得多样的视觉效果,该表现手法可为建筑在美学上、图像上、空间上、生态上带来多重意义。     

居住区公共空间社会维度的句法释义:以北京传统胡同空间中社会交往模式的探讨为例

空间句法作为理解城市空间的社会逻辑语言,深刻揭示了人类社会活动与空间形态的互动关联,并可定量而精确地描述空间结构形态,为公共空间的社会性研究提供了一种新的方法与视角.该文借助于空间句法对北京传统胡同空间形态进行定量分析,释义这些街巷空间何以成为居民社会生活多样性的支持系统,以及何以成为人们乐意聚集的交往场所空间.对今后居住区公共空间的设计具有很好的借鉴意义与参考价值.