Analysis of urbanization based on center-of-gravity movement and characteristics in Songhua River basin of China and its southern source sub-basin between 1990 and 2010

Urbanization in modern times led to a series of development strategies that brought new opportunities in China. Rapid urbanization caused severe stress to the ecosystems and the environment. Using the center-of-gravity(COG) method and parameters such as population, economy, and land, we studied the urbanization pattern in Songhua River Basin and its southern source sub-basin from 1990 to 2010. Urbanization was analyzed based on the COG position, eccentric distance, movement direction of COG, and distance of COG movement. Various characteristics of urbanization in the southern source sub-basin of the Songhua River were explained in relation to the whole Songhua River Basin. Urbanization in the southern source sub-basin of the Songhua River is balanced, relatively advanced, and stable compared to the whole Songhua River Basin. The average eccentric distance between the urbanization COGs in the Songhua River′s south source basin indicated rapid expansion of land urbanization during the span of this study. A basic pattern of urbanization COG in the whole Songhua Basin was observed, but there existed differences among the three aspects of urbanization process. Land urbanization is still in its active stage, so future studies should focus on analysis of such urbanization trends.     

Limit equilibrium method (LEM) of slope stability and calculation of comprehensive factor of safety with double strength-reduction technique

When the slope is in critical limit equilibrium(LE) state, the strength parameters have different contribution to each other on maintaining slope stability. That is to say that the strength parameters are not simultaneously reduced. Hence, the LE stress method is established to analyze the slope stability by employing the double strengthreduction(DSR) technique in this work. For calculation model of slope stability under the DSR technique, the general nonlinear Mohr–Coulomb(M–C) criterion is used to describe the shear failure of slope. Meanwhile, the average and polar diameter methods via the DSR technique are both adopted to calculate the comprehensive factor of safety(FOS) of slope. To extend the application of the polar diameter method, the original method is improved in the proposed method. After comparison and analysis on some slope examples, the proposed method's feasibility is verified. Thereafter, the stability charts of slope suitable for engineering application are drawn. Moreover, the studies show that:(1) the average method yields similar results as that of the polardiameter method;(2) compared with the traditional uniform strength-reduction(USR) technique, the slope stability obtained using the DSR techniquetends to be more unsafe; and(3) for a slope in the critical LE state, the strength parameter φ, i.e., internal friction angle, has greater contribution on the slope stability than the strength parameters c, i.e., cohesion.     

利益统筹视角下的城市更新实施路径——以广州城中村改造为例

存量建设土地再开发过程中对增值利益的合理分配是推动城市更新实施的关键,而多方参与主体为此进行的复杂利益博弈,则是城市更新工作的阻力。鉴于此,以广州城中村改造为例,基于利益主体博弈视角,分析城市更新政策演进中利益分配格局的转变,并从价值导向、权益认定和管理体系三方面阐释影响城市更新主体利益平衡难、博弈周期长的难点,进而从促进存量时代城市更新实施的目标出发,结合改造方案编制的技术要点、审批流程与制度设计,从“公共优先、权益共享、一体化实施”3个方面提出了利益统筹的对策,以及引导价值转变,到合理认定权益,并通过管理体系统筹利益分配的实施路径,以加快城市更新共识的达成,实现存量土地价值盘活。     

大型射电望远镜背架精密安装技术

对65 m射电望远镜的背架安装做了尝试,取得较满意的结果.针对天线背架尺寸大、质量重、焊接变形大、几何精度要求高等特性,采用全站仪工业测量系统实现背架的快速、无接触、高精度定位测量,点位测量精度优于1 mm;采用独特的施工工艺和焊接技术,最大限度控制焊接变形,最终点位偏差优于1.5 cm.提出基于设计坐标系建立安装测量...     

基于网络视频的建设工程监管系统研究

探讨网络视频应用于建设工程监管领域的系统建设,介绍了系统框架、数据建设、功能设计和技术路线,以重庆市重点建设工程为例进行项目开发并在建委系统取得了试用,最后指出全过程、多传感、集成的体制性建设工程监管系统是未来趋势。     

基于移动Agent的分布式地理信息查询

提出了基于移动Agent的分布式地理信息查询的新思路,给出了构建基于移动Agent的分布式地理信息查询系统的方法,并利用移动Agent开发平台Aglets开发了一个分布式地理信息查询原型系统,实现了分布式地理信息的透明访问。     

Automatic placement of GIS vector map annotation in area feature by long-diagonal

This paper discusses the placement of Chinese annotation from point of view of graphics. Area Feature is classified as simple polygon, complex polygon and special polygon. For simple ones, annotations are placed along the longest edge. For complex ones, firstly the polygon are simplified according to close points, then the longest diagonal is gotten by comparing length, lastly, annotations are placed along long-diagonal. For special ones, the polygon are partitioned into several parts by a certain rule for getting their sub-diagonals, then their annotation are placed by means of the second.     

PS-InSAR技术在郑州市地面沉降调查中的应用

本文以郑州市为研究区,利用2004年~2010年间26景Envisat-1雷达图像,采用永久散射体干涉技术(PS-InSAR)揭示了郑州市地面沉降的空间分布特征;根据InSAR解译结果开展地面沉降调查;并结合郑州市的地质构造、地下水以及城市建设等资料初步分析了郑州市地面沉降原因。     

Multi‐scale approach to mining significant spatial co‐location patterns

Spatial co‐location pattern mining aims to discover a collection of Boolean spatial features, which are frequently located in close geographic proximity to each other. Existing methods for identifying spatial co‐location patterns usually require users to specify two thresholds, i.e. the prevalence threshold for measuring the prevalence of candidate co‐location patterns and distance threshold to search the spatial co‐location patterns. However, these two thresholds are difficult to determine in practice, and improper thresholds may lead to the misidentification of useful patterns and the incorrect reporting of meaningless patterns. The multi‐scale approach proposed in this study overcomes this limitation. Initially, the prevalence of candidate co‐location patterns is measured statistically by using a significance test, and a non‐parametric model is developed to construct the null distribution of features with the consideration of spatial auto‐correlation. Next, the spatial co‐location patterns are explored at multi‐scales instead of single scale (or distance threshold) discovery. The validity of the co‐location patterns is evaluated based on the concept of lifetime. Experiments on both synthetic and ecological datasets show that spatial co‐location patterns are discovered correctly and completely by using the proposed method; on the other hand, the subjectivity in discovery of spatial co‐location patterns is reduced significantly.