GIS和RS技术在城市规划设计中的应用探讨

数字技术时代的到来,城市规划行业面临机遇和挑战。本文针对国内目前3S技术在城市规划管理层次应用较广而在规划设计方面应用薄弱这一现状,结合规划设计相关案例介绍GIS和RS技术在规划设计方面的辅助应用。案例选用ArcGIS软件介入规划设计的全过程,进行现状地形分析、三维模拟等辅助分析,并与Sketchup建模充分结合制作大范围三维漫游动画,辅助推敲规划建筑与周边环境相互关系,同时还充分利用GoogleEarth与Sketchup和ArcGIS之间的接口,将规划方案和建筑模型导入全球卫星影像,从而更好地辅助规划决策和公众参与等。     

Cartographic Symbol Design Considerations for the Space–Time Cube

The cartographic representation of geographic phenomena in the space–time cube comes with special challenges and opportunities when compared with two-dimensional maps. While the added dimension allows the display of attributes that vary with time, it is difficult to display rapidly varying temporal data given the limited display height. In this study, we adapt 2D cyclic point symbols to construct 3D surfaces designed along a helical path for the space–time cube. We demonstrate how these complex?3D helical surfaces can display detailed data, including data reported daily over 100 years and data reported in four-hour intervals over a year. To create the point symbols, each value is plotted along the curve of a helix, with each turn of the helix representing one year or week, respectively. The model is modified by varying the radii from the time axis to all points using the attribute value, in these cases maximum daily temperature and four-hourly ridership, and then creating a triangulated surface from the resulting points. Using techniques common to terrain representation, we apply hue and saturation to the surface based on attribute values, and lightness based on relief shading. Multiple surfaces can be displayed in a space–time cube with a consistent time interval facing the viewer, and the surfaces or viewer perspective can be rotated to display synchronized variations. We see this method as one example of how cartographic design can refine or enhance operations in the space–time cube.     

Hybrid simulation testing of a self‐centering rocking steel braced frame system

The self‐centering rocking steel frame is a seismic force resisting system in which a gap is allowed to form between a concentrically braced steel frame and the foundation. Downward vertical force applied to the rocking frame by post‐tensioning acts to close the uplifting gap and thus produces a restoring force. A key feature of the system is replaceable energy‐dissipating devices that act as structural fuses by producing high initial system stiffness and then yielding to dissipate energy from the input loading and protect the remaining portions of the structure from damage. In this research, a series of large‐scale hybrid simulation tests were performed to investigate the seismic performance of the self‐centering rocking steel frame and in particular, the ability of the controlled rocking system to self‐center the entire building. The hybrid simulation experiments were conducted in conjunction with computational modules, one that simulated the destabilizing P‐Δ effect and another module that simulated the hysteretic behavior of the rest of the building including simple composite steel/concrete shear beam‐to‐column connections and partition walls. These tests complement a series of quasi‐static cyclic and dynamic shake table tests that have been conducted on this system in prior work. The hybrid simulation tests validated the expected seismic performance as the system was subjected to ground motions in excess of the maximum considered earthquake, produced virtually no residual drift after every ground motion, did not produce inelasticity in the steel frame or post‐tensioning, and concentrated the inelasticity in fuse elements that were easily replaced. Copyright © 2014 John Wiley & Sons, Ltd.     

牵引式滑坡推力计算方法研究

三峡工程运行期间引发大量库区滑坡地质灾害,由于库区水位及降雨等联合影响,使得牵引式滑坡在库区滑坡中占有相当的比例。通过对库区牵引式滑坡形成机制研究,根据变形破坏模式,把牵引式滑坡分为牵引区（初始滑动区）和被牵引区,分析牵引式滑坡在演化过程中牵引区滑体与被牵引区滑体之间的相互依存关系,针对其相互作用力学特征建立合理的物理和数学力学计算模型,初步推导牵引式滑坡推力计算公式,为抗滑桩设计提供合理的设计推力。以三峡库区朱家店牵引式滑坡为例,在确定被牵引区滑体对牵引区滑体存在推力作用情况下,通过推力计算表明,推导出的公式计算得到牵引区滑体的设计推力比单独计算牵引区滑体设计推力更大,相比将牵引区滑体和被牵引区滑体视为整体计算设计推力更小,说明此方法计算的推力用于抗滑结构设计可以达到既安全又经济的效果,为牵引式滑坡治理设计提供新的思路。     

Unintentional Transgressions and Other Reflections on the Job Search Process

In this article I examine connections between my past experiences on the academic job market and my research interests, particularly in regard to the notion of transgression. I offer my personal “story” of job seeking as a contribution to the dialogue concerning the relationships between personal lives and professional experiences, and as a case study of how considerations of merit can become clouded by personal and social discomfort with difference.     

带桩筏基系统的弹塑性分析与设计方法研究

采用ABAQUS有限元程序中的线性扩展D-P模型对带桩筏基下的地基土进行弹塑性模拟,建立了带桩筏基系统的ABAQUS程序三维有限元模型。经比较各种桩、筏基础的内力与沉降关系计算结果,得到了带桩筏基的一些工作特性。在此基础上结合《建筑地基基础设计规范》(GB5007-2002),改进了传统的复合桩基设计方法,讨论了“三阶段”设计理念的可行性,并将其应用于工程实例。分析结果表明,改进的复合桩基设计方法和“三阶段”设计方法较常规设计方法更加经济合理。     

北天山隧道施工GPS控制网的建立及其贯通误差预计

介绍了北天山隧道施工GPS控制网建网的网型设计、观测和数据处理,分析了该GPS隧道控制网的观测质量,并就GPS控制测量误差对隧道横向贯通误差的影响值进行了估算。     

基于ArcGIS的土地利用现状图的编制

提出了基于ArcGIS的土地利用现状图编制的整体思路,对其中关键技术的实现进行了详细的阐述。     

Developing an algorithm for reconstruction of blocky systems in discontinuous media: two-dimensional analysis

Block detection is one of the most important steps in all discontinuous methods of analysis like Discontinuous Deformation Analysis (DDA) and Discrete Element Method (DEM). This is in fact a pre-processing step for those methods. In this study, a comprehensive computational algorithm, for tracing rock block created by discontinuities, has been developed. Using square matrices with integer elements and performing edge regularization step, reduce the size of the matrices due to elimination of unnecessary edges and vertices. Therefore speed and accuracy of block tracing operation will be increased. This algorithm is able to trace and identify all kind of blocks including convex and concave blocks formed by limited or unlimited fractures. The algorithm was programmed in C#.Net by over 3400 code lines and some cases were modeled by the code as example.     

数据库驱动程序设计初探

对用数据库驱动的程序设计方法进行了讨论，该方法使程序简化、易扩充