A Topological Representation for Taking Cities as a Coherent Whole

A city is a whole, as are all cities in a country. Within a whole, individual cities possess different degrees of wholeness, defined by Christopher Alexander as a life‐giving order or simply a living structure. To characterize the wholeness and in particular to advocate for wholeness as an effective design principle, this article develops a geographic representation that views cities as a whole. This geographic representation is topology‐oriented, so fundamentally differs from existing geometry‐based geographic representations. With the topological representation, all cities are abstracted as individual points and put into different hierarchical levels, according to their sizes and based on head/tail breaks—a classification and visualization tool for data with a heavy tailed distribution. These points of different hierarchical levels are respectively used to create Thiessen polygons. Based on polygon–polygon relationships, we set up a complex network. In this network, small polygons point to adjacent large polygons at the same hierarchical level and contained polygons point to containing polygons across two consecutive hierarchical levels. We computed the degrees of wholeness for individual cities, and subsequently found that the degrees of wholeness possess both properties of differentiation and adaptation. To demonstrate, we developed four case studies of all China and U.K. natural cities, as well as Beijing and London natural cities, using massive amounts of street nodes and Tweet locations. The topological representation and the kind of topological analysis in general can be applied to any design or pattern, such as carpets, Baroque architecture and artifacts, and fractals in order to assess their beauty, echoing the introductory quote from Christopher Alexander.     

Optimal Control of Structures under Earthquakes Including Soil-Structure Interaction

It is well known that the soil-structure interaction (SSI) changes the dynamic response of a structure supported on flexible soil. The analysis of optimally controlled SSI systems has certain difficulties due to the nature of the SSI and the optimal control problem. In this paper, a two-step iteration-based numerical algorithm is proposed to handle optimally controlled SSI systems under earthquakes. First, the optimal control forces are obtained by using a fixed-base system. Then, the optimal control forces are converted to the frequency domain by the Fourier transform technique to be used in the equations of the SSI system. The lateral displacement and the rocking of the foundation are obtained from the equations of the SSI system containing the optimal control forces in the frequency domain. The lateral displacement and rocking of the foundation are then converted to the time domain by the inverse Fourier transform technique, and the lateral accelerations and the rocking accelerations of the foundation are obtained by the forward finite difference method. During the second step, the optimal control forces are calculated again by using the lateral acceleration and the rocking acceleration of the foundation along with the earthquake ground motion. Using the method explained above, the optimal control forces obtained in the time domain are used in the equations of the soil-structure system from which the behavior of foundation and structure is obtained. In the final section of the paper, a numerical study is conducted for a controlled structure supported on flexible soil.     

林则徐信札"望云庐"考等五则

海峡文艺出版社《林则徐全集》于2002年出版了,这本书以十册的巨幅收入了林则徐的奏稿、文集、诗词、信札、日记、译稿等文字,可以说是林则徐研究的一个宝库,已成了近代史研究的重要参考文献。其中仅信札就收录了一千余封,足见编者功力之深、收录之勤。不过,煌煌巨著中,难免有疏漏之处,仅就致“望云庐”等六通,未注收信人姓名三通,致怡良一通等十通信札,略陈管见,或有千虑之一得。一该书中收录林则徐致“望云庐”的信6封,但是关于“望云庐”的真实身份,编者仅注云,“考其人在内阁或军机处任职,职位不高,升迁亦缓”,而未深入考究。其实排比这…     

四川五代两宋墓葬中的猪首人身俑

猪首人身俑是川西五代两宋墓葬较为常见的随葬明器之一,可分站立、骑鼓或击鼓、手执锤钻三种不同类型。其性质不是十二生肖俑,亦不是墓主属相,而是古文献记载中经常提到的雷公。它在西蜀地区流行,与道教雷法的影响有关。     

基于出行调查和GIS分析的县域公共服务设施配置评价研究——以德兴市医疗设施为例

针对传统的县域公共服务设施布局分析主要考虑空间可达性的问题,提出一套更全面和贴近实际的公共服务设施配置评价方法体系。公共服务设施配置评价应能反映服务设施的空间可达性、服务质量、居民的需求与选择三方面内容,为此应综合采用GIS、问卷调查、出行路线图分析等多种技术。在具体操作上,提出"建立县域公共服务设施等级体系--基于时间距离的设施可达性计算--考虑个体行为选择的服务区划分--基于服务区的设施使用状况评价"的"四步法"。主要有两个创新点:①引入了基于出行调查的服务区分析,反映了设施的异质性带来的居民的自主选择和跨区域流动情况;②对设施服务质量的考虑更全面,不仅限于传统的设施规模,还考虑了医生水平、硬件设备、科室设置等因素。     

多尺度视角下饭店劳工移民地方感知与关系研究——以北京开元集团饭店为例

占据移民主体的劳工移民因涉及地方变迁与心理感知而成为地方感研究的重要对象。对于劳工移民而言,其所谋生的企业与城市间在感知判断中是否存在关联以及如何关联对探究其感知与行为特征等有着重要意义。以劳工移民汇聚地"北京"和集聚地"饭店"为案例,探究此背景下的地方感关系与路径。数据与结构模型分析表明:①在饭店与北京市两尺度中地方依赖均显著影响着地方依恋与认同,凸显了依赖这一功能性感知在地方感构建中的重要作用;②证实了饭店劳工移民的地方感在两尺度间存在关联,而且是以饭店地方依恋及北京地方依赖为关联维度;③得出了一种地方感由微观环境向宏观环境拓展的路径,由饭店地方依赖开始,至北京地方依恋与认同。     

陇东地区城镇等级规模结构的分形研究

城镇体系的分形研究是城市地理学研究的新方向。文章从分形理论在城镇体系研究中的应用入手,以豪斯道夫(Hausdorff)维数为依据,借助Zipf公式,对甘肃省陇东地区的城镇等级规模结构进行了分维测算,结果表明该区域城镇体系具有分形特征,说明分形理论适合陇东地区城镇等级规模结构的测算分析。在分形的基础上分析了本区城镇规模结构的分布特点及其存在的问题:①首位城市规模不突出,其经济带动和功能辐射力量薄弱;②中间位序的城镇分布过于集中,人口分布显得比较均衡;③陇东地区城镇体系建设缺乏区际空间规模结构的发展。最后基于分形理论的测算与分析结果,提出了陇东地区城镇体系结构和功能优化的建议。     

湖北随州枣树林墓地青铜器表面纹饰的填彩分析

春秋时期青铜器表面装饰技术发展迅速,装饰方法多样,纹样繁复,纹饰中多有填彩现象以凸显其表面图案的装饰性,但目前与此相关的科技分析较少——相关研究多围绕其艺术价值和文化含义展开,尤其是白色填彩的分析仍处于空白。湖北随州枣树林墓地是春秋时期诸侯国曾国的一处高等级贵族墓地,出土了大量的青铜器。本研究使用红外光谱、扫描电子显微镜-能谱、X射线衍射和热裂解气相色谱-质谱联用等手段,对该墓地出土青铜器表面纹饰阴线中的白色填充物质进行分析,结果表明其主要成分为石英和某种黏土矿物混合而成。该研究为东周时期青铜器表面纹饰的填彩工艺提供了新的证据,可为相关研究提供借鉴。     

关于旅游现象的生存论本质

旅游现象的生成是建立在生存论的前提基础上,即人首先要满足生理生存需求和谋生生存需要,才会有旅游需求和行为的发生。人们在居住地惯常生活环境的生存谋生状态,决定了休闲和旅游的本质差异。旅游研究只有回到生存论前提,旅游现象和概念的本质才有可能得到深刻揭示：旅游就是人们通过筹划,离开和返回惯常生活环境,体验并满足非谋生需求的生存活动。