基于GDP规模分布的中国城市等级变化研究——等级结构扁平化抑或是等级性加强

基于规模分布的观点,对1990-2006年市辖区GDP排序前200位的中国地级以上城市进行分析,以此来判断中国城市等级变化的趋势,并对其进行影响因素分析。发现:第一,中国城市体系的等级性仍处于逐年加强的趋势中,这不同于当代发达国家的城市等级扁平化的趋势,但这种加强的趋势有减弱的势头;第二,二次模型相对于一次模型可以更好地拟合城市GDP规模的分布情况;第三,近年来中国城市体系等级性的加强趋势在较大程度上受到以下因素正方向的作用力:第三产业产值、货物周转量、研究生毕业生数、城镇居民家庭人均可支配收入、利用外资金额;而受到以下因素负方向的作用力:财政收入、进出口总额、第一产业产值、全社会固定资产投资、旅客周转量、第二产业产值。     

Distance,intervening opportunities,city hierarchy and air travel

Summary and Conclusions This study examines the influence of the spatial structure of city locations on air travel by considering the factors of intervening opportunities and the hierarchical system of cities in addition to the simple dimension of distance. The statistical results show that the familiar strength of the gravity model is matched by that of the intervening opportunities model, but only when all cities are analyzed together. The disaggregation of cities by size and region (hierarchy) leads to a spotty performance by both models. The generality of the gravity and intervening opportunities models is thus called into question, and the potency of the hierarchical city organization as a contributing influence determining air traffic flows is demonstrated.     

城市建设投资对城市经济贡献的研究

城市建设是城市的供给基础,是城市化的质量保证。将CES生产函数应用于城市建设经济分析,推导并建立了用于测定城市建设投资的二级常数替代弹性CES生产函数模型,提供了从数量角度研究城市建设投资对城市经济拉动的方法,反应了城市建设的特殊性,克服了城市建设投资统计资料不健全的缺陷,弥补了以往对城市建设投资规律认识的不足。并对我国城市进行了实证研究,指出我国城建投资对城市经济发展起着重要作用;通过对东中西部地区城市生产函数模型的建立和相关经济技术指标的比较分析,对三大地区城市的发展提出了建设性意见,促进城市之间的协调发展,从而更好地带动地区的发展。     

城市功能定位的理论和方法思考

从城市功能定位的角度,对城市功能、区域和定位三个概念的内涵进行深刻剖析,认为城市功能具有复合性、等级性、动态性、内部复杂性和空间具体性等特征;区域与城市腹地范围有所区别,不仅仅是一个空间范围,而是具有丰富的内涵。在城市功能定位过程中,要注意现状区域与定位区域两个时间层面定位。城市功能定位是在对城市自身优劣势、区位条件、外部环境等深入分析的基础上,通过确定城市在区域当中的区位,使城市在区域中占据一个独特的位置,获得更大城市竞争力的过程。在此基础上,从城市功能定位与职能分类的区别,城市规模与城市功能定位的关系和选取定位方法应注意的问题等方面进行论述,深刻理解城市功能定位的基本内涵。最后提出城市功能定位的基本原则,设计城市功能定位的技术路线,以供城市功能定位工作参考。     

Optimization of central places in an industrial economy

This paper presents a model to determine the optimal number, size, location and allocation of central places in industrial economies. We consider a hierarchy of central places ranging from towns, cities and a regional capital. The model is based upon the minimization of the total cost (sum of the manufacturing cost and distribution cost). The manufacturing cost is taken as a function of city size and the optimal distribution of manufacturing firms is the same as the optimal distribution of central places. The total cost function is a non-linear one and it has integer variables. A heuristic procedure is described for the solution. To extend the model into a more generalized form by including other activities is also discussed.     

城市规模与产出关系的分形研究——以新疆城市为例

基于新疆19个主要城市1995-2007年的规模和产出时间序列数据,利用具有分形性质的城市规模-产出模型对新疆城市规模与产出的因果关系进行探讨,得出一些主要结论与启示:城市规模-产出关系的分形模型用于新疆城市个体时拟合效果良好,而对于新疆城市体系则相关性不高;新疆城市规模与城市产出一般呈正相关,但城市规模不是城市产出的决定性因素;新疆城市体系在自组织演化过程中没有出现良性发展态势;城市产出效益与城市规模无相关性,但与城市规模等级分布密切相关,可以作为城市体系的系统结构优化的定量判据之一,这从理论上揭示了合理的城市体系结构是决定城市产出能力的重要因素。因此,合理发展大城市,完善新疆城市体系的规模等级结构有利于新疆经济社会的跨越式发展。     

A RESIDENTIAL LAND USE MODEL WITH A GENERAL LANDOWNERSHIP: EXISTENCE AND UNIQUENESS OF EQUILIBRIUM

ABSTRACT This paper is focused on equilibrium in a spatial model with two income groups. In Fujita and Tokunaga (1993), we have proposed a basic model of residential land use, called an α-landownership model, in which a group of city residents was assumed to own the circular area from the CBD to a radius α-However, the assumption of a circular land area was very restrictive Therefore in this paper a general model of residential land use called the S-landownership model is presented. This model assumes that a group of city residents jointly owns a part of the city's land, and it includes both the absentee landownership model and the public landownership model as special eases. The existence and uniqueness of the land use equilibrium for this S-landownership model are demonstrated.     

谈秦皇岛物流园区功能定位

通过对秦皇岛发展物流业的宏观环境——环渤海经济圈、中观环境——市域经济产业概况、微观环境——园区自身条件等分层级分析,确定秦皇岛物流园区的功能定位为:环渤海重要的物流枢纽、城市生产生活体系的重要支撑平台、城市物流产业的孕育基地,从而打造有市场针对性的专业化物流园区。     

引入道路服务水平的阻抗函数研究

针对普通交通阻抗中主要考虑时间和费用忽略道路服务水平的局限性,建立了引进服务水平的道路阻抗函数,经过分析,利用层次分析法确定了公共交通和私家车的服务水平系数权重分别为0.19和0.81。     

Resilient urban forms: A macro-scale analysis

Cities need to build on their resilience to cope with a broad range of natural and manmade hazards that threaten their competitiveness, livability, and functionality. Recognizing this need, the resilience concept is increasingly used as an organizing principle to guide research design and facilitate a more informed decision-making process. However, despite the abundance of studies on urban resilience, research on the link between urban form and resilience is limited and fragmented. This study sheds more light on this issue by reviewing and synthesizing theoretical and empirical evidence on how physical structure of cities can facilitate or hinder urban resilience. Acknowledging that each city is located within a nested hierarchy of scales that is characterized by cross-scale dynamics, only the macro-level aspects and elements of urban form are analyzed in this paper. These are namely ‘scale hierarchy’, ‘city size’, ‘development type’, ‘degree of clustering’, and ‘landscape/habitat connectivity’. Key criteria and indicators for analyzing resilience of each element/aspect are specified and used to discuss how macro-scale urban form is related to various resilience properties such as robustness, redundancy, resourcefulness, modularity, flexibility, adaptability, and efficiency. Findings indicate that urban form has major implications for social, ecological, and economic functionality of cities and can play a key role in enhancing their resilience and sustainability.     

Urban rent and urban dynamics: The determinants of urban development in Italy

Many empirical analyses have proved the existence of an optimal city size through the measurement of economies or diseconomies of scale, generally applied either to the costs of urban services or to elegant econometric estimates of urban and sectoral production functions. But, unfortunately these studies have never produced a common result, and have often been subject to criticism for their restrictive hypotheses. The aim of the present paper is twofold. First of all, urban dynamics in Italy is described through an indicator of urban costs and advantages, i.e. urban rent. House prices are in fact a good indicator of the attraction of an urban area, as they are synthetic and avoid a time lag between the occurrence of phenomena such as demographic change, and the availability of data to capture these phenomena. This study is based on the idea that the difference in house prices between large and small cities is a measure of their relative attraction (and thus their relative location advantage). The second aim is to highlight the determinants of urban dynamics, and especially to understand whether urban development patterns are similar in cities of different size. For this second issue, the paper enters the debate on the existence of an optimal city size for all cities and draws attention to other possible determinanats of urban development. Received: May 2000/Accepted: January 2002     

Historical urban growth in Europe (1300–1800)

This paper analyses the evolution of the European urban system from a long-term perspective (from 1300 to 1800). Using the method recently proposed by Clauset, Shalizi, and Newman, a Pareto-type city size distribution (power law) is rejected from 1300 to 1600. A power law is a plausible model for the city size distribution only in 1700 and 1800, although the log-normal distribution is another plausible alternative model that we cannot reject. Moreover, the random growth of cities is rejected using parametric and non-parametric methods. The results reveal a clear pattern of convergent growth in all the periods.     

基于小群体规模遗传算法的钢混单筋梁优化设计

针对遗传算法在结构优化应用中的缺点以及钢筋混凝土单筋梁的特点,提出了一种小群体规模遗传算法,同时给出适用的钢筋混凝土单筋梁优化设计的数学模型和适应度函数,采取邻域搜索技术和有限变异策略,寻求钢筋混凝土单筋梁的满足约束、造价最低的设计方案。算例表明这种方法有很强的全局搜索能力,能减少结构特性计算量,收敛速度快,能有效解决单筋梁的优化问题,并取得了较好的效果。     

A spatial equilibrium model for region size,urbanization ratio,and rural structure

"Earlier economic models of city size have either focused on urban agglomeration effects while ignoring the spatial structure of the rural hinterland, or made unrealistic assumptions (for example, uniform rural population distribution) so as to simplify the problem. Following the classic von Thunen framework, we present a two-sector spatial equilibrium model of a city located at the center of an agricultural hinterland. The city produces industrial goods, and the rural area produces agricultural goods. Both goods are consumed both by urban and by rural residents. Market equilibrium for these goods determines: (1) the spatial size of the region, (2) the urbanization ratio (urban to total population) and the population size of the city, and (3) the rural spatial structure (wage, population distribution, land rent, and agricultural yield). Given various sets of exogenous parameters pertaining to the industrial, agricultural, and transportation production functions and to population preferences, the model is solved numerically, and response functions are estimated and analyzed."     

Bern's positioning strategies: Escaping the fate of a secondary capital city?

Bern is a classic example of a so-called secondary capital city, which is defined as a capital city that is not the primary economic center of its nation. Such capital cities feature a specific political economy characterized by a strong government presence in its regional economy and its local governance arrangements. Bern has been losing importance in the Swiss urban system over the past decades due to a stagnating economy, population decline and missed opportunities for regional cooperation. To re-position itself in the Swiss urban hierarchy, political leaders and policymakers established a non-profit organization called “Capital Region Switzerland” in 2010 arguing that a capital city should not be measured by economic success only, but by its function as a political center where political decisions are negotiated and implemented. This city profile analyses Bern's strategy and discusses its ambitions and limitations in the context of the city's history, socio-economic and political conditions. We conclude that Bern's positioning strategy has so far been a political success, yet that there are severe limitations regarding advancing economic development. As a result, this re-positioning strategy is not able to address the fundamental economic development challenges that Bern faces as a secondary capital city.     

基于现代城市视角下的城市广场问题初探

通过对现代城市广场的分析,指出人情化、整体性、地域性和层次性是城市广场设计的重要因素。一个成功的城市广场不仅具有物质景观,还有场所环境和社会价值的完美互动。     

The growth of city systems with high-speed railway systems

This paper proposes a dynamic multi-regional growth model with free mobility of capital and population. The economic system consists of multiple cities interconnected by high-speed railway systems with each city consisting of one production sector as well as residential land use. The railway systems provide production sectors of different cities with the opportunity of face-to-face communication for knowledge production. The model describes the dynamic interdependence between capital and knowledge accumulation, wage and land rent structures, urban patterns with endogenous city size and inter-city interactability. It is emphasized how differences in geographic and qualitative factors of high-speed railway systems may affect regional economic development. The model simulates the dynamic processes of economic development of city systems. Received: May 1996 / Accepted: December 1996     

天津市城市建设生态学评价及对策研究

文中从城市生态系统的结构、功能和协调度三方面,探讨了天津市城市建设生态学评价的指标体系及评价标准,并采用层次分析法对天津城市建设的生态化水平进行评价,找出天津市城市生态系统中存在的问题,并提出天津市生态城市建设的建议和对策。     

One or infinite optimal city sizes? In search of an equilibrium size for cities

In this paper, the stylized assumption that one single “optimal” city size exists for all cities—achieved when marginal location costs equal marginal location benefits—is abandoned, as well as the opposite view that each city operates on its own cost and production curves, defining a specific optimal size. Instead, this work maintains the comparability among cities and demonstrates that urban specificities in functions performed, quality of life, industrial diversity and social conflicts shift up and down the benefits and costs linked to pure physical size, leading to different “equilibrium” sizes for cities. In order to achieve this result, a model of equilibrium urban size is set up, based on urban costs and urban benefits, merging elements suggested both by the traditional urban economics literature as well as by updated approaches considering also environmental quality, urban form and inter-urban cooperation networks. The model is then estimated on a sample of 59 European cities with data at FUA level. Empirical results allow the identification of city-specific “equilibrium” sizes. The error term, that is, the difference between actual urban population and the “equilibrium” one predicted by the model can be explained, beyond a measure of our ignorance, by good or bad governance, thereby suggesting future strategies for more efficient urban planning.     

明代筑城规模研究

中国古代城墙是重要的历史文化遗产,城池规模是古代筑城形制的重要表现内容之一。通过对反映明代筑城规模的城池城周数据的全面梳理与量化分析,探寻明代城池规模的分布规律,发现:明代城池规模表现出明显的等级特征和地域特征。影响城池规模的因素,既有人为因素,包括等级、历史、政治、经济、人口等,又有客观因素,包括位置、地理环境等,但在诸多因素中,城市的等级仍是主导明代城池规模的最重要因素。