Two‐regime Pattern in Human Mobility: Evidence from GPS Taxi Trajectory Data

Research on complex systems has identified various aggregate relationships in phenomena that describe these systems. Travel length has been characterized by negative power distributions. Controversy, however, exists over whether mobility patterns can be modeled in terms of a simple power law (Lévy flight model) or that more complicated power laws (exponential power law, truncated Pareto) are required. This study concentrates on two issues: testing the validity of exponential power laws and truncated Pareto distributions in urban systems to describe aggregate mobility patterns, and examining differences in mobility patterns for different travel purposes. The article describes the results of an analysis of Global Positioning System (GPS) taxi trajectory data, collected in Guangzhou, China, to identify mobility patterns in the city. The least squares statistic is used to estimate the parameters of the distribution functions. Results suggest that a fusion of functions, based on an exponential power law and a truncated Pareto distribution, represents the travel time distribution best. Moreover, the findings of this study indicate different mobility patterns to exist for different travel purposes.     

Gibrat Revisited: An Urban Growth Model Incorporating Spatial Interaction and Innovation Cycles. 再评吉尔布瑞特：顾及空间相互作用和创新周期的城市增长模型

We designed a geographical model for simulating the distribution of urban growth in systems of cities. The model incorporates the hierarchical and spatial diffusion of innovation cycles through gravitational interactions within a set of cities. Using theoretical simulations, we demonstrate that this model is able to reproduce the observed properties of urban systems for the log‐normal distribution of city sizes as well as the observed distribution of growth rates. Our experimentation was performed on a large harmonized historical database that includes a few hundred French urban agglomerations between 1831 and 1999 (Pumain‐INED database). Both spatial interaction and innovation cycles are necessary ingredients to explain the evolution of urban hierarchies. We suggest that Gibrat's generic stochastic growth model based on independent entities should be replaced by a more relevant model of spatially and temporally interdependent geographical entities.     

城市系统中的竞争与协同机制研究

本文在剖析城市自组织系统耗散结构特征的基础上,重点从区域尺度和城市尺度两种空间尺度解析城市系统自组织演化的驱动力:竞争与协同。研究表明竞争与协同两种力量共同决定城市系统的发展演化,协同性竞争(良性的竞争)有利于城市系统的发展,推进城市可持续发展;反之,过度竞争或竞争乏力则会导致产生无序状态的产生,阻碍城市的发展。     

Generating Alternative Land‐use Allocation for Mixed Use Areas: Multi‐Objective Optimization Approach

Current research is carried out with an intention to present an optimization approach for the urban land‐use allocation problem by generating Pareto optimum solutions considering two objectives—maximizing compatibility among adjacent space uses of a study area without compromising the area’s total land price and maximizing the price of plot of each individual owner. Considering the non‐linear characteristics of the objective functions, a multi‐objective evolutionary algorithm approach called Non‐Dominated Sorting Genetic Algorithm‐II (NSGA‐II) is applied to obtain Pareto optimal land‐use allocation subject to different set of constraints. The objective functions are tested over a case study area of Dhaka, Bangladesh. The resulting NSGA‐II model produces 24 Pareto optimal solutions of land‐use allocation, allowing tradeoff between maximizing compatibility and land price from one solution to other. This research also expresses the potential of the model to aid the policymakers and city planners of development authorities by providing alternative land‐use plans, and thereby predicting the consequences of any plan before practical application.     

Land Markets in the Harris-Todaro Model: A New Factor Equilibrating Rural-Urban Migration

Recent research in the Harris-Todaro (HT) tradition has added an important new element to the model by incorporating an urban land market. Brueckner and Zenou (1999) (hereafter BZ) argue that a model where migration equalizes expected wages between city and countryside may overlook another important force that equilibrates the process of rural-urban migration. This force is the migration-induced rise in the urban cost of living, which occurs principally through escalation of urban land rents as the city population expands. Land-rent escalation, which tends to limit rural-urban migration, provides an important additional force that may help determine city sizes in developing countries. The present paper provides a simpler alternative to BZ's analysis by assuming that urban residents smooth their income as they cycle between formal and informal employment. This allows migration decisions to be based on the expected wage, as in the usual HT framework, in a model that includes a land market. The analysis shows that this modified framework generates results slightly different from those of BZ.     

European plans for the smart city: from theories and rules to logistics test case

City evolution is connected to social, economic and technological evolutions. New technologies induce further changes, which are highly innovative, which again affect the urban and territorial systems. The city once again adjusts to new opportunities in relation to information and communications technologies, energy and mobility. In this paper, smart city, configured as a set of interacting systems with people, is focused as a possible model to follow for pursuing sustainability in real cities of the twenty-first century. Three processes are recalled: city development, city planning theories and city rules. Smart city seems to be the convergent point for all processes evolving in European urban areas. Theoretical definitions of smart city are recalled. At the same time, the European Commission is promoting smart city rules for implementation. Moreover, in the last years some local decision-makers implemented specific measures that today can be considered in the class of smart city measures. The objective of the paper is to analyse the European perspectives for smart city, trying to separate the three processes that are strongly integrated, but without formal links. To verify the European smart city approach, a study case concerning city logistics is considered.     

基于物流企业网络的中国城市网络空间结构特征研究

借鉴世界城市网络研究代表性学者Taylor等提出的世界城市网络研究方法,以中国主要物流企业总部及分公司的分布数据为基础,生成国内物流企业网络,并从物流企业网络中各城市网络连接度、网络总体形态结构和三大城市群网络格局比较三方面分析解读中国城市网络空间结构特征。发现了中国城市网络节点城市连接度层次分布情况,城际网络联系强度分等,以及环渤海、长三角、珠三角三大巨型城市群内外部网络格局差异等结构现象,对中国城市网络空间特征研究做出了有效尝试。     

基于GIS的盐城城市内部空间结构演变分析

根据1984、1997、2003、2006年4个时相数据,运用GIS的空间分析方法,对盐城城市工业、居住、公共服务用地的空间分异特征进行分析,并利用多种景观格局指数,分析了三种功能用地的完整性、集聚性和异质性特征。结果表明:1984-2006年盐城城市内部空间结构演变过程可划分为集聚、分散、再集聚三个阶段,同时演变中存在"工业围城"、城市中心区的工业和居住用地比重偏大等问题。     

THE SIZE DISTRIBUTION OF URBAN AREAS: TESTING FOR THE APPROPRIATENESS OF THE PARETO DISTRIBUTION USING A GENERALIZED BOX-COX TRANSFORMATION FUNCTION*

ABSTRACT A widely held opinion among urban economists and geographers is that the Pareto distribution is an accurate representation of the urban size distribution of many countries around the world. This paper focuses attention on the appropriateness of the procedures used in the literature in arriving at this conclusion. We employed the generalized Box-Cox transformation function, which permits estimation of many functional forms for testing the Pareto distribution as special cases. The results obtained are illuminating albeit somewhat surprising. Except for one country the Pareto distribution is overwhelmingly rejected in favor of the general Box-Cox function. In more than 30 percent of all countries this form collapses to a reciprocal function. Moreover, as far as the overall goodness of fit is concerned, our results show that the General Box-Cox function is superior to the Pareto form.     

OLS ESTIMATION AND THE t TEST REVISITED IN RANK‐SIZE RULE REGRESSION*

ABSTRACT The rank‐size rule and Zipf's law for city sizes have been traditionally examined by means of OLS estimation and the t test. This paper studies the accurate and approximate properties of the OLS estimator and obtains the distribution of the t statistic under the assumption of Zipf's law (i.e., Pareto distribution). Indeed, we show that the t statistic explodes asymptotically even under the null, indicating that a mechanical application of the t test yields a serious type I error. To overcome this problem, critical regions of the t test are constructed to test the Zipf's law. Using these corrected critical regions, we can conclude that our results are in favor of the Zipf's law for many more countries than in the previous researches such as Rosen and Resnick (1980) or Soo (2005) . By using the same database as that used in Soo (2005) , we demonstrate that the Zipf law is rejected for only one of 24 countries under our test whereas it is rejected for 23 of 24 countries under the usual t test. We also propose a more efficient estimation procedure and provide empirical applications of the theory for some countries.     

CITIES AND DEVELOPMENT

ABSTRACT This paper starts with a “primer” on what we know about the conceptual and empirical links between development and urbanization. While historical experience of developed countries is reviewed, today's rapid urbanization in developing countries offers an intense set of challenges. Rapid urbanization requires massive population movements and enormous local and inter‐city infrastructure investments in a modern context of heavy government interventions in economies. This context raises under‐researched issues, discussed in the second part of the paper. First concerns the spatial form of development. How much development should be focused in mega‐cities, or huge urban clusters, as opposed to being more spatially dispersed, a critical question facing China and India today? How do we conceptualize and measure both the benefits and costs of increased urban concentration; and how are they linked to a country's evolving national industrial composition? Second, what is the evolution of spatial income inequality under massive rural‐urban migration? Is inequality heightened today relative to the past by national government policies which “favor” certain cities and regions and by local government policies in those cities that may try to deflect migrants by offering them poor living conditions?     

Urban Pattern Dichotomy in Tirana: Socio-spatial Impact of Liberalism

Transition from a centralized to a market economy yielded different responses from the former Eastern Bloc countries with economic performance directly affecting spatial composition of the cities. Post-socialist urban transformations across Central and Eastern Europe exhibit main, common features but always preserve singularities, characteristic of individual states. This paper, by using comparative methods and urban planning analyses, emphasizes differences in the degree of change for inner city areas under same transition conditions. Drawing on empirical evidence from Tirana, the paper stresses the fact that besides the obvious general change in the communism-inherited urban fabric, the degree of this change is predicated on the area's centrality and its pre-transitional urban pattern. It is pointed out that this spatial change follows a mutually interactive, parallel path with the socio-economic composition of the city. The peculiarity of Tirana stands in the fact that post-socialist socio-spatial transformations are better defined by Balkanization (implying individuality and hostility) rather than segregation (which implies clustering).     

A CONSOLIDATED MODEL OF MONOCENTRIC CITIES AND AN EMPIRICAL ANALYSIS OF URBAN SCALES AND LAND PRICES IN CHINESE CITIES*

ABSTRACT Motivated by the newly established Chinese urban land markets, we develop a theoretical model that unifies the “closed” and “open” features of the classical monocentric city model. The model features interactions between permanent urban residents and migrants and exhibits a distinctive equilibrium pattern. The theoretical model is tested empirically, using recent Chinese city‐level data. The empirical findings indicate that market forces now play an important role in urban expansion and land price formation, while various forms of government planning are still influential. Our results show that migrants exert a less pronounced impact than the classical “open” city model has suggested.     

城市系统演化的复杂性研究

城市演化是由复杂多样的动力和主体推动的,受全球、国家和地方尺度的多重影响,表现出复杂的演化规律和特征。笔者认为城市系统演化模式与过程的研究需要发展一个基于复杂性理论的跨学科的分析框架。本文首先提出一个城市系统演化的概念模型,然后运用层次理论分析了城市系统演化的复杂相互作用,论述了城市系统演化的组成异质性、时空复杂性、决策复杂性等复杂性表征,最后讨论了城市系统演化的各种复杂规律。     

ON THE VALUE OF FOREGONE OPEN SPACE IN SPRAWLING CITIES

Foregone benefits of the open space that is sacrificed through urban sprawl are hard to quantify. We obtain a simple benchmark measure by introducing a demand for trips beyond the urban boundary into the monocentric city model. The externality arises from the increase in travel costs that expansion of the city imposes on its prior inhabitants. An empirical application illustrates the moderate informational requirements. It indicates that open space externalities warrant rather mild restrictions on urban expansion.     

城市生活质量与生活空间质量研究评介与展望

在当今的社会-文化进程阶段,新人本主义强调人与社会(文化)和谐的可持续发展观,其目标体现在人们的生活质量上,其焦点是城市(社会)生活质量构成与城市(社会)生活质量空间耦合的建构。从新人本主义理念出发探讨城市(社会)生活质量与其对应(社会)生活空间质量对政府部门和学术界都是全新的课题。二者在不同领域,不同学科之间的研究并行不悖。对前者的研究是人文社会与管理学科聚焦的方向,对后者的探讨是区域与城市诸学科聚焦的方向。它们充分体现学科融合的新理念/原理及其前沿性。本文从研究源起、研究意义、研究阶段以及评价指标体系的构建等不同角度对二者的国内外研究动态及方向进行了评介与展望,目的在于明晰二者的研究方法,理论框架与研究趋势,为社会与城市发展及其规划指明方向,提供理论基础与科学依据。     

城市负债的效应及测评研究进展与展望

全球城市化进程的加速使得用于城市发展建设的资金规模日益扩大,特别是通过现代化融资借贷手段为城市发展筹集资金的方式给城市建设提供了巨大的支持和动力。但是,全球经济金融危机和地区性主权债务危机的蔓延,也使得城市债务的累积和扩大问题愈发严重。为了更加清晰地了解城市负债的影响效应机制和测度预警内容与方法,为城市的健康可持续发展提供指导和借鉴,本文对相关内容研究进行了文献梳理和分析总结,并展望了进一步研究的重点方向。结果表明:国外的研究已取得了不少成果,而国内的研究尚处于初期阶段,研究视角较局限,缺乏多学科、广领域、立体层次的研究。因此,未来研究应注重从人文地理学的角度,综合分析城市负债对于城市发展的影响路径、累积效应、互动耦合作用等,通过多种分析方法对多层次尺度的数据进行更加细化深入和全面的分析,探索城市负债和经济社会发展的时空分异格局、演变规律和作用机理。     

企业主义视角下大城市保障房建设的策略选择及其社会空间后果

城市企业主义是理解地方政府行为与城市空间变迁的重要政治经济视角,在中国推进经济全球化和住房市场化的背景下,企业化的地方政府,特别是大城市政府,在保障房的建设实践中往往采取偏向性的策略选择。本文着重讨论企业主义视角下大城市政府保障房建设的策略选择及其社会空间后果。研究发现,大城市政府主要通过实施保障房政策的异化和保障房住区的边远化策略,来履行其住房保障职责。然而,这种选择性策略带来的直接的社会空间后果是低收入群体的边缘化,具体表现为外来务工人员等在保障政策上的边缘化,以及保障房居民在社会空间上的边缘化。文章进一步指出,保障房应回归其保障本位,以满足低收入群体的真实需求。     

LUTI模型原理、实现及应用综述

经济全球化背景下可持续发展已成为当今世界发展的主题。快速城镇化下的中国,城市空间的可持续性发展提上日程。为此,期待有力的、可操作的工具用于定量模拟城市空间演化过程、预测不同政策下城市空间的发展趋势,为城市化持续健康发展提供决策支持。本文分析了LUTI模型的基本原理、构建思路、实现框架和建立中国城市LUTI模型面临的问题,并回顾了国内外利用LUTI模型模拟城市空间演化过程,以辅助表明城市空间决策的研究现状,希望能为中国的城市空间可持续发展模拟分析研究提供参考。     

巨型城市走廊理念及其规划与管制

城市走廊是城市系统的空间形式之一,在区域与城市发展及规划中由来已久。随着全球化、信息化、经济一体化的发展,巨型城市走廊开始显现。本文以基础设施带、区域发展核心及规划理念等几个方面阐述巨型城市走廊理念。以发达国家和发展中国家的巨型城市走廊为实例,探讨巨型城市走廊发展中存在的问题及其规划与管制。