A Partitioning Model of Urban Retail Structure

A model based on renewal theory generates the number of retail establishments in a place as the outcome of a competitive partitioning process. The available market, measured for example by population or by existing retail sales, is shared among businesses until no market potential market remains. Competing businesses obtain different shares of the market, and the number of establishments is predicted as a discrete random variable. Several alternative formulations are presented of varying generality. One version is successfully tested, using GLIM, on ten business types (SIC two-digit classes) in 232 cities of New York State for 1977 and 1987. The model correctly predicts the form and the variance structure of the relationship between number of establishments and place size. It is shown how the model may be combined with models of city-size distributions to predict aggregate frequency distributions of retail establishments across urban systems.     

A Climatic Model of Urban Energy Budgets

A deductive model of the energy budgets of urban landscapes, based on the exchanges of energy, mass, and momentum, is introduced. The absorption of shortwave and longwave radiation and their dissipation via the channels of reradiation, convection, conduction, and evaporation are generated by the model in order to simulate the interplay of the many energy cascades among the myriad of city surfaces. A city can be geographically analyzed by determining its energy budget and resultant surface temperatures on a block-by-block basis. In spite of some simplifying assumptions, the predictions of surface temperatures of this initial model compare favorably with observations.     

Commuting Distances and Gender: A Spatial Urban Model

In any urban center the commuting distances are a function of the spatial structure of the center and of the characteristics of the commuters. In this paper theoretical relationships between commuting distances and distances of residences to city centers are derived for monocentric and polycentric cities. These relationships are then linked to the sociological determinants of commuting distances. An econometric model encompassing both spatial structure variables and social variables is constructed and estimated using data for sixteen urban centers. Gender differences are focused upon. The expansion method is used.     

A Model for Measuring the Sustainability Level of Historic Urban Quarters

The main aim of this paper is to propose a model for measuring the sustainability level of historic urban quarters and to indicate an appropriate strategy for their revitalization. Based on this aim, this study first presents the theoretical review on the concept of “revitalization”, and its relationship with sustainability; next, it introduces the characteristics, role, selection process and scaling method of sustainability indicators, which are essential for measuring the level of sustainability. The paper then, as the main contribution of this paper, proposes the model for measuring the level of sustainability in historic urban quarters and determines some proposals to achieve revitalized and sustainable historic urban quarters. Depending on the proposed model, there is a direct relationship between type and the level of obsolescence (revitalization) and the level of sustainability in the physical, economic and social structures of a particular area. Therefore, when the level of sustainability is high in any one of these three structures, it means that the level of obsolescence is low in the same structures of an historic urban quarter. The result of this paper leads us to say that, the level of sustainability is a new (additional) input in the strategic planning process of revitalization and sustainable urban revitalization of historic urban quarters. Finally, the paper concludes with a brief summary on the general arguments of the paper.     

An Integrated Network Equilibrium Model of Urban Location and Travel Choices

This paper develops a mixed, combined, and stochastic user-equilibrium model for urban location and travel choices with variable origin and destination costs. Different types of travelers will be considered explicitly, including: workers with fixed residences seeking jobs, workers with fixed job locations seeking residences, and workers with both fixed residences and jobs. The costs or benefits of residing or working in a zone are described by appropriate location functions. In order to reflect effects of activity congestion the location function includes variables such as the total number of persons residing in a zone and of persons working in a zone. We prove that the proposed model is equivalent to a convex optimization problem that can be solved by a convergent method of successive averages. A numerical example is presented to demonstrate the application of the model and algorithm.     

都市传说初探

当有人告诉你:“如果你去拉斯维加斯玩,小心哪个人体器官犯罪集团把你的肾偷了!“这时你可能碰到都市传说了. 　　如果同样一个人把这个故事讲述得真实细密--某个商人去拉斯维加斯度假,一天夜里他遇到一位迷人的姑娘,言来语去,两人熟络起来.那女子邀请他到她房间里喝点什么,他欣然应允.第二天,他醒来的时候却发现自己独自躺在满是碎冰的浴缸里,而且更惊讶的是,他的腰部被动了手术:他的一只肾被取走了!他环顾四周,发现墙上留下了几个字:“赶快拨打911吧,否则你就丢小命了!“--这时,你肯定碰到都市传说了.……     

Urban Centrality: A Simple Index

This study introduces a new measure of urban centrality. The proposed urban centrality index (UCI) constitutes an extension to the spatial separation index. Urban structure should be more accurately analyzed when considering a centrality scale (varying from extreme monocentricity to extreme polycentricity) than when considering a binary variable (monocentric or polycentric). The proposed index controls for differences in size and shape of the geographic areas for which data are available, and can be calculated using different variables such as employment and population densities, or trip generation rates. The properties of the index are illustrated with simulated artificial data sets and are compared with other similar measures proposed in the existing literature. The index is then applied to the urban structure of four metropolitan areas: Pittsburgh and Los Angeles in the United States; São Paulo, Brazil; and Paris, France. The index is compared with other traditional spatial agglomeration measures, such as global and local Moran's I, and density gradient estimations. El presente estudio introduce una nueva medida de centralidad. El índice de centralidad urbana propuesto (UCI, por sus siglas en inglés) es una extensión al índice de separación espacial (spatial separation index)(Midelfart‐Knarvik et al. 2000). El análisis de la estructura urbana resulta más preciso al usar el índice cuando se toma en cuenta una escala de continua de centralidad (que puede variar de un monocentrismo extremo a un policentrismo extremo) que cuando se considera una variable binaria (monocéntrica o policéntrica). El índex propuesto controla las diferencias de tamaño y forma de las áreas geográficas de las que se tienen datos, y puede ser calculada utilizando diferentes variables, como empleo y densidad poblacional, o tasas de generación de viajes. Las propiedades del índice se ilustran con conjuntos de datos artificiales simulados, y se comparan con otras mediciones similares en la literatura ya existente. Posteriormente, el índice es aplicado a la estructura urbana de cuatro áreas metropolitanas: Pittsburgh y Los Ángeles, en EEUU; San Pablo, en Brasil; y París, Francia. Finalmente, se compara el índice con otras mediciones tradicionales de aglomeración espacial, como el índice de Moran local y global, y estimaciones de gradiente de densidad. 本文介绍了一种度量城市中心性的新方法,提出的城市中心性指数（UCI）是对空间分离指数的扩展。当涉及到中心性规模（从极单中心到极多中心）,不仅仅是二元变量（单中心或多中心）,城市结构则需更加精确的测度。本文构建的指数可以通过数据可获取的不同大小和形状的地理单元控制,并通过不同变量（如就业与人口密度或者旅次产生率）测算得到。该指数的属性可以通过人工数据集的模拟示例说明,或者通过对比已有文献对相似指数的阐述加以说明。然后,通过将该指数应用于全球四个大都市区（美国匹兹堡和洛杉矶、巴西圣保罗和法国巴黎）的城市结构中进行检验。最后,将该指数与其他测度传统空间集聚指数如全局和局部Moran指数及密度梯度估计进行对比.     

Creativity,Culture and Urban Strategies: A Fallacy in Cultural Urban Strategies

Two fields of knowledge have been of special importance for the emergence of culture-led urban planning in Norwegian cities: one concerns the understanding of the potential of culture as an economic driving force in urban regeneration, while the other focuses on the emergence of the concept of the “creative class” and has drawn attention to the importance of competence and creativity in urban development. Despite clear connections between the two fields, it may appear that false connections have been made in regeneration strategies in a number of cities. Based on analyses of the culture-led urban strategy of Kristiansand, a small Norwegian city, these knowledge fields are discussed and it is claimed that there seems to be a fallacy in how they are treated in the culture-led urban strategy. The fallacy concerns the way that creativity is equated with culture and further how theories about the emergence of the creative class are equated with a culture industry approach to urban planning. Questions are raised about the potential of culture industry strategies and it is argued that the potential for growth in small cities may not be as great as the public debate and research conducted in large metropolises might suggest.     

城市环境与健康专栏导论

城市与健康的关系并不是一个新议题,但随着全球范围内人口向城市区域的集聚,通过城市环境的建设与设计来干预公共健康问题成为一种新思路。其背后的逻辑在于城市环境中的诸多要素,例如住房、交通、能源、公共空间、医疗设施等能有效地影响到体力活动、环境(如污染,噪音等)暴露、社会交往等健康相关的行为以及相应的生理与心理健康效果。     

A Model of Lottery Participation

With the spread of state–sponsored lotteries to all but 17 states, it is important to understand the circumstances and perspectives of those who contribute to lottery revenues. A multivariate model of percent of income spent on lottery tickets indicates that participation is a declining function of income and education, and that it is higher among black, male, and older respondents. In addition, participation is affected by the social context of the respondent and the respondent's attitudes regarding the lottery as enjoyable and an escape. Attitudes favorable to lottery play are concentrated disproportionately among less advantaged groups, particularly the least educated.     

重谈石家庄城市建设问题

这篇文章作者已在去年送石家庄市领导审阅,引起市领导的重视,有的意见已被采纳,文中观点颇有深意,特予发表。     

The Role of the Development Industry in Shaping Urban Social Space: a Conceptual Model

Socio‐spatial differentiation or the spatial arrangement of social groups in cities has long been the subject of scholarly attention in urban studies from a variety of perspectives. In many contemporary societies, the development industry plays an important and growing role in socio‐spatial differentiation. This paper presents a conceptual model for the empirical analysis of the role of this industry in shaping urban social space.     

中国城市民俗研究述论

城市民俗是民俗学十分重要的研究领域.从历史发展看,我国的城市脱胎于原始社会的民族村落制度,商代出现了城,西周就出现了城郭相连的都城格局,产生了城隍的信仰,城市民俗应运而生.《周礼·考工记》中记述了帝都的六职、百工以及丰京、镐京的"匠人营园"等城市民俗文化情景,从此揭开了城市民俗研究的序幕.本文在对我国城市民俗研究历程探讨的基础上,对当代城市民俗研究成果进行评析,进而提出该研究领域的拓展方向,以更好地促进城市民俗研究的勃兴.