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Network Structure and City Size

Levinson, David
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 12/01/2012 EN
Relevância na Pesquisa
46.07%
Network structure varies across cities. This variation may yield important knowledge about how the internal structure of the city affects its performance. This paper systematically compares a set of surface transportation network structure variables (connectivity, hierarchy, circuity, treeness, entropy, accessibility) across the 50 largest metropolitan areas in the United States. A set of scaling parameters are discovered to show how network size and structure vary with city size. These results suggest that larger cities are physically more inter-connected. Hypotheses are presented as to why this might obtain. This paper then consistently measures and ranks access to jobs across 50 US metropolitan areas. It uses that accessibility measure, along with network structure variables and city size to help explain journey-to-work time and auto mode share in those cities. A 1 percent increase in accessibility reduces average metropolitan commute times by about 90 seconds each way. A 1 percent increase in network connectivity reduces commute time by 0.1 percent. A 1 percent increase in accessibility results in a 0.0575 percent drop in auto mode share, while a 1 percent increase in treeness reduces auto mode share by 0.061 percent. Use of accessibility and network structure measures is important for planning and evaluating the performance of network investments and land use changes.

Understanding the City Size Wage Gap*

Baum-Snow, Nathaniel; Pavan, Ronni
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.07%
In this paper, we decompose city size wage premia into various components. We base these decompositions on an estimated on-the-job search model that incorporates latent ability, search frictions, firm-worker match quality, human capital accumulation and endogenous migration between large, medium and small cities. Counterfactual simulations of the model indicate that variation in returns to experience and differences in wage intercepts across location type are the most important mechanisms contributing to observed city size wage premia. Variation in returns to experience is more important for generating wage premia between large and small locations while differences in wage intercepts are more important for generating wage premia betwen medium and small locations. Sorting on unobserved ability within education group and differences in labor market search frictions and distributions of firm-worker match quality contribute little to observed city size wage premia. These conclusions hold for separate samples of high school and college graduates.

Inequality and City Size*

Baum-Snow, Nathaniel; Pavan, Ronni
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.12%
Between 1979 and 2007 a strong positive monotonic relationship between wage inequality and city size has developed. This paper investigates the links between this emergent city size inequality premium and the contemporaneous nationwide increase in wage inequality. After controlling for the skill composition of the workforce across cities of different sizes, we show that at least 23 percent of the overall increase in the variance of log hourly wages in the United States from 1979 to 2007 is explained by the more rapid growth in the variance of log wages in larger locations relative to smaller locations. This influence occurred throughout the wage distribution and was most prevalent during the 1990s. More rapid growth in within skill group inequality in larger cities has been by far the most important force driving these city size specific patterns in the data. Differences in the industrial composition of cities of different sizes explain up to one-third of this city size effect. These results suggest an important role for agglomeration economies in generating changes in the wage structure during the study period.

Is There a Metropolitan Bias? The Inverse Relationship between Poverty and City Size in Selected Developing Countries

Ferre, Celine; Ferreira, Francisco H.G.; Lanjouw, Peter
Fonte: Banco Mundial Publicador: Banco Mundial
Relevância na Pesquisa
66.12%
This paper provides evidence from eight developing countries of an inverse relationship between poverty and city size. Poverty is both more widespread and deeper in very small and small towns than in large or very large cities. This basic pattern is generally robust to choice of poverty line. The paper shows, further, that for all eight countries, a majority of the urban poor live in medium, small, or very small towns. Moreover, it is shown that the greater incidence and severity of consumption poverty in smaller towns is generally compounded by similarly greater deprivation in terms of access to basic infrastructure services, such as electricity, heating gas, sewerage, and solid waste disposal. The authors illustrate for one country -- Morocco -- that inequality within large cities is not driven by a severe dichotomy between slum dwellers and others. The notion of a single cleavage between slum residents and well-to-do burghers as the driver of urban inequality in the developing world thus appears to be unsubstantiated -- at least in this case. Robustness checks are performed to assess whether the findings in the paper are driven by price variation across city-size categories...

Governance and the City : An Empirical Exploration into Global Determinants of Urban Performance

Kaufmann, Daniel; Léautier, Frannie; Mastruzzi, Massimo
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Relevância na Pesquisa
56.18%
The authors contribute to the field of urban governance and globalization through an empirically-based exploration of determinants of the performance of cities. They construct a preliminary worldwide database for cities, containing variables and indicators of globalization (at the country and city level), city governance, city performance (access and quality of infrastructure service delivery), as well as other relevant city characteristics. This city database, encompassing hundreds of cities worldwide, integrates existing data with new data gathered for this research. The findings suggest that good governance and globalization (at both the country and city level) do matter for city-level performance in terms of access and quality of delivery of infrastructure services. The authors also find that globalization and good city governance are significantly related with each other. Furthermore, the evidence suggests that there are complex interactions between technology choices, governance, and city performance, as well as evidence of a nonlinear (U-shaped) relationship between city size and performance, challenging the view that very large cities necessarily exhibit lower performance and pointing instead to potential agglomeration economies. The framework also suggests a way of bridging two seemingly competing strands of the literature...

Urbanization and the Geography of Development

Henderson, J. Vernon
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
EN_US
Relevância na Pesquisa
46.14%
This paper focuses on three interrelated questions on urbanization and the geography of development. First, although we herald cities with their industrial bases as "engines of growth," does industrialization in fact drive urbanization? While such relationships appear in the data, the process is not straightforward. Among developing countries, changes in income or industrialization correlate only weakly with changes in urbanization. This suggests that policy and institutional factors may also influence the urbanization process. In fact, the relationship between industrialization and urbanization is absent in Sub-Saharan Africa. Second, do development policies have a big-city bias and, if so, what does this imply for growth and inequality? Intelligent public infrastructure investment inevitably involves picking winners. One hopes that such choices are based on market indicators, such as where industry is starting to agglomerate and where there are clear needs. Yet governments seem to favor the biggest cities which in turn draw firms and migrants to these cities. To try to avoid excessive in-migration and oversized...

Is There a Metropolitan Bias? The Relationship between Poverty and City Size in a Selection of Developing Countries

Ferre, Celine; Ferreira, Francisco H.G.; Lanjouw, Peter
Fonte: Oxford University Press on behalf of the World Bank Publicador: Oxford University Press on behalf of the World Bank
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
46.03%
This paper provides evidence from eight developing countries of an inverse relationship between poverty and city size. Poverty is both more widespread and deeper in very small and small towns than in large or very large cities. This basic pattern is generally robust to the choice of poverty line. The paper shows, further, that for all eight countries, a majority of the urban poor live in medium, small or very small towns. Moreover, it is shown that the greater incidence and severity of consumption poverty in smaller towns is generally compounded by similarly greater deprivation in terms of access to basic infrastructure services, such as electricity, heating gas, sewerage and solid waste disposal. We illustrate for one country – Morocco – that inequality within large cities is not driven by a severe dichotomy between slum dwellers and others. Robustness checks are performed to assess whether the findings in the paper hinge on a specific definition of “urban area”; are driven by differences in the cost of living across city-size categories; by reliance on an income-based concept of well-being; or by the application of small-area estimation techniques for estimating poverty rates at the town and city level.

Essays on City Size Distribution and Real Estate Bubbles

Lucas, John Paul
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
56.01%
This is a dissertation about urban systems; within this broad subject I tackle three issues, one that focuses on an observed inter-city relationship and two that focus on an intra-city phenomenon. In Chapter II I adapt a model of random emergence of economic opportunities from the firm growth literature to the urban dynamics situation and present several predictions for urban system dynamics. One of these predictions is that the older the city the larger and more diversified it is going to be on average, which I proceed to verify empirically using two distinct datasets. In Chapter III I analyze the Residential Real Estate Bubble that took place in Miami-Dade County from 1999 to 2006. I adopt a Spatial-Economic model developed for the Paris Bubble episode of 1984-1993 and formulate an innovative test of the results in terms of speculative intensity on the basis of proxies of investor activity available in my dataset. My results support the idea that the best or more expensive areas are also where the greatest speculative activity takes place and where the rapid increase in prices begins. The most significant departure from previous studies that emerges in my results is the absence of a wider gap between high priced areas and low priced areas in the peak year. I develop a measure of dispersion in value among areas and contrast the Miami-Dade and Paris episodes. In Chapter IV I analyze the impact on tax equity of a Florida tax-limiting legislation known as Save Our Homes. I first compare homesteaded and non-homesteaded properties...

City Development Strategy South Asia Region : Progress Report

World Bank
Fonte: Washington, DC Publicador: Washington, DC
Tipo: Publications & Research :: Working Paper; Publications & Research
ENGLISH; EN_US
Relevância na Pesquisa
46.02%
This report highlights the discussion, processes, lessons learned in examining innovative options for participation by all stakeholders in seeking new social and economic contracts between civil society and urban governments. The improvement in relationships is geared towards providing better services for urban poor and directly contributing to urban poverty alleviation. The report attempts to capture the new wave of enthusiasm and entrepreneurial inclination to city management that is more transparent and responsive to citizens as 'customers'.

Urbanization and the Geography of Development

Henderson, J. Vernon
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Working Paper; Publications & Research
ENGLISH; EN_US
Relevância na Pesquisa
46.19%
This paper focuses on several interrelated key questions on the geography of development. Although we herald cities with their industrial bases as 'engines of growth,' does industrialization in fact drive urbanization?1 What economic activities do cities of different sizes undertake? Does this change as countries develop? If so, what are the policy implications? Do development policies have a big-city bias? If so, what does this imply for growth and inequality, and what are appropriate place-based policies? Should countries have policies concerning optimal city sizes or city-size distributions? Urbanization is central to the development process. Employment shifts out of agriculture into industry, and industrial production proceeds most effectively in cities, with their agglomeration economies. Cities are thus viewed as engines of growth. While such relationships appear in the data, the process is not straightforward. Among developing countries, changes in income or industrialization correlate only weakly with changes in urbanization. This suggests that policy and institutional factors may also influence the urbanization process...

The Italian primary school-size distribution and the city-size: a complex nexus

Belmonte, Alessandro; Di Clemente, Riccardo; Buldyrev, Sergey V.
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 23/06/2014 EN
Relevância na Pesquisa
46%
We characterize the statistical law according to which Italian primary school-size distributes. We find that the school-size can be approximated by a log-normal distribution, with a fat lower tail that collects a large number of very small schools. The upper tail of the school-size distribution decreases exponentially and the growth rates are distributed with a Laplace PDF. These distributions are similar to those observed for firms and are consistent with a Bose-Einstein preferential attachment process. The body of the distribution features a bimodal shape suggesting some source of heterogeneity in the school organization that we uncover by an in-depth analysis of the relation between schools-size and city-size. We propose a novel cluster methodology and a new spatial interaction approach among schools which outline the variety of policies implemented in Italy. Different regional policies are also discussed shedding lights on the relation between policy and geographical features.

Modeling Fractal Structure of City-Size Distributions Using Correlation Functions

Chen, Yanguang
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 20/09/2011 EN
Relevância na Pesquisa
46.09%
Zipf's law is one the most conspicuous empirical facts for cities, however, there is no convincing explanation for the scaling relation between rank and size and its scaling exponent. Using the idea from general fractals and scaling, I propose a dual competition hypothesis of city development to explain the value intervals and the special value, 1, of the power exponent. Zipf's law and Pareto's law can be mathematically transformed into one another, but represent different processes of urban evolution, respectively. Based on the Pareto distribution, a frequency correlation function can be constructed. By scaling analysis and multifractals spectrum, the parameter interval of Pareto exponent is derived as (0.5, 1]; Based on the Zipf distribution, a size correlation function can be built, and it is opposite to the first one. By the second correlation function and multifractals notion, the Pareto exponent interval is derived as [1, 2). Thus the process of urban evolution falls into two effects: one is the Pareto effect indicating city number increase (external complexity), and the other the Zipf effect indicating city size growth (internal complexity). Because of struggle of the two effects, the scaling exponent varies from 0.5 to 2; but if the two effects reach equilibrium with each other...

Global Patterns of City Size Distributions and Their Fundamental Drivers

Decker, Ethan H.; Kerkhoff, Andrew J.; Moses, Melanie E.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 26/09/2007 EN
Relevância na Pesquisa
46.02%
Urban areas and their voracious appetites are increasingly dominating the flows of energy and materials around the globe. Understanding the size distribution and dynamics of urban areas is vital if we are to manage their growth and mitigate their negative impacts on global ecosystems. For over 50 years, city size distributions have been assumed to universally follow a power function, and many theories have been put forth to explain what has become known as Zipf's law (the instance where the exponent of the power function equals unity). Most previous studies, however, only include the largest cities that comprise the tail of the distribution. Here we show that national, regional and continental city size distributions, whether based on census data or inferred from cluster areas of remotely-sensed nighttime lights, are in fact lognormally distributed through the majority of cities and only approach power functions for the largest cities in the distribution tails. To explore generating processes, we use a simple model incorporating only two basic human dynamics, migration and reproduction, that nonetheless generates distributions very similar to those found empirically. Our results suggest that macroscopic patterns of human settlements may be far more constrained by fundamental ecological principles than more fine-scale socioeconomic factors.

The spatial meaning of Pareto's scaling exponent of city-size distribution

Chen, Yanguang
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 19/09/2013
Relevância na Pesquisa
46.07%
The scaling exponent of a hierarchy of cities used to be regarded as a fractal parameter. The Pareto exponent was treated as the fractal dimension of size distribution of cities, while the Zipf exponent was treated as the reciprocal of the fractal dimension. However, this viewpoint is not exact. In this paper, I will present a new interpretation of the scaling exponent of rank-size distributions. The ideas from fractal measure relation and the principle of dimension consistency are employed to explore the essence of Pareto's and Zipf's scaling exponents. The Pareto exponent proved to be a ratio of the fractal dimension of a network of cities to the average dimension of city population. Accordingly, the Zipf exponent is the reciprocal of this dimension ratio. On a digital map, the Pareto exponent can be defined by the scaling relation between a map scale and the corresponding number of cities based on this scale. The cities of the United States of America in 1900, 1940, 1960, and 1980 and Indian cities in 1981, 1991, and 2001 are utilized to illustrate the geographical spatial meaning of Pareto's exponent. The results suggest that the Pareto exponent of city-size distribution is not a fractal dimension, but a ratio of the urban network dimension to the city population dimension. This conclusion is revealing for scientists to understand Zipf's law and fractal structure of hierarchy of cities.; Comment: 23 pages...

The scaling of human interactions with city size

Schläpfer, Markus; Bettencourt, Luis M. A.; Grauwin, Sebastian; Raschke, Mathias; Claxton, Rob; Smoreda, Zbigniew; West, Geoffrey B.; Ratti, Carlo
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.02%
The size of cities is known to play a fundamental role in social and economic life. Yet, its relation to the structure of the underlying network of human interactions has not been investigated empirically in detail. In this paper, we map society-wide communication networks to the urban areas of two European countries. We show that both the total number of contacts and the total communication activity grow superlinearly with city population size, according to well-defined scaling relations and resulting from a multiplicative increase that affects most citizens. Perhaps surprisingly, however, the probability that an individual's contacts are also connected with each other remains largely unaffected. These empirical results predict a systematic and scale-invariant acceleration of interaction-based spreading phenomena as cities get bigger, which is numerically confirmed by applying epidemiological models to the studied networks. Our findings should provide a microscopic basis towards understanding the superlinear increase of different socioeconomic quantities with city size, that applies to almost all urban systems and includes, for instance, the creation of new inventions or the prevalence of certain contagious diseases.

Modeling fractal structure of city-size distributions using correlation function

Chen, Yanguang
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 25/04/2011
Relevância na Pesquisa
46.09%
Zipf's law is one the most conspicuous empirical facts for cities, however, there is no convincing explanation for the scaling relation between rank and size and its scaling exponent. Based on the idea from general fractals and scaling, this paper proposes a dual competition hypothesis of city develop to explain the value intervals and the special value, 1, of the power exponent. Zipf's law and Pareto's law can be mathematically transformed into one another. Based on the Pareto distribution, a frequency correlation function can be constructed. By scaling analysis and multifractals spectrum, the parameter interval of Pareto exponent is derived as (0.5, 1]; Based on the Zipf distribution, a size correlation function can be built, and it is opposite to the first one. By the second correlation function and multifractals notion, the Pareto exponent interval is derived as [1, 2). Thus the process of urban evolution falls into two effects: one is Pareto effect indicating city number increase (external complexity), and the other Zipf effect indicating city size growth (internal complexity). Because of struggle of the two effects, the scaling exponent varies from 0.5 to 2; but if the two effects reach equilibrium with each other, the scaling exponent approaches 1. A series of mathematical experiments on hierarchical correlation are employed to verify the models and a conclusion can be drawn that if cities in a given region follow Zipf's law...

Urban Skylines: building heights and shapes as measures of city size

Schläpfer, Markus; Lee, Joey; Bettencourt, Luís M. A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 02/12/2015
Relevância na Pesquisa
46.07%
The shape of buildings plays a critical role in the energy efficiency, lifestyles, land use and infrastructure systems of cities. Thus, as most of the world's cities continue to grow and develop, understanding the interplay between the characteristics of urban environments and the built form of cities is essential to achieve local and global sustainability goals. Here, we compile and analyze the most extensive data set of building shapes to date, covering more than 4.8 million individual buildings across several major cities in North America. We show that average building height increases systematically with city size and follows theoretical predictions derived from urban scaling theory. We also study the allometric relationship between surface area and volume of buildings in terms of characteristic shape parameters. This allows us to demonstrate that the reported trend towards higher (and more voluminous) buildings effectively decreases the average surface-to-volume ratio, suggesting potentially significant energy savings with growing city size. At the same time, however, the surface-to-volume ratio increases in the downtown cores of large cities, due to shape effects and specifically to the proliferation of tall, needlelike buildings. Thus...

The Italian primary school-size distribution and the city-size: a complex nexus

Belmonte, Alessandro; Di Clemente, Riccardo; Buldyrev, Sergey V.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 17/07/2014
Relevância na Pesquisa
46%
We characterize the statistical law according to which Italian primary school-size distributes. We find that the school-size can be approximated by a log-normal distribution, with a fat lower tail that collects a large number of very small schools. The upper tail of the school-size distribution decreases exponentially and the growth rates are distributed with a Laplace PDF. These distributions are similar to those observed for firms and are consistent with a Bose-Einstein preferential attachment process. The body of the distribution features a bimodal shape suggesting some source of heterogeneity in the school organization that we uncover by an in-depth analysis of the relation between schools-size and city-size. We propose a novel cluster methodology and a new spatial interaction approach among schools which outline the variety of policies implemented in Italy. Different regional policies are also discussed shedding lights on the relation between policy and geographical features.; Comment: 16 pages, 10 figures

Cross sectional evolution of the US city size distribution

Overman, Henry G.; Ioannides, Yannis
Fonte: Centre for Economic Performance, London School of Economics and Political Science Publicador: Centre for Economic Performance, London School of Economics and Political Science
Tipo: Monograph; NonPeerReviewed Formato: application/pdf
Publicado em /11/2000 EN; EN
Relevância na Pesquisa
46.07%
We report nonparametrically estimated stochastic transition kernels for the evolution of the distribution of US metropolitan area populations, for the period 1900 to 1990. These suggest a fair amount of uniformity in the patterns of mobility during the study period. The distribution of city sizes is predominantly character-sed by persistence. Additional kernel estimates do not reveal any stark differences in intra-region mobility patterns. We characterise the nature of intra-size distribution dynamics by means of measures that do not require discretisation of the city size distribution. We employ these measures to study the degree of mobility within the US city size distribution and, separately, within regional and urban subsystems. We find that different regions show different degrees of intra-distribution mobility. Second-tier cities show more mobility than top-tier cities.

Cross-sectional evolution of the U.S. city size distribution

Overman, Henry G.; Ioannides, Yannis Menelaos
Fonte: London School of Economics and Political Science Research Publicador: London School of Economics and Political Science Research
Tipo: Article; PeerReviewed Formato: application/pdf
Publicado em /05/2001 EN; EN
Relevância na Pesquisa
46.12%
We report nonparametrically estimated nonlinear stochastic transition kernels for the evolution of the distribution of populations of metropolitan areas, for the period 1900 to 1990, based on US Census data. Comparison of kernels across successive time periods with the kernel for a pooled sample suggests a fair amount of uniformity in the patterns of mobility during the study period. The distribution of city sizes is predominantely characterised by persistence. Comparison of the kernel for the pooled sample with the kernel for city sizes relative to their own regional average does not reveal any stark differences in intra-region mobility patterns. We then develop measures that allow us to characterise the nature of intra-distribution dynamics for the city size distribution: one is the first-order "serial" (across the ranking) correlation coefficient of the differences in relative sizes of cities with successive rankings; the second is the mean squared variation of the differences in relative sizes of cities with successive rankings. These measures have the major advantages that they do not require discretization of the city size distribution, nor do they obscure subtle changes within the distribution. We employ these measures to study the degree of mobility within the US city size distribution and...