DEVELOPMENT POLICIES,URBAN UNEMPLOYMENT AND DEFORESTATION: THE ROLE OF INFRASTRUCTURE AND TAX POLICY IN A TWO-SECTOR MODEL*

ABSTRACT. We model an economy of a developing country that produces an exportable manufactured good in an urban sector and a nontradable rural good. Manufacturing faces a fixed wage, which encourages urban unemployment. Changes in cultivated area in the rural sector involve deforestation or reforestation at frontiers. Government taxes to pay for urban infrastructure that assists the manufacturing sector. Increases in urban infrastructure may relieve or exacerbate frontier deforestation but expands manufacturing employment and reduces urban unemployment. Rural transportation improvements exacerbate frontier deforestation but expand employment in the urban manufacturing sector. A larger population, ceteris paribus, widens the rural-urban wage gap and exacerbates deforestation, but may cause manufacturing employment to expand or contract.     

THE DETERMINANTS OF DISTANCE TO SHOPPING CENTERS IN AN URBAN MODEL CONTEXT

ABSTRACT. We discuss the distance to shopping in the context of three fundamental theories: The Optimal City Theory, the Central Business District Theory and a Cost-Benefit Theory. Each is described and estimated separately by econometric models. The three theories are combined in a final model using the expansion method. The final model, including all three theories, is based on enquiry data from 15 Danish towns.     

SOLVING A THREE-DIMENSIONAL URBAN ACTIVITY MODEL OF LAND USE INTENSITY AND TRANSPORT CONGESTION*

ABSTRACT Recent developments in combining input-output and transportation planning models have made it possible to construct realistic comprehensive urban and regional activity models of land use intensity. These models form the basis for a rigorous approach to studying the interactions among urban activities. However, efficient computational solution methods for implementing such comprehensive models are still not available. In this paper, an efficient solution method for a nonlinear programming urban systems model is developed by combining Evans's partial linearization technique with Powell's hybrid method. The solution algorithm is applied to a small but realistic urban area with a detailed transportation network.     

现代城市管理新模式:城市网格化管理综述

随着现代城市的快速发展,传统的城市管理手段和方式远远不能满足现代城市管理的要求,将现代城市管理理论与"数字城市"技术相结合而形成了新的城市管理模式-城市网格化管理。该模式将城市管理过程分为信息收集、案卷建立、任务派遣、任务处理、处理反馈、核实结案等环节,它采用的网格管理法、城市部件管理法、两个轴心的管理体制等是对现代城市管理模式的极大创新。     

人口的区位过程与城市的分形形态——关于城市生长的一个理论探讨

基于中心地假设,从城市人口分布的Sherratt模型和Naroll Bertalanffy的城乡人口异速生长关系出发导出关于人口分布空间动力学和城市扩展时空过程的数学模型,然后借助Batty等关于城市生长的DLA -DBM模拟结果证明人口的区位选择过程与城市的分形形态存在着内在关系。文章提出了关于区域人口运动和城市形态演化的三个基本原理:信息火商增原理、异速生长原理和Logistic发展原理。     

FROM THE FIRM GROUND OF RESULT AND FACT TO THE TOSSING SEA OF CAUSE AND THEORY: THE ROLE OF GOVERNMENT IN URBAN DEVELOPMENT*

Are government policies of any real significance in shaping the pattern of development in metropolitan regions? This essay summarizes the widely-held view that ‘economic forces’ determine the distribution of jobs and residences in urban areas, and argues that this conclusion involves serious conceptual difficulties. The essay then shows how the theory of political influence and related concepts can be used to clarify the issue of causation in urban development, and summarizes the authors' own substantive conclusions—that under certain specifiable conditions government activities do have a highly significant role in shaping metropolitan growth.     

MIGRATION AS A WAY TO DIVERSIFY: EVIDENCE FROM RURAL TO URBAN MIGRATION IN THE U.S.

This paper extends the utility maximization model of migration by introducing income and unemployment‐related uncertainties as determinants of utility, and analyzes the effects of the informational advantages of migrants. The paper maintains that migration would expand an individual's economic choices and opportunities and allow diversification. Consequently, diversification advantages influence the location decisions of migrants, an effect captured by the correlation of incomes at the origin and potential destinations. We use the discrete choice model based on random utility maximization as the framework for our empirical investigation of migration from the United States rural to urban counties. This paper takes advantage of an equivalent relation between the conditional logit model and Poisson regression to study the migration decisions using aggregate data among a large set of spatial alternatives. The results show that the diversification concerns have significant effects on location decisions of the rural‐urban migrants in the United States.