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.     

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.……     

Russia's Energy Policy: A Divergent View

A noted American analyst of Russian, Central Asian, and Transcaucasian oil and gas industries and markets offers his own perspective on issues raised in the preceding paper on Russia's energy policy (Milov et al., 2006). While generally concurring that Russia indeed pursues an ad hoc (rather than systemic) energy policy, he expresses divergent views on the role of government-regulated versus market-based pricing in final and primary energy use, reasons for the intense flows of oil and gas to Europe, the role of pipelines in determining oil export allocations, and the contribution of regional monopolies and refining capacity to domestic oil product prices. Journal of Economic Literature, Classification Numbers: L71, O13, Q40, Q48. 20 references.     

China's Energy Future: A Framing Comment

A noted Hong Kong-based specialist on China's energy industries presents a comment on three papers comprising a symposium on that country's rapidly expanding oil, natural gas, and nuclear power sectors. He frames his observations around five overarching themes that have shaped China's energy sector development over recent decades and will continue to do so in the future. These include observations to the effect that: (a) China's energy policy seeks broadly similar objectives to those of other countries; (b) the country's energy resource endowment is not particularly rich when viewed in relation to the size of its population; (c) its energy mix continues to be dominated by coal, with important implications for the environment and domestic freight transportation; (d) the country's economy is confronting a pronounced spatial mismatch between the location of energy resources and the markets where they are consumed; and (e) strategies for energy developments in China are closely tied to overriding political and economic concerns at any given point in time.     

Russia's Energy Policy: A Framing Comment

A prominent specialist on the Russian economy provides a framing comment on two preceding papers entitled "Russia's Energy Policy" (by Vladimir Milov, Leonard Coburn, and Igor Danchenko) and "Russia's Energy Policy: A Divergent View" (by Matthew J. Sagers). The author argues that Russia's current energy policy should be viewed as an outcome of competition between three overlapping programs. In this context, he identifies three policy models—the old Soviet, the liberal or oligarchic, and the most recent state capitalist. The latter is currently supported by President Putin, who prioritizes diversification of the country's economy at the expense of diminished investments in the oil and gas sector. Journal of Economic Literature, Classification Numbers: L71, O13, Q40, Q48. 2 tables, 2 figures, 22 references.     

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.     

Global Climatic Change: the Difficulties of Assessing Impacts

The Intergovernmental Panel on Climate Change (IPCC) report, initiated in 1988, is complete, was debated at the Second World Climate Conference in November, 1990 and was subsequentty submitted to the United Nations General Assembly. IPCC: (i) asserted the reality of humanity's disturbance of the natural climate system; (ii) demanded studies to improve our knowledge of processes vulnerable to climatic changes: and (iii) called for policy responses to mitigate and adapt to these changes. Two fundamental issues are: how will global climatic change affect natural resources and human population and how will the impetus towards policy responses, particularly greenhouse gas emission reduction treaties, affect industry, the economy and trade? A necessary first step in the highly desirable and geographical aspiration of striving to link numerical climate modelling to the predictions of socioeconomic systems is increased awareness and improved understanding of current physical and social models. In this paper I review the status of numerical climatic modelling especially as it pertains to scenarios of the effects of human-enhanced greenhouse warming. These projections are of futures which are themselves the result of socio-economic predictions. Development of appropriate adaptive strategies depends crucially upon improved simulation of the continental near-surface climate and on improved spatial resolution of climate models by at least two orders of magnitude. Such increased resolution is likely to demand a thousandfold increase in computing power. The physical results of global climatic change are likely to be less significant than the social and economic effects resulting from international agreements on emission reduction Recent shifts in international research and policy responses place today's studies of global climatic change firmly at the focus of human-environment interactions and hence at the core of modern geography.