Artículos con la etiqueta ‘ciudades medianas y pequeñas’

An allometric scaling relation based on logistic growth of cities

Por • 25 dic, 2013 • Category: Opinion

The relationships between urban area and population size have been empirically demonstrated to follow the scaling law of allometric growth. This allometric scaling is based on exponential growth of city size and can be termed «exponential allometry», which is associated with the concepts of fractals. However, both city population and urban area comply with the course of logistic growth rather than exponential growth. In this paper, I will present a new allometric scaling based on logistic growth to solve the abovementioned problem. The logistic growth is a process of replacement dynamics. Defining a pair of replacement quotients as new measurements, which are functions of urban area and population, we can derive an allometric scaling relation from the logistic processes of urban growth, which can be termed «logistic allometry». The exponential allometric relation between urban area and population is the approximate expression of the logistic allometric equation when the city size is not large enough. The proper range of the allometric scaling exponent value is reconsidered through the logistic process. Then, a medium-sized city of Henan Province, China, is employed as an example to validate the new allometric relation. The logistic allometry is helpful for further understanding the fractal property and self-organized process of urban evolution in the right perspective.



Devil in details of grand urban plan

Por • 7 mar, 2013 • Category: sociologia

Chinese leaders love to think long-term, and so were trying to address also this issue when planning a gigantic development program of 40 trillion yuan (US$6.4 trillion) for the urbanization of 400 million people in the next 10 years. The mammoth urbanization plan will be concentrated mainly in small and medium cities with less than 2 million residents, with the 40 trillion yuan investment financed by a massive issuance of bonds in the next 10 years, something that will change the financial structure of the country in the longer term. The medium-term goal is to spur China’s development by steadily bringing into the cities the 400 million people who now live part of the year, or year-round, in the countryside.