检索规则说明:AND代表“并且”;OR代表“或者”;NOT代表“不包含”;(注意必须大写,运算符两边需空一格)
检 索 范 例 :范例一: (K=图书馆学 OR K=情报学) AND A=范并思 范例二:J=计算机应用与软件 AND (U=C++ OR U=Basic) NOT M=Visual
机构地区:[1]北京大学城市与环境学系,中国北京100871
出 处:《经济地理》2003年第4期476-481,共6页Economic Geography
基 金:国家自然科学基金(40071035);河南省自然科学基金(004071200)资助项目的部分内容。
摘 要:在分形性质非退化的前提下,城市规模(S)与产出(Y)之间具有双对数关系Y=a+bS,式中b为具有广义分维性质,且一般b>1。这暗示,在正常情况下,城市规模越大,城市的人均产出一般也就越高;城市的产出效率决定城市规模,城市规模反作用于城市的产出能力。城市规模与产出的相关性强弱可以反映出城市与城市体系性状的好坏。The component parts of a city as a system are related to the economic output of the city, if a function, Y=f(x1,x2,...,xn), is given, a generalised Cobb-Douglas function, Y=μni=1xiσi can be derived from it as a priori model, where xi is a certain measurement of the ith element of the city, Y is the output, μ, σi are parameters and σi=dlnY/dlnxi (i=1,2,...,n; n is the number of the urban component parts, or elements). All of these indicate that a city may be self-affine and has fractal nature. Considering the allometric relationship between xi and xj, namely, xi∝xjαij, the C-D function can be reduced to a two-variable model, e.g., Y∝xidi where αij, di are paremeters, and the former is usually called the allometric coefficient. Amongst the component parts of a city, population is the most important one, and the relationships between the population sizes and the economic outputs of cities draw much attention in China these years. In this paper, a fractal model on urban size-output relationship is advanced as Y=aSb,based on some of the studies made by Prof. Zhou Yixing, where S is the city population size, Y is the urban economic output, a is a proportionality coefficient, and b is called scaling factor which is regarded as generalized fractal dimension because b=D1/D2, here D1 is the dimension of city size and D2 is the dimension of urban output. It is discovered that, ①The larger the city size is, the more the corresponding urban economic output is, for b>1.②The population size of a city is determined by its capability of economic output and in turn reacts on it.③The fractal relationship of urban size output is a kind of good relationship for a city as a system or a system of cities, which indicates that urban systems can be optimized by means of fractal idea related.
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在链接到云南高校图书馆文献保障联盟下载...
云南高校图书馆联盟文献共享服务平台 版权所有©
您的IP:3.20.221.0