Research On Dual Structure Model Of Population Flow In The Process Of China's Urbanization

To aim at the limitations of the classical models of Lewis and Todaro in the analysis of china's population flow. Begin with the mechanism model of dual structure dynamic mechanism of population flow. By comparing and analyzing P-N junction theoretical model and obvious dual structure factor existing in the process our country's urbanization, combining with relevant theories and models of urbanization at home and abroad. Describing dual structure dynamic characteristic of population flow and building a new model of population flow in the process of urbanization based on P-N junction model.The model can give us a rational explanation on variable corresponding and the mechanism of population flow. At the same time, the model combines population flow with the different urbanization stages and considers the different trend and intensity of population flow in different stages of urbanization. It gives us a reverse population flow critical value which can judge whether urbanization comes into reverse urbanization. What's more, this model also uses the probability of population flow to adjust the formal P-N junction model, which makes it more reasonable. In the process of mechanism explanation, we consider the following factors: the development of rural area, migration of urban industry, the migratory cost, frictional cost and psychological cost exist in rural labors'flow. In order to be beneficial to quantitative analysis, we use expected income differential between rural and urban area which is proposed by Todaro's model also. Finally, using Dalian's data of population flow to check this model and achieving satisfactory results.On the basis of this model's research, we get further study by contrast the population flow model we built with two classical models .And we find that the model we built can also makes a good compensation for the limitations of the two classic models and can combine the two models organically. What's important is that it can give us a reasonable explanation of population flow under dual wage-decided structure.Put the research of this model inside the process of urbanization. By further analysis and research, we find out that there is a intrinsic consistence between our model and Northam's curve. We can deduce Northam's curve through the population flow model we built. This also tells us that our model can not only give an explanation of the tendency of population flow but also can reflect the intrinsic rule of urbanization itself.