Study On The Transportation Model In Economic Circles Based On System Dynamics

The economic circle is formed of economic globalization and regional economic integration, which is an inevitable trend of urbanization development. Along with the rapid economic development, the three core economic circles involved Yangtze River delta, Pearl River Delta and Around Bohai Area are developed further, as well as other sub-economic circles are formed and developing gradually. The transportation system in economic circle is a large opening and complicated system, its integration and optimization decide the distribution and radiation function of economic system. Only realized the maximum benefit of the whole transportation system, the regional economic can be promoted furthest, and the transportation demand in economic circle also can be satisfied furthest.Taking the transportation system in economic circle as the research object, this dissertation analyzes the evolution rule of transportation system, the coordinated operation between regional economic and transportation, and supply-demand equilibrium in economic circle. On the basis of the relationship among regional economic, transportation demand and supply, the system dynamics model for transportation in economic circle is built.Transportaion in economic circle is a spatial complex system with dissipative structure. It has some basic characteristics such as across-region, strong economical central city, globlity, co-ordination, stratified, dynamics, distribution and radiation function and so on. From the causalities relationship between economic circle and transportation, it is put forward that regional economy is the dynamic basis, transportation demand is the intrinsic motivation, and transportation supply is the media force for the transportation system in economic circle.Applying the symbiosis theory, it is pointed out that the symbiosis between transportation and regional economy is a surviving material connection among subjects in the circle. It is also a relationship for symbiosis units according to one symbiosis mode under a certain environment. Using the Logistic Model on the biology, the mathematical model described transportation and regional economy is established, which analyzes their coordinated relationship. Then the stable symbiosis requirement is solved.Demand and supply are the important components for the transportation system in economic circle. This dissertation proposes several of facters influencing supply-demand equilibrium in the circle, which are taken as the basic dataset to bulid system dynamic model. The elastic model of total equilibrium and the entropy model of structure equilibrium are built, with analyzing combined an example.Based on the relationship between economic development and transportation system, the interaction with every facter in this system is studied, considering the dynamic development of demand and supply, as well as economic level, demand, supply and strategy. The system structure equations and therein parameters are determined to build the system dynamics model for transportation in economic circle.With the system dynamics model as the core, the practicability and validity of the model are tested by simulating analysis, acoording to the dataset of Guanzhong-Tianshui economic circle. Thus the transportation demand-supply status and the economical level trend are holded on a macro. Finally, it can be given reasonable suggestions for the sustainable development of transportation in economic circle by means of testing different policies based on the system dynamics model.