Network Flow Assignment Applied In National Economic Evaluation Of Planned Port Construction Project

Port construction project need a great amount of investment and resources, which will impact the regional economics greatly, so national economic evaluation must go ahead before the construction. And the compare of whether having the project is the key to national economic evaluation. Under the condition of having the project, we need forecast the flow direction and quantity of the supply of goods in the hinterland after project begin to run. Under the condition of having no project, we need forecast the flow direction and quantity of the supply of goods in the hinterland in the same period. All the problems need to be solved by network flow assignment.The thesis first introduce the basic concept and some common methods of network flow assignment, after analysis the limitation of these methods, put forward the negative exponent network flow assignment model. The model is concise and practical, which contains the character of shortest path factors and randomness in path choice. In order to imitate the realistic condition better, this thesis improves the model by introducing the inclination coefficient to the model and give the solving method of the model.Finally, this thesis applied the model to a realistic example, the national economic evaluation of a certain port construction in Shenzhen, explain the mode of solving the problem that whether having the project by negative exponent network flow model and get a satisfactory result.By now, there is no simple and practical network flow model that can applied to the network flow in real transportation. The model put up in this thesis attempt to do some work in this field and have some practical value.