Study And Application On Method Of System Dynamics Structural Model

Building System Dynamics structural model is the base of doing qualitative analysis or quantitative analysis. Experts in different areas have different views on the system structure modeling, the so-called opinion, but it is lack of model standardization. Therefore, how to standardize the establishment of a system dynamics model is an important issue.The method of system structure model are reviewed, then the necessary of standardize the establishment of system structure model is proposed. According to the system scientific theory and through differential equation theory analysis, an improvement method of Two Branch Diagram in establishing Structure Model of In-tree for SD is present, and an example is given to do theoretical analysis and simulation analysis. The effectiveness of the new method is proved.Based on the characteristics of modeling method and the special advantages of structural equation model and the demand of establishing system dynamics model, the step of establishing SD Structure is proposed. First, identify a problem. Second, determine system boundaries. Third, system is divided into a number of sub systems by factor analysis method, and then the element set of subsystems are determined by the Diamond thought. Fourth, system structure model is established by Structural equation modeling method. Fifth, SD structure model is established. And Taking Ganjiang river basin water ecological carrying capacity for an example to analysis. A SD structure model for GanJiang river basin water ecological carrying capacity is established.