Abstract
When we analyse various dynamic behaviours of a real system under consideration by the method of system dynamics (SD), we must begin with construction of an SD model which serves modeler's purposes. The most essential step in the modeling process is to include some major structures necessary to represent the relevant dynamic behaviours of the real systems. At this point, clarifying the characteristic of the included structure is very important. Usual methods for describing the charcteristic are intuitive devices applying causal-loop diagrams, flow diagrams, structural equations and verbal statements. But only these are not always sufficient for such description. Therefore, we must go over the step which merely explain structural equations and causal relations among system elements and then it is necessary to establish the theoretical method which exactly describe and analyse all characteristics of the model's structure.
In the present paper, we shall try to provide the means of solving the need. Accordingly, after establishing the general SD model by an axiomatic method, we construct geometrical representations of the SD model and the total flow diagram by the application of the combinatorial topology. On the basis of the representations, we can make clear the relation between integral cycles of the complexes and feedback loops in the SD model, thereby determine the structures of the SD model and the feedback loops.
