The bond-graph method for technological forecasting and resource policy analysis

Bond graphs are succinct, pictorial statements of mathematical models. These statements are so precise that computers can be programmed to derive sets of differential equations from them: the so-called state variable equations. Previously, bond graphs have been used to describe physical systems only; however, in this paper the authors extend the method to the analysis of nonlinear, dynamic economic systems. An explicit set of rules is provided for the construction of economic bond graphs and for the step by step derivation of the state equations. The use of the rules is illustrated with a large number of examples.