Construction by Replacement: A new approach to simulation modeling

Simulation modeling can be valuable in many areas of management science, but is often costly, time-consuming and difficult to do. This paper describes a new approach to simulation that has the potential to be much cheaper, faster and easier to use in many situations. In this approach, users start with a very simple generic model and then progressively replace parts of the model with more specialized "molecules" from a systematically organized library of predefined components. At each point, the system lets the user select from lists of possible substitutions, and then either automatically creates a new running model or shows the user where further manual changes are needed.The paper describes an extensive experiment with using this approach to construct system dynamics models of supply chain processes in a large manufacturing company. The experiment included developing a comprehensive catalog of system dynamics molecules analogous to the periodic table in chemistry. The experiment also included developing an innovative "tangible user interface" with which users can create simulation models by moving actual physical objects around on a special table called a Sensetable. The paper concludes with a discussion of the benefits and limitations of this approach and how it could be used in other situations.