Simulation modeling of body weight dynamics and web game development

Abstract

In this thesis, we rst build a valid simulation model of the body weight dynamics system of a healthy, adult person. The model simulates the long term dynamics of the body weight, based upon Hall's body weight simulation model [1]. We perform extensive validation testing of Hall's model by using system dynamics approach to evaluate the validity of the model's causal structure. The validation tests show that the model has realistic behaviors under various dieting regimes. There are a few modi cation areas in which our model di ers from Hall's original model. Firstly, our model has some simpli cations that highlight the causality relationships more clearly, while maintaining the validity. Secondly, our model incorporates a hypothesized process called secondary oxidation to make the system produce valid behavior under very high energy expenditures. Thirdly, we render the model generic for any healthy, adult person, and we deduce the formulas of metabolic parameters to customize the generic model to the speci c, simulated person. In the second part of the thesis, we develop a software (Mashap) that automatically generates and runs a web based simulation game for any system dynamics model. Our software has some important advantages over the existing ones: First, it is an open platform on which new tools can be built. Second, it is built for generating web games for all system dynamics modeling software. We nally use the game generator to develop a web based game for our modi ed body weight dynamics model. The game generator will enable the system dynamics researchers to build web based gaming environments for their own models.