Qualitative Simulation in Physiology with Bond Graphs

Abstract

The simulation of a physiological system involves the construction of a model. generally in the form of mathematical equations. the manipulation of this model to obtain the solution of the equations, and finally the interpretation of the result. In a qualitative simulation, in a certain sense, we go directly from the real system to the interpretation without use of the mathematical model. This approach was introduced using artificial intelligence techniques, where we try to reproduce a human reasoning explaining the behavior of the physical system. The qualitative model is constituted by facts and functioning rules. However it is not easy to chose the cause and effect of a functioning rule well suited in each case. The main goal of the work is to present a methodology, based on bond graphs, and the causal stroke algorithm (CASA for short), to obtain the antecedent and consequent of rules, model that explains the functioning of a physiological system. To illustrate the methodology, it is discussed a qualitative dynamic compliance model of a ventricle.