Qualitative modeling and simulation: promise or illusion [basic definitions]

Some basic definitions that serve as a basis for the discussion of qualitative modeling and simulation are presented. The author begins by stating the types of mathematical models that exist i.e. continuous time models (lumped parameter, linear and distributed parameter models), discrete time models and discrete event models. The author distinguishes between quantitative and qualitative models. He defines qualitative variables as having either nominal measures, ordinal measures, interval measures or ratio measures. He then considers four main types of qualitative models: naive physics models, inductive reasoning models, symbolic discrete event models and neural net models. Finally he points to the need to investigate combined quantitative and qualitative models