Introducing boundary conditions in semi-quantitative simulation

Boundary value problems specifying how external influences on dynamic systems vary over time greatly extend the scope of qualitative reasoning techniques, enabling them to achieve a much wider applicability. This paper discusses conceptual and practical aspects that underlie the problem of handling boundary conditions in SQPC, a sound program for modeling and simulating dynamic systems in the presence of incomplete knowledge. Issues concerning the ontology (actions us . measurements), the temporal scale (instantaneous vs . extended changes), the impact of discontinuity on model structure and the consequences of incompleteness in predictions are discussed . On the basis of the experimentation done so far it is claimed that given the generality of the assumptions underlying the techniques presented in the paper, and given the relatively low computational cost that is often required to solve a boundary value problem, they are viable and can be utilized to widen the applicability spectrum of Qualitative Reasoning .