A divide-and-conquer strategy for qualitative simulation of complex dynamical systems

This paper presents a divide-and-conquer approach that aims at making QSIM simulation tractable. We consider dynamical systems the structure of which can be represented by compartments. The system model is decomposed into sub-models tightly connected through shared variables on the basis of the analysis of the causality relations intrinsically captured by the compartmental model structure. The sub-models are separately simulated but their behaviors are constrained by the information on the shared variables generated from the simulation. The partition of the complete model into smaller ones prevents the construction of temporal correlations between variables in different sub-models, and thus the generation of a complete temporal ordering of all unrelated events that is one of the major causes of intractable branching in qualitative simulation. The strategy we propose is discussed through a case study in the field of Plant Pathology, namely the germination process of Plasmopara viticola oospores.