Qualitative Probabilistic Networks in Medical Diagnosis

We will present an overview of qualitative probabilistic networks in the context of skin diseases with children. The basic framework will be explained, with particular attention to the notions of qualitative influence, product synergy and intercausal reasoning. The drawbacks of this basic approach soon become apparent; most notably, the problem of overabstraction or overgeneralization. Answering the need for refinement, we discuss the formalism of enhanced qualitative probabilistic networks. Finally, we will propose to include the noisy-MAX concept from Bayesian networks into the qualitative scheme. To this end, we provide a proof for the qualitative product synergy the noisy-MAX displays and show how it can function as a guideline to incorporate multi-valued variables in the enhanced qualitative paradigm.