Using QR to solve quantitative modeling problems: an application to intracellular thiamine kinetics

Recent works carried out within the Qualitative Reasoning (QR) research framework are centred on the exploitation of QR techniques to address the problem of quantitative System Identification (SI) with the goal to enhance the overall process, namely the selection of a proper model identifier and the parameter estimation procedure. Traditional SI, both parametric and non-parametric, may be really problematic for those application domains, such as the medical/physiological one, of which either the available knowledge is incomplete or the structural model is not identifiable or the observed data are poor in number and in quality. This paper deals with the application of an hybrid method, which builds a fuzzy system identifier upon a qualitative structural model, to solve identification problems of the intracellular kinetics of Thiamine (vitamin B1). The model obtained is not as much informative as a purely structural one but robust enough to be used as a simulator, and then to provide physiologists with a deeper understanding of the Thiamine metabolism in the cells.