1. Data Analysis & Modeling Group, Transportation Research Institute, Hasselt University, Building D, 3590 Diepenbeek, Belgium, ProMeta, Interfacultary Center for Proteomics and Metabolomics, K.U.Leuven, Herestraat 49, bus 1023, 3000 Leuven, Belgium, and Laboratory for Functional Genomics and Proteomics, Naamsestraat 59, Leuven, Belgium