Journal ArticleParameter Identifiability and Reduction for Smooth and Nonsmooth Differential-Algebraic Equation SystemsAbdelfattah, Hesham; Stechlinski, Peter; Eisa, Sameh AWe extend the sensitivity rank condition (SERC), which tests for identifiability of smooth input-output systems, to a broader class of systems. Particularly, we build on our recently developed lexicographic SERC (L-SERC) theory and methods to achieve an identifiability test for differential-algebraic equation (DAE) systems for the first time, including nonsmooth systems. Additionally, we develop a method to determine the identifiable and non-identifiable parameter sets. We show how this new theory can be used to establish a (non-local) parameter reduction procedure and we show how parameter estimation problems can be solved. We apply the new methods to problems in wind turbine power systems and glucose-insulin kinetics.Institute of Electrical and Electronics Engineers Inc.2024-12-2310582562IEEE Control Systems Letters83159 to 31642475-1456https://doi.org/10.1109/LCSYS.2024.35214272318773; 2318772Differential algebraic systemsnonlinear systems identificationhybrid systems.National Science Foundation