We consider experimental (in)validation of a nominal discrete-time model by determining if observed input/output data is consistent with a system within a given nu-gap distance from the model (in light of given constraints on possible input and output noise). The general problem has been shown to be NP-hard; however we present linear matrix inequality (LMI) sufficient conditions for model consistency along with LMI necessary and sufficient conditions for invalidation with respect to a special class of input/output noise. A logical extension which considers time-varying perturbations of the nominal model is presented in parallel with the time-invariant nu-gap results.

Keywords: model validation, nu-gap metric, time-domain