title: Nonlinearities in NARX polynomial models: representation and estimation
abstract: It is shown how nonlinearities are mapped in NARX polynomial models. General expressions are derived for the gain and eigenvalue functions in terms of the regressors and coefficients of NARX models. Such relationships are useful in grey-box identification problems. The results are illustrated using simulated and real data
keyphrases: eigenvalue functions regressors grey-box identification problems NARX polynomial model nonlinearities nonlinearity representation nonlinearity estimation gain functions nonlinear autoregressive exogenous-input polynomial model