Parametric and Nonparametric Nonlinear Modeling of Renal Autoregulation Dynamics
The generality of Volterra-Wiener analysis has led to the broad use of nonparamet-ric models of nonlinear systems. However, compact model representation of physiological systems cannot be achieved with nonparametric methods. Parametric modeling methods (i.e., Nonlinear Auto-Regressive Moving-Average (NARMA) models) may offer the means for parsimonious model representation. This pa-per explores the use of NARMA modeling via Korenberg’s fast orthogonal search algorithm (which allows us to gauge the significance of the candidate difference equation terms) in order to obtain compact parametric models for nonlinear systems. Computer simulations, as well as experimental renal blood pressure and flow data, are used to demonstrate the potential of this approach for efficient parametric modeling and examine its advantages or disadvantages relative to nonparametric modeling using Volterra-Wiener analysis.
KeywordsRenal Blood Flow Kernel Estimate Volterra Model Volterra Kernel Renal Autoregulation
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- 1.Billings, S.A. and Leontaritis, I.J. (1982) Parameter estimation techniques for nonlinear systems. 6th IFAC Symp. Ident. & Par. Est, Washington D.C., pp. 427–432.Google Scholar
- 3.Chon, K.H., Chen, Y.M., Marmarelis, V.Z., Marsh, D.J. and Holstein-Rathlou, N.-H. (1994) Detection of interactions between the myogenic and TGF mechanisms using nonlinear analysis. Am.]. Physiol, (in press).Google Scholar
- 4.Haber, R., and Keviczky, L. (1976) Identification of nonlinear dynamic systems, IFAC Symp. Ident. & Sys. Param. Est., Tbilisi, Georgia, pp. 62–112.Google Scholar
- 5.Holstein-Rathlou, N.-H., Wagner, A.J. and Marsh, D.J. (1991) Tubuloglomerular feedback dynamics and renal blood flow autoregulation in rats. Am.]. Physiol, 260 (Renal Fluid Electrolyte Phsiol. 29), pp. F53–F68.Google Scholar
- 6.Korenberg, M.J. (1987) Functional expansions, parallel cascades and nonlinear difference equations,” In: Marmarelis, V.Z., (ed). Advanced Methods of Physiological System Modeling, Vol. I, Biomedical Simulations Resource, University of Southern California, Los Angeles, California, pp. 221–240.Google Scholar