An online algorithm for controlling a monotone Wiener system

This paper proposes and studies an online algorithm (`NORTKNAR´) for controlling a monotone Wiener system to a given level. Such systems consist of a FIR model, followed by a monotonically in- or decreasing nonlinear static function. We consider phenomena which obey such system up to stochastic perturbations. We study almost sure convergence under weak regularity assumptions. Theoretical results are complemented by empirical results on the control of a PharmacoKinetics-PharmacoDynamic (PK-PD) system regulating concentrations of levuodopa in the bloodstream. Finally, we indicate how those ideas find application to regulating the rate of events in pulsatile systems.