This paper describes INVENT, a system for selecting ventilator setting based on physiological models and penalty functions. The models and penalty functions included in INVENT are first described followed by an example of the use of the system in selecting ventilator settings for a patient residing in the intensive care unit. For this patient, the advice given by the system is shown to be reaso...

Perturbations of Karush-Kuhn-Tucker conditions play an important role for primal-dual interior point methods. Beside the usual logarithmic barrier various further techniques of sequential unconstrained minimization are well known. However other than logarithmic embeddings are rarely studied in connection with Newton path-following methods. A key property that allows to extend the class of metho...

This paper deals with the Hessian matrices of penalty functions, evaluated at their minimizing point. It is concerned with the condition number of these matrices for small values of a controlling parameter. At the end of the paper a comparison is made between different types of penalty functions on the grounds of the results obtained. 1. Classification of penalty-function techniques Throughout ...

We use a primal-dual scheme to devise a new update rule for a penalty function method applicable to general optimization problems, including nonsmooth and nonconvex ones. The update rule we introduce uses dual information in a simple way. Numerical test problems show that our update rule has certain advantages over the classical one. We study the relationship between exact penalty parameters an...