A primal-dual interior point method for optimal control problems with PDE constraints is considered. The algorithm is directly applied to the infinite dimensional problem. Existence and convergence of the central path are analyzed. Numerical results from an inexact continuation method applied to a model problem are shown. AMS MSC 2000: 49M15, 90C48, 90C51

The aim of this paper is to study how efficiently we evaluate a system of multivariate polynomials and their partial derivatives in homotopy continuation methods. Our major tool is an extension of the Horner scheme, which is popular in evaluating a univariate polynomial, to a multivariate polynomial. But the extension is not unique, and there are many Horner factorizations of a given multivaria...

This paper clearly shows that the recently proposed terrain methodology of Lucia and Yang (2003) can be used to solve steady-state distillation problems in a reliable and efficient manner. Numerical results are presented that show that terrain methods are superior to Newton’s method and homotopy-continuation for distillation examples with multiple solutions. © 2004 Elsevier Ltd. All rights rese...

Major sources of information for the estimation of the size of the sh stocks and the rate of their exploitation are samples from which the agecomposition of catches may be determined. However, the age-composition in the catches often varies as a result of several factors. Strati cation of the sampling is desirable because it leads to better estimates of the agecomposition and the corresponding ...

The process of wave equation continuation (migration) is adapted for refraction data in order to produce velocity-depth models directly from the recorded data. The procedure consists of two linear transformations: a slant stack of the data produces a wave field in the p T plane which is then downward continued using T = 0 as the imaging condition. The result is that the data wave field is linea...

CONTEXT Communication campaigns might be a viable means of improving contraceptive continuation; however, few such interventions aimed at reducing contraceptive discontinuation have been evaluated. METHODS Data were collected from independent samples of new injectable users in Nyando District, Kenya-site of a communication campaign to increase contraceptive continuation-and in a comparison di...

We present a novel transformation method that allows us to map unstructured cyclic business process models to functionally equivalent workflow specifications that support structured cycles only. Our solution is based on a continuation semantics, which we developed for the graphical representation of a process model. By using a rule-based transformation method originally developed in compiler th...