@article{ito_kunisch_2011, title={KARUSH-KUHN-TUCKER CONDITIONS FOR NONSMOOTH MATHEMATICAL PROGRAMMING PROBLEMS IN FUNCTION SPACES}, volume={49}, ISSN={["0363-0129"]}, DOI={10.1137/100817061}, abstractNote={Lagrange multiplier rules for abstract optimization problems with mixed smooth and convex terms in the cost, with smooth equality constrained and convex inequality constraints, are presented. The typical case for the equality constraints that the theory is meant for is given by differential equations. Applications are given to $L^1$-minimum norm control problems, $L^\infty$-norm minimization, and a class of optimal control problems with distributed state constraints and nonsmooth cost.}, number={5}, journal={SIAM JOURNAL ON CONTROL AND OPTIMIZATION}, author={Ito, Kazufumi and Kunisch, Karl}, year={2011}, pages={2133–2154} }
 @article{ito_kunisch_2011, title={MINIMAL EFFORT PROBLEMS AND THEIR TREATMENT BY SEMISMOOTH NEWTON METHODS}, volume={49}, ISSN={["0363-0129"]}, DOI={10.1137/100784667}, abstractNote={The paper introduces minimum effort control problems. These provide an answer to the question of the smallest possible control bound which still allows us to drive the system to a target within a fixed time $T$. This is a counterpart to the time optimal control problem which minimizes the time required to drive the system to the target, given a control bound. The problem is formulated as an optimal control problem with pointwise constraint on the control. The necessary conditions of optimality are derived by Lagrange multiplier theory. The semismooth Newton method is applied to a properly regularized problem. Well-posedness and superlinear convergence of the semismooth Newton method are proved for linear control systems under a controllability condition. Numerical results are presented for demonstrating the applicability and feasibility of the proposed method.}, number={5}, journal={SIAM JOURNAL ON CONTROL AND OPTIMIZATION}, author={Ito, Kazufumi and Kunisch, Karl}, year={2011}, pages={2083–2100} }
 @article{ito_kunisch_2010, title={Optimal control of parabolic variational inequalities}, volume={93}, ISSN={["0021-7824"]}, DOI={10.1016/j.matpur.2009.10.005}, abstractNote={Optimal control of parabolic variational inequalities is studied in the case where the spatial domain is not necessarily bounded. First, strong and weak solutions concepts for the variational inequality are proposed and existence results are obtained by a monotone and a finite difference technique. An optimal control problem with the control appearing in the coefficient of the leading term is investigated and a first order optimality system in a Lagrangian framework is derived. On étudie le contrôle optimal d'inégalités variationnelles dans le cas où le domaine spatial n'est pas nécessairement borné. Tout d'abord, on introduit des concepts de solutions fortes et faibles pour l'inégalité variationnelle et on obtient des résultats d'existence par une méthode de différences finies et monotone. On examine ensuite un problème de contrôle optimal avec un contrôle apparaissant dans le coefficient du terme principal et on en déduit un système d'optimalité du premier ordre dans un cadre lagrangien.}, number={4}, journal={JOURNAL DE MATHEMATIQUES PURES ET APPLIQUEES}, author={Ito, Kazufumi and Kunisch, Karl}, year={2010}, month={Apr}, pages={329–360} }
 @article{ito_kunisch_2008, title={Semi-smooth Newton methods for the Signorini problem}, volume={53}, ISSN={["0862-7940"]}, DOI={10.1007/s10492-008-0036-7}, abstractNote={Semi-smooth Newton methods are analyzed for the Signorini problem. A proper regularization is introduced which guarantees that the semi-smooth Newton method is superlinearly convergent for each regularized problem. Utilizing a shift motivated by an augmented Lagrangian framework, to the regularization term, the solution to each regularized problem is feasible. Convergence of the regularized problems is shown and a report on numerical experiments is given.}, number={5}, journal={APPLICATIONS OF MATHEMATICS}, author={Ito, Kazufumi and Kunisch, Karl}, year={2008}, month={Oct}, pages={455–468} }
 @article{ito_kunisch_2007, title={Optimal control of obstacle problems by H-1-obstacles}, volume={56}, ISSN={["1432-0606"]}, DOI={10.1007/s00245-007-0877-6}, number={1}, journal={APPLIED MATHEMATICS AND OPTIMIZATION}, author={Ito, Kazufumi and Kunisch, Karl}, year={2007}, pages={1–17} }
 @article{ito_kunisch_2004, title={The primal-dual active set method for nonlinear optimal control problems with bilateral constraints}, volume={43}, ISSN={["1095-7138"]}, DOI={10.1137/S0363012902411015}, abstractNote={The primal-dual active set method has proved to be an efficient numerical tool in the context of diverse applications. So far it has been investigated mainly for linear problems. This paper is devoted to the study of global convergence of the primal-dual active set method for nonlinear problems with bilateral constraints. Utilizing the close relationship between the primal-dual active set method and semismooth Newton methods, local superlinear convergence of the method is investigated as well.}, number={1}, journal={SIAM JOURNAL ON CONTROL AND OPTIMIZATION}, author={Ito, K and Kunisch, K}, year={2004}, pages={357–376} }
 @article{ito_kunisch_2003, title={Semi-smooth Newton methods for state-constrained optimal control problems}, volume={50}, ISSN={["1872-7956"]}, DOI={10.1016/s0167-6911(03)00156-7}, abstractNote={A regularized optimality system for state-constrained optimal control problems is introduced and semi-smooth Newton methods for its solution are analyzed. Convergence of the regularized problems is proved. Numerical tests confirm the theoretical results and demonstrate the efficiency of the proposed methodology.}, number={3}, journal={SYSTEMS & CONTROL LETTERS}, author={Ito, K and Kunisch, K}, year={2003}, month={Oct}, pages={221–228} }