Torsten Hein

Learn More
We introduce and discuss an iterative method of relaxed Landwe-ber type for the regularization of the solution operator of the operator equation F (x) = y, where X and Y are Banach spaces and F is a non-linear, continuous operator mapping between them. We assume that the Banach space X is smooth and convex of power type. We will show that under the(More)
Correct pricing of options and other financial derivatives is of great importance to financial markets and one of the key subjects of mathematical finance. Usually, parameters specifying the underlying stochastic model are not directly observable, but have to be determined indirectly from observable quantities. The identification of local volatility(More)
In this paper two basic SQP-approaches for solving implicitly defined inverse problems are presented. Such problems often arises in parameter identification for differential equations. We also include regularization strategies which differ from similar problems in Optimal control. The main focus is on formulating saddle point problems for calculating the(More)
In this paper, we consider an iterative regularization scheme for linear ill-posed equations in Banach spaces. As opposed to other iterative approaches, we deal with a general penalty functional from Tikhonov regularization and take advantage of the properties of the regularized solutions which where supported by the choice of the specific penalty term. We(More)
In this paper, we are going to improve the enhanced convergence rates for Tikhonov regularization of nonlinear ill-posed problems in Banach spaces presented by Neubauer in [14]. The new message is that rates are shown to be independent of the residual norm exponents 1 ≤ p < ∞ in the functional to be minimized for obtaining regularized solutions. However, on(More)
In this paper we consider an iterative regularization scheme for linear ill-posed equations in Banach spaces. As opposite to other iterative approaches, we deal with a general penalty functional from Tikhonov regularization and take advantage of the properties of the regularized solutions which where supported by the choice of the specific penalty term. We(More)
Correct pricing of options and other financial derivatives is of great importance to financial markets and one of the key subjects of mathematical finance. Usually, parameters specifying the underlying stochastic model are not directly observable, but have to be determined indirectly from observable quantities. The identification of local volatility(More)
Static and fatigue tests of the small Orthofix unilateral external fixator frame and its main components were performed. The use of six pins increased torsional rigidity, but this configuration failed at lower bending loads when compared to the four-pin configuration, reflecting the uneven holding strength of the pin clamp on three pins. The ball joint(More)
Insufficient holding strength on a pin within a clamp may result in the diminution of the overall fixation rigidity as well as pin movement at the pin-bone interface. In this study the holding strength of pin fixation clamps in two representative external fixators (Hoffmann and Orthofix) was evaluated by determination of the torque resistance of pins within(More)
  • 1