Eberhard P. Hofer

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A quantitative biomechanical model describes the tissue transformation during healing of a transverse osteotomy of a sheep metatarsal. The model predicts bridging of the bone ends through cartilage, followed by the growth of a callus cuff, and finally, the resorption of callus after ossification of the interfragmentary gap. We suggest bone density or the(More)
A biomathematical model of granulocytopoiesis is described and used to analyze the blood granulocyte changes seen in the blood of dogs and humans after continuous and after acute external radiation exposure. This allows to relate the cell change pattern seen to the extent of stem cell damage in the hematopoietic bone marrow distributed as semi-autonomous(More)
In this paper, interval simulation methods are presented to determine guaranteed enclosures of state variables of an activated sludge process in biological wastewater treatment. This process is characterized by nonlinearities and uncertain but bounded parameters. In uncertain systems an axis-parallel interval box is mapped to a complexly shaped region in(More)
In this paper a dynamic model of granulocytopoiesis is used to estimate stem cell numbers after acute and chronic irradiation. Regeneration data from irradiation accidents and bone marrow transplantation are investigated in the case of acute irradiation. Data from dogs living in a low-dose irradiation field are investigated for the case of chronic(More)
In this paper, interval arithmetic techniques for controller design of nonlinear dynamical systems with uncertainties are summarized. The main reason for the application of interval techniques in this context is the quantification of the influence of uncertainties and modeling errors. They result from neglecting nonlinear phenomena in the mathematical(More)
The management of acute radiation syndrome in persons inadvertently exposed to total-body irradiation greatly benefits from the experience gained in previous clinical management situations. Within the framework of exposure to high doses, one of the most critical issues is the question of whether hematopoietic stem cell transplantation is indicated. A valid(More)
This paper proposes a control method of active ankle-foot prostheses. The main goal of this research is to determine the feasibility of generating adequate plantar flexion force by using the internal model control design. The prototype of the powered ankle prosthesis is developed to evaluate proposed controllers. The paper shows that the prototype is able(More)
Control strategies for nonlinear dynamical systems often make use of special system properties, which are, for example, differential flatness or exact input-output as well as input-to-state linearizability. However, approaches using these properties are unavoidably limited to specific classes of mathematical models. To generalize design procedures and to(More)
In this paper, an overview of the potential use of validated techniques for the analysis and design of controllers for linear and nonlinear dynamical systems with uncertainties is given. In addition to robust pole assignment for linear dynamical systems with parameter uncertainties, mathematical system models and computational techniques are considered in(More)