Georg Bretthauer

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OBJECTIVE To test whether basic skills acquired on a virtual endoscopic surgery simulator are transferable from virtual reality to physical reality in a comparable training setting. SUMMARY BACKGROUND DATA For surgical training in laparoscopic surgery, new training methods have to be developed that allow surgeons to first practice in a simulated setting(More)
A new experimental hand prosthesis design is presented that differs from that of conventional prostheses. With the objective of addressing consumers' requirements, functionality was increased and cosmetic appearance became more natural. By integrating a hydraulic system with 8 small fluidic actuators at the digit joints, different important grasping(More)
Directional coupling analysis of bivariate time series is an important subject of current research. In this letter, a method based on symbolic dynamics for the detection of time-delayed coupling is presented. The symbolic coupling traces, defined as the symmetric and diametric traces of the bivariate word distribution, allow for the quantification of(More)
The different sleep stages modulate the autonomous functions blood pressure and heart rate as well as their complex interactions. The method of symbolic coupling traces (SCT) is used to analyse and quantify time-delayed couplings of these measurements. The SCT is defined by the difference of the symmetric and diametric traces of a bivariate word(More)
PURPOSE Consumers want new prosthetic hand designs that have increased functionality, better cosmetic appearance, and lower weight. METHODS New lightweight hands that fulfill these demands can be designed by integrating a hydraulic system with small fluidic actuators at the digit joints. RESULTS Two different designs of lightweight experimental(More)
Safe handling of dynamic inner-city scenarios with autonomous road vehicles involves the problem of stabilization of precalculated state trajectories. In order to account for the practical requirements of the holistic autonomous system, we propose two complementary nonlinear Lyapunov-based tracking-control laws to solve the problem for speeds between(More)
This paper proposes a new tracking algorithm within a 3D-SLAM framework that takes segmented range images as observations. The framework has two layers: the local layer tracks the view path and correspondences across the image sequence, using ambiguous landmark surfaces, and provides multiple hypotheses. The global layer conjectures and closes loops. We(More)
In this article the design of a new upper limb rehabilitation system will be presented. A lightweight, modular, and portable system is achieved by the combination of electromyographic (EMG) control, functional electrical stimulation (FES), and the use of miniaturized flexible fluidic actuators (FFA) integrated in an elbow orthosis. First, the state of the(More)
BACKGROUND Despite recent work hour restrictions, 24-hour calls remain an important part of patient care. The aim of this study was to assess the impact of 24-hour night calls on the psychomotor and cognitive skills of surgeons with a virtual surgery simulator (VSS) and psychometric tests. We hypothesized that sleep loss impairs surgical skills and(More)