Michael Methfessel

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Wireless sensor and actor networks based on Bluetooth technology require an algorithm to build up and maintain a Bluetooth scatternet. Although much research has been done, actual deployment is rare because a self-organizing and self-healing procedure suitable for actual Bluetooth nodes has not yet been developed. We present the SFX algorithm to build a(More)
Bluetooth scatternets are constructed from overlapping piconets, allowing any number of nodes to be connected into a multi-hop wireless network. Although the topic has been researched for 15 years, no deployments of self-organized scatternets have been published. Recently we have presented the SFX algorithm, which was implemented on commercial Bluetooth(More)
The reconstruction mechanism of (001) fcc transition metal surfaces is investigated using a full-potential all-electron electronic structure method together with density-functional theory. Total-energy calculations confirm the experimental finding that a close-packed quasi-hexagonal overlayer reconstruction is possible for the late 5d-metals Ir, Pt, and Au,(More)
Even in light-weight wireless computing applications, processing of network-protocols becomes more and more computationand energy-hungry, with increasing data rated and the need for security operations. To cope with such requirements and as alternative to heavyweight computation systems we propose an embedded system that is build for fast network-processing(More)
A known problem for TCP connections over wireless links is that errors in the wireless channel interfere with the TCP protocol even for minor packet loss. In the first part of this paper we evaluate how the data rate reduction depends on the channel delay. For comparatively short delays in the order of 100 ms, the decrease of the throughout is noticeable(More)
Industry 4.0 is a subject of current relevance which targets detailed information acquisition from industrial production processes. Wireless communication to ease this acquisition process is highly interesting but suffers today from problems of low reliability, high latency and small flexibility. ParSec addresses these subjects by investigating an(More)