Michael Methfessel

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Even in lightweight wireless computing applications, processing of network-protocols becomes more and more computation-and 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)
—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)
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)
The paper presents a recently developed full-potential linear muun-tin orbital (FP-LMTO) method which does not require empty spheres and can calculate the forces accurately. Similar to previous approaches, this method uses numerical integration to calculate the matrix elements for the interstitial potential, which is the limiting step for any FP-LMTO(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)