Till Wollenberg

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The visual analysis of dynamic networks is a challenging task. In this paper, we introduce a new approach supporting the discovery of substructures sharing a similar trend over time by combining computation, visualization and interaction. With existing techniques, their discovery would be a tedious endeavor because of the number of nodes, edges as well as(More)
Modern buildings are often equipped with universal bus systems. The purpose of these bus systems is to control the functions of houses such as lighting, climate control, and heating. In this paper we present a case study that shows how privacy issues evolve out of an untypical utilization of those control systems. As a controversial example, we show that we(More)
In this paper we focus on measuring channel occupancy in the 2.4 GHz ISM band in a way that transmissions from Wireless LAN stations and other spectrum users can be distinguished. Most current 802.11 hardware does not offer methods to capture channel occupancy caused by non-802.11 transmissions accurately. We therefore combine a commodity 802.11 Wireless(More)
The basic idea presented in this paper is to use interference aware routing with predicted interference. Noise and other values are measured over a long time and within a wide area in order to find recurring patterns. Routing parameters are then adjusted according to these patterns. The objective is to improve the general network performance without(More)
The basic idea presented in this paper is to use interference aware routing with predicted interference. Noise values are measured over a long time and within a wide area in order to find recurring patterns. Routing parameters are adjusted according to these patterns. The objective is to improve the general network performance without permanently(More)
Authentication is crucial for every real-world wireless network to prevent unauthorized access. In many cases, incorporating the user's position in a two-factor authentication strengthens the security of the network. Current positioning techniques are either manipulable, require extra hardware or violate the 802.11 standard. We propose three methods for(More)
Aufgrund der hohen Verbreitung und intensiven Nutzung von WLAN kommt es insbesondere in Bereichen mit hoher Gerätedichte (wie z. B. universitären Lehrgebäuden) schon heute zu Kapazitätsengpässen, die durch ausgelastete Funkkanäle verursacht werden. Eine Vorhersage der Funkkanalauslastung kann die Probleme durch bessere Nutzung der vorhanden(More)
The basic idea presented in this paper is to use interference aware routing with predicted interference. Noise and other values are measured over a long time and within a wide area in order to find recurring patterns. Routing parameters are then adjusted according to these patterns. The objective is to improve the general network performance without(More)