http://dl.gi.de/handle/20.500.12116/29354 Tue, 21 Jul 2026 13:28:01 GMT 2026-07-21T13:28:01Z http://dl.gi.de/handle/20.500.12116/29526 A robust generation technique of common information based on characteristic of multipath fading channel by shaking handheld devices Iwamoto, Tomohiro; Tagashira, Shigeaki; Arakawa, Yutaka; Fukuda, Akira Mühl, Gero; Richling, Jan; Herkersdorf, Andreas A rapid increase in handheld devices with wireless communication capabilities, such as cellular phones and smart phones, enables data communication in face-toface situations. The easy realization of secure data communication in such situations is necessary for ensuring safe and reliable networking environments as short-range wireless networks become more popular. One approach involving the generation of secret keys in each communication device using variations of the received signal strength indication (RSSI) values has been proposed in literature. However, it has a problem in that there are positions where eavesdroppers are able to obtain RSSI values that are highly correlated with those of legitimate devices. To address this problem, we propose a filtering technique that eliminates eavesdroppable parts from RSSI variations. Additionally, it is important to shake either one or both of two legitimate devices to change the propagation, considering that the elimination exploits the periodicity of the shake. Furthermore, we implemented a prototype system realizing the proposed method and evaluated its effectiveness. The results indicate that the proposed method can increase the robustness of common information, which is generated into the secret key without degrading its generation speed. Sun, 01 Jan 2012 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/29526 2012-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/29527 Towards integration of user interaction and context event processing in intelligent living environments Lehmann, Simon; Schäfer, Jan; Dörner, Ralf; Schwanecke, Ulrich Mühl, Gero; Richling, Jan; Herkersdorf, Andreas Event processing plays a significant role in the current development of intelligent living environments. It ranges from processing of information produced by a magnitude of sensors to gain insight into the activities of the inhabitants on a more global scale, to the processing of immediate and rather short-lived events of user input on and around interactive systems embedded in common household furniture like tabletops or tablets. Based on the work conducted separately in those two fields, we found that the still evolving field of complex event processing (CEP) provides the methods and tools to handle those distinct use-cases equally. Especially the application to interactive systems, while being novel and uncommon, is well suited and further shows the broad applicability of CEP. The comparison of the two application fields shows that, even though the events occurring in them are distinguished by their intention, commonalities do exist and provide integration points. Furthermore, the integration of those applications within the context of smart homes allows to provide demand-oriented resource management, which realizes self adaptation and control. Sun, 01 Jan 2012 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/29527 2012-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/29523 Cellular location determination - reliability and trustworthiness of GSM location data Zahoransky, Richard M.; Rechert, Klaus; Meier, Konrad; Wehrle, Dennis; Suchodoletz, Dirk von Mühl, Gero; Richling, Jan; Herkersdorf, Andreas While using mobile telephony networks, the serving network infrastructure is able to determine the mobile station's location. Until now, cellular telephony has been built on self-contained infrastructure, i.e. all network components have been certified and especially users have been unable to take over control over their mobile equipment's behavior. With the rising awareness on privacy issues, software-based mobile phone network stacks became available and thereby a new freedom degree for mobile subscribers is introduced. While slight modification to the mobile phones behavior will not impair with the general functionality of the network, cellular location determination becomes less reliable and trustworthy. We discuss user imposed measures to detect external location determination attempts and to obfuscate generated location information. With a dedicated testbed setup, the effects of location obfuscation were evaluated. Sun, 01 Jan 2012 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/29523 2012-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/29525 Goal-snapping: an empirical evaluation of object snapping in tangible and multi-touch interfaces Schmitt, Sebastian; Luderschmidt, Johannes; Haubner, Nadia; Lehmann, Simon; Dörner, Ralf; Schwanecke, Ulrich Mühl, Gero; Richling, Jan; Herkersdorf, Andreas We present “Goal-snapping”, a novel approach for applying snapping techniques to tangible and multi-touch interfaces. It can be used to support users in accomplishing basic tasks such as aligning, sorting or grouping of virtual objects. As using snapping on large surfaces poses challenges in interaction design, we identify and discuss according parameters in Goal-snapping. For sorting and aligning, we propose to use snappers that attract objects within a target zone and visually arrange them to present an overview. For exchanging objects among users, we propose that each user has a target snapper that acts as a goal to which objects can be flicked. A user study has shown that although participants embrace the use of snapping to automatically group objects in a sorting task, snapping does not accelerate the completion time and increases the error rate by accidently snapped objects. In a long distance positioning task, the use of snapping significantly increases task completion. Sun, 01 Jan 2012 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/29525 2012-01-01T00:00:00Z