Ott, MarkusLuderschmidt, JohannesDörner, RalfKim, HyungSeokKim, Jee-InReiterer, HaraldDeussen, Oliver2017-11-222017-11-222012978-3-486-71879-9https://dl.gi.de/handle/20.500.12116/7790In this paper, we introduce our concept of tangible contexts in the field of seamless interaction in shared workspaces between mobile devices and tabletop systems. We model the context as a relationship between a user, the user s mobile device and objects on the surface of an interactive tabletop system. The tabletop represents the public part of the context and the mobile device embodies the private part of the context in a tangible form. The mobile device s touchscreen provides an additional workspace, its gyroscopic sensors allow for detection of the device s orientation in the air and it can be used as multi-purpose tangible object on the tabletop s surface. Additionally, an interaction performed with a mobile device can be technically and conceptually linked to its owner. In particular, users can automatically authenticate interactions by using their own device. Therefore, by employing tangible contexts it is possible complementing public interaction on the tabletop with private interaction on the mobile device and providing an ownership metaphor of UI elements on an interactive surface.enMulti-TouchTangible User InterfacesMobileText/Conference Paper