One Way Interaction: interactivity over unidirectional links

Autor: Jörg Baus and Andreas Butz and Antonio Krüger

Herausgeber:

In this paper we describe a strategy to achieve limited interactivity in situations where part of the communication is restricted to one direction. We illustrate this strategy in a scenario in which a stationary presentation system generates adapted interactive graphical way descriptions for mobile users in the form of hypergraphics. These descriptions are shown on a mobile display unit with very limited computing capacity. For technical reasons the communication between the presentation system and the mobile display system is restricted to one direction (i.e. the broadcasting of information by the presentation system) and to a relatively low bandwidth. A limited form of interactivity of the generated graphical presentations can be achieved without sending back information from the mobile unit to the server. By anticipating all possible interactions with a generated hypergraphical presentation the necessary variations can be generated and broadcast. If the transmission of the different levels of this presentation tree follows a certain scheme, the available level of interactivity of a presentation increases over time (as its exploration consumes time), while a very fast availability of the first and most simplistic presentation can still be guaranteed. Furthermore, any delay that could be caused by communicating back and forth with the presentation system over the low bandwidth connection is avoided, since all the necessary presentation parts are cached on the display device after one broadcasting cycle.