AD LOC: Location-based Infrastructure-free Annotation
Derek J. Corbett, Daniel Cutting · 2006
We introduce AD LOC, a system for mobile users to col-laboratively tie persistent virtual notes to physical locations without the need for any servers embedded in the environment or accessed via the Internet. Instead, all notes are proactively cached solely on the mobile devices of passing participants and served up to others in the vicinity via ad hoc wireless protocols like WiFi. By making use of any of the increasingly ubiquitous positioning technologies, such as GPS, devices at-tempt to ensure notes remain cached at the physical locations they were published. Through simulation we demonstrate AD LOC’s behaviour under different scenarios and caching strate-gies. Our results show that despite the unpredictable and in-constant storage medium, surprisingly few participants are re-quired for remarkably robust note persistence. Furthermore, the number of transmissions between devices needed to re-alise the caching strategies is relatively low and increases lin-early with the number of participants.