The Hong Kong Multimedia Technology Research Center (MTREC) has an interesting project that implements a dementia anti-wandering system using iBeacons.
A paper (pdf) explains how it uses a novel multi-hop system to track targets using mobile sensors. The multi-hop approach extends the sensing area and reduces the deployment cost.
The system uses a particle filter which analyses the temporal and spatial information of the targets to achieve 4.37m and 9.46m tracking error in a campus and a shopping mall respectively.
Read about Beacons in Life Sciences