Social Emergency Alert Service - A Location-Based Privacy-Aware Personal Safety Service

The advanced capabilities for location-based services of smart phones are mostly used for travel applications, navigation or business fleet management. We motivate a social emergency alert service that makes use of the wide availability of smart phones and activates nearby social contacts in cases of emergency. Research has shown, that especially in busy urban districts help from fellow citizens is hard to receive because of the so-called bystander-effect: Nearby people often do not recognize or take responsibility for ongoing emergency situations. A simple and fast mechanism to call for help is necessary. Additional to local authorities as the police or rescue services, assistance from family or acquaintances is a valuable and fast(er) supplement. We describe the architecture of an emergency alert service providing the functionality required for the activation of social contacts and present a prototype. The distribution of tasks between mobile devices and server infrastructure and the underlying communication protocol are designed energy-efficient and privacy preserving. The central tracking of geo-positions is avoided.