SHIELD: Social sensing and Help In Emergency using mobiLe Devices

School and College campuses face a perceived threat of violent crimes and require a realistic plan against unpredictable emergencies and disasters. Existing emergency systems (e.g., 911, campus-wide alerts) are quite useful, but provide delayed response (often tens of minutes) and do not utilize proximity or locality. There is a need to exploit proximity-based help for immediate response and to deter any crime. In this paper, we propose SHIELD, an on-campus emergency rescue and alert management service. It is a fully distributed infrastructureless platform based on proximity-enabled trust and cooperation. It relies on nearby localized responses sent using Bluetooth and/or WiFi to achieve minimal response time and maximal availability thereby augmenting the traditional notion of centralized emergency services. Analysis of campus crime statistics and WLAN traces surprisingly show a strong positive correlation (over 55%) between on-campus crime statistics and spatiotemporal density distribution of on-campus mobile users. This result is promising to develop a platform based on mutual trust and cooperation. Finally, we also show a prototype application to be used in such scenarios.