An accident can happen anywhere. Patrol units cannot cover
every single area of community all the time. Alternatively, it
may require lot of resources for emergency response agency to
cover every area such as civilian cameras in every corner for
event detection, and fast image processing to analyze
suspected activities. These requirements cost high investment
with imperfect accuracy [9]. In contrast, civilians of the
community are everywhere. Most of emergency events occur
in open area where people live in. People can do both event