Technology against crime
How about a wearable computer (maybe a wrist band) that tracks your location and not only send out SOS notifications to pre-defined end points (relatives, patrolling police, nearest police stations etc) but also sends out alerts to nearby sister/affiliated devices? In layman terms: a smart wrist band that tracks your location & on one panic button press, it notifies the whole neighborhood of wrist band warriors + your relatives + police. ...