Violence and vandalism used to plague Sacramento's racially mixed John F. Kennedy High School. "It is a fantastic mixture of haves and have-nots," says Principal Frank Schimandle, "and that is the problem."
Schimandle assumed his job after the school's former principal was felled by a heart attack in the midst of a 1968 student riot. Determined to stop the troubles, he worked with the National Aeronautics and Space Administration on a $1,300,000 project that produced an ultrasonic system to monitor the sprawling 44-acre campus.
Each student is assigned a four-digit number that is recorded in classrooms by the teacher and fed into a...