The city of Groningen has installed an aggression-detector at a busy intersection in an area full of pubs. Elevated microphones spaced 30 meters apart run along both sides of the street, joining an existing network of cameras. These connect to a computer at the police station in Groningen.

If the system hears certain sound patterns that correspond with aggression, it sends an alert to the police station, where the police can assess the situation by examining closed-circuit monitors: if necessary, officers are dispatched to the scene.

From “Hello, HAL: The battle to make computers understand” in the June 23 issue of the New Yorker.