U.S. Justice Department: Does Neighborhood Watch reduce crime? Neighborhood Watch programs became popular in the 1970s and 1980s; by 2000, roughly 40% of the U.S. residential population was covered by such citizen crime-watching programs.
Definition of actuarial. 1  1 : of or relating to actuaries. 2  2 : relating to statistical calculation especially of life expectancy.
actuator. A mechanical, electrical, or hydraulic device, or their combination, used to effect some predetermined linear, rotary, or oscillating movement. An actuator essentially converts hydraulic or air pressure into mechanical force. Basically, there are two types of actuators: single-acting and double-acting. In the single-acting actuator, the piston moves in a single direction as a result of system pressure. In a double-acting system, the actuator's piston moves in either direction.