Responding to chronic complaints about crime in public housing, the Philadelphia Housing Authority (PHA) will almost triple its police force in the year ahead, adding up to 50 new officers. The move reverses an approach to policing that had been implemented by former executive director Carl R. Greene. During his tenure from 1998 to 2010, Greene reduced the number of officers from 300 to 30, while increasing the ranks of security guards employed by private firms. Kelvin Jeremiah, interim PHA executive director, said the new hires would cost about $5 million. He said PHA would pay for them by shifting money away from private contractors.