From office watcher to farm protector and crop duster, unmanned aircraft playing unusual roles

At exactly 5 p.m. one recent Friday at Taisei Co., a flying drone alerted workers at the building maintenance firm that the day's work was done. The fully automatic drone, which goes by the name T-Frend, is an example of the unique ways unmanned aerial vehicles are being used to seize control of what people are failing at or incapable of. "This drone will identify who remains in the office after hours. . . . And by accessing recorded data, human resources or administration departments will be able to deal with those who abuse overtime," said Chikara Kato, manager of the Tokyo firm's corporate planning division and inventor of the device. In recent years, Japan has been strengthening efforts to limit overtime amid outrage sparked by the continuing deaths caused by Japan's excessively long working hours.