A Roman sentry stands watch with a look of panic, as fireballs crash down around him and bodies lie strewn among the rubble in the last moments of Pompeii.
The robot sentry, the Samson Remote Weapon Station, could function without human intervention, says David Ishai of Rafael, its Israeli manufacturer, based in Haifa.
This impasse reflects China's equivocal relationship with its troublesome neighbour and North Korea's unequivocal commitment to nuclear weapons.By tradition, China has viewed North Korea as an ideological soulmate that can "stand sentry" against American forces stationed in South Korea, points out Ren Xiao of Fudan University.
Every time it moves, it has to get past yet another sentry, called an interface, hired by whichever vendor was subcontracted to build that particular intersection.
Abdul Bari Atwan, editor of a radical Arab daily, Al Quds al Arabi, outlined a scenario whereby Israel would be made "the trusted sentry guarding the oil fields while the Arabs, or what remains of them, revert to rearing camels".Such alarmism has triggered calls for a stronger diplomatic response.
"We have nodes that take turns staying awake for longer periods, called sentry nodes, and if their sensors detect vibrations or winds that are above a certain threshold, they send a signal to the gateway that tells it to send a wake-up call to all the sleeping nodes," explains Dr Rice.
If you have just graduated summa cum laude from Harvard or Yale, manning a sentry box on the Greek-Turkish border or sharing a ship's cabin with 30 seasick youths seems a waste of time.
But push a cigarette or two through the car window, and the miserable conscripts on sentry duty at the barrier will turn a blind eye.
That came a day after a man in the Canadian capital, Ottawa, shot dead a ceremonial sentry at the war memorial and then ran into the parliament, where he was shot and killed.Such attacks appear to be perpetrated by "lone wolves" rather than by organised groups.
Firms that offer this service install "sentry" software and machines on clients' networks which relay a stream of messages to a central secure operations centre.
Now the fighting began, and Captain Wake showed herself more than willing to take part, readily joining raiding parties, blowing up local Gestapo headquarters and ambushing German patrols.She did not enjoy killing a German sentry with her bare hands, but she was unsentimental.
