As the robot slides down the snowy mountain we can see an impressive ability to self balance, change direction, and autonomously sense and navigate around race gates.

A gyroscope, four sensors mounted between the skis, and motor position sensors support the lower control of stability and joints.

A simple USB camera and a GPS system allow the robot to gather the necessary input to determine its position and calculate what action it should take next.

Giant Torayan, a huge aluminum robot, looks down on a puny human at the lobby of the Osaka City Hall. The robot, a statuesque 7.2 meters tall, responds only to instructions from children, according to its creator, Osaka native Kenji Yanobe. When feeling chipper, the robot can sing and make simple dance movements. But do not anger Giant Torayan: It spews fire when miffed. The robot's job is to promote Aqua Metropolis Osaka 2009, an event highlighting the city's water-related attractions that starts Saturday.

These days robot-loving Japanese are tinkering with screwdrivers and motors instead of heading to the beach or hot springs during the holidays. Tokyo's major store devoted to robots, Vstone Robot Center in the bustling Akihabara electronics district, sells robots of all sizes and shapes, including the tiny scuttling Robo-Q from Tomy Co. and the Pleo animatronic dinosaur toy from Ugobe Inc. of the U.S.

A science-savvy robot called Adam has successfully developed and tested its first scientific hypothesis, all without human intervention. This hints at a future where robots could spare lab assistants and post-docs some of the drudgery of research.

NetTansor etc.

Indeed, Stair represents a new wave of AI, one that integrates learning, vision, navigation, manipulation, planning, reasoning, speech and natural-language processing. It also marks a transition of AI from narrow, carefully defined domains to real-world situations in which systems learn to deal with complex data and adapt to uncertainty.

Tuesday marked the theatrical debut for the bot, which appeared onstage alongside real-life actors in a play that's being hailed as a first in robot-human artistic collaboration. Hataraku Watashi ("I, Worker"), by playwright Oriza Hirata, focuses on a couple who own two housekeeping robots, one of which loses its motivation to work.

Something of a mix between the exoskeleton of a crustacean and the suit worn by Robocop, ReWalk helps paraplegics - people paralysed below the waist - to stand, walk and climb stairs.