When it comes to hunting down humans running speeds, MIT's cheetah might come second to Boston Dynamics' own high-velocity quadruped, but by substituting pneumatics with motors, MIT's version apparently runs far more efficiently. At the recent International Conference on Robotics and Automation, the Institute of Technology showed of its newest version, which reached a top speed of 13.7 mph. To accomplish this, the runner still needs parallel support bars to constrain movement in one dimension, reducing any roll, yaw -- and the chances of a pretty expensive fall. The team says the new version's cost of transport (COT is...