Animations of legged creatures running over rough terrain were generated automatically, using physical modelling and animation with newly developed techniques from robotics and artificial intelligence. The 2D animations correctly simulate gravity, inertia, balance, and friction. The running motion generated is not repetitive; each stride is different, as dictated by the terrain. Dramatic movement effects such as slips, falls, struggling on slippery surfaces, and fall recoveries were demonstrated.>

Most prior work on congestion in datagram systems focuses on buffer management. We find it illuminating to consider the case of a packet switch with infinite storage. Such a packet switch can never run out of buffers. It can, however, still become congested. The meaning of congestion in an infinite-storage system is explored. We demonstrate the unexpected result that a datagram network with infinite storage, first-in, first-out queueing, at least two packet switches, and a finite packet lifetime will, under overload, drop all packets. By attacking the problem of congestion for the infinite-storage case, we discover new solutions applicable to switches with finite storage.

Despite the attractiveness of the concept, attempts to date to use proof of correctness techniques on production software have been generally unsuccessful. The obstacles encountered are not fundamental. We have implemented a proof of correctness system to be used for improving the realiability of certain small, real-time programs. It appears that many of the problems of past systems can be avoided.This work is supported by the Long Range Research Program of the Ford Motor Company, Dearborn, Michigan.