augmenting its reactive component whenever it is forced to plan. When used to control a laboratory mobile robot, the We describe a robot control architecture which Theo-Agent in simple cases learns to reduce its reaction combines a stimulus-response subsystem for rapid time for new tasks from several minutes to less than a reaction, with a search-based planner for handling second. unanticipated...

A 67-year-old white man presented to Hermann Hospital upon referral from an Austin, Tex, physician for evaluation of recurrent chest pain. Eighteen months before admission the patient first noted episodes of chest discomfort, which he described as a left parasternal sensation of heaviness or tightness variably associated with moderate physical exertion. The discomfort would last 3 to 4 minutes ...