An intelligent system is one that has the inherent capability to achieve specified ends in the face of variations, complexities and uncertainties posed by its task environment . Consequently, an intelligent system must be able to integrate information from a variety of sources and, based on that information, plan and execute a course of action. The focus of this paper is on real-time planning for the class of intelligent systems which includes decision-support systems for piloted vehicles and completely autonomous vehicles.
"A Hierarchical Planner For Intelligent Systems", Proc. SPIE 0548, Applications of Artificial Intelligence II, (5 April 1985); doi: 10.1117/12.948432; https://doi.org/10.1117/12.948432