Reference: Hayes-Roth, B. Opportunistic Control of Action in Intelligent Agents. 1992.
Abstract: Given its multiple goals, limited resources, and dynamic environment, an intelligent agent must decide which of many possible actions to execute at each point in time. Planning and reactive models embody two different modes of control. By contrast, we characterize a two-dimensional space of control modes, each of which maximizes the quality of run-time behavior in the corresponding region of a two-dimensional space of control situations. The situation space is defined by dimensions representing the predictability of the agent's task environment and the constraint imposed by its goals. The space of control modes is defined by corresponding dimensions representing the agent's sevsitivity to run-time events and its commitment to specific actions prepared in advance. The corners of the mode space are anchored by extreme modes that an agent rarely uses: open-loop plan execution, goal-specific reactivity, dead reckoning, and reflex modes. The large interior is occupied by a space of more practical strategic control modes that modulate the balance of sesitivity and commitment for situations embodying different combinations of predictability and cosntraint. To support behavior throughout the space of control modes, we propose an opportunistic contol model: run-time conditions trigger a subset of possible actions and strategic plans controls action execution. The model is operationalized as an agent architecture and an associated representation language for actions and plans. We show how the model allows an agent to move continuously throughout the space of control modes and report preliminary empirical results.
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