Situation ActionPlanner Situation ActionReactivePolicy A ) B ) C ) Situation

Dyna is an AI architecture that integrates learning, planning, and reactive execution. Learning methods are used in Dyna both for compiling planning results and for updating a model of the eeects of the agent's actions on the world. Planning is incre-mental and can use the probabilistic and ofttimes incorrect world models generated by learning processes. Execution is fully reactive in the sense that no planning intervenes between perception and action. Dyna relies on machine learning methods for learning from examples|these are among the basic building blocks making up the architecture|yet is not tied to any particular method. This paper brieey introduces Dyna and discusses its strengths and weaknesses with respect to other architectures.