Unit 1 -- Oct 10, 2011 Terminology Perception -> Action Cycle -- see, then do agent with sensors and actuators interacts with environment Environment -> Deterministic or Stochastic Discrete or Continuous Benign or Adversarial Observable -> Fully or Partially Full has implicit memory in the environment Partial may use internal Memory of previous State schip's own definitons: The scope of each of the classes is important, so... * Fully vs Partially Observable -- Is the CURRENT state fully known? Observability covers just the current system state and doesn't preclude being uncertain about future states. Homework edit: If the Agent needs internal memory to know the full system state then it's Partially Observable. If _everything_ is maintained in the Environment, then it's Fully Observable. * Discrete vs Continuous -- Are the ACTION's steps or real-valued? If you get a result that can take: A sub-set of values, it's Discrete; Any real-number value, it's Continuous. Note that DvsC can apply to sensor inputs as well, but it's not clear if that makes the whole environment Continuous... * Deterministic vs Stochastic -- Are the RESULTs known before taking an Action? If you can know the full Result of a Action before executing it, then the Result is Deterministic. Otherwise Stochastic, e.g.: a coin toss or dice throw. * Benign vs Adversarial -- Will SUBSEQUENT States change in order to counter your Actions? I.e.: Is the Environment out to get you? This can be a feature of the Environment itself, but often requires a second Agent who is in competition. An example from the video is Weather, it's in the Environment and may interfere with your actions but it's not actively plotting against you (in most cases....), so it's Benign. Whereas a opponent in chess is trying to counter your moves and is thus Adversarial. AI as uncertainty management: "what to do when you don't know what to do" Reasons for uncertainty -- Sensor limits Adversaries Stochastic environment Laziness & Ignorance Did not mention Rationality at all until the summary....!?