3Agents An AI program = An intelligent Agent An agent is anything that can be viewed as perceiving its environment though sensors and acting upon that environment though actuators.Perception-Action Cycle
4Application of Intelligent Agents AI has successfully been used inFinance?Robotics?Games?Medicine?The Web?
10AI and the WebWorldWideWebCrawlerWeb PagesDBQueryYou
11Percept: the agent’s perceptual inputs at any given instant Percept Sequence: the complete history of everything the agent has ever perceivedThe agent function maps from percept histories to actions: [f: P* A] (abstract)The agent program runs on the physical architecture to produce f. (implementation)
12Vacuum-Cleaner World Percepts: location and contents, e.g., [A, Dirty] Actions: Left, Right, Suck, NoOp
17Internet Shopping Agent Performance measure? price, quality, appropriateness, efficiencyEnvironment? WWW sites, vendors, shippersActuators? display to user, follow URL, fill in formSensors? HTML pages (text, graphics, scripts)
18Environment TypesFully observable (vs. partially observable): An agent’s sensors give it access to the complete state of the environment at each point in time.Card game vs. poker (needs internal memory)Deterministic (vs. stochastic): The next state of the environment is completely determined by the current state and the action executed by the agent.Chess vs. game with dice (uncertainty, unpredictable)Episodic (vs. sequential): The agent’s experience is divided into atomic “episodes” (each episode consists of the agent perceiving and then performing a single action), and the choice of action in each episode depends only on the episode itself.Chess and taxi driving
19Environment TypesStatic (vs. dynamic): The environment is unchanged while an agent is deliberation. (The environment is semidynamic if the environment itself does not change with the passage of time but the agent’s performance score does.)Taxi driving vs. chess (when played with a clock) vs. crossword puzzlesDiscrete (vs. continuous): A limited number of distinct, clearly defined percepts and actions.Chess vs. taxi driving (infinite)Single agent (vs. multiagent): An agent operating by itself in an environment.Crossword puzzle vs. chess
20SolitaireChess with a clockInternet ShoppingTaxiObservable?Deterministic?Episodic?Static?Discrete?Single-agent?
21SolitaireChess with a clockInternet ShoppingTaxiObservable?YesNoDeterministic?Episodic?Static?SemiDiscrete?Single-agent?YewThe real world is (of course) partially observable, stochastic, sequential, dynamic, continuous, multi-agent.
22Agent Types Four basic types: - simple reflex agents - model-based reflex agents- goal-based agents- utility-based agentsAll these can be turned into learning agents.
28SummaryAgents interact with environments though actuators and sensors.The agent function describes what the agent does in all circumstances.Agent programs implement agent functions.PEAS descriptions define task environments.Environment are categorized along several dimensions:observable? deterministic? episodic? static? discrete? single-agent?Several basic agent architectures exist:reflex, reflex with state, goal-based, utility-based
29Try out some intelligent agents! A Chatbot is a computer program designed to simulate an intelligent conversation with one or more human users via auditory or textual methods, primarily for engaging in small talk.ALICE:Won the Loebner Prize three times (in 2000, 2001 and 2004)ELIZA:One of the classic chat bots, written at MIT by Joseph Weizenbaum between 1964 and 1966Automated online assistants