Unit Three

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Unit Three

• Knowledge and Reasoning

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Lets play a game of Wumpus
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Wumpus World Description
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A Typical Wumpus World
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Lets play a game of Wumpus
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Motivating KB Agents

• Reflex agents keep the world clean, in large
  part, by dumb luck
• Searching algorithm can find the shortest path
  from Arad to Bucharest, but cant easily adjust
  when the road from Rimnicu Vilcea to Pitesti is
  closed for maintenance.
• Logic (Knowledge-Based) agents combine general
  knowledge with current percepts to infer hidden
  aspects of current state prior to selecting
  actions

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Knowledge Bases
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Knowledge Base

• A knowledge base (KB) is a set of
  representations (sentences) of facts about the
  world.
• TELL and ASK - two basic operations
• to add new knowledge to the KB
• to query what is known to the KB
• Infer - what should follow after the KB has been
  TELLed.
• A generic KB agent (Fig 7.1)

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Generic KB-Based Agent
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Simple Knowledge-Based Agent
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Representing Knowledge Problems PAGE Formulation

• Percepts
• What can agent observe?
• What can sensors tell it?
• Actions
• What actuators does agent have?
• In what context are they applicable?
• Goals
• What are agents goals? Preferences (utilities)?
• How does agent evaluate them (check environment,
  deliberate, etc.)?
• Environment
• What are rules of the world?
• How can these be represented, simulated?

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Wumpus World PAGE Description
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Wumpus World PEAS Description
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Lets Play Wumpus!

• You are in Cell (1,1) facing North
• None of the sensors register anything.
• Find the gold.

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Exploring the Wumpus World
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Exploring the Wumpus World
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Exploring the Wumpus World
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Exploring the Wumpus World
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Exploring the Wumpus World
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Exploring the Wumpus World
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Exploring the Wumpus World
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Exploring the Wumpus World
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Other tight spots
(0.86 vs. 0.31)
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Other tight spots
(0.86 vs. 0.31)
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Other tight spots
(0.86 vs. 0.31)
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Other tight spots
(0.86 vs. 0.31)