What is an Agent?

• The main point about agents is they are autonomous: capable of acting independently,
exhibiting control over their internal state
• Thus: an agent is a computer system capable of autonomous action in some environment in
order to meet its design objective

• These agents have some internal data structure, which is typically used to record information about the environment state and history. Let I be the set of all internal states of the agent.
• The perception function see for a state-based agent is unchanged:
see : E ↦ → P er
The action-selection function action is now defined as a mapping
action : I ↦ → A
from internal states to actions. An additional function next is introduced, which
maps an internal state and percept to an internal state:
next : I ↦ → P er ↦ → I
 

Knowledge Bases

• Knowledge base is a set of sentences in a formal language
• Declarative approach to building an agent:
— Tell it what it needs to know
— So it can Ask itself what to do (answers should follow)

知识库是一个集合，其中包含了一系列使用正式语言编写的句子。在人工智能领域，这些句子通常被称为事实、规则或信念。知识库是代理理解其环境、做出决策和采取行动的基础。它包含了代理需要知道的所有信息，包括事实、规则、模式、关系等。

• The agent must be able to:
— Represent states, actions etc
— Incorporate new percepts
— Update internal representations of
the world
— Deduce hidden properties of the world
— Deduce appropriate actions

• hidden properties 代理需要能够推断出环境中不直接感知到的属性或关系。这可能涉及到更复杂的推理过程，如模式识别、因果推断等。

Wumpus World 

• Performance Measure
— gold = 1000
— death = -1000
— step = -1
— arrow = -10PIT1 2 3 4
• Environment
— Squares adjacent to wumpus have a stench
— Squares adjacent to pits are breezy
— Square where gold is glitters
— Shooting kills wumpus if you are facing it (only one arrow, though)
— Grabbing picks up gold if in same square

• Actuators
— Left turn (90◦)
— Right turn (90◦)
— Forward
— Grab
— Shoot (only once)
— Climb

• Sensors
— Stench
— Breeze
— Glitter
— Bump
— Scream

Wumpus World Characterisation

• Observable? No - only local perception
• Deterministic? Yes - outcomes exactly specified
• Static? Yes - Wumpus and Pits do not move
• Discrete? Yes
• Single-agent? Yes - Wumpus essentially a natural feature