The Wumpus World’s agent is an example of a knowledge-based agent that represents Knowledge representation, reasoning and planning. Knowledge-Based agent links general knowledge with current percepts to infer hidden characters of current state before selecting actions. Its necessity is vital in partially observable environments.
The Wumpus world is a cave with 16 rooms (4×4). Each room is connected to others through walkways (no rooms are connected diagonally). The knowledge-based agent starts from Room[1, 1]. The cave has – some pits, a treasure and a beast named Wumpus. The Wumpus can not move but eats the one who enters its room. If the agent enters the pit, it gets stuck there. The goal of the agent is to take the treasure and come out of the cave. The agent is rewarded, when the goal conditions are met. The agent is penalized, when it falls into a pit or being eaten by the Wumpus.
Some elements support the agent to explore the cave, like -The wumpus’s adjacent rooms are stenchy. -The agent is given one arrow which it can use to kill the wumpus when facing it (Wumpus screams when it is killed). – The adjacent rooms of the room with pits are filled with breeze. -The treasure room is always glittery.
PEAS represents Performance Measures, Environment, Actuators, and Sensors. The PEAS description helps in grouping the agents.
PEAS Description for the Wumpus World problem:
- Performance measures:
- Agent gets the gold and return back safe = +1000 points
- Agent dies = -1000 points
- Each move of the agent = -1 point
- Agent uses the arrow = -10 points
- A cave with 16(4×4) rooms
- Rooms adjacent (not diagonally) to the Wumpus are stinking
- Rooms adjacent (not diagonally) to the pit are breezy
- The room with the gold glitters
- Agent’s initial position – Room[1, 1] and facing right side
- Location of Wumpus, gold and 3 pits can be anywhere, except in Room[1, 1].
Devices that allow the agent to perform the following actions in the environment.
- Move forward
- Turn right
- Turn left
Devices which helps the agent in sensing the following from the environment.
- Scream (When the Wumpus is killed)
- Bump (when the agent hits a wall)
Wumpus World Characterization:
- Partially Observable: knows only the local perceptions
- Deterministic: outcome is precisely specified
- Sequential: subsequent level of actions performed
- Static: Wumpus, pits are immobile
- Discrete: discrete environment
- Single-agent: The knowledge-based agent is the only agent whereas the wumpus is considered as the environment’s feature.