The Structure of Intelligent Agents

Agent’s structure can be viewed as −

● Agent = Architecture + Agent Program

● Architecture = the machinery that an agent executes on.

● Agent Program = an implementation of an agent function.

Simple Reflex Agents

● They choose actions only based on the current percept.

● They are rational only if a correct decision is made only on the basis of current precept.

● Their environment is completely observable.

Condition-Action Rule − It is a rule that maps a state (condition) to an action.

Model Based Reflex Agents

They use a model of the world to choose their actions. They maintain an internal state.

Model − The knowledge about how the things happen in the world.

Internal State − It is a representation of unobserved aspects of current state depending on percept history.

Updating the state requires the information about −

● How the world evolves.

● How the agent’s actions affect the world.

Goal Based Agents

They choose their actions in order to achieve goals. Goal-based approach is more flexible than reflex agent since the knowledge supporting a decision is explicitly modeled, thereby allowing for modifications.

Goal − It is the description of desirable situations.

Utility Based Agents

They choose actions based on a preference (utility) for each state. Goals are inadequate when −

● There are conflicting goals, out of which only few can be achieved.

● Goals have some uncertainty of being achieved and you need to weigh likelihood of success against the importance of a goal.