CHAPTER 2: Intelligent Agents

Intelligent agents are entities that use sensors to perceive the environment, make a decision, and act upon that information using actuators. An intelligent agent could be a robot, machine, or even a human or an animal. The sensor that takes in the environment could be a camera, rain sensor, or nose. The intelligent agent processes this information and decides to act upon it. The action could be saving a video, turning off a sprinkler system, or looking for the nearest pizza shop. The actuator is the part that takes action. Intelligent agents make decisions in real time, and the rate of success versus error varies. The purpose of an intelligent agent is to respond to the environment around it.

Intelligent agents are found throughout many aspects of life. Refrigerators sense temperature in order to determine when additional cooling is needed. Smoke detectors sense the presence of smoke before sounding an alarm. A dog that barks as a stranger approaches the door also counts as an intelligent agent. Complex intelligent agents include the SpaceX Dragon spacecraft and self-driving cars. These intelligent agents take information from many different sensors, make real-time decisions, and adjust actions based on the information.

2.1 Agents and Environments

2.1.1 What are Agent and Environment?

An agent is anything that can perceive its environment through sensors and acts upon that environment through effectors. A human agent has sensory organs such as eyes, ears, nose, tongue and skin parallel to the sensors, and other organs such as hands, legs, mouth, for effectors. A robotic agent replaces cameras and infrared range finders for the sensors, and various motors and actuators for effectors. A software agent has encoded bit strings as its programs and actions , receives keystrokes, file contents, and network packets as sensory inputs, and acts on the environment by displaying on the screen, writing files, and sending network packets. We use the term percept to refer to the agent’s perceptual inputs at any given instant. An agent’s percept sequence is the complete history of everything the agent has ever perceived. In general, an agent’s choice of action at any given instant can depend on the entire percept sequence observed to date, but not on anything it hasn’t perceived. By specifying the agent’s choice of action for every possible percept sequence, we have said more or less everything .

2.1.2 Agent Terminology

Performance Measure of Agent − It is the criteria, which determines how successful an agent is.

Behavior of Agent − It is the action that agent performs after any given sequence of percepts.

Percept − It is agent’s perceptual inputs at a given instance.

Percept Sequence − It is the history of all that an agent has perceived till date.

Agent Function − It is a map from the precept sequence to an action.

2.1.3 Properties of Environment

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