3AgentsAn agent is anything that can be viewed as perceiving its environment through sensors and acting upon that environment through actuatorsHuman agent:Eyes, Ears, and other organs for Sensors;Hands, Legs, Mouth, and other body parts for Actuators.Robotic agent:Cameras and Infrared range finders for Sensors;Various Motors for Actuators.
4Agents and Environments [f: P* A]The agent program runs on the physical architecture to produce A.agent = architecture + program
5Vacuum-cleaner worldFunction : (agent keeps Right and Left if both rooms are clean)
6Vacuum-cleaner world Action Percept Right [A, Clean] Suck [A, Dirty] Left[B, Clean][B, Dirty]Nop[A, Clean] [B, Clean]
7Rational agentsAn agent should strive to "do the right thing", based on what it can perceive and the actions it can perform.Performance measure: An objective criterion for success of an agent's behavior.EX: Performance measure of a vacuum-cleaner agent:- amount of dirt cleaned up,- amount of time taken,- amount of electricity consumed,- amount of noise generated, etc.
8Rational agents Rational Agent: For each possible percept sequence, a rational agent should select an action that is expected to maximize its performance measure, given some built-in knowledge the agent has about the environment.The performance measure that defines the criterion of success:– The agent’s percept sequence to data.– The agent’s prior knowledge of the environment.– The actions that the agent can perform.
9Rational agents • Is a vacuum-agent rational? (Depends!) • Performance measure– amount of dirt cleaned up,– amount of time taken,– amount of electricity consumed,– amount of noise generated, etc..• A priori بداهة– Geography of the environment is known (two squares, A is on left and B is on right, etc.).– Perception is trustable (no illusion وهم).– Sucking cleans the current square .
10Rational agents Actions – Left, right, suck. • Current percept – [location, dirt]• Possible extensions– The agent have partial memory (reasoning percept histories).– The geography of the environment is unknown.– The agent cannot percept its current location.– Agent can learn from experience.
11Rational agentsAgents can perform actions in order to modify future percepts so as to obtain useful information (information gathering, exploration).An agent is autonomous مستقل بذاته if its behavior is determined by its own experience (with ability to learn and adapt).
12Specify the setting for intelligent agent design: PEAS Description P : Performance measureE : EnvironmentA : ActuatorsS : SensorsMust first specify the settings for intelligent agent design.
15PEAS Agent: Interactive English tutor Performance measure: Maximize student's score on testEnvironment: Set of studentsSensors: KeyboardActuators: Screen display (exercises, suggestions, corrections)
16PEAS Agent: Part-picking robot Performance measure: Percentage of parts in correct bins صناديقEnvironment: Conveyor belt with parts, binsSensors: Camera, joint angle sensorsActuators: Jointed arm and hand
17Environment types Fully observable (vs. partially observable): An agent's sensors give it access to the complete state of the environment at each point in time.– Playing chess? Fully.– Medical diagnosis? Partially.– Taxi driving? Partially.
18Environment types Deterministic (vs. stochastic) قطعي/محدد: The next state of the environment is completely determined by the current state and the action executed by the agent.– Medical diagnosis? Stochastic.– Battle field ميدان المعركة? Stochastic.– E-shopping? Deterministic.– E-auction? Stochastic.– Playing chess? Strategic .Strategic : If the environment is deterministic except for the actions of other agents.
19Environment types Episodic (vs. sequential) سببي / حدثي : An agent’s action depends only on an “episode” (snapshot) of the environment, i.e. history independent.– Chess? Sequential.– Web search? Episodic.
20Environment types Static (vs. dynamic): The environment does not change over time.– Playing crossword puzzle كلمات متقاطعة? Static.– Playing soccer? Dynamic.– Battle field? Dynamic.
21Environment typesDiscrete (vs. continuous): A limited number of distinct, clearly defined percepts and actions.– Playing chess? Discrete.– Taxi driving? Continuous
22Environment types • Single agent (vs. multi-agent): An agent operating by itself in an environment.– Crossword puzzle? Single– Playing chess? Multi– Taxi driving? Multi
23Environment typesChess with Chess without Taxi drivinga clock a clockFully observable Yes Yes NoDeterministic Strategic Strategic NoEpisodic No No NoStatic Semi Yes NoDiscrete Yes Yes NoSingle agent No No NoThe environment type largely determines the agent designThe real world is (of course) partially observable, stochastic, sequential, dynamic, continuous, multi-agent
24Relationship between Agents • Collaborative vs. Competitive– Playing chess? Competitive.– Taxi driving? Cooperative,• Trustworthy جدير بالثقة vs. Suspicious مشبوه• Same capabilities or different• Share information or not• Delegate responsibility يفوض المسؤلية or not
25Agent functions and programs An agent is completely specified by the agent function mapping percept sequences to actionsOne agent function (or a small equivalence class) is rationalAim: find a way to implement the rational agent function concisely بايجاز
26Agent types • Table-lookup agent – Huge table. – Take a long time to build the table.– No autonomy.– Even with learning, need a long time to learn the table entries.
27Agent types Four basic types in order of increasing generality: Simple reflex agentsModel-based reflex agentsGoal-based agentsUtility-based agents