Nothing Special   »   [go: up one dir, main page]

CSC462-AI Lec02 Slides

Download as pdf or txt
Download as pdf or txt
You are on page 1of 27

Lecture # 2

CSC462 ARTIFICIAL INTELLIGENCE


CREDIT HOURS: 3(2, 1)

Course Instructor: SAIF ULLAH IJAZ


Lecturer CS Dept, CUI Vehari
MSc University of Leicester, UK
BSc COMSATS University Islamabad
AGENTS AND ENVIRONMENTS

2
AGENTS
systems that can reasonably be called intelligent. e.g. Human
Agent, Robotic Agent, Software Agent (software robot or softbot)

ENVIRONMENT
The environment could be everything—the entire
universe! or a subset of universe e.g. Road, classroom,
virtual environments

3
AGENTS AND ENVIRONMENTS

• The observation that some agents behave better than


others leads naturally to the idea of a rational agent—
one that behaves as well as possible.
• How well an agent can behave depends on the nature of
the environment; some environments are more difficult
than others.
• An agent perceive environment through sensors, and then
act upon that environment through actuators.

4
5
PERCEPT SEQUENCE
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 its built-in knowledge and on the
entire percept sequence observed to date, but not on
anything it hasn’t perceived.

6
AGENT FUNCTION
an agent’s behavior is described by the agent function
that maps any given percept sequence to an action.

Internally, the agent function for an artificial agent will


be implemented by an agent program

7
8
RATIONAL AGENT
A rational agent is one that does the right thing.

PERFORMANCE MEASURES
• We evaluate an agent’s behavior by its consequences.
• When an agent is plunked down in an environment, it generates a sequence of
actions according to the percepts it receives.
• This sequence of actions causes the environment to go through a sequence of states.
• If the sequence is desirable, then the agent has performed well.
• This notion of desirability is captured by a performance measure that evaluates
any given sequence of environment states.
10
RATIONALITY
What is rational at any given time depends on four things:

• The performance measure that defines the criterion of success.


• The agent’s prior knowledge of the environment.
• The actions that the agent can perform.
• The agent’s percept sequence to date.

11
SPECIFYING THE TASK ENVIRONMENT
In designing an agent, the first step must always be to specify the task
environment as fully as possible including
• the performance measure
• the environment
• the agent’s actuators
• the agent’s sensors

PEAS (Performance, Environment, Actuators, Sensors)

12
PROPERTIES OF TASK ENVIRONMENTS
• FULLY OBSERVABLE VS. PARTIALLY OBSERVABLE
• SINGLE-AGENT VS. MULTI-AGENT
• DETERMINISTIC VS. NONDETERMINISTIC
• EPISODIC VS. SEQUENTIAL
• STATIC VS. DYNAMIC
• DISCRETE VS. CONTINUOUS
• KNOWN VS. UNKNOWN
AGENT PROGRAM & AGENT ARCHITECTURE
• The job of AI is to design an agent program that implements the
agent function—the mapping from percepts to actions.
• this program will run on some sort of computing device with physical
sensors and actuators—we call this the agent architecture:

agent = architecture + program

17
AGENT PROGRAMS
• SIMPLE REFLEX AGENTS
• MODEL-BASED REFLEX AGENTS
• GOAL-BASED AGENTS
• UTILITY-BASED AGENTS
• LEARNING AGENTS
SIMPLE REFLEX AGENT
SIMPLE REFLEX AGENTS
AN AGENT PROGRAM FOR VACUUM AGENT
MODEL-BASED REFLEX AGENT
GOAL-BASED AGENTS
UTILITY-BASED AGENTS
LEARNING AGENT

You might also like