18CSC305J - Artificial Intelligence UNIT 1
12M:
Explain the types of intelligent agents.
Agent:
An agent is anything is anything that can be viewed as perceiving its environment through sensors and acting upon the environment through actuators
Agent Program:
Agent’s behavior is mathematically described by an agent function
Agent’s behavior is practically described by an agent program
It is the real implementation
AI designs the agent program
To design an agent program, we need to understand
Percepts
Actions
Goals
Environment
Types:
Simple reflex agents
Model based reflex agents
Goal based agents
Utility based agents
Simple reflex agents:
Uses just condition action rules
Works only if the environment is fully observable
Model based reflex agents:
For the world that is partially observable
The agent has to keep track of an internal state that depends on the percept history
Goal based agents:
Current state of the environment is always not enough
The goal is to achieve correctness
Utility based agents:
Goals alone are not enough to generate high quality behavior
If goal means success, utility means the degree of success
Problem Solving:
Problem solving process:
Components of problems:
A problem can be defined formally by 5 components:
Initial state
actions/ operators
Transition model
A goal test
Path cost
Problem formulation:
Choosing relevant set of states and feasible set of operators for moving from one state to another
Toy world problem:
Intended to illustrate various problem solving methods
Real world problems:
One whose solutions people actually care about
Problem types:
Deterministic or observable
Non observable
Non deterministic or partially observable
Unknown state space
Example: (Toy world problem)
4-Queens:
Given a 4 x 4 chessboard, we have to place 4 queens such that no two queens attack each other
4M:
What is an agent? / What is an agent program?
Agent:
An agent is anything is anything that can be viewed as perceiving its environment through sensors and acting upon the environment through actuators
Agent Program:
Agent’s behavior is mathematically described by an agent function
Agent’s behavior is practically described by an agent program
It is the real implementation
AI designs the agent program
To design an agent program, we need to understand
Percepts
Actions
Goals
Environment
What is meant by a cognitive model?
The goal is to make systems think like humans
Simulating human problem solving and mental processing in a computerized model
It is used in various AI applications like NLP, robotics, VR, neural networks
Give complete solutions to 4 Queens problem
The aim of the n queens problem is to place n queens in a chessboard in such a way that no queens can attack each other ( no two queens are placed diagonally, vertically or horizontally)
What are the important AI techniques?
AI technique is a method that achieves knowledge.
The main AI techniques are
Search
Use of knowledge
Abstraction
A search program finds solution for a problem by trying various sequences of actions until a solution is found (best way but not always possible because of large state space)
The use of knowledge provides a way of solving complicated problems by manipulating the structures of the objects that are concerned
Abstraction finds a way of separating important features and notifications from the unimportant ones that would otherwise confuse any process
Types of constraints in a CSP problem
CSP is a special class of search problems
The goal test is a set of constraints
Types of constraints:
Unary constraints: involve a single variable (Eg: SA != green)
Binary constraints: involve pairs of variables (Eg: SA != WA)
Higher order constraints: involve 3 or more variables (Eg: O + O = R + 10 . X1)
Preferences (soft constraints): gives constrained optimization problems (Eg: red is better than green)
What are the various constraint satisfaction problems?
Finding a solution that meets a set of constraints is the goal of constraint satisfaction problems
There are mainly 3 basic components of a CSP:
Variables
Domains
Constraints
CSP can be categorized according to the type of domain:
Finite: finite domains have a finite number of possible values such as colors or integers
Infinite: infinite domains have a infinite number of possible values such as real numbers
Continuous: continuous domains have a infinite number of possible values but can be represented by a finite set of parameters
Examples:
Cryptarithmetic puzzles
Map coloring problems
Sudoku
crosswords
Give PEAS description for online bus reservation system
PEAS stands for
Performance measures
Environment
Actuators
Sensors
Performance measures:
Response time
Accuracy
User satisfaction
Environment:
Users
Bus routes
Payment gateways
Actuators:
Seat reservation
Cancellation
Payment processing
Sensors:
Seat availability sensors
Payment status sensors
Describe various AI models
What are the characteristics of intelligent agents?
An agent is anything that can be viewed as perceiving its environment through sensors and acting upon that environment through actuators
Common characteristics of intelligent agents are adaptation based on experience, real-time problem-solving, analysis of error or success rates, and the use of memory-based storage and retrieval.
Human 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
What are problem solving agents?
A simple problem solving agent first
formulates a goal and a problem
Searches for a sequence of actions that would solve the problem
Then execute the actions one at a time
When this is complete, it formulates another goal and starts over
What are the problems in simple reflex agents?
They cannot compute complex equations or solve complicated problems.
They work only in environments that are fully-observable in the current percept, ignoring any percept history.
What are the conceptual components of a Learning agent?
Four conceptual components
Learning element - Making improvement
Performance element - Selecting external actions
Critic - Tells the Learning element how well the agent is doing with respect to fixed performance standards. (Feedback from users or examples, good or not?)
Problem generator - Suggest actions that will lead to new and informative experiences.
What are the parameters of Measuring problem-solving performance?
the search cost--how long the agent takes to come up with the solution to the problem, and
the path cost--how expensive the actions in the solution are.
The total cost of the solution is the sum of the above two quantities.
Completeness: Is the algorithm guaranteed to find a solution when there is one?
Optimality: Does the strategy find the optimal solution (i.e., lowest path cost among all solutions)
Time complexity: How long does it take to find a solution?
Space complexity: How much memory is needed to perform the search?
Define heuristic function
Backtracking allows to go to the previous decision-making node to eliminate the invalid search space with respect to constraints
Heuristics plays a very important role here
If we are in position to determine which variables should be assigned next, then backtracking can be improved
Heuristics help in deciding the initial state as well as subsequent selected states
Selection of a variable with minimum number of possible values can help in simplifying the search
This is called as Minimum Remaining Values Heuristic (MRV) or Most Constraint Variable Heuristic
Data acquisition:
There are 2 things that AI needs code and training data
The more accurate the training data, the more powerful the tool
What are rational agents?
Ideal Rational agents are ones that are capable of doing expected actions to maximize its performance measure
Rationality of an agent depends on
Performance measure
Percept sequence
Knowledge about environment
Action able to be performed
The problem can be categorized by PEAS
Comments
Post a Comment