Uncertainty handling in
Artificial Intelligence
Uncertainty ?
• Lack of exact information
• Doubtful information
?
There are Six Tea Cups on top
of the table if one falls down and
how many are remaining?
5
Note
Most Intelligence Systems have some degree
of uncertainty associated with them
All birds Fly !!!
Most of the birds Fly !!!
95% of the birds Fly !!!
Sources of Uncertainty
• Uncertain Inputs
• Uncertain Knowledge
• Uncertain Outputs
To Solve Uncertainty
• How to Represent Uncertain Data?
• How to combine two or more pieces of Uncertain Data?
• How to draw inference using certain data?
Approaches to handling Uncertainty
• Default reasoning
• Worst- case reasoning
• Probabilistic reasoning
Methods for Managing Uncertain Information
• Probability
• Bayesian belief network
• Temporal Models
• Hidden Markov Models
The Wumpus World in Artificial intelligence
https://www.javatpoint.com/the-wumpus-world-in-artificial-intelligence
Real time example for uncertainty
• My car doesn’t break down
• Run out of gas
• I don’t get in to an accident
• There are no accidents on the bridge
• Plane doesn’t leave early
Example of rule for dental diagnosis
using
p Symptom(p, Toothache) ⇒ Disease(p, Cavity)
• This rule is wrong and in order to make it true we have
to add an almost unlimited list of possible causes:
• p Symptom(p, Toothache) ⇒ Disease(p, Cavity) ∨ Disease(p,
GumDisease) ∨ Disease(p, Abscess)…
What is the role of
probability and inference in AI?
• Many algorithms are designed as if knowledge is perfect, but it rarely is.
• There are almost always things that are unknown, or not precisely known.
• Examples: - bus schedule
- quickest way to the airport
- sensors
- joint positions
- finding an H-bomb
• An agent making optimal decisions must take into account uncertainty
Probability as frequency:
k out of n possibilities
• Suppose we’re drawing cards from a standard deck:
- P(card is the Jack ♥ | standard deck) = 1/52
- P(card is a ♣ | standard deck) = 13/52 = 1/4
• General probability of event given some conditions:
P(event | conditions)
Making rational decisions when faced with
uncertainty
• Probability
-the precise representation of knowledge and uncertainty
• Probability theory
-how to optimally update your knowledge based on new
information
• Decision theory: probability theory + utility theory how to use this
information to achieve maximum expected Utility
Basic Postulates by taking an Example
Uncertainty in AI
Uncertainty in AI
Uncertainty in AI
Uncertainty in AI

Uncertainty in AI

  • 1.
  • 2.
    Uncertainty ? • Lackof exact information • Doubtful information ?
  • 3.
    There are SixTea Cups on top of the table if one falls down and how many are remaining? 5
  • 4.
    Note Most Intelligence Systemshave some degree of uncertainty associated with them
  • 5.
    All birds Fly!!! Most of the birds Fly !!! 95% of the birds Fly !!!
  • 6.
    Sources of Uncertainty •Uncertain Inputs • Uncertain Knowledge • Uncertain Outputs
  • 7.
    To Solve Uncertainty •How to Represent Uncertain Data? • How to combine two or more pieces of Uncertain Data? • How to draw inference using certain data?
  • 8.
    Approaches to handlingUncertainty • Default reasoning • Worst- case reasoning • Probabilistic reasoning
  • 9.
    Methods for ManagingUncertain Information • Probability • Bayesian belief network • Temporal Models • Hidden Markov Models
  • 10.
    The Wumpus Worldin Artificial intelligence https://www.javatpoint.com/the-wumpus-world-in-artificial-intelligence
  • 12.
    Real time examplefor uncertainty • My car doesn’t break down • Run out of gas • I don’t get in to an accident • There are no accidents on the bridge • Plane doesn’t leave early
  • 13.
    Example of rulefor dental diagnosis using p Symptom(p, Toothache) ⇒ Disease(p, Cavity) • This rule is wrong and in order to make it true we have to add an almost unlimited list of possible causes: • p Symptom(p, Toothache) ⇒ Disease(p, Cavity) ∨ Disease(p, GumDisease) ∨ Disease(p, Abscess)…
  • 14.
    What is therole of probability and inference in AI? • Many algorithms are designed as if knowledge is perfect, but it rarely is. • There are almost always things that are unknown, or not precisely known. • Examples: - bus schedule - quickest way to the airport - sensors - joint positions - finding an H-bomb • An agent making optimal decisions must take into account uncertainty
  • 15.
    Probability as frequency: kout of n possibilities • Suppose we’re drawing cards from a standard deck: - P(card is the Jack ♥ | standard deck) = 1/52 - P(card is a ♣ | standard deck) = 13/52 = 1/4 • General probability of event given some conditions: P(event | conditions)
  • 16.
    Making rational decisionswhen faced with uncertainty • Probability -the precise representation of knowledge and uncertainty • Probability theory -how to optimally update your knowledge based on new information • Decision theory: probability theory + utility theory how to use this information to achieve maximum expected Utility
  • 19.
    Basic Postulates bytaking an Example