Page 116 - DCAP506_ARTIFICIAL_INTELLIGENCE

Artificial Intelligence

Notes 6. Initially, I gaze out of the window and saw at the clouds on the horizon. I conclude that I
consider there is a 0.6 chance of rain. Half an hour later I make the same observation and
now consider there is a 0.4 chance of rain.
(a) What are my primary disbelief and certainty factors that it will rain?
(b) What are the new estimates of belief, disbelief and certainty factors based on both
observations?
I then catch a climate forecast states that there 50am. What is my belief, disbelief and
certainty factors depending on my observations and the weather forecast?

7. Peter, Paul and Mary are 3 suspects in a murder case. Only one of them committed the
crime. There is some evidence that provides equal support for the murderer being male or
female. There is also evidence that Peter was has an alibi for the time of the killing.
(a) Combine the information above and represent it in the Dempster-Shafer formalism.
(b) Calculate the Belief and Plausibility for each suspect.
8. Consider the following facts:

(a) I saw my cat in the living room 3 hours ago.
(b) Two hours ago my door blew open.
(c) Three quarters of the time my door blows open my cat runs outside through the
door.
(d) On hour ago I thought I heard a cat-noise in my living. Assume I was half certain.
(e) In any one hour period the probability that the cat will leave the room is 0.2. There
is also a 0.2 probability that he may enter the room.
What is the Certainty that the cat is in my living room? Use Bayesian networks to answer
this.

9. Design a Bayesian network for each of the following problems:
(a) Choosing a menu for a dinner party.
(b) Planning a holiday.
(c) Selecting final year computer science options based on second and first year
prerequisites.
10. Describe how Fuzzy Logic is used in representing uncertainty.

Answers: Self Assessment

1. Statistical 2. Probabilities

3. Conditional 4. hypotheses
5. A|B 6. total number of outcomes
7. rules 8. disease
9. independence 10. Bayesian
11. directed 12. dependencies

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