20. A Bayesian Network
A Bayesian network is made up of:
1. A Directed Acyclic Graph
A
B
C D
2. A set of tables for each node in the graph
A P(A) A B P(B|A) B D P(D|B) B C P(C|B)
false 0.6 false false 0.01 false false 0.02 false false 0.4
true 0.4 false true 0.99 false true 0.98 false true 0.6
true false 0.7 true false 0.05 true false 0.9
true true 0.3 true true 0.95 true true 0.1
22. A Set of Tables for Each Node
A P(A) A B P(B|A) Each node Xi has a
false 0.6 false false 0.01
true 0.4 false true 0.99
conditional probability
true false 0.7
distribution P(Xi | Parents(Xi))
true true 0.3 that quantifies the effect of
the parents on the node
B C P(C|B)
false false 0.4 The parameters are the
false true 0.6 A probabilities in these
true false 0.9 conditional probability tables
true true 0.1 (CPTs)
B
B D P(D|B)
false false 0.02
C D
false true 0.98
true false 0.05
true true 0.95
39. Person Model (Initial Prototype)
Anthrax Release
Time Of Release Location of Release
…
…
Gender
Age Decile Age Decile Gender
Home Zip Home Zip
Other ED Other ED
Anthrax Infection Disease Anthrax Infection Disease
Respiratory Respiratory CC Respiratory Respiratory CC
from Anthrax From Other from Anthrax From Other
Respiratory Respiratory
CC CC
ED Admit ED Admit ED Admit ED Admit
from Anthrax from Other from Anthrax from Other
Respiratory CC Respiratory CC
When Admitted When Admitted
ED Admission ED Admission
40. Person Model (Initial Prototype)
Anthrax Release
Time Of Release Location of Release
…
Female
… 20-30 50-60 Male
Gender
Age Decile Age Decile Gender
Home Zip Home Zip
Other ED Other ED
Anthrax Infection 15213 Disease Anthrax Infection 15146 Disease
Respiratory Respiratory CC Respiratory Respiratory CC
from Anthrax From Other from Anthrax From Other
Respiratory Respiratory
CC CC
ED Admit ED Admit ED Admit ED Admit
Unknown
from Anthrax False from Other from Anthrax from Other
Respiratory CC Respiratory CC
When Admitted When Admitted
Yesterday ED Admission never ED Admission