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Eric Xing
© Eric Xing @ CMU, 20062008
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Machine Learning
Machine Learning
10
10
701/15
701/15
781, Fall 2008
781, Fall 2008
Bayesian Network II
Bayesian Network II
Inference
Inference
Eric Xing
Eric Xing
Lecture 18, November 12, 2008
Reading: Chap. 8, C.B book
X1
X2
X3
X4
X5
X6
X7
X8
Visit to Asia
Tuberculosis
Tuberculosis
or Cancer
XRay Result
Dyspnea
Bronchitis
Lung Cancer
Smoking
Eric Xing
© Eric Xing @ CMU, 20062008
2
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Recap of BN Representation
z
Joint probability dist. on multiple variables:
z
If
X
i
's are
independent
: (
P
(
X
i

·)=
P
(
X
i
))
z
If
X
i
's are
conditionally independent
(as described by a
GM
), the joint can be factored to simpler products, e.g.,
∏
=
=
i
i
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P
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