curs_13_pac
TRANSCRIPT
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Invatare automata
Universitatea Politehnica BucurestiAnul universitar 2008-2009
Adina Magda Floreahttp://turing.cs.pub.ro/inva_09 si
curs.cs.pub.ro
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Curs nr. 13
Invatare Bayesiana
Invatare PA
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Invatare Bayesiana
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Retele Bayesiene
4
Cutremur
Alarma
TelMihai TelDana
HotP!"
0.00!PC"
0.00"
! C PA"
# # 0.9$
# F 0.9%
F # 0."9
F F 0.00!
A P#"
# 0.9
F 0.0$
A P$"
# 0.&
F 0.0!
P# $ A! C " %
P#&A"' P$&A"'PA&
!
C "'P
!"
P
C"%
0.9 ' 0.( ' 0.001 ' 0.999 ' 0.998 % 0.000)2
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Invatarea in retele Bayesiene
Invatare *arametrii
Invatare structura
#o+ele +iscrete Modele continue
$ate com*lete
'ate inco(plete ) variabile ascunse *neobservabile+
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I*ote,a cea mai *roaila
MAP ,earning - (ai(u( aposteriori *curs !"+ e ac predictii pe ba1a ipote1ei celei (ai probabile
P*23++ )4 P*23hMAP+P*hMAP3++
Probabilitatea iecarei ipote1e:
P*hi3++ ) P*+3hi+ P*hi+
are ipote1a (ai(i1ea1a aceasta epresie5
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I*ote,a cea mai *roaila
Bo(boane de cirese si la(aie - o punga ontinuu de ipote1e asupra distributiei de bo(boane
Modela( cu o RB
P*F)cirese+ 6 7777 F - aro(a *var aleatoare+ 6 - para(etrul care se invata
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Aroma - F
F P
cirese
lamaie 1-
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I*ote,a cea mai *roaila
8tragebo(boane ccirese si l)7cla(aie
P*+3h6+) ;
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I*ote,a cea mai *roaila
Bo(boane de cirese si la(aie - a(bala< verde sau rosu Modela( cu o RB
@ariabile aleatoare: - aro(a /7 a(bala