Graphical Models Representing Probabilistic Features in Log-Linear Models
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Representation Probabilistic Graphical Models Template Models Shared Features in Log-Linear Models
Intelligence I(s1) I(s2) Grade G(s1) G(s2) Students s
Nested Plates Courses c Difficulty Intelligence Grade Students s D(c1) D(c2) I(s1,c1) I(s2,c1) I(s1,c2) I(s2,c2) G(s1,c1) G(s2,c1) G(s1,c1) G(s2,c1)
Overlapping Plates Difficulty Intelligence Grade Courses c Students s D(c2) D(c1) I(s1) I(s2) G(s1,c1) G(s1,c2) G(s2,c1) G(s2,c2)
Explicit Parameter Sharing D I G D(c2) D(c1) I(s1) I(s2) G(s1,c1) G(s1,c2) G(s2,c1) G(s2,c2)
C Welcome to Geo101 Welcome to A low high CS101 Collective Inference easy / hard low / high
Plate Dependency Model • For a template variable A(U1,…,Uk): • Template parents B1(U1),…,Bm(Um) • CPD P(A | B1,…, Bm)
Ground Network • A(U1,…,Uk) with parents B1(U1),…,Bm(Um)
Plate Dependency Model • For a template variable A(U1,…,Uk): • Template parents B1(U1),…,Bm(Um)
Summary • Template for an infinite set of BNs, each induced by a different set of domain objects • Parameters and structure are reused within a BN and across different BNs • Models encode correlations across multiple objects, allowing collective inference • Multiple “languages”, each with different tradeoffs in expressive power