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Markov Logic and Deep Networks. Pedro Domingos Dept. of Computer Science & Eng. University of Washington. Weight of formula i. No. of true instances of formula i in x. Markov Logic Networks. Basic idea: Use first-order logic to compactly specify large non-i.i.d. models
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Markov Logic and Deep Networks Pedro Domingos Dept. of Computer Science & Eng. University of Washington
Weight of formula i No. of true instances of formula i in x Markov Logic Networks • Basic idea: Use first-order logic tocompactly specify large non-i.i.d. models • MLN = Set of formulas with weights • Formula = Feature template (Vars→Objects) • E.g., HMM: State(+s,t) ^ State(+s',t+1) Obs(+o,t) ^ State(+s,t)
State of the Art in MLNs • Many algorithms for learning and inference • Inference: Millions of variables, billions of features • Learning: Generative, discriminative, max-margin, etc. • Best-performing solutions in many application areas • Natural language, robot mapping, social networks,computational biology, activity recognition, etc. • Open-source software/Web site: Alchemy • Book: Domingos & Lowd, Markov Logic,Morgan & Claypool, 2009. alchemy.cs.washington.edu
Deep Uses of MLNs • Very large scale inference • Defining architecture of deep networks • Adding knowledge to deep networks • Transition to natural language input • Learning with many levels of hidden variables
MLNs for Deep Learning • Basic idea: Use small amounts of knowledgeand large amounts of joint inferenceto make up for lack of supervision • Relational clustering: • Cluster objects with similar relations to similar objects • Cluster relations that hold between similar sets of objects • Coreference resolution: Outperforms supervised approaches on MUC and ACE benchmarks • Semantic network extraction: Learns thousands of concepts and relations from millions of Web triples
Example:Unsupervised Semantic Parsing • Goal: Read text and answer questions • No supervision or annotation • Input: Dependency parses of sentences(Nodes→Unary predicates / Edges→Binary preds.) • Outputs: Semantic parser and knowledge base • Basic idea: Cluster expressions with similar subexpressions • Maps syntactic variants to common meaning • Discovers its own meaning representation • “Part of” lattice of clusters • Applied to corpus of biomedical abstracts • Three times more correct answers than next best