Constituency-based Hyponymy Extraction COMP 762 Chianyu Liu, - PowerPoint PPT Presentation

Constituency-based Hyponymy Extraction COMP 762 Chianyu Liu, 260576898

Hyponym and Hypernym ● Describes a “ type-of” relationship E.g. ● Meronym : describes a part-whole relationship ● Homonym : a word that has two unrelated meanings ● ● Polyseme : a word with two related meanings

Constituency-based parse tree ● Ordered, rooted tree that represents the syntactic structure of a text Breaks a sentence, S, into sub-phrases (e.g. NP, VP, PP etc.) ● ○ Nodes are phrases ○ Leafs are words ○ Edges are unlabeled ● Vs. Dependency-based parse tree ● http://nlp.stanford.edu:8080/parser/index.jsp

Tregex ● An utility for identifying patterns in trees Like regular expressions for strings ● Use symbols to denote relations ● ○ A < B: A is the parent of B A << B: A is an ancestor of B ○ ○ A$B: A and B are siblings

Tregex Example

Pattern Matching ● Hyponymy categories defined in the paper Pattern Description Example HKO Hypernym -> Keywords -> Hyponym …, such as … OKH Hyponym -> Keyworks -> Hypernym … are considered as … HO Hyponym -> Hyponym Section header KHO Keywords -> Hypernym -> Hyponym Following types of …

WordNet ● A large lexical database of English Nouns, verbs, adjectives and adverbs are grouped into sets of synsets ● Synsets are interlinked by means of conceptual-semantic and lexical relations ● ● The most frequently encoded relation among synsets is the super-subordinate relation (i.e. hypernym and hyponym) ● http://wordnetweb.princeton.edu/perl/webwn

Ontology ● A specification of a conceptualization Describes the representation and relationships that can exist for entities ● (objects, properties, etc.) in a particular domain Ontology is a standard to represent knowledge, and enables knowledge to be ● shared and reused

References G. Andrew, “The Wonderful World of Tregex,” in Stanford: Natural Language Processing . M. C. Evans, J. Bhatia, S. Wadkar, and T. D. Breaux, “An Evaluation of Constituency-Based Hyponymy Extraction from Privacy Policies,” 2017 IEEE 25th International Requirements Engineering Conference (RE) , 2017. P. University, “What is WordNet?,” Princeton University , 17-Mar-2015. [Online]. Available: https://wordnet.princeton.edu/. S. Gole, “Part of speech tagging using OpenNLP,” Sager Gole's Blog , 18-Jun-2015.