Lecture 19 Word Meanings II Topics Description Logic III Overview of MeaningReadings: Text Chapter 189NLTK book Chapter 10 March 27, 2013 CSCE 771 Natural Language Processing

– 2 – CSCE 771 Spring 2013 Overview Last Time (Programming) Wordnet overviewToday Computational Semantics Feature based grammarsReadings: Text 19 NLTK Book: Chapters 9 and 10 Next Time: Computational Lexical Semantics

– 3 – CSCE 771 Spring 2013 HW review Dropboxes Soon to exist: NER for handbook 1.frequency distribution - Handbook Assignmentfrequency distribution - Handbook Assignment 2.Regular Expression /urllib2 - Identify prerequisites AssignmentRegular Expression /urllib2 - Identify prerequisites Assignment 3.Extend backoff tagger to include trigram AssignmentExtend backoff tagger to include trigram Assignment 4.Test1Test1

– 4 – CSCE 771 Spring 2013 Wordnet Most synsets are connected to other synsets via a number of semantic relations. These relations vary based on the type of word, and include: Nouns hypernyms: Y is a hypernym of X if every X is a (kind of) Y (canine is a hypernym of dog) “superordinate” “superclass” hypernyms hyponyms: Y is a hyponym of X if every Y is a (kind of) X (dog is a hyponym of canine) “IS-A” hyponyms coordinate terms: Y is a coordinate term of X if X and Y share a hypernym (wolf is a coordinate term of dog, and dog is a coordinate term of wolf) “sibling” holonym: Y is a holonym of X if X is a part of Y (building is a holonym of window) “HAS-PART” holonym meronym: Y is a meronym of X if Y is a part of X (window is a meronym of building) “IS-PART” “IS-MEMBER” meronym

– 5 – CSCE 771 Spring 2013 Verbs hypernym: the verb Y is a hypernym of the verb X if the activity X is a (kind of) Y (to perceive is an hypernym of to listen) troponym: the verb Y is a troponym of the verb X if the activity Y is doing X in some manner (to lisp is a troponym of to talk) entailment: the verb Y is entailed by X if by doing X you must be doing Y (to sleep is entailed by to snore) coordinate terms: those verbs sharing a common hypernym (to lisp and to yell) Adjectives related nouns similar to participle of verb Adverbs root adjectives

– 6 – CSCE 771 Spring x

– 7 – CSCE 771 Spring 2013 Wordnet online Fig 19-1

– 8 – CSCE 771 Spring 2013 Word senses A word sense is a distinct meaning Synonym sets are relations among word senses couch/sofa, car/automobilecouch/sofa, car/automobile antonyms also long/short, big/large, rise/falllong/short, big/large, rise/fall extremes; or opposite in directionextremes; or opposite in direction

– 9 – CSCE 771 Spring 2013 Fig 19-2 Noun relations in wordnet

– 10 – CSCE 771 Spring 2013 Fig 19-3 Verb relations in wordnet

– 11 – CSCE 771 Spring 2013 Fig19-4-like IS-A (hyponym) Chain for lemma bass#7

– 12 – CSCE 771 Spring 2013 Sister terms (= coordinate terms)

– 13 – CSCE 771 Spring 2013 Thematic Roles “Sasha broke the window.” exists e,x,y breaking(e) & breaker(e, Sasha) & brokenThing(e, y) & window(y) Pat opened the door. Deep or thematic roles Panini (Indian grammarian) circa 7 th -4 th century BCPanini (Indian grammarian) circa 7 th -4 th century BC Fillmore 1968, Gruber 1965Fillmore 1968, Gruber 1965

– 14 – CSCE 771 Spring 2013 Fig 19.5 Common Thematic Roles

– 15 – CSCE 771 Spring Examples of Thematic Roles

– 16 – CSCE 771 Spring 2013 Variations of expression John broke the window.John broke the window. John broke the window with a rock.John broke the window with a rock. The rock broke the window.The rock broke the window. The window broke.The window broke. The window was broken by John.The window was broken by John.

– 17 – CSCE 771 Spring 2013 Case Frames for verbs Break Agent: Subject, Theme:ObjectAgent: Subject, Theme:Object Agent: Subject, Theme:Object, Instrument: PP-withAgent: Subject, Theme:Object, Instrument: PP-with Instrument:Subject, Theme:ObjectInstrument:Subject, Theme:Object Theme: SubjectTheme: Subject

– 18 – CSCE 771 Spring Problems with Thematic Roles Example  the cook opened the jar with the new gadget.  the new gadget opened the jar. Example  Shelly ate the banana with a fork.  *The fork ate the banana.

– 19 – CSCE 771 Spring 2013 Prop Bank PropBank is a corpus that is annotated with verbal propositions and their arguments—a "proposition bank". corpusannotatedcorpusannotated

– 20 – CSCE 771 Spring 2013 PropBank Online

– 21 – CSCE 771 Spring 2013 FrameNet

– 22 – CSCE 771 Spring 2013 Framenet Core Roles

– 23 – CSCE 771 Spring 2013 FrameNet

– 24 – CSCE 771 Spring 2013 Selectional restrictions of roles from PropBank

– 25 – CSCE 771 Spring 2013 Fig 19-7 Hamburger Edible?

– 26 – CSCE 771 Spring 2013 Figure 19.8 Shank’s Conceptual Dependencies

– 27 – CSCE 771 Spring 2013

– 28 – CSCE 771 Spring 2013