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Lecture 19 Word Meanings II

This lecture covers topics such as computational semantics, feature based grammars, and word sense relations in WordNet. It also discusses thematic roles, case frames for verbs, and conceptual dependencies.

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Lecture 19 Word Meanings II

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

  2. Overview • Last Time (Programming) • Wordnet overview • Today • Computational Semantics • Feature based grammars • Readings: • Text 19 • NLTK Book: Chapters 9 and 10 • Next Time: Computational Lexical Semantics

  3. HW review • Dropboxes • Soon to exist: • NER for handbook

  4. 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” • hyponyms: Y is a hyponym of X if every Y is a (kind of) X (dog is a hyponym of canine) “IS-A” • 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” • meronym: Y is a meronym of X if Y is a part of X (window is a meronym of building) “IS-PART” “IS-MEMBER” http://en.wikipedia.org/wiki/WordNet

  5. 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 http://en.wikipedia.org/wiki/WordNet

  6. http://wordnet.princeton.edu/ • x

  7. WordnetonlineFig 19-1

  8. Word senses • A word sense is a distinct meaning • Synonym sets are relations among word senses • couch/sofa, car/automobile • antonyms also • long/short, big/large, rise/fall • extremes; or opposite in direction

  9. Fig 19-2 Noun relations in wordnet

  10. Fig 19-3 Verb relations in wordnet

  11. Fig19-4-like IS-A (hyponym) Chain for lemma bass#7

  12. Sister terms (= coordinate terms)

  13. Thematic Roles • 19.19 “Sasha broke the window.” • exists e,x,y breaking(e) & breaker(e, Sasha) & brokenThing(e, y) & window(y) • 19.20 Pat opened the door. • Deep or thematic roles • Panini (Indian grammarian) circa 7th-4th century BC • Fillmore 1968, Gruber 1965

  14. Fig 19.5 Common Thematic Roles

  15. 19.6 Examples of Thematic Roles

  16. Variations of expression • John broke the window. • John broke the window with a rock. • The rock broke the window. • The window broke. • The window was broken by John.

  17. Case Frames for verbs • Break • Agent: Subject, Theme:Object • Agent: Subject, Theme:Object, Instrument: PP-with • Instrument:Subject, Theme:Object • Theme: Subject

  18. 19.4.3 Problems with Thematic Roles • Example 19.27 • the cook opened the jar with the new gadget. • the new gadget opened the jar. • Example 19.28 • Shelly ate the banana with a fork. • *The fork ate the banana.

  19. Prop Bank • PropBank is a corpus that is annotated with verbal propositions and their arguments—a "proposition bank". • http://verbs.colorado.edu/~mpalmer/projects/ace.html http://en.wikipedia.org/wiki/PropBank

  20. PropBank Online • http://verbs.colorado.edu/~mpalmer/projects/ace.html

  21. FrameNet

  22. Framenet Core Roles

  23. FrameNet Examples • ... [Cook the boys] ... GRILL [Food their catches] [Heating_instrumenton an open fire]. • [Avenger I] 'll GET EVEN [Offender with you] [Injury for this]! • [ Punishment This attack was conducted] [Support in] RETALIATION [ Injury for the U.S. bombing raid on Tripoli... • [Sleeper They] [Copula were] ASLEEP [Duration for hours]

  24. FrameNet Index of Lexical Units

  25. Selectional restrictions of rolesfrom PropBank

  26. Fig 19-7 Hamburger Edible?

  27. Figure 19.8 Shank’s Conceptual Dependencies • Roger Schank 1969  Professor at Yale aclweb.org/anthology-new/C/C69/C69-0201.pdf

  28. Conceptual Dependency • Governing Categories • PP – an actor or object corresponds to concrete nominal nouns • ACT – an action • LOC – a location of a conceptualization • T – time of a conceptualization • Assisting Categories • PA – attribute of a PP • AA – attribute of an ACT • Graphical representation aclweb.org/anthology-new/C/C69/C69-0201.pdf

  29. Conceptual syntax rules • Ref: ??? • Elaine Rich’s • Text on AI www.csc.csudh.edu/jhan/Fall2006/csc411/Notes/Chapter%207.ppt

  30. CD Examples • John ran. • John is tall. • John is a doctor. • A nice boy. • John’s dog • John pushed the cart • John took the book from Mary • John drank milk • john fertilized the field • the plants grew • Bill shot Bob www.csc.csudh.edu/jhan/Fall2006/csc411/Notes/Chapter%207.ppt

  31. CD for “John at the egg.” • . www.csc.csudh.edu/jhan/Fall2006/csc411/Notes/Chapter%207.ppt

  32. CD “John prevented Mary from giving the book to Bill.” • .More tenses and modes • p past • f future • t transition • k continuing • c conditional • / negative • ? Interrogative • pil present www.csc.csudh.edu/jhan/Fall2006/csc411/Notes/Chapter%207.ppt

  33. RestaurantScript • Roger Schank again • Collection of scenes describing typical events • e.g. “visit a restaurant” • Entering • Ordering • Eating • Paying/Leaving www.csc.csudh.edu/jhan/Fall2006/csc411/Notes/Chapter%207.ppt

  34. Modifiers

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