WORDNET
Reporter: Nguyen Duc Minh Khoi
@ Ho Chi Minh City University of Technology
Thursday, November 01, 2012
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Contents

            Intro to WordNet

              Nouns

              Modifiers

              Verbs

            WordNet system
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   INTRODUCTION TO WORDNET
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Overview
• WordNet is lexical database for the English language that
  groups English word into set of synonyms called synset
• Authors: the Cognitive Science Laboratory of Princeton
  University under the direction of psychology professor
  George A. Miller
• Used by:
   • Linguistics Scientist
   • Psychologist
   • Artificial intelligence Scientist
   • Natural Language Processing Scientist
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Contents of WordNet
• WordNet distinguish between nouns, verbs, adjectives,
  adverbs – 4 major syntactic categories
• WordNet contains basic units:
   • Compounds
   • Phrasal verbs
   • Collocations
   • Idiomatic phrases
• WordNet as a dictionary:
  • Give definitions
  • Sample sentences
  • Contains synonym sets
• WordNet as a thesaurus:
  • Conceptual level: semantic conceptual relations
  • Lexical level: lexical relation
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Other information
• Lexical database can be built by:
   • Automatic acquisition
   • Craft one dictionary by hand
• Knowledge engineering:
  • Lexical level: contains information about synonyms, antonyms...
  • Domain level: refer to the topic of discourse
  • Application specific level: relates objects and events
• Tennis problem:
   • Contains no relations that indicate the word’s shared membership in a
     topic of discourse
   • E.g. not link racquet, ball, net => court game
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   NOUNS
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Introduction to nouns in WordNet
• WordNet is machine readable dictionary
• Noun in WordNet doesn’t give:
  • pronunciation
  • Derivative morphology
  • Etymology
  • Usage notes
  • Pictorial illustration
• WordNet try to make semantic relations by extract synonym
  from thesaurus manually
• WordNet lexicalized concept by making synset relate to that
  concept
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Lexical hierarchy
• Tree graph: graph without circular loop
• Assumptions:
  • Longer distance in hierarchy  longer traverse in thoughts
  • More lexical information must be stored in every lexicalized concepts
    than is required to establish in hierarchy.
• Noun’s unique beginner:
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Lexical hierarchy (cont.)
• Examples:
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Noun relations
• Hyponyms (~):
  • A word of more specific meaning than a general or superordinate term
    applicable to it.
  • For example, {bowl} is a hyponym of {dish}: {bowl} ~-> {dish}
• Hypernyms (@):
  • A word with a broad meaning that more specific words fall under; a
    superordinate.
  • For example, {color} is a hypernym of {red}: {color} @-> {red}
• Meronyms (#):
  • The semantic relation that holds between a part and the whole.
  • For example, {beak} and {wing} are meronyms of {bird}: {beak, wing} #-> bird
  • Three kinds: component, member, made from
• Holonyms (%):
  • The semantic relation that holds between a whole and its parts
  • For example, {building} is a holonym of {window}: {building} %-> {window}
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Noun relations (cont.)
• Antonyms (!):
  • A word opposite in meaning to another
  • For example, {man} !-> {woman}
• Polysemous nouns:
   • Nous that have many meanings
   • For example, {mouse} living animal or computer device
   • Rules: two meanings of a word are similar then the meaning of their
     hyponyms should also be similar in the same way.
• Attribute (=) and modifications:
  • Values of attribute are expressed by adjectives
  • Modification can also be nouns
  • For examples, chair -> small chair, big chair
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   MODIFIERS
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Adjectives
• Main functions: modifying nouns
• Types:
   • Descriptive adjectives
   • Participle adjectives
   • Relational adjectives
• Format:
   • A(x) = adj
   • E.g.: WEIGHT(package) = heavy
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Adjectives Relations
• Antonyms (!):
  • Basic semantic relation among descriptive adjectives
  • Means “IS ANOYNYMOUS TO”, e.g. heavy is anonymous to light
  • Can be direct, e.g. heavy/light
  • Or can be indirect, e.g. heavy/airy
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Adjectives Relations (cont.)
• Other relations
  • Troponym (~):
  • Hypernym (@):
  • Entailment (*):
  • Cause (>):
  • Also see (^):
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Gradation
• Contrary: one of propositions can be true or both are false
• Adjectives can be use to express different level of action
• For example:
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Other stuffs
• Markedness:
  • Normal linguistic unit (unmarked term) compare to unit possible
    irregular forms (marked term)
  • E.g.: The pool is 5 feet deep, NOT: The pool is 5 feet shallow
  • So deep  marked term, shallow  unmarked term
• Polysemy and selectional preferences:
   • E.g.: old can be not young  modify persons
           old can be not new  modify things
   • Some adjectives can modify almost any nouns
      • E.g.: good / bad, desirable / undesirable
   • Some adjectives can strictly restricted to some nouns
      • E.g.: editable / ineditable
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Other types of descriptive adjectives
• Color adjectives:
   • Server as nouns and adjectives
• Quantifiers:
  • E.g.: all, some, many, few…
• Participle adjectives:
   • Means “PRINCIPLE PART OF”
   • E.g.: breaking is principle part of break
   • Can be –ing/-ed: running water, elapsed time
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Relational adjectives
• Differ from descriptive adjectives by
  • Do not relate to attribute of nouns
  • Can not be gradable
  • Occur only attribute position
  • Lack of direct antonym
• E.g.: criminal behavior
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Adverbs
• Derived from adjectives by suffixation:
  • -ly:
      • Specify manner: e.g.: beautifully
      • Specify degree: e.g.: extremely
   • Other suffix:
      • -wise, -way, -ward
      • E.g.: northward, forward

• Inherit their adjectives about:
   • Antonym
   • Gradation
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   VERBS
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Organizations
• Types of semantic verbs:
   • motion, perception, communication, competition, change, cognitive,
     consumption, creation, emotion, possession, body care, functions, social
     behavior, interaction.
• Stative verb:
   • Collaborate with be: resemble, belong, suffice
   • Control verb: want, fail, prevent, succeed, begin
• Cannot group all verbs in unique beginner like nouns
• English has fewer verb than nouns BUT approximate twice as
  polysemous as noun
• Verb synset:
   • Synonym and near synonym: e.g.: pass away vs. die vs. kick the bucket
   • Idiom and metaphors:
      • Kick the bucket include synset
      • Die include synonym: break, break down (for car and computer)
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Verb Relations
• Entailment (*):
   • The verb Y is entailed by X if by doing X you must be doing Y
   • E.g.: to snore entails to sleep
   • Not mutual: V1 * V2 NOT V2  V1
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Verb relations
• Troponym (~):
   • The verb Y is a troponym of the verb X if the activity Y is doing X in
     some manner
   • E.g.: to lisp is a troponym of to talk
   • Special case of entailment
   • Most frequently coded in WordNet
• Antonym (!):
  • E.g.: give/take, buy/sell, lend/borrow, teach/learn
  • Can also be troponym: fail/succeed entails try, forget entails know
• Hypernym (@):
  • The verb Y is a hypernym of the verb X if the activity X is a (kind of) Y
  • E.g.: to perceive is an hypernym of to listen
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   WORDNET SYSTEM
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WordNet system
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Lexical files
• WordNet store nouns, adjectives, adverbs and nouns into
  synset  lexical source files by syntactic categories
   • Nouns and verbs: grouped according to semantic fields
   • Adjectives are divided among three files (adj.all, adj.ppl, adj.pert)
   • Adverb are store in single file
• Relation pointers store in WordNet
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Sample Application use WordNet
• NLTK is a platform for building Python programs to work
  with human language data
• Sample commands:
   • Work with nouns:
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Sample Application use WordNet (cont.)




• Work with verbs