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This article discusses the Japanese court's dismissal of a lawsuit filed by former Chinese slave workers seeking massive compensation. It highlights the sense tagging issues in machine translation and the impact on automatic word sense disambiguation.
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Different Sense Granularities Martha Palmer, Olga Babko-Malaya September 20, 2004
Statistical Machine Translation results • CHINESE TEXT • The japanese court before china photo trade huge & lawsuit. • A large amount of the proceedings before the court dismissed workers. • japan’s court, former chinese servant industrial huge disasters lawsuit. • Japanese Court Rejects Former Chinese Slave Workers’ Lawsuit for Huge Compensation.
Outline • MT example • Sense tagging Issues highlighted by Senseval1 • Senseval2 • Groupings, • Impact on ITA • Automatic WSD, impact on scores
WordNet - Princeton • On-line lexical reference (dictionary) • Words organized into synonym sets <=> concepts • Hypernyms (ISA), antonyms, meronyms (PART) • Useful for checking selectional restrictions • (doesn’t tell you what they should be) • Typical top nodes - 5 out of 25 • (act, action, activity) • (animal, fauna) • (artifact) • (attribute, property) • (body, corpus)
WordNet – president, 6 senses • president-- (an executive officer of a firm or corporation) -->CORPORATE EXECUTIVE, BUSINESS EXECUTIVE… LEADER 2. President of the United States, President, Chief Executive -- (the person who holds the office of head of state of the United States government; "the President likes to jog every morning")-->HEAD OF STATE, CHIEF OF STATE 3. president -- (the chief executive of a republic) -->HEAD OF STATE, CHIEF OF STATE 4. president, chairman, chairwoman, chair, chairperson -- (the officer who presides at the meetings of an organization; "address your remarks to the chairperson")--> PRESIDING OFFICER LEADER 5. president -- (the head administrative officer of a college or university)--> ACADEMIC ADMINISTRATOR …. LEADER 6. President of the United States, President, Chief Executive -- (the office of the United States head of state; "a President is elected every four years") --> PRESIDENCY, PRESIDENTSHIP POSITION
Limitations to WordNet • Poor inter-annotator agreement (73%) • Just sense tags - no representations • Very little mapping to syntax • No predicate argument structure • no selectional restrictions • No generalizations about sense distinctions • No hierarchical entries
SIGLEX98/SENSEVAL • Workshop on Word Sense Disambiguation • 54 attendees, 24 systems, 3 languages • 34 Words (Nouns, Verbs, Adjectives) • Both supervised and unsupervised systems • Training data, Test data • Hector senses - very corpus based (mapping to WordNet) • lexical samples - instances, not running text • Replicability over 90%, ITA 85% ACL-SIGLEX98,SIGLEX99, CHUM00
Hector - bother, 10 senses • 1. intransitive verb, - (make an effort), after negation, usually with to infinitive; (of a person) to take the trouble or effort needed (to do something). Ex. “About 70 percent of the shareholders did not bother to vote at all.” • 1.1 (can't be bothered), idiomatic, be unwilling to make the effort needed (to do something), Ex. ``The calculations needed are so tedious that theorists cannot be bothered to do them.'' • 2. vi; after neg; with `about" or `with"; rarely cont – (of a person) to concern oneself (about something or someone) “He did not bother about the noise of the typewriter because Danny could not hear it above the sound of the tractor.” • 2.1 v-passive; with `about" or `with“ - (of a person) to be concerned about or interested in (something) “The only thing I'm bothered about is the well-being of the club.”
Mapping WN-Hector via VerbNet SIGLEX99, LREC00
SENSEVAL2 –ACL’01 Adam Kilgarriff, Phil Edmond and Martha Palmer All-words task Lexical sample task Czech Basque Dutch Chinese English English Estonian Italian Japanese Korean Spanish Swedish
English Lexical Sample - Verbs • Preparation for Senseval 2 • manual tagging of 29 highly polysemous verbs (call, draw, drift, carry, find, keep, turn,...) • WordNet (pre-release version 1.7) • To handle unclear sense distinctions • detect and eliminate redundant senses • detect and cluster closely related senses NOT ALLOWED
WordNet – call, 28 senses • name, call -- (assign a specified, proper name to; "They named their son David"; "The new school was named after the famous Civil Rights leader") -> LABEL 2. call, telephone, call up, phone, ring -- (get or try to get into communication (with someone) by telephone; "I tried to call you all night"; "Take two aspirin and call me in the morning") ->TELECOMMUNICATE 3. call -- (ascribe a quality to or give a name of a common noun that reflects a quality; "He called me a bastard"; "She called her children lazy and ungrateful") -> LABEL
WordNet – call, 28 senses 4. call, send for -- (order, request, or command to come; "She was called into the director's office"; "Call the police!") -> ORDER 5. shout, shout out, cry, call, yell, scream, holler, hollo, squall -- (utter a sudden loud cry; "she cried with pain when the doctor inserted the needle"; "I yelled to her from the window but she couldn't hear me") -> UTTER 6. visit, call in, call -- (pay a brief visit; "The mayor likes to call on some of the prominent citizens") -> MEET
Groupings Methodology • Double blind groupings, adjudication • Syntactic Criteria (VerbNet was useful) • Distinct subcategorization frames • call him a bastard • call him a taxi • Recognizable alternations – regular sense extensions: • play an instrument • play a song • play a melody on an instrument
Groupings Methodology (cont.) • Semantic Criteria • Differences in semantic classes of arguments • Abstract/concrete, human/animal, animate/inanimate, different instrument types,… • Differences in entailments • Change of prior entity or creation of a new entity? • Differences in types of events • Abstract/concrete/mental/emotional/…. • Specialized subject domains
WordNet: - call, 28 senses WN2 , WN13,WN28 WN15 WN26 WN3 WN19 WN4 WN 7 WN8 WN9 WN1 WN22 WN20 WN25 WN18 WN27 WN5 WN 16 WN6 WN23 WN12 WN17 , WN 11 WN10, WN14, WN21, WN24
WordNet: - call, 28 senses, groups WN2, WN13,WN28 WN15 WN26 WN3 WN19 WN4 WN 7 WN8 WN9 WN1 WN22 WN20 WN25 WN18 WN27 WN5 WN 16 WN6 WN23 WN12 WN17 , WN 11 WN10, WN14, WN21, WN24, Phone/radio Bird or animal cry Request Label Call a loan/bond Challenge Visit Loud cry Bid
WordNet – call, 28 senses, Group1 • name, call -- (assign a specified, proper name to; "They named their son David"; "The new school was named after the famous Civil Rights leader") --> LABEL 3. call -- (ascribe a quality to or give a name of a common noun that reflects a quality; "He called me a bastard"; "She called her children lazy and ungrateful") --> LABEL 19. call-- (consider or regard as being; "I would not call her beautiful")--> SEE 22. address, call -- (greet, as with a prescribed form, title, or name; "He always addresses me with `Sir'"; "Call me Mister"; "She calls him by first name") --> ADDRESS
Sense Groups: verb ‘develop’ WN1 WN2 WN3 WN4 WN6 WN7 WN8 WN5 WN 9 WN10 WN11 WN12 WN13 WN 14 WN19 WN20
Maximum Entropy WSDHoa Dang (in progress) • Maximum entropy framework • combines different features with no assumption of independence • estimates conditional probability that W has sense X in context Y, (where Y is a conjunction of linguistic features • feature weights are determined from training data • weights produce a maximum entropy probability distribution
Features used • Topical contextual linguistic feature for W: • presence of automatically determined keywords in S • Local contextual linguistic features for W: • presence of subject, complements • words in subject, complement positions, particles, preps • noun synonyms and hypernyms for subjects, complements • named entity tag (PERSON, LOCATION,..) for proper Ns • words within +/- 2 word window
Maximum Entropy WSDHoa Dang, Senseval2 Verbs (best) • Maximum entropy framework, p(sense|context) • Contextual Linguistic Features • Topical feature for W: +2.5%, • keywords(determined automatically) • Local syntactic features for W: +1.5 to +5%, • presence of subject, complements, passive? • words in subject, complement positions, particles, preps, etc. • Local semantic features for W: +6% • Semantic class info from WordNet (synsets, etc.) • Named Entity tag (PERSON, LOCATION,..) for proper Ns • words within +/- 2 word window
Grouping improved sense identification for MxWSD • 75% with training and testing on grouped senses vs. 43% with training and testing on fine-grained senses • Most commonly confused senses suggest grouping: • (1) name, call--assign a specified proper name to; ``They called their son David'' • (2) call--ascribe a quality to or give a name that reflects a quality; ``He called me a bastard''; • (3) call--consider or regard as being; ``I would not call her beautiful'' • (4) address, call--greet, as with a prescribed form, title, or name; ``Call me Mister''; ``She calls him by his first name''
Criteria to split Framesets • Semantic classes of arguments, such as animacy vs. inanimacy Serve 01. Act, work • Group 1: function (His freedom served him well) • Group 2: work (He served in Congress)
Criteria to split Framesets • Semantic type of event (abstract vs. concrete) See 01. View • Group 1: Perceive by sight (Can you see the bird?) • Group 5: determine, check (See whether it works)
Overlap with PropBank Framesets WN5, WN16,WN12 WN15 WN26 WN3 WN19 WN4 WN 7 WN8 WN9 WN1 WN22 WN20 WN25 WN18 WN27 WN2 WN 13 WN6 WN23 WN28 WN17 , WN 11 WN10, WN14, WN21, WN24, Loud cry Bird or animal cry Request Label Call a loan/bond Challenge Visit Phone/radio Bid
Overlap between Senseval2Groups and Framesets – 95% Frameset2 Frameset1 WN1 WN2 WN3 WN4 WN6 WN7 WN8 WN5 WN 9 WN10 WN11 WN12 WN13 WN 14 WN19 WN20 develop
Framesets →Groups→ WordNet Frameset3 Frameset1 Frameset2 WN11 WN1 WN2 WN9 WN8 WN3 WN4 WN12 WN5 WN16 WN18 WN14 WN7 WN15 WN10 WN6 WN13 drop
An Example of Mapping: verb ‘serve’Assignment: Do you agree?
Frameset Tagging Results: overall accuracy 90%* (baseline 73.5%) * Gold Standard parses
Sense Hierarchy • PropBank Framesets – ITA 94% coarse grained distinctions 20 Senseval2 verbs w/ > 1 Frameset Maxent WSD system, 73.5% baseline, 90% accuracy • Sense Groups (Senseval-2) - ITA 82% (now 89%) Intermediate level (includes Levin classes) – 69% • WordNet – ITA 71% fine grained distinctions, 60.2%
Summary of WSD • Choice of features is more important than choice of machine learning algorithm • Importance of syntactic structure (English WSD but not Chinese) • Importance of dependencies • Importance of an hierarchical approach to sense distinctions, and quick adaptation to new usages.