Presentation at SMC 2013

1. Clause Anaphora Resolution for
Japanese Demonstrative Determiner
based on Semantic Similarity
between Different Parts-of-Speech
Yukino Ikegami
Ernesto Damiani
Akihiro Urano
Setsuo Tsuruta
At SMC 2013

2. Background
• Informal/colloquial style texts often contain
anaphoric expressions
(e.g.) I like such words.
• What is “such” in “such words” means?
The answer depends on context
There is an ambiguity
Anaphora resolution:
Automatically resolving anaphoric relation
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3. Related works
• Conventional anaphora resolutions mainly
deal with nominal anaphoric
• Heuristic rule & ontology based anaphora
resolution [Murata 2000]
– Resolves {nominal, adjective, adverb} anaphoric
– It assumes that
antecedent is noun phrase or previous sentence
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4. Problems on Anaphora Resolution
• Conventional anaphora resolutions are not
enough to resolve following case:
Demonstrative determiner refers a clause
– We call “clause anaphoric”
– E.g. He inquire xxx. I think such question ---.
– Part-of-speech (POS) of anaphor and POS of
antecedent are often different in this case
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5. Our proposed method
• Semantic similarity based anaphora resolution
for Japanese demonstrative determiner
• Consider synonymous relationship crossing
parts-of-speech
– E.g.
Deal with the verb “talk” as synonym of the noun
“tale”
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6. Procedure of our method
• Preprocessing phase
1. Dependency Parsing
2. Semantic Role Labeling & Giving word semantics
3. Conceptual Dependency structure parsing
• Anaphora Resolution phase
1. Find demonstrative pronouns
2. Extend semantics of anaphor words using
Semantically relationship table
3. Choose the most similar candidate
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7. Preprocessing
1. Syntactic dependency structure parsing
– CaboCha [Kudo et al. 2002]
2. Semantic role labeling & giving word semantics
– ASA [Takeuchi et al. 2010]
3. Conceptual Dependency Structure Parsing
– Conceptual dependency [Schank 1972]
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8. Anaphora resolution (1)
Find Demonstrative Determiner
• Finds demonstrative determiner by
morphological analysis
• If not found, terminates anaphora resolution
(e.g.)
I wonder what that story told by the managing director was.
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9. Anaphora resolution (2)
Extend word semantics
1. Extract similar words from semantically
relationship table
1. Add semantics of similar words to semantics
of the anaphor phrase
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言う (say)
- 発声 (utterance)
Semantic relation Table
言う (say) – 話 (story)
話 (story)
- 発言(statement)
- 言葉 (word)
- 発声 (utterance)
Add

10. Anaphora resolution (3)
Choose the most similar candidate
• Measure semantic similarity
between anaphor phrase and each candidates
• Ontology path similarity
sim w1,w2( ) =
Lm
L1
+
Ln
L2
Lm + Ln
• The most similar word is chosen as antecedent
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11. Evaluation Experiment
Counseling
dialogue
Twitter Novel
Accuracy 100% 63.04% 62.5%
Dataset: Contain the phrase あの話 (“that conversation”)
Accuracy: Agreement rate between human and our method
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12. Major causes of failures
in evaluation experiments
• Lack of synonymous relationship
– Need automatically acquiring synonymous
relationship
• Specific expression in written language
– E.g. Use quotation marks instead of verbs
– Need cooperating with rule based method
• Cataphoric/exophoric expression
– Need detecting implied reference
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13. Conclusion
• Semantic similarity based anaphora resolution
for Japanese demonstrative determiners
– Consider synonymous relationship
crossing Parts-of-speech (POS)
– Can resolve clause anaphoric, not only nominal
anaphoric
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14. References
• [Murata 2000] M. Murata, “ Anaphora resolution in japanese
sentences using surface expressions and examples, ” arXiv:preprint,
cs/0009011, 2000.
• [Kudo et al. 2002] T.Kudo and Y.Matsumoto. “Japanese dependency
analysis using cascaded chunking”, in Proc. of the 6th Conference
on Natural Language Learning 2002, pp. 63-69, 2002.
• [Takeuchi et al. 2010] K. Takeuchi, S. Tsuchiyama, M. Moriya and Y.
Moriyasu, “ Construction of argument structure analyzer toward
searching same situations and actions ” (in Japanese), IEICE
technical report Natural language understanding and models of
communication, vol. 109, No.390, pp.1-6, 2010.
• [Schank, 1972] R. Schank. “ Conceptual dependency: a theory of
natural language understanding, ” Cognitive Psychology, Vol.3, No.4,
1972.
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