47 th Annual Meeting of the Association for Computational Linguistics and 4 th International Joint...
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47 th Annual Meeting of the Association for Computational Linguistics and 4 th International Joint Conference on Natural Language Processing Of the AFNLP 2-7 Aug 2009
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Transcript of 47 th Annual Meeting of the Association for Computational Linguistics and 4 th International Joint...
47th Annual Meeting of the Association for Computational Linguistics
and
4th International Joint Conference onNatural Language ProcessingOf the AFNLP
2-7 Aug 2009
Do Automatic Annotation Techniques Have Any Impact on Supervised Complex Question Answering?
Shafiq R. JotyDept. of Computer ScienceUniversity of British ColumbiaVancouver, BC, Canada
Yllias Chali and Sadid A. HasanDept. of Computer ScienceUniversity of LethbridgeLethbridge, AB, Canada
“Given a complex question (topic description) and a collection of relevant documents, the task is to synthesize a fluent, well-organized 250-word summary of the documents that answers the question(s) in the topic”.
Example: Describe steps taken and worldwide reaction prior to the introduction of the Euro on January 1, 1999. Include predictions and expectations reported in the press.
-Use supervised learning methods.-Use automatic annotation techniques.
Research Problem and Our Approach
Motivation Huge amount of annotated or labeled data is a
prerequisite for supervised training. When humans are employed, the whole process
becomes time consuming and expensive. In order to produce a large set of labeled data we
prefer the automatic annotation strategy.
Automatic Annotation Techniques Using ROUGE Similarity Measures. Basic Element (BE) Overlap Measure. Syntactic Similarity Measure. Semantic Similarity Measure. Extended String Subsequence Kernel (ESSK).
Support Vector Machines (SVM). Conditional Random Fields (CRF). Hidden Markov Models (HMM). Maximum Entropy (MaxEnt).
Supervised Systems
Feature Space Query-related features:
n-gram overlap, Longest Common Subsequence (LCS), Weighted LCS (WLCS), skip-bigram, exact word overlap, synonym overlap, hypernym/hyponym overlap, gloss overlap, Basic Element (BE) overlap and syntactic tree similarity measure
Important features: position of sentences, length of sentences, Named Entity
(NE), cue word match and title match
Experimental Results
Conclusion
Sem annotation is the best for SVM. ESSK works well for HMM, CRF and MaxEnt
systems.
