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LING 573 Deliverable 3. Jonggun Park Haotian He Maria Antoniak Ron Lockwood. Closed Class filters 14. Animals, colors, companies, continents, countries, sports team, languages, occupations, periodic table, race, us-cities, us-presidents, us-states, and us-universities. Query EXPAANSSION!.
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LING573Deliverable3 JonggunParkHaotianHe MariaAntoniakRonLockwood
Closed Class filters 14 • Animals, colors, companies, continents, countries, sports team, languages, occupations, periodic table, race,us-cities, us-presidents, us-states, and us-universities.
Query Expansion • Who is the president of the United States? • President united states nations council • How long did it take to build the Tower of Pisa? • long build tower pisawomen’s station
Question Classification Software package: Mallet Classification algorithms: MaxEnt, NaiveBayes, Winnow, DecisionTree Training Data: - TREC-2004.xml - Training set 5 (5500 labeled questions) (Li & Roth) Test Data: - TREC-2005.xml - Testing set (Li & Roth)
Featureselection: -Unigram -Bigram -Trigram -Questionword -NER tags
Conclusion: Maximumaccuracy: TREC-2005astestfile:0.8535911602209945 -MaxEnt,Unigram+Bigram+Wh-words TREC-10astestfile:0.854 -MaxEnt,Unigram+Bigram+Wh-words
Otherfindings: Trigramdoesnothelpsanddragstheaccuracydown. NERfeaturedoesnothelpsandcausesaslightdrop-down.
Web Boosting • Resources: jsoup, Bing.com • Query: original question + target string • Results: top 50 web snippets, stored in a text file
Web Boosting Challenges and Successes • Which search engine or answer website to use? • How to avoid throttling? • How to integrate results into our system? • How to edit results to make them more useful for our answer ranking system?
Main Changes • Use web query as input to the redundancy-based answer extraction engine • This replaces our paragraph based index • Answer type classification now feeds into answer extraction • Filtering of candidate answers by answer type in combination with NER on the answers • Following types are handled: NUM, LOC, HUM, ENTY
Main changes (continued) • Filtering of closed class questions using lists • E.g. pro sports teams, colors, etc. • Filtering out of terms with occurrences in less than 2 snippets • Return 250 char. answer instead of 1-4 words
Answer Extraction Details • Input to the Extraction Engine • Query word list • Stop-word list • Focus-word list (e.g. meters, liters, miles, etc.) • Passage list – the paragraph results of the query • N-gram generation and occurrence counting • Filtering out stop words and query words • Filter by answer type
Answer Extraction Details 4. Combining unigram counts with n-gram counts 5. Weighting candidates with idf scores 6. Re-rank candidates • Eliminate ones that don’t have evidence in at least 2 snippets • Eliminate ones that don’t match a closed class list (for certain questions.) 7. Verifying candidates in documents • Use bag of words query from the candidate sub-snippet + query words against Lucene index
Results D2: strict = 0.01 lenient = 0.064 D3: strict = 0.133 lenient = 0.371