Natural language processing for the web
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Natural Language Processing for the Web. Prof. Kathleen McKeown 722 CEPSR, 939-7118 Office Hours: Wed, 1-2; Tues 4-5 TA: Yves Petinot 719 CEPSR, 939-7116 Office Hours: Thurs 12-1, 8-9. Today.

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Natural Language Processing for the Web

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Natural language processing for the web

Natural Language Processing for the Web

Prof. Kathleen McKeown

722 CEPSR, 939-7118

Office Hours: Wed, 1-2; Tues 4-5

TA:

Yves Petinot

719 CEPSR, 939-7116

Office Hours: Thurs 12-1, 8-9


Today

Today

  • Next week: Invited Speaker SandaHarabagiu, Need 2 Discussants, location 414 CEPSR. This is not a class to miss!

    • Open Domain Question Answering (Lauren)

    • Natural language based reformulation resource and web exploitation for question answering (Kathy)

    • Improving QA Accuracy by Question Inversion (Vikas)

    • A Classification Approach to QA in Discussion Boards (Kenny)

    • Discussants: William, Shrenik


When qa is difficult

When QA is difficult

  • When the answer string does not use the same words as the question string:

    • Who discovered America?

      • Columbus discovered America

      • Columbus Day celebrates the Italian Navigator who first landed in the New World on Oct. 12, 1942.


Proposed solution

Proposed Solution

  • Paraphrase Templates

  • How did Mahatma Gandhi die?

    • Mahatma Gandhi died <how>

    • Mahatma Gandhi died of <what>

    • Mahatma Gandhi died from <what>

    • Mahatma Gandhi’s death from <what>

    • Mahatma Gandhi drowned

    • Mahatma Gandhi suffocated

    • Mahatma Gandhi froze to death

    • <who> killed Mahatma Gandhi

    • <who> assassinated Mahatma Gandhi

    • Mahatma Gandhi was killed


Natural language processing for the web

Use

  • In IR to find documents more likely to contain answer

  • To rank sentences within documents that are returned by IR


Reformulations

Reformulations

  • Hand-built or manual generalizations of automatically produced paraphrases

  • Specify type of relation to original

  • Number of reformulations: 1-30, ave: 3.24


Other reformulation types

Other Reformulation Types

  • Lexical:

    • Buy/sell: John sold the laptop to Mary = Mary bought the laptop from John

  • Syntactic:

    • How deep is Crater Lake?

    • Crater Lake has a depth of <what distance>

  • Inference

  • Reformulation Chains

    • Where did Bill Gates go to college?

    • Bill Gates was a student at <which college>?

    • Bill Gates dropped out of <which college>?

    • Bill Gates was a <which college> dropout?

    • Text: Bill Gates was a Harvard dropout.


But their web ir system

But…. Their Web IR System

  • Preserve quoted terms and quote the smallest NPs:

    • “What is the longest river in the United States?” -> “longest river” and “United States”

  • Expand the query using Wordnet Synonyms

    • “What is the length of the border between Ukraine and Russia?” -> (“length” or “distance”) and (“border” or “surround”) and (“Ukraine” or “Ukrainia”) and (“Russia” or “Soviet Union”) and (“between” or “betwixt”)

  • Using Contexrefomulations, add quoted reformulations of the question’s declarative form

    • “What is an atom?” -> “is an atom”, “an atom is” “an atom is one of”


  • Evaluation

    Evaluation


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