Leksička semantika i pragmatika

4. predavanje

Question Answering

• What does “door” mean?• What year was Abraham Lincoln born?• How many states were in the United

States when Lincoln was born?• Was there a military draft during the

Hoover administration?• What do US scientists think about whether

human cloning should be legal?

Modern QA systems

• Still in infancy• Simple factoid questions beginning to work

OK• Annual government-sponsored “bakeoff”

called TREC

• Ambiguity!

• World Knowledge – it’s needed for understanding, but computers don’t have it

NLP 4

Ambiguity

• Computational linguists are obsessed with ambiguity

• Ambiguity is a fundamental problem of computational linguistics

• Resolving ambiguity is a crucial goal

Ambiguity

• Find at least 5 meanings of this sentence:– I made her duck