G22.2590 - Natural Language Processing -- Spring 2003 -- Prof. Grishman
February 6, 2003
You may want to use the Jet parser for the first three exercises, and
particularly for #2. Keep in mind in doing these exercises that many
words have several parts of speech.
Using the tiny grammar below, draw the
two parse trees for the sentence “The fair features live music.”
Suggest a constraint which would resolve this ambiguity.
Using the same tiny grammar, compare
the efficiency of the top-down backtracking parser, a bottom-up (immediate
constituent) parser, and a top-down chart parser on the sentence “The program
answers questions.” For the two grammar symbols, S and NP
Modify this grammar to capture subject-verb number agreement. Does
it now produce one parse?
J&M exercise 8.1. (practice tagging some text)
compare the backtracking and chart parsers
with respect to the number of times the symbol is expanded
compare all three parsers with respect
to the number of times a complete constituent using that symbol is generated
sentence := np v | np v np;
Due February 13th.
np := n | art n | art adj n;