SECTION 4 HIGHLIGHTS THE MANAGEMENT OF THE INTER-FORMANCE OF A SYSTEM...

9

. Here,

*,+

?

measures the rel-

then considered to be a candidate answer passage.

-

to a particular document

evance of a subtopic

,

The text window of each candidate answer passage

.-

to an-

while

*/+

G

measures the relevance of

is then expanded to include the following sentence.

other subtopic,

B

.

If the answer rank does not increase with the addi-

We use a different learner for each subtopic in or-

tion of the succeeding sentence, then the price (

!

) of

der to train simultaneously on each iteration. (The

the candidate answer passage is incremented by 1,

calculation of topic signatures continues to iterate

otherwise it is decremented by 1. The text window

until there are no more relations that can be added

of each candidate answer passage continues to ex-

to the overall topic signature.) When the precision

pand until

!

_^

. Before the ranked list of candidate

is computed, it takes

of a relation to a subtopic

answers can be considered by the Question Genera-

into account the negative evidence of its relevance

tion module, answer passages with a positive price

!

8

B

. If

to any other subtopic

JI

JKML

,

are stripped of the last

!

sentences.

the relation is not included in the topic signature,

ANSWER

where relations are ranked by the score

)

In the early 1970s, Egyptian President Anwar Sadat

N

validates that Egypt has a BW stockpile.

!

+

O

4 entities