SECTION 3.1 INTRODUCES THE QUERY SNOWBALL (QSB)METHOD WHICH COMPUTES T...

4.2 Baseline

which nuggets were extracted as input to the multi-

MMR is a popular approach in query-oriented sum-

document summarizers. That is, in our problem set-

marization. For example, at the TAC 2008 opin-

ting, the relevant documents are already given, al-

ion summarization track, a top performer in terms

though the given document sets also occasionally

of pyramid F score used an MMR-based method.

contain documents that were eventually never used

Our own implementation of an MMR-based base-

for nugget extraction (Mitamura et al., 2008; Mita-

line uses an existing algorithm to maximize the fol-

mura et al., 2010).

lowing summary set score function (Lin and Bilmes,

We preprocessed the Japanese documents basi-