lecture1-intro-handout-6-per

Needindextocaptureposioninformaonindocs

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: is
disjunc)on,
not
conjunc)on!
   Long,
precise
queries;
proximity
operators;
 incrementally
developed;
not
like
web
search
   Many
professional
searchers
s)ll
like
Boolean
search
   Exercise:
Adapt
the
merge
for
the
queries:
 
Brutus
AND NOT
Caesar Brutus
OR NOT
Caesar Can
we
s)ll
run
through
the
merge
in
)me
O(x+y)?
 What
can
we
achieve?
   You
know
exactly
what
you
are
geqng
   But
that
doesn’t
mean
it
actually
works
beber….
 Introduc)on to Informa)on Retrieval 28
 Sec. 1.3 Merging
 Sec. 1.3 Introduc)on to Informa)on Retrieval Query
op)miza)on
 What
about
an
arbitrary
Boolean
formula?
 (Brutus
OR Caesar) AND NOT (Antony OR Cleopatra)
   Can
we
always
merge
in
“linear”
)me?
   What
is
the
best
order
for
query
processing?
   Consider
a
query
that
is
an
AND
of
n
terms.
   For
each
of
the
n
terms,
get
its
pos)ngs,
then
 AND
them
together.
   Linear
in
what?
   Can
we
do
beber?
 Brutus 2 Caesar 1 Calpurnia 4 2 8 16 32 64 128 3 5 8 16 21 34 13 16 Query: Brutus
AND
Calpurnia
AND
Caesar 29
 30
 5 Sec. 1.3 Introduc)on to Informa)on Retrieval Introduc)on to Inf...
View Full Document

This document was uploaded on 02/26/2014.

Ask a homework question - tutors are online