Natural Language Processing

172 Natural Language Processing: Semantic Aspects

G

VP:

< v

3

: chasing (event, verb)> when Δ = VP

END FOR ALL

FOR ALL different pairs <G

1

,G

2

> of sub-graphs G

Δ

⊆

G

MDDQL

CREATE

connecting edges E(<G

1

,G

2

>, C) with respect to the

ontological constraints C

e.g., < e

2

: “”> connecting v

1

: children (noun, subject, class) with v

3

:

chasing (event, verb) and, therefore, connecting G

SU

with G

VP

<e

3

: “”> connecting v

3

: chasing (event, verb) with v

4

: dogs (noun,

object, class) and, therefore, connecting G

VP

with G

OB

END FOR ALL

Phase2—Query Expansion: The output of the MDDQL parsing

phase is a set of initial query terms which becomes the input to

the query expansion phase. The query expansion process involves

expanding the initial query using lexicons and ontologies. ...