Next: Dependency relations
The simplest disambiguation method consists of
hand-written `penalty' rules which implement a variety of preferences.
Each such penalty rule describes a partial parse tree. For a given
parse tree, the system computes how often a sub-tree matches
with a penalty rule, giving rise to the total penalty of that parse. The
following lists characterizes some of the penalty rules:
- complementation is preferred over modification
- subject topicalization is preferred over object topicalization
- long distance dependencies are dis-preferred
- certain rules are dis-preferred (e.g. rules which coordinate
categories without an explicit coordinator)
- certain lexical entries are dis-preferred (e.g. the preposition readings
for the words aan, bij, in, naar, op, uit, voor, tussen are
preferred over the adjectival, noun and/or verb readings).
- certain guesses for unknown words are preferred over others
As can be concluded from the preliminary results presented in
table 3, it appears to be the case that about 60% of the
disambiguation problem can be solved using this very simple technique.
Noord G.J.M. van