This is because its evolution power
allows more retrieval results. The system was tested with a product list database.
The effectiveness was measured by testing a series of queries with and without using
GA. For example, a query, ???
<<> <3>???,
can only retrieve nine items when a normal search was performed but can retrieve
98 items when GA was performed. Table 1 shows the other results obtained by
other queries.
Figure 3. Screenshot of a feedback frame
.
Query Format on and Informat on Retr eval w th Ontology
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By comparing the results shown in Table 1, it is obvious that using GA does, in fact,
retrieve more items than using a normal search.
Effect of the Fitness Function
The fitness function in a GA determines how well it can optimize a query. The
OntoQuery system tested out various fitness functions to improve the power of
the GA. The usage of triangle or Gaussian functions to evaluate the fitness for the
number of documents retrieved suggested some ways to counter the ???too many or
too few retrieved documents??? dilemma in typical search engines.
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