the first twenty documents on each retrieval
output was classified as being “relevant” or “nonrelevant”.
Afterwards, precision and normalized recall ratios were calculated at various cut-off points
to evaluate keyword-based search engines and the
semantic search engine. Overall, Yahoo showed the
best performance in terms of precision ratio, whereas
Google turned-out to be the best search engine in
terms of normalized recall ratio. However, it was
found that semantic search performance of search
engines was low for both keyword-based search
engines and the semantic search engine.