Publications

02 June 2009 Vetenskapsr�det (The Swedish Research Council)

Internet search engines virtually always create a ranking of all pages, and then they choose only those pages that contain the right words. In his doctoral dissertation, Ola �gren, Ume� University in Sweden, describes a new approach that yields more relevant hits and faster search engines.

The goal of all search engines is to attain the most relevant responses as quickly as possible. When search engines calculate their search results, they are steered by an algorithm that assigns higher or lower values to features of Web pages. The most common search engines on the Net, such as Google, generate a gigantic single ranking based on a search of all pages available on the Net.

The algorithm that Ola �gren has developed ranks pages, instead, on the basis of each relevant starting page, and includes pages that are directly or indirectly linked to by the starting page. Then a normalised mean value of the relevance of the various pages is calculated.

A page that has links to it from several different pages is therefore assigned a higher value than those that are found only once. In this way it is faster to find pages of interest. For ordinary standard algorithms it takes more than seven days to go through and rank Web pages in a certain database. Using his algorithm, Ola �gren has managed to do this in 158 seconds.

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