SALSA algorithm: Difference between revisions

Revision as of 16:25, 20 June 2012

Revision as of 16:38, 20 June 2012

Line 7:

SALSA is inspired by two other link-based ranking algorithms, namely [[HITS algorithm|HITS]] and [[PageRank]], in the following ways:

* like HITS, the algorithm assigns two scores to each web page: a hub score and an authority score. An authority is a page which significantly more relevant to a given topic than other pages whereas a hub is a page which contains many links to authorities;

* like HITS, SALSA also works on a ''focused subgraph'' which is topic-dependent. This focused subgraph is obtained by first finding alla theset of pages that aremost relevant to a given topic (e.g. take the top-n pages returned by a text-based search algorithm) and then augmenting itthis set with web pages that linkslink directly to themit andor are linked directly from themit. Because of this selection process, the hub and authority scores are topic-dependent;

* like PageRank, the algorithm computes the scores by simulating a random walk through a [[Markov chain]] that represents the graph of web pages. SALSA however works with two different Markov chains: a chain of hubs and a chain of authorities.