Athors: Pablo Fierens, Jose Ignacio Hamelin, Jose Orlicki
Conference: 5th International Conference on Web Information Systems and Technologies (WEBIST 2009) http://www.webist.org/
Subtitle: Efficient Algorithms For Ranking Users Based On A Set Of Tags
When: March 23-26, 2009.
Where: Lisboa, Portugal
Abstract:
Multimedia content is uploaded, tagged and recommended by users of collaborative systems such as YouTube and Flickr. These systems
can be represented as tagged-graphs, where nodes correspond to users and taggedlinks to recommendations. In this paper we analyze the online
computation of user-rankings associated to a set of tags, called a facet. A simple approach to faceted ranking is to apply an algorithm
that calculates a measure of node centrality, say, PageRank, to a subgraph associated with the given facet. This solution, however, is not
feasible for online computation. We propose an alternative solution: (i) first, a ranking for each tag is computed offline on the basis of
tag-related subgraphs; (ii) then, a faceted order is generated online by merging rankings corresponding to all the tags in the facet. Based on
empirical observations, we show that step (i) is scalable. We also present efficient algorithms for step (ii), which are evaluated by
comparing their results to those produced by the direct calculation of node centrality based on the facet-dependent graph.
