The Chinese University of Hong Kong
Department of Computer Science and Engineering


Title: Ranking Users in a Social Space: A Case Study of Collective Semantics
Date: November 6, 2009 (Friday)
Time: 2:30 p.m. - 3:30 p.m.
Venue: Room 121, 1/F, Ho Sin-hang Engineering Building,
The Chinese University of Hong Kong,
Shatin, N.T.
Speaker: Dr. Albert Au Yeung
Research Associate
NTT Communication Science Laboratories
Kyoto, Japan


The World Wide Web has been an important platform for social interactions in recent years with the large number of social Websites such as Delicious, Youtube, LibraryThing and Facebook. Users are attracted to these Websites because they can share their favourite resources with their friends, and, more importantly, to discover new information through online social ties. An effective way of discovering new information is to follow users who are knowledgeable in particular topics. To identify knowledgeable users in a social space, we propose an algorithm, SPEAR, based on mutual reinforcement and implicit endorsement for ranking users in collaborative tagging systems. We show that the algorithm does not only help identifying expert users in particular topics, but is also very resistant to spamming activities on the Web. We also discuss the relations between user ranking and collective semantics, a term used to describe the implicit qualities/characteristics of online entities uncovered by studying the collective behaviours of Web users.


Albert Au Yeung is currently a research associate at the NTT Communication Science Laboratories in Kyoto, Japan. He received his BEng degree from the Department of Information Engineering and MPhil degree from the Department of Computer Science and Engineering at the Chinese University of Hong Kong. He obtained his PhD degree in Electronics and Computer Science from the University of Southampton, UK in 2009. His research interests include social computing, online social network analysis and applications of linked data on the Semantic Web. He visited the Massachusetts Institute of Technology under the Web Science Exchange Programme in 2008. His research project on social tagging systems was awarded the third prize in the Student Research Competition at the ACM Hypertext Conference 2009. He was the recipient of the R C Lee Centenary Scholarship in 2006.

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