Tutorial 14-A - Detecting, Understanding and Exploiting Web communities

Athena Vakali, Aristotle University of Thessaloniki

Ioannis Kompatsiaris, Informatics and Telematics Institute


Collective user activities on multiple, often heterogeneous and evolving Web sources contributes in the formation of Web communities which are either derived from Web documents/pages, or by users navigational tasks and more recently by tags and social frameworks. Defining, deriving and exploiting communities is not a trivial task since several parameters (large‐scale, complexity, evolving information etc) are involved.

This tutorial aims at providing answers for crucial questions raised about communities emerging in the Web and it will initially walk the audience on issues involved towards different community definitions such that then, the problem of community detection (which is well matured and researched in the past) is understood. The tutorial will emphasize and discuss the most important methodologies and techniques which deal with large populations of Web documents participating in vast hyperlinked networks, or networks formed from crawling (part of) the web and more recently, networks reflecting the social relations and/or interactions among people. It is important to understand and categorize community identification efforts by taking into account that different levels of granularity and different views are often used for community identification. Next step of the tutorial will be to point applications and implementations which may be benefited by exploiting Web communities and certain application scenarios will be presented. The emphasis is on the intuition behind all these methodologies and implementations, and on their practical impact for tasks of recommendation, searching, content outsourcing, data administration etc.


Prof. Athena Vakali is a faculty member at the Department of Informatics of Aristotle University, Thessaloniki, Greece (currently associate professor) since 1997, where she’s leading the research group of Web data management. Her current research interests include Web usage mining, content delivery networks on the Web, Web and social Web data clustering and Web data caching/outsourcing. Prof. Vakali has co‐edited 3 books (Springer, IGI), co‐authored 7 book chapters, 40 papers in refereed journals and more than 60 papers in international conferences. She is in the editorial board of "Computers & Electrical Engineering" Journal (Elsevier) and the International Journal of Grid and High Performance Computing (IGI publishing). She has participated in more than 20 research and development projects from which she has scientifically leaded 13. Prof. Vakali has served as a PC member to many international conferences, and she has been general chair and organizer of the EDBT’04 Workshop on Clustering Information over the Web (ClustWeb’04), the 2005 and 2006 ICDE‐Workshop on Challenges in Web Information Retrieval and Integration (WIRI’05, ‘06) and the ESWC’08‐Workshop on “Collective Semantics: Collective Intelligence and the Semantic Web” (CISWEB’08). She has also presented a tutorial “Clustering on the Web: Theory and Practices” at the 10th East‐European Conference on Advances in Databases and Information Systems, September 2006.

Dr. Yiannis Kompatsiaris received the Diploma degree in electrical engineering and the Ph.D. degree in 3‐D model based image sequence coding from Aristotle University of Thessaloniki (AUTH), Thessaloniki, Greece in 1996 and 2001, respectively. He is a Senior Researcher with the Informatics and Telematics Institute, Thessaloniki and currently he is leading the Multimedia Knowledge Group. His research interests include multimedia and the Semantic Web, social content analysis, multimedia content processing, context aware inference for semantic multimedia analysis, personalization and retrieval. He is the coauthor of 10 book chapters, 30 papers in refereed journals and more than 90 papers in international conferences. He has served as a regular reviewer for a number of international journals and conferences. He is a member of IEEE, ACM and IEE.