Exploiting User Generated Content to Improve Search

Prof. Wolfgang Nejdl, Universität Hannover

Abstract:

More and more information is available on the Web, and the current
search engines do a great job to make it accessible. Yet, optimizing
for a large number of users, they usually provide good answers only to
``most of us'', and have yet to provide satisfying mechanisms to
search for audiovisual content.  In this talk I will present some
ongoing work at L3S addressing these challenges, done in the context
of several European Union funded projects on personal information
management and web search.

Regarding personalization, I will talk about personalizing Web Search
based on user content, which goes beyond simple user profiles used in
other systems. The algorithms presented improve Web queries by
expanding them with terms collected from each user's personal
information repository, thus implicitly personalizing the search
output. Generating the additional query keywords is done by analyzing
user data at increasing granularity levels, ranging from term and
compound level analysis up to global co-occurrence statistics, as well
as to using external thesauri.  Extensive empirical analysis shows
some of these approaches to perform very well, especially on ambiguous
queries, producing a very strong increase in the quality of the output
rankings.

Regarding search for audiovisual content, I will focus on exploiting
user generated information, and discuss what kinds of tags are used
for different resources and how they can help for
search. Collaborative tagging has become an increasingly popular means
for sharing and organizing Web resources, leading to a huge amount of
user generated metadata. These tags represent different aspects of the
resources they describe and it is not obvious whether and how these
tags or subsets of them can be used for search. I will present an
in-depth study of tagging behavior for different kinds of resources -
Web pages, music, and images. The results are promising and provide
more insight into both the use of different kinds of tags for
improving search and possible extensions of tagging systems to support
the creation of potentially search-relevant tags.

Zur Person:

Prof. Dr. Wolfgang Nejdl (born 1960) has been full professor of
computer science at the University of Hannover since 1995.  He
received his M.Sc.  (1984) and Ph.D. degree (1988) at the Technical
University of Vienna, was assistant professor in Vienna from 1988 to
1992, and associate professor at the RWTH Aachen from 1992 to 1995.
He worked as visiting researcher / professor at Xerox PARC, Stanford
University, University of Illinois at Urbana-Champaign, EPFL Lausanne,
and at PUC Rio.

Prof. Nejdl heads the Distributed Systems Institute / Knowledge Based
Systems (http://www.kbs.uni-hannover.de/) as well as the L3S Research
Center (http://www.l3s.de/), and does research in the areas of search
and information retrieval, semantic web technologies, peer-to-peer
information systems, technology-enhanced learning, databases and
artificial intelligence. Relevant projects in the L3S context include
the PHAROS Integrated Project on audio-visual search, the OKKAM IP
focusing on entities on the Web, the Digital Library EU project LiWA,
coordinated by L3S, which investigates Web archive management and
advanced search in such an archive, and the FET IP project
LivingKnowledge, which is developing algorithms and methods to handle
and exploit diversity, bias and opinion on the Web.

Wolfgang Nejdl published more than 220 scientific articles, as listed at
DBLP, and has been program chair, program committee and editorial board
member of numerous international conferences and journals, see also

http://www.kbs.uni-hannover.de/~nejdl/

Wann 10.02.2010
von 16:00 bis 18:00
Wo D239
Teilnehmer Prof. Wolfgang Nejdl, Universität Hannover
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