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Projekt: OySTER
Projektleitung: Prof. Dr.-Ing. C. R. Rollinger
Projektbetreuung: Martin E. Müller
Studentische Hilfskraft des Instituts: Chr. Heißing, F. Sievertsen
Stichworte: User Modeling, Machine Learning, Information Retrieval, Web Search
The World Wide Web offers a huge number of documents which deal with information concerning nearly any
topic. The question of whether to find information has become the question of how to find information and
of how to find relevant information only. Search engines with crawler based indexes vary in recall and offer
a very bad precision. Meta search tries to boost precision by information aggregation. Only few search
engines employ intelligent techniques in order to increase precision.
User modeling techniques have become more and more popular since they proved to be a useful means for
user centered information filtering and presentation. It is a straightforward idea to incorporate the idea of
machine learning based user modeling methods into web search services. OySTER is a research prototype
which is being developed at the University of Osnabrück and which offers a kind of a workbench architecture
for developing, testing and evaluating machine learning algorithms for user modeling. The basic ideas
behind OySTER are as follows: Using a user model, a search query can be refined before being forwarded to
other search engines. In this very first step we can already try to avoid ambiguous results - since we
generate different queries depending on whether the user who seeks for morphology is a dentist, a biologist
or a linguist. The same model is used for filtering the results. User models are described with respect to a
document type and a document content hierarchy. Similarly, URLs are classified using those concept
hierarchies. A search result is interesting, if it is included in the user model.
OySTER is a research prototype. Our aim is to test new ideas for user modeling and machine learning in the
context of information retrieval from the web. In order to achieve both a testbed for new technologies that
is easy to maintain and to guarantee an any-time behaviour of the search engine, the system is realized as a
multi agent system. User interfaces (e.g. CGI scripts), user requests, database update agents and web page
classification components act as individual agents which compete and co-operate in order to wipe out all
tasks that are written on a blackboard. Communication is realized by a special protocol language that is
platform independent. Thus, any component/agent can be run on another machine. For further information,
please see http://mir.cl-ki.uni-osnabrueck.de/oyster/. OySTER was presented with great success on the
CeBIT 2000.
Müller, M. E. (Hrsg.): Benutzermodellierung: Zwischen Kognition und Maschinellem Lernen, Proc. 8. GI
Workshop "Adaptivität und Benutzermodellierung in interaktiven Softwaresystemen" (ABIS 2000), Internal
Report, Institut für Semantische Informationsverarbeitung, Osnabrück, 2000.
Müller, M. E.: OySTER: Web Search as a playground for User Modeling Techniques, In: Müller, M. E.:
Benutzermodellierung: Zwischen Kognition und Maschinellem Lernen, Proc. 8. GI Workshop "Adaptivität und
Benutzermodellierung in interaktiven Softwaresystemen" (ABIS 2000), Osnabrück, 2000.
Müller, M. E.: Inductive Logic Programming for Learning User Models, In: Proc. Fachgruppentreffen
Maschinelles Lernen FGML-00, GMD-Report 114, GMD, Sankt Augustin, 2000.
Müller, M. E.: Tagungsbericht Lernen-Wissen-Adaptivität '99, KI 2/2000.
Müller, M. E.: Learning Comprehensible Conceptual User Models for User Adaptive Meta Web Search, AAAI
Spring Symposium on Adaptive User Interfaces, Stanford, 2000.
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