Past seminars at the Faculty of Informatics

Informatics Seminar on Wednesdy, May 28 at 14.00 - Thomas Roelleke

The Faculty of Informatics is pleased to announce a seminar given by Thomas Roelleke


TITLE: Modelling Retrieval Models in a Probabilistic Relational Algebra with a new Operator: The Relational Bayes

SPEAKER: Thomas Roelleke

DATE: Wednesday, May 28th, 2008

PLACE: USI Università della Svizzera italiana, room SI-006, Informatics building (Via G. Buffi 13)

TIME: 14.00-15.00



The work on probabilistic DB technology led to results that feed into

DB+IR technology. The talk will browse research on probabilistic DB and

reasoning including Cavallo/Pitarelli:VLDB:87 (theory of probabilistic DB), Fuhr/Roelleke:TOIS:97, Chaudhuri...Weikum:04/06 (probabilistic ranking of tuples), Dalvi/Suciu:04/05 (efficient processing of safe expressions), and our recent contribution, the relational Bayes.


The relational Bayes is a new probabilistic relational operator.

Traditional database technology is based on five operators.

Probabilistic extensions based on those five only captured probability aggregation, but not estimation. The Bayes operator embeds probability estimation conceptually into the probabilistic relational paradigm.


Through the relational Bayes, IR models such as tf-idf, binary-independent retrieval, and language modelling can be expressed in probabilistic logical models. This will be illustrated in examples and a system demo. The outlook addresses optimisation, design and verification of probabilistic logical programs, and applications such as RSS retrieval.



Thomas Roelleke is a researcher and lecturer at Queen Mary University of London (QMUL). Thomas previously worked at Nixdorf Computer, the University of Dortmund, and as IT bank consultant. He was a co- organiser of the DB+IR workshop at SIGIR 04, a member of the panel "DB and IR: Rethinking the great divide" at SIGMOD 05, and he is the founder of a spin-out to exploit innovative DB+IR technology for information management.

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