Dr. Lawrence Cayton, Max Planck Institute for Biological Cybernetics, Tuebingen

Lecture
                              V O R T R A G
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                  Oesterreichisches Forschungsinstitut 
                   fuer Artificial Intelligence(OFAI)                   
                        Freyung 6/6, A-1010 Wien
Tel.: +43-1-533611-20,  Fax: +43-1-5336112-77,  Email: sec@ofai.at
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Dr. Lawrence Cayton
Max Planck Institute for Biological Cybernetics, Tuebingen

"Fast similarity search for Bregman divergences"


Nearest neighbor (NN) search is a core ingredient in many algorithms for
machine learning, information retrieval, and elsewhere.  Reducing the
complexity of NN search has been extensively studied for decades;
however, most of the research applied only to standard Euclidean
distance or, more generally, metrics.  In many modern applications,
including text and image analysis, non-metrics notions of distance have
become popular; for instance, documents are often modeled as probability
distributions, and hence a natural notion of distance is the
KL-divergence (relative entropy).

In this talk, I'll present the first techniques for efficient similarity
search when the notion of distance is given by a Bregman divergence.
Bregman divergences are a broad class of distance-like functions that
have attracted much attention in machine learning in recent years.  They
present a challenge for efficient similarity search because they can
behave quite exotically; for example, they can be asymmetric and the
triangle inequality need not hold.  These techniques rely heavily on
geometric properties of Bregman divergences which we developed with
convex analysis tools.

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        Zeit: Donnerstag, 29. Oktober 2009, 18:30 Uhr pktl.

            Ort:  Oesterreichisches Forschungsinstitut
                   fuer Artificial Intelligence, OFAI
                    Freyung 6, Stiege 6, 1010 Wien.


               OESTERREICHISCHES FORSCHUNGSINSTITUT
                   FUER ARTIFICIAL INTELLIGENCE

                 Univ.-Prof. Ing. Dr. Robert Trappl

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