[Colloquium] REMINDER: Research at TTIC: Ryota Tomioka, TTIC

[Dawn Ellis]

When:     Friday, January 9th at Noon

Where:    TTIC, 6045 S Kenwood Avenue, 5th Floor, Room 526

Who:       Ryota Tomioka, TTIC

Title:       Multitask learning meets tensor factorization: task imputation
              via convex optimization

Abstract:

We study a multitask learning problem in which each task is parametrized by
a weight vector and indexed by a pair of indices, which can be e.g,
(consumer, time). The weight vectors can be collected into a tensor and the
(multilinear-)rank of the tensor controls the amount of sharing of
information among tasks. Two types of convex relaxations have recently been
 proposed  for the tensor multilinear rank. However, we argue that both of
them are not optimal in the context of multitask learning in which the
dimensions or multilinear rank are typically heterogeneous. We propose a
new norm, which we call the scaled latent trace norm and analyze the excess
risk of all the three norms. The results apply to various settings
including matrix and tensor completion, multitask learning, and multilinear
multitask learning. Both the theory and experiments support the advantage
of the new norm when the tensor is not equal-sized and we do not a priori
know which mode is low rank.


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Research at TTIC Seminar Series

TTIC is hosting a weekly seminar series presenting the research currently
underway at the Institute. Every week a different TTIC faculty member will
present their research.  The lectures are intended both for students
seeking research topics and adviser, and for the general TTIC and
University of Chicago communities interested in hearing what their
colleagues are up to.

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mailing list: https://groups.google.com/a/ttic.edu/group/talks/subscribe

Speaker details can be found at: http://www.ttic.edu/tticseminar.php.

For additional questions, please contact David McAllester at
mcallester at ttic.edu



-- 
*Dawn Ellis*
Administrative Coordinator,
Bookkeeper
773-834-1757
dellis at ttic.edu

TTIC
6045 S. Kenwood Ave.
Chicago, IL. 60637
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