[Colloquium] REMINDER: 10/9 TTIC Colloquium: Samory Kpotufe, Princeton

[Mary Marre via Colloquium]

When:     Monday, October 9th at 11:00 a.m.

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

Who:       Samory Kpotufe, Princeton


Title:       Adaptive rates in Active Learning with label noise

Abstract: In active learning (for classification tasks), the learner has
the ability to request the labels of carefully chosen points over space.
Intuitively, this might speedup the learning process — in terms of the
number of labels required to achieve a fixed error— over the usual passive
setting where the learner accesses i.i.d labeled data. Unfortunately,
despite significant progress on the subject, the benefits of active over
passive learning remain largely unclear: for example, in the usual PAC
setting with VC classes, label requirements in active learning are of the
same order as in passive learning outside of strong assumptions on label
noise.

In this talk, we aim to gain new insights on the benefits of active
learning over passive learning. In particular, we will consider 3
parametrizations of label noise that help capture the continuum of easy to
hard classification problems, and elicit a clearer picture of the benefits
of active learning. The first such parametrization draws on intuition from
the so-called `cluster assumption’ in ML, while the last two consist of
so-called ‘noise margin assumptions’ common in ML and Statistics. Our
results exhibit interesting phase transitions (in label requirements)
driven by the interaction between noise parameters, marginal distribution,
and data dimension. Furthermore, our algorithmic strategies are adaptive,
i.e., require no a priori knowledge of distributional or noise parameters,
yet are rate-optimal.

The talk is based on recent collaborations with S. Ben-David, R. Urner, A.
Locatelli, and A. Carpentier.


Host: Nathan Srebro <nati at ttic.edu>


For more information on the colloquium series or to subscribe to the
mailing list, please see http://www.ttic.edu/colloquium.php




Mary C. Marre
Administrative Assistant
*Toyota Technological Institute*
*6045 S. Kenwood Avenue*
*Room 504*
*Chicago, IL  60637*
*p:(773) 834-1757*
*f: (773) 357-6970*
*mmarre at ttic.edu <mmarre at ttic.edu>*
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