2,651 research outputs found
Czech Text Document Corpus v 2.0
This paper introduces "Czech Text Document Corpus v 2.0", a collection of
text documents for automatic document classification in Czech language. It is
composed of the text documents provided by the Czech News Agency and is freely
available for research purposes at http://ctdc.kiv.zcu.cz/. This corpus was
created in order to facilitate a straightforward comparison of the document
classification approaches on Czech data. It is particularly dedicated to
evaluation of multi-label document classification approaches, because one
document is usually labelled with more than one label. Besides the information
about the document classes, the corpus is also annotated at the morphological
layer. This paper further shows the results of selected state-of-the-art
methods on this corpus to offer the possibility of an easy comparison with
these approaches.Comment: Accepted for LREC 201
Unsupervised Dialogue Act Induction using Gaussian Mixtures
This paper introduces a new unsupervised approach for dialogue act induction.
Given the sequence of dialogue utterances, the task is to assign them the
labels representing their function in the dialogue.
Utterances are represented as real-valued vectors encoding their meaning. We
model the dialogue as Hidden Markov model with emission probabilities estimated
by Gaussian mixtures. We use Gibbs sampling for posterior inference.
We present the results on the standard Switchboard-DAMSL corpus. Our
algorithm achieves promising results compared with strong supervised baselines
and outperforms other unsupervised algorithms.Comment: Accepted to EACL 201
A Characterization of Locally Testable Affine-Invariant Properties via Decomposition Theorems
Let be a property of function for
a fixed prime . An algorithm is called a tester for if, given
a query access to the input function , with high probability, it accepts
when satisfies and rejects when is "far" from satisfying
. In this paper, we give a characterization of affine-invariant
properties that are (two-sided error) testable with a constant number of
queries. The characterization is stated in terms of decomposition theorems,
which roughly claim that any function can be decomposed into a structured part
that is a function of a constant number of polynomials, and a pseudo-random
part whose Gowers norm is small. We first give an algorithm that tests whether
the structured part of the input function has a specific form. Then we show
that an affine-invariant property is testable with a constant number of queries
if and only if it can be reduced to the problem of testing whether the
structured part of the input function is close to one of a constant number of
candidates.Comment: 27 pages, appearing in STOC 2014. arXiv admin note: text overlap with
arXiv:1306.0649, arXiv:1212.3849 by other author
Stationary-state electronic distribution in quantum dots
We wish to draw an attention to a non-gibbsian behavior of zero-dimensional
semiconductor nanostructures, which appears to be manifested in experiments by
an effect of incomplete depopulation from electronic excited states or by an
effect of up-conversion of electronic level occupation after preparing the
system in the ground state of electronic excitation. In the present work the
effect is interpreted with help of electron-LO-phonon interaction, which is
supposed to play a role in these structures in the form of multiple-scattering
of electron on the optical phonons. Quantum kinetic equation describing the
process of electronic ralaxation with the inclusion of electronic multiple
scattering on phonons is considered. The multiple electron scattering
interpretation of the effect is supported by pointing out a considerable degree
of agreement between the theoretical picture presented and a rather extensive
amount of existing experimental data.Comment: 8 pages, 3 figure
Laser Spinning of Nanotubes: A path to fast-rotating microdevices
We show that circularly polarized light can spin nanotubes with GHz
frequencies. In this method, angular moments of infrared photons are resonantly
transferred to nanotube phonons and passed to the tube body by "umklapp"
scattering. We investigate experimental realization of this ultrafast rotation
in carbon nanotubes, levitating in an optical trap and undergoing mechanical
vibrations, and discuss possible applications to rotating microdevices.Comment: 4 pages, 3 Postscript figure
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