22,113 research outputs found
Cross Language Text Classification via Subspace Co-Regularized Multi-View Learning
In many multilingual text classification problems, the documents in different
languages often share the same set of categories. To reduce the labeling cost
of training a classification model for each individual language, it is
important to transfer the label knowledge gained from one language to another
language by conducting cross language classification. In this paper we develop
a novel subspace co-regularized multi-view learning method for cross language
text classification. This method is built on parallel corpora produced by
machine translation. It jointly minimizes the training error of each classifier
in each language while penalizing the distance between the subspace
representations of parallel documents. Our empirical study on a large set of
cross language text classification tasks shows the proposed method consistently
outperforms a number of inductive methods, domain adaptation methods, and
multi-view learning methods.Comment: Appears in Proceedings of the 29th International Conference on
Machine Learning (ICML 2012
Topological states and quantized current in helical molecules
We report a theoretical study of electron transport along helical molecules
under an external electric field, which is perpendicular to the helix axis of
the molecule. Our results reveal that the topological states could appear in
single-helical molecule and double-stranded DNA in the presence of the
perpendicular electric field. And these topological states guarantee adiabatic
charge pumping across the helical molecules by rotating the electric field in
the transverse plane and the pumped current at zero bias voltage is quantized.
In addition, the quantized current constitutes multiple plateaus by scanning
the Fermi energy as well as the bias voltage, and hold for various model
parameters, since they are topologically protected against perturbations. These
results could motivate further experimental and theoretical studies in the
electron transport through helical molecules, and pave the way to detect
topological states and quantized current in the biological systems.Comment: 5 pages, 5 figure
Exemplar-Centered Supervised Shallow Parametric Data Embedding
Metric learning methods for dimensionality reduction in combination with
k-Nearest Neighbors (kNN) have been extensively deployed in many
classification, data embedding, and information retrieval applications.
However, most of these approaches involve pairwise training data comparisons,
and thus have quadratic computational complexity with respect to the size of
training set, preventing them from scaling to fairly big datasets. Moreover,
during testing, comparing test data against all the training data points is
also expensive in terms of both computational cost and resources required.
Furthermore, previous metrics are either too constrained or too expressive to
be well learned. To effectively solve these issues, we present an
exemplar-centered supervised shallow parametric data embedding model, using a
Maximally Collapsing Metric Learning (MCML) objective. Our strategy learns a
shallow high-order parametric embedding function and compares training/test
data only with learned or precomputed exemplars, resulting in a cost function
with linear computational complexity for both training and testing. We also
empirically demonstrate, using several benchmark datasets, that for
classification in two-dimensional embedding space, our approach not only gains
speedup of kNN by hundreds of times, but also outperforms state-of-the-art
supervised embedding approaches.Comment: accepted to IJCAI201
4-Bromoanilinium perchlorate 18-crown-6 clathrate
The reaction of 4-bromoaniline, 18-crown-6, and perchloric acid in methanol yields the title compound, C6H7BrN+·ClO4
−·C12H24O6, in which the protonated –NH3
+ group forms three bifurcated N—H⋯O hydrogen bonds to the O atoms of the crown ether
1-Cyanomethyl-1,4-diazoniabicyclo[2.2.2]octane tetrachloridomanganate(II)
In the crystal structure of the title compound, (C8H15N3)[MnCl4], the Mn atom is coordinated by four chloride ligands in a slightly distorted tetrahedral geometry. Each [MnCl4]2− anion is connected to the 1-cyanomethyl-1,4-diazoniabicyclo[2.2.2]octane dications by N—H⋯Cl hydrogen bonds, forming chains parallel to [001]
Spin-Selective Transport of Electron in DNA Double Helix
The experiment that the high spin selectivity and the length-dependent spin
polarization are observed in double-stranded DNA [Science , 894
(2011)], is elucidated by considering the combination of the spin-orbit
coupling, the environment-induced dephasing, and the helical symmetry. We show
that the spin polarization in double-stranded DNA is significant even in the
case of weak spin-orbit coupling, while no spin polarization appears in
single-stranded DNA. Furthermore, the underlying physical mechanism and the
parameters-dependence of the spin polarization are studied.Comment: 5 pages; 4 figure
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