9,753 research outputs found
Test and Measure for Partial Mean Dependence Based on Deep Neural Networks
It is of great importance to investigate the significance of a subset of
covariates W for the response Y given covariates Z in regression modeling. To
this end, we propose a new significance test for the partial mean independence
problem based on deep neural networks and data splitting. The test statistic
converges to the standard chi-squared distribution under the null hypothesis
while it converges to a normal distribution under the alternative hypothesis.
We also suggest a powerful ensemble algorithm based on multiple data splitting
to enhance the testing power. If the null hypothesis is rejected, we propose a
new partial Generalized Measure of Correlation (pGMC) to measure the partial
mean dependence of Y given W after controlling for the nonlinear effect of Z,
which is an interesting extension of the GMC proposed by Zheng et al. (2012).
We present the appealing theoretical properties of the pGMC and establish the
asymptotic normality of its estimator with the optimal root-N converge rate.
Furthermore, the valid confidence interval for the pGMC is also derived. As an
important special case when there is no conditional covariates Z, we also
consider a new test of overall significance of covariates for the response in a
model-free setting. We also introduce new estimator of GMC and derive its
asymptotic normality. Numerical studies and real data analysis are also
conducted to compare with existing approaches and to illustrate the validity
and flexibility of our proposed procedures
SpreadCluster: Recovering Versioned Spreadsheets through Similarity-Based Clustering
Version information plays an important role in spreadsheet understanding,
maintaining and quality improving. However, end users rarely use version
control tools to document spreadsheet version information. Thus, the
spreadsheet version information is missing, and different versions of a
spreadsheet coexist as individual and similar spreadsheets. Existing approaches
try to recover spreadsheet version information through clustering these similar
spreadsheets based on spreadsheet filenames or related email conversation.
However, the applicability and accuracy of existing clustering approaches are
limited due to the necessary information (e.g., filenames and email
conversation) is usually missing. We inspected the versioned spreadsheets in
VEnron, which is extracted from the Enron Corporation. In VEnron, the different
versions of a spreadsheet are clustered into an evolution group. We observed
that the versioned spreadsheets in each evolution group exhibit certain common
features (e.g., similar table headers and worksheet names). Based on this
observation, we proposed an automatic clustering algorithm, SpreadCluster.
SpreadCluster learns the criteria of features from the versioned spreadsheets
in VEnron, and then automatically clusters spreadsheets with the similar
features into the same evolution group. We applied SpreadCluster on all
spreadsheets in the Enron corpus. The evaluation result shows that
SpreadCluster could cluster spreadsheets with higher precision and recall rate
than the filename-based approach used by VEnron. Based on the clustering result
by SpreadCluster, we further created a new versioned spreadsheet corpus
VEnron2, which is much bigger than VEnron. We also applied SpreadCluster on the
other two spreadsheet corpora FUSE and EUSES. The results show that
SpreadCluster can cluster the versioned spreadsheets in these two corpora with
high precision.Comment: 12 pages, MSR 201
Is the late near-infrared bump in short-hard GRB 130603B due to the Li-Paczynski kilonova?
Short-hard gamma-ray bursts (GRBs) are widely believed to be produced by the
merger of two binary compact objects, specifically by two neutron stars or by a
neutron star orbiting a black hole. According to the Li-Paczynski kilonova
model, the merger would launch sub-relativistic ejecta and a
near-infrared/optical transient would then occur, lasting up to days, which is
powered by the radioactive decay of heavy elements synthesized in the ejecta.
The detection of a late bump using the {\em Hubble Space Telescope} ({\em HST})
in the near-infrared afterglow light curve of the short-hard GRB 130603B is
indeed consistent with such a model. However, as shown in this Letter, the
limited {\em HST} near-infrared lightcurve behavior can also be interpreted as
the synchrotron radiation of the external shock driven by a wide mildly
relativistic outflow. In such a scenario, the radio emission is expected to
peak with a flux of Jy, which is detectable for current radio
arrays. Hence, the radio afterglow data can provide complementary evidence on
the nature of the bump in GRB 130603B. It is worth noting that good
spectroscopy during the bump phase in short-hard bursts can test validity of
either model above, analogous to spectroscopy of broad-lined Type Ic supernova
in long-soft GRBs.Comment: 4 pages, 2 figures, published in ApJ Lette
A supra-massive magnetar central engine for short GRB 130603B
We show that the peculiar early optical and in particular X-ray afterglow
emission of the short duration burst GRB 130603B can be explained by continuous
energy injection into the blastwave from a supra-massive magnetar central
engine. The observed energetics and temporal/spectral properties of the late
infrared bump (i.e., the "kilonova") are also found consistent with emission
from the ejecta launched during an NS-NS merger and powered by a magnetar
central engine. The isotropic-equivalent kinetic energies of both the GRB
blastwave and the kilonova are about erg, consistent
with being powered by a near-isotropic magnetar wind. However, this relatively
small value demands that most of the initial rotational energy of the magnetar
is carried away by gravitational wave
radiation. Our results suggest that (i) the progenitor of GRB 130603B would be
a NS-NS binary system, whose merger product would be a supra-massive neutron
star that lasted for about seconds; (ii) the equation-of-state of
nuclear matter would be stiff enough to allow survival of a long-lived
supra-massive neutron star, so that it is promising to detect bright
electromagnetic counterparts of gravitational wave triggers without short GRB
associations in the upcoming Advanced LIGO/Virgo era.Comment: Five pages including 1 Figure, to appear in ApJ
2-[1-(1-PhenylÂethÂyl)imidazolidin-2-ylÂidene]malononitrile
In the title compound, C14H14N4, the imidazolidine moiety is nearly planar, having an N—C—N—C torsion angle of 4.43 (3)°. The crystal structure is characterized by classical N—H⋯N hydrogen bonds, which form inversion dimers
Quantum Correction in Exact Quantization Rules
An exact quantization rule for the Schr\"{o}dinger equation is presented. In
the exact quantization rule, in addition to , there is an integral term,
called the quantum correction. For the exactly solvable systems we find that
the quantum correction is an invariant, independent of the number of nodes in
the wave function. In those systems, the energy levels of all the bound states
can be easily calculated from the exact quantization rule and the solution for
the ground state, which can be obtained by solving the Riccati equation. With
this new method, we re-calculate the energy levels for the one-dimensional
systems with a finite square well, with the Morse potential, with the symmetric
and asymmetric Rosen-Morse potentials, and with the first and the second
P\"{o}schl-Teller potentials, for the harmonic oscillators both in one
dimension and in three dimensions, and for the hydrogen atom.Comment: 10 pages, no figure, Revte
Discourse Level Factors for Sentence Deletion in Text Simplification
This paper presents a data-driven study focusing on analyzing and predicting
sentence deletion -- a prevalent but understudied phenomenon in document
simplification -- on a large English text simplification corpus. We inspect
various document and discourse factors associated with sentence deletion, using
a new manually annotated sentence alignment corpus we collected. We reveal that
professional editors utilize different strategies to meet readability standards
of elementary and middle schools. To predict whether a sentence will be deleted
during simplification to a certain level, we harness automatically aligned data
to train a classification model. Evaluated on our manually annotated data, our
best models reached F1 scores of 65.2 and 59.7 for this task at the levels of
elementary and middle school, respectively. We find that discourse level
factors contribute to the challenging task of predicting sentence deletion for
simplification.Comment: Accepted in AAAI 2020. Adding more details on manual data annotatio
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