15,773 research outputs found
Interior Estimates for the -dimensional Abreu's Equation
We study the Abreu's equation in n-dimensional polytopes and derive interior
estimates of solutions under the assumption of the uniform K-stability.Comment: 14 pages. Comments are welcom
Zeno effect of the open quantum system in the presence of 1/f noise
We study the quantum Zeno effect (QZE) and quantum anti-Zeno effect (QAZE) in
a two-level system(TLS) interacting with an environment owning 1/f noise. Using
a numerically exact method based on the thermo field dynamics(TFD) theory and
the matrix product states(MPS), we obtain exact evolutions of the TLS and
bath(environment) under repetitive measurements at both zero and finite
temperatures. At zero temperature, we observe a novel transition from a pure
QZE in the short time scale to a QZE-QAZE crossover in the long time scale, by
considering the measurement induced non-Markvoian effect. At finite
temperature, we exploit that the thermal fluctuation suppresses the decay of
the survival probability in the short time scale, whereas it enhances the decay
in the long time scale.Comment: 9 pages, 6 figure
Known-class Aware Self-ensemble for Open Set Domain Adaptation
Existing domain adaptation methods generally assume different domains have
the identical label space, which is quite restrict for real-world applications.
In this paper, we focus on a more realistic and challenging case of open set
domain adaptation. Particularly, in open set domain adaptation, we allow the
classes from the source and target domains to be partially overlapped. In this
case, the assumption of conventional distribution alignment does not hold
anymore, due to the different label spaces in two domains. To tackle this
challenge, we propose a new approach coined as Known-class Aware Self-Ensemble
(KASE), which is built upon the recently developed self-ensemble model. In
KASE, we first introduce a Known-class Aware Recognition (KAR) module to
identify the known and unknown classes from the target domain, which is
achieved by encouraging a low cross-entropy for known classes and a high
entropy based on the source data from the unknown class. Then, we develop a
Known-class Aware Adaptation (KAA) module to better adapt from the source
domain to the target by reweighing the adaptation loss based on the likeliness
to belong to known classes of unlabeled target samples as predicted by KAR.
Extensive experiments on multiple benchmark datasets demonstrate the
effectiveness of our approach
Generative Poisoning Attack Method Against Neural Networks
Poisoning attack is identified as a severe security threat to machine
learning algorithms. In many applications, for example, deep neural network
(DNN) models collect public data as the inputs to perform re-training, where
the input data can be poisoned. Although poisoning attack against support
vector machines (SVM) has been extensively studied before, there is still very
limited knowledge about how such attack can be implemented on neural networks
(NN), especially DNNs. In this work, we first examine the possibility of
applying traditional gradient-based method (named as the direct gradient
method) to generate poisoned data against NNs by leveraging the gradient of the
target model w.r.t. the normal data. We then propose a generative method to
accelerate the generation rate of the poisoned data: an auto-encoder
(generator) used to generate poisoned data is updated by a reward function of
the loss, and the target NN model (discriminator) receives the poisoned data to
calculate the loss w.r.t. the normal data. Our experiment results show that the
generative method can speed up the poisoned data generation rate by up to
239.38x compared with the direct gradient method, with slightly lower model
accuracy degradation. A countermeasure is also designed to detect such
poisoning attack methods by checking the loss of the target model
Storage of polarization-encoded cluster states in an atomic system
We present a scheme for entanglement macroscopic atomic ensembles which are
four spatially separate regions of an atomic cloud using cluster-correlated
beams. We show that the cluster-type polarization-encoded entanglement could be
mapped onto the long-lived collective ground state of the atomic ensembles, and
the stored entanglement could be retrieved based on the technique of
electromagnetically induced transparency. We also discuss the efficiency of,
the lifetime of, and some quantitative restrictions to the proposed quantum
memory.Comment: 7 pages, 4 figure
Prescribed Scaler Curvatures for Homogeneous Toric Bundles
In this paper, we study the generalized Abreu equation on a Delzant ploytope
and prove the existence of the constant scalar
metrics of homogeneous toric bundles under the assumption of an appropriate
stability.Comment: 28 pages,1 figure. Any comments are welcom
On the quantification of the dissolved hydroxyl radicals in the plasma-liquid system using the molecular probe method
Hydroxyl (OH) radical is the most important reactive species produced by the
plasma-liquid interactions, and the OH in the liquid phase (dissolved OH
radical, OHdis) takes effect in many plasma-based applications due to its high
reactivity. Therefore, the quantification of the OHdis in the plasma-liquid
system is of great importance, and a molecular probe method usually used for
the OHdis detection might be applied. Herein we investigate the validity of
using the molecular probe method to estimate the [OHdis] in the plasma-liquid
system. Dimethyl sulfoxide is used as the molecular probe to estimate the
[OHdis] in an air plasma-liquid system, and the partial OHdis is related to the
formed formaldehyde (HCHO) which is the OHdis-induced derivative. The analysis
indicates that the true concentration of the OHdis should be estimated from the
sum of three terms: the formed HCHO, the existing OH scavengers, and the OHdis
generated H2O2. The results show that the measured [HCHO] needs to be corrected
since the HCHO destruction is not negligible in the plasma-liquid system. We
conclude from the results and the analysis that the molecular probe method
generally underestimates the [OHdis] in the plasma-liquid system. If one wants
to obtain the true concentration of the OHdis in the plasma-liquid system, one
needs to know the destruction behavior of the OHdis-induced derivatives, the
information of the OH scavengers (such as hydrated electron, atomic hydrogen
besides the molecular probe), and also the knowledge of the OHdis generated
H2O2.Comment: 17 pages, 4 figures,3 table
Phase Structure and QNMs of A Charged AdS Dilaton Black Hole
We investigate the phase structure of a charged AdS dilaton black hole in the
extended phase space which takes the cosmological constant, i.e. the
AdS- parameter as pressures. Through both thermal ensemble and
quasinormal mode analysis, we find that stable phase of the black hole with
non-trivial dilaton profiles always exists for both large and small couplings
when the AdS- is considered dynamical degrees of freedom. This forms a
somewhat contrast with previous works which does not do so. Our results provide
new examples for the parallelism or equivalences between thermal ensemble
methods and dynamic perturbation analysis for black hole phase structures.Comment: version to appear in Phys. Rev.
HRank: A Path based Ranking Framework in Heterogeneous Information Network
Recently, there is a surge of interests on heterogeneous information network
analysis. As a newly emerging network model, heterogeneous information networks
have many unique features (e.g., complex structure and rich semantics) and a
number of interesting data mining tasks have been exploited in this kind of
networks, such as similarity measure, clustering, and classification. Although
evaluating the importance of objects has been well studied in homogeneous
networks, it is not yet exploited in heterogeneous networks. In this paper, we
study the ranking problem in heterogeneous networks and propose the HRank
framework to evaluate the importance of multiple types of objects and meta
paths. Since the importance of objects depends upon the meta paths in
heterogeneous networks, HRank develops a path based random walk process.
Moreover, a constrained meta path is proposed to subtly capture the rich
semantics in heterogeneous networks. Furthermore, HRank can simultaneously
determine the importance of objects and meta paths through applying the tensor
analysis. Extensive experiments on three real datasets show that HRank can
effectively evaluate the importance of objects and paths together. Moreover,
the constrained meta path shows its potential on mining subtle semantics by
obtaining more accurate ranking results.Comment: 12 pages, 11 figure
CSIFT Based Locality-constrained Linear Coding for Image Classification
In the past decade, SIFT descriptor has been witnessed as one of the most
robust local invariant feature descriptors and widely used in various vision
tasks. Most traditional image classification systems depend on the
luminance-based SIFT descriptors, which only analyze the gray level variations
of the images. Misclassification may happen since their color contents are
ignored. In this article, we concentrate on improving the performance of
existing image classification algorithms by adding color information. To
achieve this purpose, different kinds of colored SIFT descriptors are
introduced and implemented. Locality-constrained Linear Coding (LLC), a
state-of-the-art sparse coding technology, is employed to construct the image
classification system for the evaluation. The real experiments are carried out
on several benchmarks. With the enhancements of color SIFT, the proposed image
classification system obtains approximate 3% improvement of classification
accuracy on the Caltech-101 dataset and approximate 4% improvement of
classification accuracy on the Caltech-256 dataset.Comment: 9 pages, 5 figure
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