537 research outputs found
AutoEncoder Inspired Unsupervised Feature Selection
High-dimensional data in many areas such as computer vision and machine
learning tasks brings in computational and analytical difficulty. Feature
selection which selects a subset from observed features is a widely used
approach for improving performance and effectiveness of machine learning models
with high-dimensional data. In this paper, we propose a novel AutoEncoder
Feature Selector (AEFS) for unsupervised feature selection which combines
autoencoder regression and group lasso tasks. Compared to traditional feature
selection methods, AEFS can select the most important features by excavating
both linear and nonlinear information among features, which is more flexible
than the conventional self-representation method for unsupervised feature
selection with only linear assumptions. Experimental results on benchmark
dataset show that the proposed method is superior to the state-of-the-art
method.Comment: accepted by ICASSP 201
Cohomologies, extensions and deformations of differential algebras with any weights
As an algebraic study of differential equations, differential algebras have
been studied for a century and and become an important area of mathematics. In
recent years the area has been expended to the noncommutative associative and
Lie algebra contexts and to the case when the operator identity has a weight in
order to include difference operators and difference algebras. This paper
provides a cohomology theory for differential algebras of any weights. This
gives a uniform approach to both the zero weight case which is similar to the
earlier study of differential Lie algebras, and the non-zero weight case which
poses new challenges. As applications, abelian extensions of a differential
algebra are classified by the second cohomology group. Furthermore, formal
deformations of differential algebras are obtained and the rigidity of a
differential algebra is characterized by the vanishing of the second cohomology
group.Comment: 21 page
Degradation of Cry1Ac Protein Within Transgenic Bacillus thuringiensis Rice Tissues Under Field and Laboratory Conditions
To clarify the environmental fate of the Cry1Ac protein from Bacillus thuringiensis subsp. kurstaki (Bt) contained in transgenic rice plant stubble after harvest, degradation was monitored under field conditions using an enzyme-linked immunosorbent assay. In stalks, Cry1Ac protein concentration decreased rapidly to 50% of the initial amount during the first month after harvest; subsequently, the degradation decreased gradually reaching 21.3% when the experiment was terminated after 7 mo. A similar degradation pattern of the Cry1Ac protein was observed in rice roots. However, when the temperature increased in April of the following spring, protein degradation resumed, and no protein could be detected by the end of the experiment. In addition, a laboratory experiment was conducted to study the persistence of Cry1Ac protein released from rice tissue in water and paddy soil. The protein released from leaves degraded rapidly in paddy soil under flooded conditions during the first 20 d and plateaued until the termination of this trial at 135 d, when 15.3% of the initial amount was still detectable. In water, the Cry1Ac protein degraded more slowly than in soil but never entered a relatively stable phase as in soil. The degradation rate of Cry1Ac protein was significantly faster in nonsterile water than in sterile water. These results indicate that the soil environment can increase the degradation of Bt protein contained in plant residues. Therefore, plowing a field immediately after harvest could be an effective method for decreasing the persistence of Bt protein in transgenic rice field
Homotopy Rota-Baxter operators, homotopy -operators and homotopy post-Lie algebras
Rota-Baxter operators, -operators on Lie algebras and their
interconnected pre-Lie and post-Lie algebras are important algebraic structures
with applications in mathematical physics. This paper introduces the notions of
a homotopy Rota-Baxter operator and a homotopy -operator on a
symmetric graded Lie algebra. Their characterization by Maurer-Cartan elements
of suitable differential graded Lie algebras is provided. Through the action of
a homotopy -operator on a symmetric graded Lie algebra, we arrive
at the notion of an operator homotopy post-Lie algebra, together with its
characterization in terms of Maurer-Cartan elements. A cohomology theory of
post-Lie algebras is established, with an application to 2-term skeletal
operator homotopy post-Lie algebras.Comment: 29 page
Adversarially Robust Neural Architectures
Deep Neural Network (DNN) are vulnerable to adversarial attack. Existing
methods are devoted to developing various robust training strategies or
regularizations to update the weights of the neural network. But beyond the
weights, the overall structure and information flow in the network are
explicitly determined by the neural architecture, which remains unexplored.
This paper thus aims to improve the adversarial robustness of the network from
the architecture perspective with NAS framework. We explore the relationship
among adversarial robustness, Lipschitz constant, and architecture parameters
and show that an appropriate constraint on architecture parameters could reduce
the Lipschitz constant to further improve the robustness. For NAS framework,
all the architecture parameters are equally treated when the discrete
architecture is sampled from supernet. However, the importance of architecture
parameters could vary from operation to operation or connection to connection,
which is not explored and might reduce the confidence of robust architecture
sampling. Thus, we propose to sample architecture parameters from trainable
multivariate log-normal distributions, with which the Lipschitz constant of
entire network can be approximated using a univariate log-normal distribution
with mean and variance related to architecture parameters. Compared with
adversarially trained neural architectures searched by various NAS algorithms
as well as efficient human-designed models, our algorithm empirically achieves
the best performance among all the models under various attacks on different
datasets.Comment: 9 pages, 3 figures, 5 table
A hybrid EDA for load balancing in multicast with network coding
Load balancing is one of the most important issues in the practical deployment of multicast with network coding. However, this issue has received little research attention. This paper studies how traffic load of network coding based multicast (NCM) is disseminated in a communications network, with load balancing considered as an important factor. To this end, a hybridized estimation of distribution algorithm (EDA) is proposed, where two novel schemes are integrated into the population based incremental learning (PBIL) framework to strike a balance between exploration and exploitation, thus enhance the efficiency of the stochastic search. The first scheme is a bi-probability-vector coevolution scheme, where two probability vectors (PVs) evolve independently with periodical individual migration. This scheme can diversify the population and improve the global exploration in the search. The second scheme is a local search heuristic. It is based on the problem-specific domain knowledge and improves the NCM transmission plan at the expense of additional computational time. The heuristic can be utilized either as a local search operator to enhance the local exploitation during the evolutionary process, or as a follow-up operator to improve the best-so-far solutions found after the evolution. Experimental results show the effectiveness of the proposed algorithms against a number of existing evolutionary algorithms
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