653 research outputs found
Scaling limit of the local time of the random walk
It is well known (Donsker's Invariance Principle) that the random walk
converges to Brownian motion by scaling. In this paper, we will prove that the
scaled local time of the random walk converges to that of the Brownian
motion. The results was proved by Rogers (1984) in the case . Our proof is
based on the intrinsic multiple branching structure within the random
walk revealed by Hong and Wang (2013)
Exact Asymptotic Behavior of Singular Positive Solutions of Fractional Semi-Linear Elliptic Equations
In this paper, we prove the exact asymptotic behavior of singular positive
solutions of fractional semi-linear equations with an isolated singularity, where
and .Comment: 11 page
Qualitative analysis for an elliptic system in the punctured space
In this paper, we investigate the qualitative properties of positive
solutions for the following two-coupled elliptic system in the punctured space:
where and are all positive
constants, . We establish a monotonicity formula that completely
characterizes the singularity of positive solutions. We prove a sharp global
estimate for both components of positive solutions. We also prove the
nonexistence of positive semi-singular solutions, which means that one
component is bounded near the singularity and the other component is unbounded
near the singularity.Comment: 27 page
Scaling limit of the local time of the Sinai's random walk
We prove that the local times of a sequence of Sinai's random walks
convergence to those of Brox's diffusion by proper scaling, which is accord
with the result of Seignourel (2000). Our proof is based on the convergence of
the branching processes in random environment by Kurtz (1979)
Recurrent Regression for Face Recognition
To address the sequential changes of images including poses, in this paper we
propose a recurrent regression neural network(RRNN) framework to unify two
classic tasks of cross-pose face recognition on still images and video-based
face recognition. To imitate the changes of images, we explicitly construct the
potential dependencies of sequential images so as to regularize the final
learning model. By performing progressive transforms for sequentially adjacent
images, RRNN can adaptively memorize and forget the information that benefits
for the final classification. For face recognition of still images, given any
one image with any one pose, we recurrently predict the images with its
sequential poses to expect to capture some useful information of others poses.
For video-based face recognition, the recurrent regression takes one entire
sequence rather than one image as its input. We verify RRNN in static face
dataset MultiPIE and face video dataset YouTube Celebrities(YTC). The
comprehensive experimental results demonstrate the effectiveness of the
proposed RRNN method
CFSNet: Toward a Controllable Feature Space for Image Restoration
Deep learning methods have witnessed the great progress in image restoration
with specific metrics (e.g., PSNR, SSIM). However, the perceptual quality of
the restored image is relatively subjective, and it is necessary for users to
control the reconstruction result according to personal preferences or image
characteristics, which cannot be done using existing deterministic networks.
This motivates us to exquisitely design a unified interactive framework for
general image restoration tasks. Under this framework, users can control
continuous transition of different objectives, e.g., the perception-distortion
trade-off of image super-resolution, the trade-off between noise reduction and
detail preservation. We achieve this goal by controlling the latent features of
the designed network. To be specific, our proposed framework, named
Controllable Feature Space Network (CFSNet), is entangled by two branches based
on different objectives. Our framework can adaptively learn the coupling
coefficients of different layers and channels, which provides finer control of
the restored image quality. Experiments on several typical image restoration
tasks fully validate the effective benefits of the proposed method. Code is
available at https://github.com/qibao77/CFSNet.Comment: Accepted by ICCV 201
Tensor graph convolutional neural network
In this paper, we propose a novel tensor graph convolutional neural network
(TGCNN) to conduct convolution on factorizable graphs, for which here two types
of problems are focused, one is sequential dynamic graphs and the other is
cross-attribute graphs. Especially, we propose a graph preserving layer to
memorize salient nodes of those factorized subgraphs, i.e. cross graph
convolution and graph pooling. For cross graph convolution, a parameterized
Kronecker sum operation is proposed to generate a conjunctive adjacency matrix
characterizing the relationship between every pair of nodes across two
subgraphs. Taking this operation, then general graph convolution may be
efficiently performed followed by the composition of small matrices, which thus
reduces high memory and computational burden. Encapsuling sequence graphs into
a recursive learning, the dynamics of graphs can be efficiently encoded as well
as the spatial layout of graphs. To validate the proposed TGCNN, experiments
are conducted on skeleton action datasets as well as matrix completion dataset.
The experiment results demonstrate that our method can achieve more competitive
performance with the state-of-the-art methods
On Isolated Singularities of Fractional Semi-Linear Elliptic Equations
In this paper, we study the local behavior of nonnegative solutions of
fractional semi-linear equations with an isolated
singularity, where \sg \in (0, 1) and \frac{n}{n-2\sg} < p <
\frac{n+2\sg}{n-2\sg}. We first use blow up method and a Liouville type
theorem to derive an upper bound. Then we establish a monotonicity formula and
a sufficient condition for removable singularity to give a classification of
the isolated singularities. When \sg=1, this classification result has been
proved by Gidas and Spruck (Comm. Pure Appl. Math. 34: 525-598, 1981).Comment: 19 page
Scaling limit theorems for the -transient random walk in random and non-random environment
Kesten et al.( 1975) proved the stable law for the transient RWRE (here we
refer it as the -transient RWRE). After that, some similar interesting
properties have also been revealed for its continuous counterpart, the
diffusion proces in a Brownian environment with drift . In the present
paper we will investigate the connections between these two kind of models,
i.e., we will construct a sequence of the -transient RWREs and prove it
convergence to the diffusion proces in a Brownian environment with drift
by proper scaling. To this end, we need a counterpart convergence for
the -transient random walk in non-random environment, which is
interesting itself
Spatial-Temporal Recurrent Neural Network for Emotion Recognition
Emotion analysis is a crucial problem to endow artifact machines with real
intelligence in many large potential applications. As external appearances of
human emotions, electroencephalogram (EEG) signals and video face signals are
widely used to track and analyze human's affective information. According to
their common characteristics of spatial-temporal volumes, in this paper we
propose a novel deep learning framework named spatial-temporal recurrent neural
network (STRNN) to unify the learning of two different signal sources into a
spatial-temporal dependency model. In STRNN, to capture those spatially
cooccurrent variations of human emotions, a multi-directional recurrent neural
network (RNN) layer is employed to capture longrange contextual cues by
traversing the spatial region of each time slice from multiple angles. Then a
bi-directional temporal RNN layer is further used to learn discriminative
temporal dependencies from the sequences concatenating spatial features of each
time slice produced from the spatial RNN layer. To further select those salient
regions of emotion representation, we impose sparse projection onto those
hidden states of spatial and temporal domains, which actually also increases
the model discriminant ability because of this global consideration.
Consequently, such a two-layer RNN model builds spatial dependencies as well as
temporal dependencies of the input signals. Experimental results on the public
emotion datasets of EEG and facial expression demonstrate the proposed STRNN
method is more competitive over those state-of-the-art methods
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