1,123 research outputs found
BSDEs driven by a multi-dimensional martingale and their applications to market models with funding costs
We establish some well-posedness and comparison results for BSDEs driven by
one- and multi-dimensional martingales. On the one hand, our approach is
largely motivated by results and methods developed in Carbone et al. (2008) and
El Karoui and Huang (1997). On the other hand, our results are also motivated
by the recent developments in arbitrage pricing theory under funding costs and
collateralization. A new version of the comparison theorem for BSDEs driven by
a multi-dimensional martingale is established and applied to the pricing and
hedging BSDEs studied in Bielecki and Rutkowski (2014) and Nie and Rutkowski
(2014). This allows us to obtain the existence and uniqueness results for
unilateral prices and to demonstrate the existence of no-arbitrage bounds for a
collateralized contract when both agents have non-negative initial endowments
Dilated Deep Residual Network for Image Denoising
Variations of deep neural networks such as convolutional neural network (CNN)
have been successfully applied to image denoising. The goal is to automatically
learn a mapping from a noisy image to a clean image given training data
consisting of pairs of noisy and clean images. Most existing CNN models for
image denoising have many layers. In such cases, the models involve a large
amount of parameters and are computationally expensive to train. In this paper,
we develop a dilated residual CNN for Gaussian image denoising. Compared with
the recently proposed residual denoiser, our method can achieve comparable
performance with less computational cost. Specifically, we enlarge receptive
field by adopting dilated convolution in residual network, and the dilation
factor is set to a certain value. We utilize appropriate zero padding to make
the dimension of the output the same as the input. It has been proven that the
expansion of receptive field can boost the CNN performance in image
classification, and we further demonstrate that it can also lead to competitive
performance for denoising problem. Moreover, we present a formula to calculate
receptive field size when dilated convolution is incorporated. Thus, the change
of receptive field can be interpreted mathematically. To validate the efficacy
of our approach, we conduct extensive experiments for both gray and color image
denoising with specific or randomized noise levels. Both of the quantitative
measurements and the visual results of denoising are promising comparing with
state-of-the-art baselines.Comment: camera ready, 8 pages, accepted to IEEE ICTAI 201
Instance-based Deep Transfer Learning
Deep transfer learning recently has acquired significant research interest.
It makes use of pre-trained models that are learned from a source domain, and
utilizes these models for the tasks in a target domain. Model-based deep
transfer learning is probably the most frequently used method. However, very
little research work has been devoted to enhancing deep transfer learning by
focusing on the influence of data. In this paper, we propose an instance-based
approach to improve deep transfer learning in a target domain. Specifically, we
choose a pre-trained model from a source domain and apply this model to
estimate the influence of training samples in a target domain. Then we optimize
the training data of the target domain by removing the training samples that
will lower the performance of the pre-trained model. We later either fine-tune
the pre-trained model with the optimized training data in the target domain, or
build a new model which is initialized partially based on the pre-trained
model, and fine-tune it with the optimized training data in the target domain.
Using this approach, transfer learning can help deep learning models to capture
more useful features. Extensive experiments demonstrate the effectiveness of
our approach on boosting the quality of deep learning models for some common
computer vision tasks, such as image classification.Comment: Accepted to WACV 2019. This is a preprint versio
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