156 research outputs found
Remove Cosine Window from Correlation Filter-based Visual Trackers: When and How
Correlation filters (CFs) have been continuously advancing the
state-of-the-art tracking performance and have been extensively studied in the
recent few years. Most of the existing CF trackers adopt a cosine window to
spatially reweight base image to alleviate boundary discontinuity. However,
cosine window emphasizes more on the central region of base image and has the
risk of contaminating negative training samples during model learning. On the
other hand, spatial regularization deployed in many recent CF trackers plays a
similar role as cosine window by enforcing spatial penalty on CF coefficients.
Therefore, we in this paper investigate the feasibility to remove cosine window
from CF trackers with spatial regularization. When simply removing cosine
window, CF with spatial regularization still suffers from small degree of
boundary discontinuity. To tackle this issue, binary and Gaussian shaped mask
functions are further introduced for eliminating boundary discontinuity while
reweighting the estimation error of each training sample, and can be
incorporated with multiple CF trackers with spatial regularization. In
comparison to the counterparts with cosine window, our methods are effective in
handling boundary discontinuity and sample contamination, thereby benefiting
tracking performance. Extensive experiments on three benchmarks show that our
methods perform favorably against the state-of-the-art trackers using either
handcrafted or deep CNN features. The code is publicly available at
https://github.com/lifeng9472/Removing_cosine_window_from_CF_trackers.Comment: 13 pages, 7 figures, submitted to IEEE Transactions on Image
Processin
Optimal Upfc Control And Operations For Power Systems
The content of this dissertation consists of three parts. In the first part, optimal control strategies are developed for Unified Power Flow Controller (UPFC) following the clearance of fault conditions. UPFC is one of the most versatile Flexible AC Transmission devices (FACTs) that have been implemented thus far. The optimal control scheme is composed of two parts. The first is an optimal stabilization control, which is an open-loop ‘Bang’ type of control. The second is an suboptimal damping control, which consists of segments of ‘Bang’ type control with switching functions the same as those of a corresponding approximate linear system. Simulation results show that the proposed control strategy is very effective in maintaining stability and damping out transient oscillations following the clearance of the fault. In the second part, a new power market structure is proposed. The new structure is based on a two-level optimization formulation of the market. It is shown that the proposed market structure can easily find the optimal solutions for the market while takeing factors such as demand elasticity into account. In the last part, a mathematical programming problem is formulated to obtain the maximum value of the loadibility factor, while the power system is constrained by steady-state dynamic security constraints. An iterative solution procedure is proposed for the problem, and the solution gives a slightly conservative estimate of the loadibility limit for the generation and transmission system
Learning Diverse Tone Styles for Image Retouching
Image retouching, aiming to regenerate the visually pleasing renditions of
given images, is a subjective task where the users are with different aesthetic
sensations. Most existing methods deploy a deterministic model to learn the
retouching style from a specific expert, making it less flexible to meet
diverse subjective preferences. Besides, the intrinsic diversity of an expert
due to the targeted processing on different images is also deficiently
described. To circumvent such issues, we propose to learn diverse image
retouching with normalizing flow-based architectures. Unlike current flow-based
methods which directly generate the output image, we argue that learning in a
style domain could (i) disentangle the retouching styles from the image
content, (ii) lead to a stable style presentation form, and (iii) avoid the
spatial disharmony effects. For obtaining meaningful image tone style
representations, a joint-training pipeline is delicately designed, which is
composed of a style encoder, a conditional RetouchNet, and the image tone style
normalizing flow (TSFlow) module. In particular, the style encoder predicts the
target style representation of an input image, which serves as the conditional
information in the RetouchNet for retouching, while the TSFlow maps the style
representation vector into a Gaussian distribution in the forward pass. After
training, the TSFlow can generate diverse image tone style vectors by sampling
from the Gaussian distribution. Extensive experiments on MIT-Adobe FiveK and
PPR10K datasets show that our proposed method performs favorably against
state-of-the-art methods and is effective in generating diverse results to
satisfy different human aesthetic preferences. Source code and pre-trained
models are publicly available at https://github.com/SSRHeart/TSFlow
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Surface-Bound Cucurbit[8]uril Catenanes on Magnetic Nanoparticles Exhibiting Molecular Recognition.
We demonstrate the preparation of surface-bound cucurbit[8]uril (CB[8]) catenanes on silica nanoparticles (NPs), where CB[8] was employed as a tethered supramolecular "handcuff" to selectively capture target guest molecules. In this catenane, CB[8] was threaded onto a methyl viologen (MV(2+) ) axle and immobilized onto silica NPs. The formation of CB[8] catenanes on NPs were confirmed by UV/Vis titration experiments and lithographic characterization, demonstrating a high density of CB[8] on the silica NPs surface, 0.56 nm(-2) . This CB[8] catenane system exhibits specific molecular recognition towards certain aromatic molecules such as perylene bis(diimide), naphthol and aromatic amino acids, and thus it can act as a nanoscale molecular receptor for target guests. Furthermore, we also demonstrate its use as an efficient and recyclable nano-platform for peptide separation. By embedding magnetic NPs inside silica NPs, separation could be achieved by simply applying an external magnetic field. Moreover, the peptides captured by the catenanes could be released by reversible single-electron reduction of MV(2+) . The entire process demonstrated high recoverability.X. Ren thanks the CSC Cambridge Scholarship for financial support and
Dr. Ziyi Yu for template preparation. Y. Wu is financially supported
by the EP/L504920/1, J. Liu by the Marie Curie FP7 SASSYPOL ITN
(607602) programme, and G. Wu by the Leverhulme Trust.This is the author accepted manuscript. The final version is available from Wiley at http://dx.doi.org/10.1002/asia.201600875
Melatonin protects against ovarian damage by inhibiting autophagy in granulosa cells in rats
Objectives: This study sought to further verify the protective mechanism of Melatonin (MT) against ovarian damage through animal model experiments and to lay a theoretical and experimental foundation for exploring new approaches for ovarian damage treatment.
Method: The wet weight and ovarian index of rat ovaries were weighted, and the morphology of ovarian tissues and the number of follicles in the pathological sections of collected ovarian tissues were recorded. And the serum sex hormone levels, the key proteins of the autophagy pathway (PI3K, AKT, mTOR, LC3II, LC3I, and Agt5) in rat ovarian tissues, as well as the viability and mortality of ovarian granulosa cells in each group were measured by ELISA, western blotting, CCK8 kit and LDH kit, respectively.
Results: The results showed that MT increased ovarian weight and improved the ovarian index in ovarian damage rats. Also, MT could improve autophagy-induced ovarian tissue injury, increase the number of primordial follicles, primary follicles, and sinus follicles, and decrease the number of atretic follicles. Furthermore, MT upregulated serum AMH, INH-B, and E2 levels downregulated serum FSH and LH levels in ovarian damage rats and activated the PI3K/AKT/mTOR signaling pathway. Besides, MT inhibited autophagic apoptosis of ovarian granulosa cells and repressed the expression of key proteins in the autophagic pathway and reduced the expression levels of Agt5 and LC3II/I.
Conclusions: MT inhibits granulosa cell autophagy by activating the PI3K/Akt/mTOR signaling pathway, thereby exerting a protective effect against ovarian damage
Learning with Noisy Labels Using Collaborative Sample Selection and Contrastive Semi-Supervised Learning
Learning with noisy labels (LNL) has been extensively studied, with existing
approaches typically following a framework that alternates between clean sample
selection and semi-supervised learning (SSL). However, this approach has a
limitation: the clean set selected by the Deep Neural Network (DNN) classifier,
trained through self-training, inevitably contains noisy samples. This mixture
of clean and noisy samples leads to misguidance in DNN training during SSL,
resulting in impaired generalization performance due to confirmation bias
caused by error accumulation in sample selection. To address this issue, we
propose a method called Collaborative Sample Selection (CSS), which leverages
the large-scale pre-trained model CLIP. CSS aims to remove the mixed noisy
samples from the identified clean set. We achieve this by training a
2-Dimensional Gaussian Mixture Model (2D-GMM) that combines the probabilities
from CLIP with the predictions from the DNN classifier. To further enhance the
adaptation of CLIP to LNL, we introduce a co-training mechanism with a
contrastive loss in semi-supervised learning. This allows us to jointly train
the prompt of CLIP and the DNN classifier, resulting in improved feature
representation, boosted classification performance of DNNs, and reciprocal
benefits to our Collaborative Sample Selection. By incorporating auxiliary
information from CLIP and utilizing prompt fine-tuning, we effectively
eliminate noisy samples from the clean set and mitigate confirmation bias
during training. Experimental results on multiple benchmark datasets
demonstrate the effectiveness of our proposed method in comparison with the
state-of-the-art approaches
Benchmark Dataset and Effective Inter-Frame Alignment for Real-World Video Super-Resolution
Video super-resolution (VSR) aiming to reconstruct a high-resolution (HR)
video from its low-resolution (LR) counterpart has made tremendous progress in
recent years. However, it remains challenging to deploy existing VSR methods to
real-world data with complex degradations. On the one hand, there are few
well-aligned real-world VSR datasets, especially with large super-resolution
scale factors, which limits the development of real-world VSR tasks. On the
other hand, alignment algorithms in existing VSR methods perform poorly for
real-world videos, leading to unsatisfactory results. As an attempt to address
the aforementioned issues, we build a real-world 4 VSR dataset, namely
MVSR4, where low- and high-resolution videos are captured with
different focal length lenses of a smartphone, respectively. Moreover, we
propose an effective alignment method for real-world VSR, namely EAVSR. EAVSR
takes the proposed multi-layer adaptive spatial transform network (MultiAdaSTN)
to refine the offsets provided by the pre-trained optical flow estimation
network. Experimental results on RealVSR and MVSR4 datasets show the
effectiveness and practicality of our method, and we achieve state-of-the-art
performance in real-world VSR task. The dataset and code will be publicly
available
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