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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： Xue Lin Dongsheng Fang Fangfang Li Ke Wang Shandong Provincial Key Laboratory of Network Based Intelligent Computing Jinan China School of Information Science and Engineering University of Jinan Jinan China Institute of Electronics Chinese Academy of Sciences Beijing China University of Chinese Academy of Sciences Beijing China Key Laboratory of Technology in Geo-spatial Information Processing and Application System Chinese Academy of Sciences Beijing China School of Information Science and Engineering Henan University of Technology Zhengzhou China

Nonlocal interferometric phase filtering methods achieve excellent performance in both noise reduction and texture preservation, even in the case of complicated topography and low coherence. The main limitation of the nonlocal methods is the computational burden. This paper proposed a nonlocal phase filtering strategy for the practical InSAR system, which combine the nonlocal algorithm with the traditional method to improve the efficiency.

关键词： Filtering Coherence Noise reduction Frequency estimation Estimation Algorithm design and analysis Surfaces

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Solving online for time-varying pth root via ZD from real domain to complex domain

Solving online for time-varying pth root via ZD from real do...

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International Conference on information Science and Technology (ICIST)

作者： Yunong Zhang Deyang Zhang Zhengli Xiao Hongzhou Tan Zhen Li Key Laboratory of Autonomous System and Networked Control Ministry of Education Guangzhou China SYSU-CMU Shunde International Joint Research Institute Shunde China School of Information Science and Technology Sun Yat-sen University Guangzhou China

In this paper, continuous-time Zhang dynamics (CTZD) models and discrete-time Zhang dynamics (DTZD) models are proposed to solve in real time for the time-varying pth root, from real domain to complex domain. In addition, the convergence properties of the proposed Zhang dynamics (ZD) models are discussed and proved. Furthermore, exploiting different parameters in the proposed ZD models is investigated in order to achieve superior convergence and better accuracy. Computer-simulation and experiment results further substantiate the efficacy of the proposed ZD models. Moreover, the superiority of DTZD models is verified by comparing with Newton-Raphson iteration (NRI).

关键词： Computational modeling Polynomials Force Lead Convergence Logic gates

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HairDiffusion: Vivid Multi-Colored Hair Editing via Latent Diffusion

arXiv

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arXiv 2024年

作者： Zeng, Yu Zhang, Yang Liu, Jiachen Shen, Linlin Deng, Kaijun He, Weizhao Wang, Jinbao Computer Vision Institute School of Computer Science & Software Engineering Shenzhen University China Shenzhen Institute of Artificial Intelligence and Robotics for Society China National Engineering Laboratory for Big Data System Computing Technology Shenzhen University China Guangdong Provincial Key Laboratory of Intelligent Information Processing China

Hair editing is a critical image synthesis task that aims to edit hair color and hairstyle using text descriptions or reference images, while preserving irrelevant attributes (e.g., identity, background, cloth). Many existing methods are based on StyleGAN to address this task. However, due to the limited spatial distribution of StyleGAN, it struggles with multiple hair color editing and facial preservation. Considering the advancements in diffusion models, we utilize Latent Diffusion Models (LDMs) for hairstyle editing. Our approach introduces Multi-stage Hairstyle Blend (MHB), effectively separating control of hair color and hairstyle in diffusion latent space. Additionally, we train a warping module to align the hair color with the target region. To further enhance multi-color hairstyle editing, we fine-tuned a CLIP model using a multi-color hairstyle dataset. Our method not only tackles the complexity of multi-color hairstyles but also addresses the challenge of preserving original colors during diffusion editing. Extensive experiments showcase the superiority of our method in editing multi-color hairstyles while preserving facial attributes given textual descriptions and reference images. © 2024, CC BY.

关键词： Color image processing

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Learning from pseudo lesion: A self-supervised framework for covid-19 diagnosis

arXiv

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arXiv 2021年

作者： Li, Zhongliang Jin, Zhihao Li, Xuechen Shen, Linlin Computer Vision Institute College of Computer Science and Software Engineering Shenzhen University Shenzhen518060 China National Engineering Laboratory for Big Data System Computing Technology Shenzhen University Shenzhen518060 China Guangdong Key Laboratory of Intelligent Information Processing Shenzhen University Shenzhen518060 China

The Coronavirus disease 2019 (COVID-19) has rapidly spread all over the world since its first report in December 2019 and thoracic computed tomography (CT) has become one of the main tools for its diagnosis. In recent years, deep learning-based approaches have shown impressive performance in myriad image recognition tasks. However, they usually require a large number of annotated data for training. Inspired by Ground Glass Opacity (GGO), a common finding in COIVD-19 patient's CT scans, we proposed in this paper a novel self-supervised pretraining method based on pseudo lesions generation and restoration for COVID-19 diagnosis. We used Perlin noise, a gradient noise based mathematical model, to generate lesion-like patterns, which were then randomly pasted to the lung regions of normal CT images to generate pseudo COVID-19 images. The pairs of normal and pseudo COVID-19 images were then used to train an encoder-decoder architecture based U-Net for image restoration, which does not require any labelled data. The pretrained encoder was then fine-tuned using labelled data for COVID-19 diagnosis task. Two public COVID- 19 diagnosis datasets made up of CT images were employed for evaluation. Comprehensive experimental results demonstrated that the proposed self-supervised learning approach could extract better feature representation for COVID-19 diagnosis and the accuracy of the proposed method outperformed the supervised model pretrained on large scale images by 6.57% and 3.03% on SARS-CoV-2 dataset and Jinan COVID-19 dataset, respectively. © 2021, CC BY-NC-SA.

关键词： Coronavirus

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ZG control for 2-output tracking of 3-input nonlinear system with GD used additionally twice more

ZG control for 2-output tracking of 3-input nonlinear system...

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International Conference on information and Automation (ICIA)

作者： Yunong Zhang Ming Liu Yinyan Zhang Zeqi Chen Hongzhou Tan Key Laboratory of Autonomous System and Networked Control Ministry of Education Guangzhou China SYSU-CMU Shunde International Joint Research Institute Shunde China School of Information Science and Technology Sun Yat-sen University Guangzhou China

ISBN: (纸本)9781467391054

In this paper, the Zhang-gradient (ZG) method, which is a combination of Zhang dynamics (ZD) and gradient dynamics (GD) methods, is proposed for solving the tracking control problem of the multiple-input multiple-output (MIMO) system. Different from the traditional ZG method, GD is used additionally twice more in this paper to get through the derivation procedure. Moreover, each GD parameter is tunable for each GD design formula instead of being traditionally assigned the same value, which is the key point in this research for making simulations successful. Besides, simulation verifications further illustrate that the proposed controller group based on the ZG method achieves not only satisfactory tracking accuracy but also rapid tracking rate.

关键词： Trajectory Nonlinear systems MIMO Accuracy Automation Linear systems

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KLT-Based Estimation of Equivalent Channels in 5G MIMO systems

KLT-Based Estimation of Equivalent Channels in 5G MIMO Syste...

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International Conference on Computer and Communications (ICCC)

作者： Zexuan Yang Yinsheng Liu School of Electronic and Information Engineering Beijing Jiaotong University Beijing China State Key Laboratory of Rail Traffic Control and Safety Frontiers Science Center for Smart High-speed Railway System Beijing Jiaotong University Beijing China

To enable large number of antennas in massive multi-input multi-output (MIMO) systems, demodulation reference signal (DM-RS) has been widely used for accurate channel estimation in mobile systems. As DM-RS and data symbols go through the same precoding matrix before sent to channel, channel estimation based on DM-RS is actually conducted with respect to an equivalent channel, which is a combination of the precoding matrix and the physical channel. As a consequence, channel estimation has to be conducted within the frequency range of one precoding resource group (PRG), because a different precoding matrix may be used for neighbouring PRGs. In this paper, by observing that the channel frequency responses in different PRGs can share the same bases, a Karhunen-Loève Transform (KLT) based channel estimation approach is proposed. Using this approach, received signals from adjacent PRGs can be exploited to improve the quality of channel estimation for the PRG of interest. Simulation results show that the channel estimation mean square error (MSE) of our method is better than that of the Toeplitz correction by more than 3dB. Moreover, by adopting this novel channel estimation approach, the performance of symbol error ratio (SER) is close that using ideal channel estimation results.

关键词： Precoding Simulation Noise reduction Channel estimation Symbols Transforms Mean square error methods

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Plasmonic and photonic enhancement of chiral near fields

arXiv

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arXiv 2022年

作者： Hu, Li Sun, Zhiguang Nie, Yingdong Huang, Yingzhou Fang, Yurui Chongqing Engineering Laboratory for Detection Control and Integrated System School of Computer Science and Information Engineering Chongqing Technology and Business University Chongqing400067 China School of Physics Dalian University of Technology Dalian116024 China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing Key Laboratory of Soft Condensed Matter Physics and Smart Materials College of Physics Chongqing University Chongqing400044 China

A chiral near field with a highly contorted electromagnetic field builds a bridge to match the chiral molecules and light wavelengths with large size differences. It significantly enhances the circular dichroism of chiral molecules and has great prospects in chirality sensing, detection, trapping, and other chirality-related applications. Surface plasmons feature outstanding light-trapping and electromagnetic-field-concentrating abilities. Plasmonic chiral nanostructures facilitate light manipulation to generate superchiral near fields. Meanwhile, the nanophotonic structures have attracted significant interest to obtain strong chiral fields due to their unique electromagnetic resonant properties. During the interaction of light and chiral materials, the chiral near field not only bridges the light and chiral molecules but is also responsible for the optical activities. This paper reviews state-of-the-art studies on chiral near field enhancement using plasmonic and photonic nanostructures. We review the principle of chiral electromagnetic fields and the development of plasmonic and photonic nanostructures for near field enhancement. The properties and applications of enhanced chiral near fields for chiral molecule detection, spin-orbit angular interaction, and the generation of the chiral optical force are examined. Finally, we discuss current challenges and provide a brief outlook of this field. Copyright © 2022, The Authors. All rights reserved.

关键词： Dichroism

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Dynamic Passenger Demands Oriented Optimization of Virtually Coupled Train Formation Scheduling

Dynamic Passenger Demands Oriented Optimization of Virtually...

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Chinese Automation Congress (CAC)

作者： Haobei Zhang Tao Tang Hongjie Liu Yinghui Lang School of Electronics and Information Engineering Beijing Jiaotong University Beijing China State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China National Engineering Research Center of Rail Transportation Operation and Control System Beijing Jiaotong University Beijing China

The research on virtual coupling technology in metros is a hot topic recently. Intelligent automatic train units can flexibly form virtually coupled train formations (VCTFs) when needed, so that the train capacity would be able to adapt to passenger demands, which are changing dynamically with time and space. However, matching the capacity of trains with passenger demands is a difficult decision-making optimization problem. In this work, we propose a collaborative control problem to decide when and how to create a VCTF to meet the dynamic passenger demands in a metro system. A mathematical model is formulated which can simultaneously optimize the number of related train units in a VCTF, the train dwelling time at a station and the running time in a section. Performance indicators such as train load factor and number of stranded passengers are adopted to measure the satisfaction of the operators and passengers. Then, a multi-objective genetic algorithm is adopted to obtain the Pareto optimum solutions. Finally, simulation experiments are conducted, and the relationship between line efficiency and passenger demand in different discrete time periods is analyzed to verify the correctness and feasibility of the model. Compared with the traditional timetabling method, adopting the virtual coupling technology can better adapt the train capacity to meet the time changing passenger demands, which is welcomed by both metro operators and passengers in reality.

关键词： Couplings Road transportation Rails Adaptation models Analytical models Dynamic scheduling Vehicle dynamics

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An Improved Lmmse Channel Estimation Algorithm for Mimo-Ofdm system

SSRN

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SSRN 2022年

作者： Tang, Wanwei Wang, Lixia Wang, Zedai Wei, Mingzhe Zhao, Jinlong Yue, Xinwei The Key Laboratory of Intelligent Data Information Processing and Control of Hebei Province Tangshan University Tangshan063000 China The School of Engineering Hong Kong University of Science and Technology 999077 Hong Kong The School of Electronic and Information Engineering Beihang University Beijing100191 China The School of Information and Communication Engineering Beijing Information Science and Technology University Beijing100101 China

This paper studies channel estimation techniques to recover the received signal more accurately and quickly. The classical Least Squares (LS) and Linear Minimum Mean-squared Error (LMMSE) estimation have the problems of poor estimation performance and high complexity. An Fast-LMMSE channel estimation algorithm is proposed to balance the performance and complexity. In order to apply it to the actual system, the corresponding pilot is also designed. Simulation results are provided and the comparison shows the performance gains achieved by the proposed technique over LS and MMSE estimation in SISO and MIMO communication systems. © 2022, The Authors. All rights reserved.

关键词： Channel estimation

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A Space-Time Interval Based Protection Method for Virtual Coupling

A Space-Time Interval Based Protection Method for Virtual Co...

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Chinese Automation Congress (CAC)

作者： Jiayu Wang Hongjie Liu Tao Tang Xiaolin Luo Ming Chai School of Electronics and Information Engineering Beijing Jiaotong University Beijing China National Engineering Research Centerof Rail Transportation Operation and Control System Beijing Jiaotong University Beijing China State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China

As a recent hot topic in railways, Virtual Coupling (VC) is aimed at providing more frequent rail services by operating trains closer. Given that current protection methods cannot fulfill the requirements of VC in terms of safety and efficiency, the implementation of VC urgently calls for an advanced protection method that allows successive trains to drive closer on the premise of safety. Therefore, to improve efficiency, after the force analysis of the train, a train emergency braking model that can describe the real process of emergency braking is proposed. The train emergency braking distance calculated from this model is smaller compared with the traditional train emergency braking model. Then, to ensure train safety, the deficiencies of the existing relative braking distance(RBD) based protection methods are analyzed. After adding constraints of time and space to the train emergency braking process and using the train emergency braking model proposed in this paper, a space-time interval based protection method is proposed. Compared with the RBD protection method, this method can ensure that the trains can track closer under the premise of safety, which can fulfill the requirements of VC. Finally, experiments are conducted to verify the safety and efficiency of the proposed methods. When the braking performance of the preceding train is worse than that of the following train, the space-time interval based protection method avoids the train colliding during the braking process, while RBD based protection method cannot avoid train collision. Experimental results numerically show that the minimum safe distance can be reduced by 29%, compared with the RBD based protection method.

关键词： Couplings Resistance Rails Force Rail transportation Safety Trajectory

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