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arXiv 2023年

作者： Fan, Xilai Liu, Ya-Feng Liu, Liang Chang, Tsung-Hui State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing100190 China Department of Electronic and Information Engineering The Hong Kong Polytechnic University Hong Kong School of Science and Engineering The Chinese University of Hong Kong Shenzhen Research Institute of Big Data Shenzhen Shenzhen China

This paper considers the quality-of-service (QoS)based joint beamforming and compression design problem in the downlink cooperative cellular network, where multiple relay-like base stations (BSs), connected to the central processor via rate-limited fronthaul links, cooperatively transmit messages to the users. The problem of interest is formulated as the minimization of the total transmit power of the BSs, subject to all users’ signal-to-interference-plus-noise ratio (SINR) constraints and all BSs’ fronthaul rate constraints. In this paper, we first show that there is no duality gap between the considered joint optimization problem and its Lagrangian dual by showing the tightness of its semidefinite relaxation (SDR). Then, we propose an efficient algorithm based on the above duality result for solving the considered problem. The proposed algorithm judiciously exploits the special structure of an enhanced Karush-Kuhn-Tucker (KKT) conditions of the considered problem and finds the solution that satisfies the enhanced KKT conditions via two fixed point iterations. Two key features of the proposed algorithm are: (1) it is able to detect whether the considered problem is feasible or not and find its globally optimal solution when it is feasible;(2) it is highly efficient because both of the fixed point iterations in the proposed algorithm are linearly convergent and evaluating the functions in the fixed point iterations are computationally cheap. Numerical results show the global optimality and efficiency of the proposed algorithm. Copyright © 2023, The Authors. All rights reserved.

关键词： Quality of service

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A Design and Implementation of Underwater Wireless Optical Communication System 6

A Design and Implementation of Underwater Wireless Optical C...

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6th IEEE International Conference on Electronic Information and Communication Technology, ICEICT 2023

作者： Zhang, Luxian Fu, Min Li, Boxun Sun, Mengnan Li, Xinguang Qu, Junqi Ocean University of China Department of Information Science and Engineering Qingdao China Ocean University of China College of Electronic Engineering Sanya Oceanographic Institution Qingdao China Ocean University of China College of Electronic Engineering Oceanographic Institution Qingdao China China Ship Scientific Research Center Taihu Laboratory of Deepsea Technological Science State Key Laboratory of Deep-sea Manned Vehicles Wuxi China

ISBN: (纸本)9798350399059

With extremely high information rate, great data transmission capability, and strong anti-interference, underwater wireless optical communication (UWOC) becomes a promising short-range solution for various marine sensors and types of equipment. Related key technologies are discussed in this paper, and a laser diode (LD) and an avalanche photon diode (APD) are selected as light source and receiver. The 450 nm light beam will be generated, and modulated using orthogonal frequency division multiplex (OFDM) for its adaptive ability and resistance to multipath effect. Therefore, a Qualcomm QCA6410 chip with OFDM module is chosen as core processor. Furthermore, a constant current driver circuit, a TPS55340-based negative bias generator with temperature compensation, and a trans-impedance amplifier (TIA)-based post-stage signal processing unit are designed to steadily drive the LD, provide the high voltage leading to the avalanche effect of the APD and generate differential signals that can be received by the chip, respectively. Finally, a full-duplex UWOC system is implemented and tested in a one-meter-long water tank under several water conditions. Results show that a stable data link will be connected with water attenuation coefficient of less than 1.58 m-1, and an average data rate of 6.6 Mbits/s ∼ 10 Mbits/s can be achieved. © 2023 IEEE.

关键词： Water tanks

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Yellow–green–blue triple-wavelength laser for an oceanic lidar: optimizing penetration depth from inshore to open ocean water

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Applied Optics 2025年第17期64卷 4917-4921页

作者： Hongda Wu Mingzhu Yuan Junyang Dong Feitong Chen Miao Hu Liying Chen Jian Chen Bingfeng Ju Dong Liu Chong Liu State Key Laboratory of Extreme Photonics and Instrumentation College of Optical Science and EngineeringZhejiang University Hangzhou 310027 China ZJU-Hangzhou Global Scientific and Technological Innovation Center Hangzhou 311215 China College of Communication Engineering Hangzhou Dianzi University Hangzhou 310000 China State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical Engineering Zhejiang University Hangzhou 310027 China

We have demonstrated a yellow–green–blue triple-wavelength pulsed laser based on a parallel frequency-doubled optical parametric oscillator. Pumped by a 532.2 nm pulsed laser, the potassium titanyl phosphate crystal-based optical parametric oscillator generated a signal laser at 972 nm and an idler laser at 1176 nm. After two parallel second harmonic generators, the signal laser and the idler laser were simultaneously frequency-doubled to a 486 nm blue laser and a 588 nm yellow laser, corresponding to the optimal penetration wavelengths for open ocean and inshore water, respectively. The maximum single pulse energy and pulse width of the blue laser were 14.93 mJ and 5.12 ns, and the maximum single pulse energy and pulse width of the yellow laser were 10.75 mJ and 3.18 ns. In addition, the pulse energy and pulse width of the green laser were 65.8 mJ and 5.28 ns. This triple-wavelength pulsed laser has the potential to be used to enhance the penetration depth of oceanic lidar from inshore to open ocean water.

关键词： Barium borate Green lasers Nonlinear frequency conversion Optical frequency conversion Potassium titanyl phosphate Remote sensing

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Angle-resolved magneto-chiral anisotropy in a non-centrosymmetric atomic layer superlattice

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Science Bulletin 2025年第9期70卷 1406-1409页

作者： Cheng, Long Bao, Mingrui Zhang, Xue Zhang, Jingxian Yang, Qun Li, Qiang Cao, Hui Qiu, Dawei Li, Hui Cheng, Guanglei Zhou, Hua Zuo, Jian-Min Zhou, Xiaodong Shen, Jian Zhu, Zhifeng Wang, Wenbo Zhai, Xiaofang School of Physical Science and Technology ShanghaiTech University Shanghai201210 China CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences University of Science and Technology of China Hefei230026 China School of Information Science and Technology ShanghaiTech University Shanghai201210 China State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing Fudan University Shanghai200433 China X-ray Science Division Advanced Photon Source Argonne National Laboratory LemontIL60439 United States Institutes of Physical Science and Information Technology Anhui University Hefei230601 China Department of Materials Science and Engineering and Materials Research Laboratory University of Illinois Urbana–Champaign UrbanaIL61801 United States ShanghaiTech Laboratory for Topological Physics ShanghaiTech University Shanghai201210 China

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The Convergence Properties of Infeasible Inexact Proximal Alternating Linearized Minimization

arXiv

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arXiv 2022年

作者： Hu, Yukuan Liu, Xin State Key Laboratory of Scientific and Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences University of Chinese Academy of Sciences China

The proximal alternating linearized minimization method (PALM) suits well for solving blockstructured optimization problems, which are ubiquitous in real applications. In the cases where subproblems do not have closed-form solutions, e.g., due to complex constraints, infeasible subsolvers are indispensable, giving rise to an infeasible inexact PALM (PALM-I). Numerous efforts have been devoted to analyzing feasible PALM, while little attention has been paid to PALM-I. The usage of PALM-I thus lacks theoretical guarantee. The essential difficulty of analyses consists in the objective value nonmonotonicity induced by the infeasibility. We study in the present work the convergence properties of PALM-I. In particular, we construct a surrogate sequence to surmount the nonmonotonicity issue and devise an implementable inexact criterion. Based upon these, we manage to establish the stationarity of any accumulation point and, moreover, show the iterate convergence and the asymptotic convergence rates under the assumption of the Lojasiewicz property. The prominent advantages of PALM-I on CPU time are illustrated via numerical experiments on problems arising from quantum physics and 3D anisotropic frictional *** Codes 49M27, 65K05, 90C26, 90C30 © 2022, CC BY.

关键词： Linearization

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A Variance-Reduced Stochastic Gradient Tracking Algorithm for Decentralized Optimization with Orthogonality Constraints

arXiv

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arXiv 2022年

作者： Wang, Lei Liu, Xin State Key Laboratory of Scientific and Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences University of Chinese Academy of Sciences China

Decentralized optimization with orthogonality constraints is found widely in scientific computing and data science. Since the orthogonality constraints are nonconvex, it is quite challenging to design efficient algorithms. Existing approaches leverage the geometric tools from Riemannian optimization to solve this problem at the cost of high sample and communication complexities. To relieve this difficulty, based on two novel techniques that can waive the orthogonality constraints, we propose a variance-reduced stochastic gradient tracking (VRSGT) algorithm with the convergence rate of O(1/k) to a stationary point. To the best of our knowledge, VRSGT is the first algorithm for decentralized optimization with orthogonality constraints that reduces both sampling and communication complexities simultaneously. In the numerical experiments, VRSGT has a promising performance in a real-world autonomous driving application. Copyright © 2022, The Authors. All rights reserved.

关键词： Stochastic systems

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Super-Resolution of Diffusion-Weighted Images via TDI-Conditioned Diffusion Model 15th

Super-Resolution of Diffusion-Weighted Images via TDI-Cond...

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15th International Workshop on Computational Diffusion MRI, CDMRI 2024, held in conjunction with 27th International Conference on Medical Image computing and Computer-Assisted Intervention, MICCAI 2024

作者： Ma, Jiquan Teng, Yujun Chen, Geng Jiang, Haotian Zhang, Kai Liu, Feihong Rekik, Islem Shen, Dinggang School of Computer Science and Technology Heilongjiang University Harbin China National Engineering Laboratory for Integrated Aero-Space-Ground-Ocean Big Data Application Technology School of Computer Science and Engineering Northwestern Polytechnical University Xi’an China School of Biomedical Engineering and State Key Laboratory of Advanced Medical Materials and Devices ShanghaiTech University Shanghai China School of Information Science and Technology Northwest University Xi’an China BASIRA Lab Imperial-X and Department of Computing Imperial College London London United Kingdom

ISBN: (纸本)9783031869198

Diffusion-Weighted Imaging (DWI) is a significant technique for studying white matter. However, it suffers from low-resolution obstacles in clinical settings. Post-acquisition Super-Resolution (SR) can enhance the resolution of DWIs and has gained increasing research interest in recent years. An advanced generative model, the Diffusion Model (DM), exhibits particularly promising performance in image SR. However, effective conditions are required to bootstrap the DM for DWI SR. To this end, we proposed the first DM-based DWI SR model with two effective conditions based on low-solution DWIs and Track Density Imaging (TDI) maps, which possess rich high-resolution prior knowledge Additionally, we consider another condition based on features from low-resolution DWIs. These two conditions are integrated into our model, which comprises three components: DWI Resolution Enhancer (DRE), DWI Feature Extractor (DFE), and TDI Feature Extractor (TFE). DRE combines low-resolution DWI features from DFE with TDI features from TFE to progressively generate high-resolution DWIs. We performed extensive experiments on DWIs of normal subjects from human connectome projects and patients with Parkinson’s disease. The results demonstrate that our model outperforms existing DWI SR models, both qualitatively and quantitatively. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

关键词： Neurodegenerative diseases

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Breakdown of effective-medium theory by a photonic spin Hall effect

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Science China(Physics,Mechanics & Astronomy) 2023年第11期66卷 145-154页

作者： Shuaijie Yuan Xinxing Zhou Yu Chen Yuhan Zhong Lijuan Sheng Hao Hu Hongsheng Chen Ido Kaminer Xiao Lin Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Synergetic Innovation Center for Quantum Effects and ApplicationsSchool of Physics and ElectronicsHunan Normal UniversityChangsha410081China International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology Engineering Technology Research Center for 2D Material Information Function Devices and Systems of Guangdong ProvinceInstitute of Microscale OptoelectronicsShenzhen UniversityShenzhen518060China Interdisciplinary Center for Quantum Information State Key Laboratory of Extreme Photonics and InstrumentationZJU-Hangzhou Global Scientific and Technological Innovation CenterZhejiang UniversityHangzhou310027China International Joint Innovation Center Electromagnetics Academy at Zhejiang UniversityZhejiang UniversityHaining314400China School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore639798Singapore Key Laboratory of Radar Imaging and Microwave Photonics Ministry of EducationCollege of Electronic and Information EngineeringNanjing University of Aeronautics and AstronauticsNanjing211106China Key Laboratory of Advanced Micro/Nano Electronic Devices&Smart Systems of Zhejiang Jinhua Institute of Zhejiang UniversityZhejiang UniversityJinhua321099China Shaoxing Institute of Zhejiang University Zhejiang UniversityShaoxing312000China Department of Electrical Engineering Technion-Israel Institute of TechnologyHaifa32000Israel

Effective-medium theory pertains to the theoretical modelling of homogenization,which aims to replace an inhomogeneous structure of subwavelength-scale constituents with a homogeneous effective *** effective-medium theory is fundamental to various realms,including electromagnetics and material science,since it can largely decrease the complexity in the exploration of light-matter interactions by providing simple acceptable ***,the effective-medium theory is thought to be applicable to any all-dielectric system with deep-subwavelength constituents,under the condition that the effective medium does not have a critical angle,at which the total internal reflection *** we reveal a fundamental breakdown of the effective-medium theory that can be applied in very general conditions:showing it for deep-subwavelength all-dielectric multilayers even without a critical *** finding relies on an exotic photonic spin Hall effect,which is shown to be ultrasensitive to the stacking order of deep-subwavelength dielectric layers,since the spin-orbit interaction of light is dependent on slight phase accumulations during the wave *** results indicate that the photonic spin Hall effect could provide a promising and powerful tool for measuring structural defects for all-dielectric systems even in the extreme nanometer scale.

关键词： photonic spin Hall effect effective-medium theory spin-orbit interaction of light

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The reservoir learning power across quantum many-body localization transition

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Frontiers of physics 2022年第3期17卷 91-99页

作者： Wei Xia Jie Zou Xingze Qiu Xiaopeng Li State Key Laboratory of Surface Physics Institute of Nanoelectronics and Quantum Computingand Department of PhysicsFudan UniversityShanghai 200433China Shenzhen Institute for Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Shanghai Qi Zhi Institute AI TowerXuhui DistrictShanghai 200232China

Harnessing the quantum computation power of the present noisy-intermediate-size-quantum devices has received tremendous interest in the last few years. Here we study the learning power of a one-dimensional long-range randomly-coupled quantum spin chain, within the framework of reservoir computing. In time sequence learning tasks, we find the system in the quantum many-body localized (MBL) phase holds long-term memory, which can be attributed to the emergent local integrals of motion. On the other hand, MBL phase does not provide sufficient nonlinearity in learning highly-nonlinear time sequences, which we show in a parity check task. This is reversed in the quantum ergodic phase, which provides sufficient nonlinearity but compromises memory capacity. In a complex learning task of Mackey–Glass prediction that requires both sufficient memory capacity and nonlinearity, we find optimal learning performance near the MBL-to-ergodic transition. This leads to a guiding principle of quantum reservoir engineering at the edge of quantum ergodicity reaching optimal learning power for generic complex reservoir learning tasks. Our theoretical finding can be tested with near-term NISQ quantum devices.

关键词： quantum reservoir computing many-body localization quantum ergodic edge of quantum ergodicity optimal learning power

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High corrosion-resistant silver nanowire/poly(3,4-ethylene dioxythiophene)/poly(styrene sulfonate)@nickel electrode for transparent electromagnetic shielding film

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Journal of Materiomics 2022年第6期8卷 1191-1198页

作者： Xuyang Zhang Jiaqi Shan Cuilan Liu Zhengliang Li Xingzhong Guo Xiaoyu Zhao Hui Yang State Key Laboratory of Silicon Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou310027China Hangzhou Global Scientific and Technological Innovation Center Zhejiang UniversityHangzhou311200China Zhejiang Hua Display Optoelectronics Co. LtdJiaxing314115China

Silver nanowire(AgNW)has become one of the best candidates for flexible transparent electromagnetic(EMI)shielding materials,while the low corrosion resistance of AgNW hinders its application in environments with high content of corrosive ***,an AgNW/poly(3,4-ethylene dioxythiophene)/poly(styrene sulfonate)(PEDOT:PSS)@nickel electrode was prepared through ultrasonic spray coating and electroplating ***:PSS is sprayed to improve the conductivity of the AgNW network,and a 9.8-16.5 nm Ni layer is deposited on the AgNW/PEDOT:PSS to protect the AgNWs from *** AgNW/PEDOT:PSS@Ni electrode shows a sheet resistance of 29 U·sq^(-1),a transmittance of 78.18%,an average EMI shielding efficiency of 19.64 dB and excellent corrosion resistance in Na2S *** resultant AgNW/PEDOT:PSS@Ni electrode is promisingly used in high corrosion resistance transparent EMI shielding film.

关键词： Silver nanowire poly(3,4-ethylene dioxythiophene)/poly(styrene sulfonate) Nickel Electroplate

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