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Further insight into the convergence of the Fletcher-Reeves method

Science China Mathematics 1999年第9期42卷 905-916页

作者：戴彧虹 1. State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Chinese Academy of Sciences 100080 Beijing China

The convergence properties of the Fletcher-Reeves method for unconstrained optimization are further studied with the technique of generalized line search. Two conditions are given which guarantee the global convergence of the Fletcher-Reeves method using generalized Wolfe line searches or generalized Arjimo line searches, whereas an example is constructed showing that the conditions cannot be relaxed in certain senses.

关键词： unconstrained optimization conjugate gradient Fletcher-Reeves method generalid line search global convergence

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ORT image and IMT-MIMO-ResNet-based multi-mode multi-parameter joint optical performance monitoring in MDM-EON systems

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Optics Express 2025年第10期33卷 20530-20548页

作者： Fan Yang Chenglin Bai Yaozheng Yue Hengying Xu Hao Zhou Wen Zuo Lishan Yang Shunchang Bai Pengfei Li Yaojun Qiao School of Physics Science and Information Engineering Liaocheng University Liaocheng 252000 China The State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications Beijing 100876 China Department of Computing and Information Science Cornell University Ithaca NY 14853 USA qiao@***

This paper presents a novel joint optical performance monitoring (OPM) scheme for multiple spatial modes in mode division multiplexing elastic optical network (MDM-EON) systems, which integrates the optimal Radon transform (ORT) image with the improved multi-task multi-input multi-output residual neural network (IMT-MIMO-ResNet) model. The ORT images effectively enhance the differentiation among various parameters across different spatial modes. Additionally, based on the output characteristics and intrinsic correlations among spatial modes of the MDM-EON system, we design the IMT-MIMO-ResNet model. The proposed scheme overcomes the limitations of existing approaches, where a single OPM device can monitor only one spatial mode. It enables simultaneous monitoring of bit rates (BRs), modulation formats (MFs), mode coupling (MC) intensities, and optical signal-to-noise ratio (OSNR) values for each MF across five spatial modes. Moreover, the scheme demonstrates favorable robustness under conditions with large chromatic dispersion, large differential group delay, and strong fiber nonlinear effects. Both simulation and experimental results show that the accuracy of baud rate identification (BRI) and modulation format identification (MFI) for each spatial mode reaches 100%, and the average mean absolute errors (MAEs) for OSNR values and MC intensities corresponding to each MF are below 0.4 dB and 0.010, respectively. The computational complexity of the proposed scheme, evaluated using floating-point operations (FLOPs) and parameters (Params), is approximately 1/7 of that required by a typical OPM scheme.

关键词： Image enhancement Mode division multiplexing Neural networks Optical network architecture Optical networks Signal processing

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Blockchain-Enabled Secure, Fair and Scalable Data Sharing in Zero-Trust Edge-End Environment

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IEEE Journal on Selected Areas in Communications 2025年

作者： Xu, Xiaolong Meng, Ke Xiang, Haolong Cui, Guangming Xia, Xiaoyu Dou, Wanchun Nanjing210044 China Nanjing University of Information Science and Technology School of Software and the Jiangsu Province Engineering Research Center of Advanced Computing and Intelligent Services Nanjing210044 China RMIT University School of Computing Technologies MelbourneVIC3000 Australia Nanjing University State Key Laboratory for Novel Software Technology Nanjing210023 China

In edge computing, the Zero-Trust Security Model (ZTSM), as a key enabling technology for next-generation networks, plays a crucial role in providing authentication for addressing data sharing concerns, such as frequent data breaches, data misuse, and cyberattacks. However, due to the complexity and diversity of edge environments, ZTSM struggles to meet the security requirements of data sharing frameworks solely through enhanced authentication. Consequently, such frameworks with ZTSM still face challenges in ensuring data integrity, evaluating various node behaviors, and coping with the increasing complexity of node attributes. To address these issues, we propose a blockchain-enabled secure, fair and scalable data sharing framework in a zero-trust edge-end environment in this paper. Specifically, we first propose a Merkle forest-based data storage model for the classified storage of loosely coupled data, consequently enhancing the scalability of the model. Then, we design a node behavior-based reputation assessment mechanism to ensure fairness during data sharing. Moreover, a data sharing protocol supervised by smart contract is proposed, working with the aforementioned storage and assessment schemes, to ensure the security of data sharing. Finally, comprehensive security analysis validates the security, fairness and scalability of the proposed framework. Extensive experimental results show that, as transaction volume grows, the time cost of data traversal in the storage model becomes progressively more efficient. Additionally, when the size of the smart contract is increased tenfold, the maximum time cost of the data sharing protocol rises by only 4.98 times. © 1983-2012 IEEE.

关键词： Data integrity

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THE RELAXING SCHEMES FOR HAMILTON-JACOBI EQUATIONS

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计算数学(英文版) 2001年第3期19卷 231-240页

作者： Hua-zhong Tang Hua-zhong Tang Hua-mu Wu State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and Systems SciencesChinese Academy of Sciences Beijing 100080 China School of Mathematical Sciences Peking University Beijing 100871 China State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and Systems SciencesChinese Academy of Sciences Beijing 100080 China

Hamilton-Jacobiequation appears frequently in applications, e.g., in differential games and control theory, and is closely related to hyperbolic conservation laws[3, 4, 12]. This is helpful in the design of difference approximations for Hamilton-Jacobi equation and hyperbolic conservation laws. In this paper we present the relaxing system for HamiltonJacobiequations in arbitrary space dimensions, and high resolution relaxing schemes for Hamilton-Jacobi equation, based on using the local relaxation approximation. The schemes are numerically tested on a variety of 1D and 2D problems, including a problem related to optimal control problem. High-order accuracy in smooth regions, good resolution of discontinuities, and convergence to viscosity solutions are observed.

关键词： The relaxing scheme The relaxing systems Hamilton-Jacobi equation Hyperbolic conservation laws.

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Visual Class Incremental Learning with Textual Priors Guidance based on an Adapted Vision-Language Model

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IEEE Transactions on Multimedia 2025年

作者： Zhang, Wentao Yu, Tong Wang, Ruixuan Xie, Jianhui Trucco, Emanuele Zheng, Wei-Shi Yang, Xiaobo Sun Yat-sen Univerisity School of Computer Science and Engineering Guangzhou510275 China Peng Cheng Laboratory Shenzhen518066 China MOE Key Laboratory of Machine Intelligence and Advanced Computing Guangzhou510275 China Second Affiliated Hospital Guangzhou University of Chinese Medicine State Key Laboratory of Dampness Syndrome of Chinese Medicine Guangzhou510260 China Guangdong Provincial Key Laboratory of Clinical Research on Traditional Chinese Medicine Syndrome Guangzhou510120 China University of Dundee School of Science and Engineering DundeeDD1 4HN United Kingdom

An ideal artificial intelligence (AI) system should have the capability to continually learn like humans. However, when learning new knowledge, AI systems often suffer from catastrophic forgetting of old knowledge. Although many continual learning methods have been proposed, they often ignore the issue of misclassifying similar classes and make insufficient use of textual priors of visual classes to improve continual learning performance. In this study, we propose a continual learning framework based on a pre-trained vision-language model (VLM) that does not require storing old class data. This framework utilizes parameter-efficient fine-tuning of the VLM's text encoder for constructing a shared and consistent semantic textual space throughout the continual learning process. The textual priors of visual classes are encoded by the adapted VLM's text encoder to generate discriminative semantic representations, which are then used to guide the learning of visual classes. Additionally, fake out-of-distribution (OOD) images constructed from each training image further assist in the learning of visual classes. Extensive empirical evaluations on three natural datasets and one medical dataset demonstrate the superiority of the proposed framework. The source code is available at https://***/OpenMedIA/CIL_Adapterd_VLM. © 1999-2012 IEEE.

关键词： Contrastive Learning

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A Satellite-Ground Link Handover Strategy in LEO Networks Using Advantage Actor-Critic Algorithm 20th

A Satellite-Ground Link Handover Strategy in LEO Networks U...

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20th IFIP WG 10.3 International Conference on Network and Parallel computing, NPC 2024

作者： Chen, Chen Tong, Chenqiang Cong, Li Wang, Zhiyi Jin, Fan Zhou, Xiaobo Pei, Qingqi School of Telecommunication Engineering Xidian University Xi’an710071 China Xidian Guangzhou Institute of Technology Xidian University Guangzhou China Xidian Hangzhou Institute of Technology Xidian University Hangzhou China The State Grid Jilin Province Electric Power Company Changchun130000 China National Key Laboratory of Science and Technology on Space Microwave CAST Xi’an710100 China College of Intelligence and Computing Tianjin University Tianjin300350 China

ISBN: (纸本)9789819628636

Low Earth Orbit (LEO) satellite network is a crucial component of the Space-Air-Ground Integrated Network (SAGIN) architecture and Non-Terrestrial Networks (NTN). It can provide global, real-time, and seamless broadband data services to many users, playing a critical role in emergencies such as disaster relief. This paper proposes an LEO satellite networks satellite-ground link handover strategy based on Advantage Actor-Critic (A2C) to tackle challenges associated with high handover frequency among ground users, data transmission blocking, and access selection post-handover due to the high-speed cyclic motion of satellites. The strategy considers three handover factors: signal reception strength, satellite potential service time, and service quality. At first, the handover problem is modeled as a combinatorial optimization problem, subsequently transformed into a Markovian Action-Value Function (MAVF) based Multi-Agent Markov Decision Process (MAMDP), and solved in the framework of the A2C algorithm proposed in this paper. The results of simulations illustrate the superior performance of the proposed handover strategy compared to three alternative strategies, namely, Random Handover (RH), Maximum number of Free Channels (MFC), and Maximum Service Time (MST), in terms of both convergence and practicality. The average number of handover occurrences can be reduced by up to 58%, consequently lowering the probability of blocking data transmission. Moreover, signal quality exhibits more excellent stability and can be enhanced by up to 39%, thereby ensuring user communication quality. © IFIP International Federation for Information Processing 2025.

关键词： Markov processes

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SHOCK FORMATION FOR THE 2D ROTATING SHALLOW WATER EQUATIONS WITH NON-ZERO VORTICITY

arXiv

引用

arXiv 2025年

作者： Chen, Zhendong Xie, Chunjing School of Mathematical Sciences Institute of Natural Sciences Shanghai Jiao Tong University Shanghai200240 China School of Mathematical Sciences Institute of Natural Sciences Ministry of Education Key Laboratory of Scientific and Engineering Computing CMA-Shanghai Shanghai Jiao Tong University Shanghai200240 China

In the paper, the shock formation for the two-dimensional rotating shallow water system is established. We construct a large class of initial data which leads to the finite-time blow-up for the solutions. Moreover, the solutions are allowed to have non-zero large vorticity (in derivative sense), even up to the shock. Our results provide the first complete geometric description of the shock formation mechanism to the two-dimensional rotating shallow water system with vorticity. The formation of shock is characterized by the collapse of the characteristic hypersurfaces, where the first-order derivatives of the velocity, the height, and the specific vorticity blow up while the potential vorticity remains Lipschitz continuous. The methods developed in this paper should also be useful in studying the shock formation for the Euler equations with various source terms and a class of quasilinear Klein-Gordon equations in multi-dimensions. Copyright © 2025, The Authors. All rights reserved.

关键词： Euler equations

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Towards Depth-continuous Scene Representation with Displacement Field for Robust Light Field Depth Estimation

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IEEE Transactions on Multimedia 2025年

作者： Chen, Rongshan Sheng, Hao Yang, Da Cong, Ruixuan Cui, Zhenglong Wang, Sizhe Wang, Tun Zhao, Mingyuan Beihang University State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and Engineering Beijing100191 China Beihang University Key Laboratory of Data Science and Intelligent Computing International Innovation Institute 166 Shuanghongqiao Street Pingyao Town Yuhang District Hangzhou31 1115 China Macao Polytechnic University Faculty of Applied Sciences Macao999078 China

The light field (LF) captures both the spatial and angular information of scenes, enabling accurate depth estimation. However, previous deep learning methods typically model surface depth only while ignoring the continuous nature of depth in 3D scenes. In this paper, we use the displacement field (DF) to describe this continuous property, and propose a novel depth-continuous scene representation for robust LF depth estimation. Experiments demonstrate that our representation enables the network to generate highly detailed depth maps with fewer parameters and faster speeds. Specifically, inspired by the signed distance field in 3D object descriptions, we aim to exploit the intrinsic depth-continuous property of 3D scenes via DF and define a novel depth-continuous scene representation. Then, we introduce a simple, yet general, learning framework for depth-continuous scene embedding, and the proposed network, DepthDF, achieves state-of-the-art performance on both synthetic and real-world LF datasets, ranking 1st on the HCI 4D light field benchmark. Furthermore, previous LF depth estimation methods can also be seamlessly integrated into this framework. Finally, we extend this framework beyond LF depth estimation to various tasks, including multiview stereo depth inference, LF superresolution, and LF salient object detection. Our experiments demonstrate an improved performance when continuous scene representation is applied, suggesting that our framework can potentially provide insights for more fields. © 1999-2012 IEEE.

关键词： Stereo image processing

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Dynamic mode control and beam quality improvement of Laguerre–Gaussian beams in a laser amplifier

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Applied Optics 2025年第15期64卷 4366-4372页

作者： Jingsong Qu Lanyulin Li Xiaoyan Qiu Yuhong Shen Junyang Dong Bin Liu Liying Chen Chong Liu State Key Laboratory of Extreme Photonics and Instrumentation College of Optical Science and Engineering Zhejiang University Hangzhou 310027 China ZJU-Hangzhou Global Scientific and Technological Innovation Center Zhejiang University Hangzhou 311215 China Changzhou Inno Laser Technology Corporation Limited Changzhou 213164 China

High-power lasers with specially modified intensity distributions are constrained by thermally induced aberrations in solid-state amplifiers. This paper introduces a novel, to the best of our knowledge, precompensation architecture for thermal aberrations based on a spatial light modulator (SLM). For the first time, the SLM is employed both as a dynamic mode generator and as a phase compensation element. By employing a dual 4f imaging system and controlling the propagation, a precise mapping is established between the modulation and measurement planes, enabling aberration correction without relying on complex feedback algorithms. The proposed architecture effectively suppresses thermal aberration-induced degradation of the ${{\rm M}^2}$ factor while safeguarding the SLM from high-power damage in a master oscillator power amplifier system for Laguerre–Gaussian beams. Experimental results demonstrate a 15 times single-pass gain while maintaining the ${{\rm M}^2}$ factor consistent with its pre-amplification value.

关键词： Aberration correction High power lasers Laser amplifiers Laser beams Phase compensation Spatial light modulators

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Non-binary entanglement-assisted quantum stabilizer codes

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Science China(Information Sciences) 2017年第4期60卷 210-223页

作者： Lan LUO Zhi MA Zhengchao WEI Riguang LENG State Key Laboratory of Mathematical Engineering and Advanced Computing

In this paper, we present the pm-ary entanglement-assisted(EA) stabilizer formalism, where p is a prime and m is a positive integer. Given an arbitrary non-abelian "stabilizer", the problem of code construction and encoding is settled perfectly in the case of m = 1. The optimal number of required maximally entangled pairs is discussed and an algorithm to determine the encoding and decoding circuits is proposed. We also generalize several bounds on p-ary EA stabilizer codes, such as the BCH bound, the G-V bound and the linear programming bound. However, the issue becomes tricky when it comes to m > 1, in which case, the former construction method applies only when the non-commuting "stabilizer" satisfies a sophisticated limitation.

关键词： entanglement non-commutativity non-binary stabilizer codes quantum error-correction quantum circuits bounds

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