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A Decoupling-Type Strategy for the Allen-Cahn Equation on Curved Surfaces

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Journal of Mathematical Research with Applications 2025年第1期45卷 73-83页

作者： Xiaoman XIE Qing PAN School of Computer and communication Engineering Changsha University of Science & Technology

In this paper, we construct an efficient decoupling-type strategy for solving the Allen-Cahn equation on curved surfaces. It is based on an FEM-EIEQ(Finite Element Method and explicit-Invariant Energy Quadratization) fully discrete scheme with unconditional energy stability. Spatially the FEM is adopted, using a triangular mesh discretization strategy that can be adapted to complex regions. Temporally, the EIEQ approach is considered, which not only linearizes the nonlinear potential but also gives a new variable that we combine with the nonlocal splitting method to achieve the fully decoupled computation. The strategy can successfully transform the Allen-Cahn system into some completely independent algebraic equations and linear elliptic equations with constant coefficients, we only need to solve these simple equations at each time step. Moreover, we conducted some numerical experiments to demonstrate the effectiveness of the strategy.

关键词： FEM-EIEQ Allen-Cahn equation surface

Investigation on optical sinc-shaped Nyquist pulse generation based on external modulation

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Optoelectronics Letters 2025年

作者： YUAN Jin XU Xiuxiu State Key Laboratory of Media Convergence and communication， communication University of China

In this paper， a scheme for generating sinc-shaped optical Nyquist pulses based on external modulation is proposed. First， five flat optical frequency comb (OFC) lines are generated by a dual-parallel Mach-Zehnder modulator (DP-MZM) for optical carrier phase cancellation interference. Then， the phase-locked OFC is split into two paths， one of which is transmitted to a single-drive Mach-Zehnder modulator (SD-MZM) for the modulation of the even-order side-band suppression， and the other is used to remodulate the signal in order to obtain equally spaced comb lines. Eventually， equal frequency spaced phase-locked 15-line OFCs are generated and extremely narrow over-zero width Nyquist pulses are realized at 2.5GHz， 5GHz， 10GHz and 20GHz. The root-mean-square error (RMSE) is calculated for the generated Nyquist pulses which enables the verification of the signal quality.

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Offload Strategy for Edge Computing in Satellite Networks Based on Software Defined Network

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Computers, Materials & Continua 2025年第1期82卷 863-879页

作者： Zhiguo Liu Yuqing Gui Lin Wang Yingru Jiang communication and Network Laboratory Dalian UniversityDalian116622China College of Environment and Chemical Engineering Dalian UniversityDalian116622China

Satellite edge computing has garnered significant attention from researchers;however,processing a large volume of tasks within multi-node satellite networks still poses considerable *** sharp increase in user demand for latency-sensitive tasks has inevitably led to offloading bottlenecks and insufficient computational capacity on individual satellite edge servers,making it necessary to implement effective task offloading scheduling to enhance user *** this paper,we propose a priority-based task scheduling strategy based on a Software-Defined Network(SDN)framework for satellite-terrestrial integrated networks,which clarifies the execution order of tasks based on their ***,we apply a Dueling-Double Deep Q-Network(DDQN)algorithm enhanced with prioritized experience replay to derive a computation offloading strategy,improving the experience replay mechanism within the Dueling-DDQN ***,we utilize the Deep Deterministic Policy Gradient(DDPG)algorithm to determine the optimal resource allocation strategy to reduce the processing latency of *** results demonstrate that the proposed d3-DDPG algorithm outperforms other approaches,effectively reducing task processing latency and thus improving user experience and system efficiency.

关键词： Satellite network edge computing task scheduling computing offloading

RIS-Assisted Receive Spatial Modulation for High-Speed Railway communication

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China communications 2025年第2期22卷 269-282页

作者： Ding Qingfeng Wang Song Fu Tingmei Xi Tao School of Electrical and Automation Engineering East China Jiaotong UniversityNanchang 330013China China Railway communication and Signal Survey&Design Institute Co.Ltd Beijing 100071China

In high-speed railway(HSR)wireless communication,the rapid channel changes and limited high-capacity access cause significant impact on the link ***,the Doppler shift caused by high mobility leads to the inter-carrier *** this paper,we propose a reconfigurable intelligent surface(RIS)-assisted receive spatial modulation(SM)scheme based on the spatial-temporal correlated HSR Rician *** characteristics of SM and the phase shift adjustment of RIS are used to mitigate the performance degradation in high mobility *** the influence of channel spatial-temporal correlation and Doppler shift,the effects of different parameters on average bit error rate(BER)performance and upper bound of ergodic capacity are ***,a joint antenna and RIS-unit selection algorithm based on the antenna removal method is proposed to increase the capacity performance of communication *** results show that the proposed RIS-assisted receive SM scheme can maintain high transmission capacity compared to the conventional HSR-SM scheme,whereas the degradation of BER performance can be compensated by arranging a large number of *** addition,selecting more RIS-units has better capacity performance than activating more antennas in the low signal-to-noise ratio regions.

关键词： average bit error rat high-speed railway joint antenna and RIS-unit selection receive spatial modulation reconfigurable intelligent surface

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GUEST EDITORIAL Efficient Cooperative Transmission over Satellite Internet for 6G

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China communications 2025年第2期22卷 6-8页

作者： Zhu Lidong Michele Luglio Sun Zhili Zhang Gengxin Yang Mingchuan University of Electronic Science and Technology of China University of Rome “Tor Vergata” the Institute for communication Systems (ICS) Nanjing University of Posts and Telecommunications communication Research Center Harbin Institute of Technology

Satellite Internet, as a strategic public information infrastructure, can effectively bridge the limitations of traditional terrestrial network coverage, support global coverage and deep space exploration, and greatly... 详细信息

关键词： Special issues and sections Satellite communications Internet Deep-space communications Public infrastructure 5G mobile communication 6G mobile communication Information services Global communication Human factors Terrestrial communications communication systems

State-Incomplete Intelligent Dynamic Multipath Routing Algorithm in LEO Satellite Networks

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China communications 2025年第2期22卷 1-11页

作者： Peng Liang Wang Xiaoxiang School of Information and communication Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

The low Earth orbit(LEO)satellite networks have outstanding advantages such as wide coverage area and not being limited by geographic environment,which can provide a broader range of communication services and has become an essential supplement to the terrestrial ***,the dynamic changes and uneven distribution of satellite network traffic inevitably bring challenges to multipath *** worse,the harsh space environment often leads to incomplete collection of network state data for routing decision-making,which further complicates this *** address this problem,this paper proposes a state-incomplete intelligent dynamic multipath routing algorithm(SIDMRA)to maximize network efficiency even with incomplete state data as ***,we model the multipath routing problem as a markov decision process(MDP)and then combine the deep deterministic policy gradient(DDPG)and the K shortest paths(KSP)algorithm to solve the optimal multipath routing *** use the temporal correlation of the satellite network state to fit the incomplete state data and then use the message passing neuron network(MPNN)for data *** results show that the proposed algorithm outperforms baseline algorithms regarding average end-to-end delay and packet loss rate and performs stably under certain missing rates of state data.

关键词： deep deterministic policy gradient LEO satellite network message passing neuron network multipath routing

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Privacy Distributed Constrained Optimization Over Time-Varying Unbalanced Networks and Its Application in Federated Learning

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IEEE/CAA Journal of Automatica Sinica 2025年第2期12卷 335-346页

作者： Mengli Wei Wenwu Yu Duxin Chen Mingyu Kang Guang Cheng the School of Cyber Science and Engineering Southeast University IEEE the School of Mathematics Frontiers Science Center for Mobile Information Communication and Security Southeast University the Purple Mountain Laboratories the School of Mathematics Southeast University

This paper investigates a class of constrained distributed zeroth-order optimization(ZOO) problems over timevarying unbalanced graphs while ensuring privacy preservation among individual agents. Not taking into account recent progress and addressing these concerns separately, there remains a lack of solutions offering theoretical guarantees for both privacy protection and constrained ZOO over time-varying unbalanced *** hereby propose a novel algorithm, termed the differential privacy(DP) distributed push-sum based zeroth-order constrained optimization algorithm(DP-ZOCOA). Operating over time-varying unbalanced graphs, DP-ZOCOA obviates the need for supplemental suboptimization problem computations, thereby reducing overhead in comparison to distributed primary-dual methods. DP-ZOCOA is specifically tailored to tackle constrained ZOO problems over time-varying unbalanced graphs,offering a guarantee of convergence to the optimal solution while robustly preserving privacy. Moreover, we provide rigorous proofs of convergence and privacy for DP-ZOCOA, underscoring its efficacy in attaining optimal convergence without constraints. To enhance its applicability, we incorporate DP-ZOCOA into the federated learning framework and formulate a decentralized zeroth-order constrained federated learning algorithm(ZOCOA-FL) to address challenges stemming from the timevarying imbalance of communication topology. Finally, the performance and effectiveness of the proposed algorithms are thoroughly evaluated through simulations on distributed least squares(DLS) and decentralized federated learning(DFL) tasks.

关键词： Constrained distributed optimization decentralized federated learning (DFL) differential privacy (DP) time-varying unbalanced graphs zeroth-order gradient

Magnetic Induction communication in Extreme Environments:Principles,Technologies,and Challenges

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China communications 2025年第1期22卷 256-264页

作者： Jiang Tao Zhang Yixin Liu Guanghua Research Center of 6G Mobile communications School of Cyber Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China College of Information and communication National University of Defense TechnologyWuhan 430030China

Wireless communications in extreme environments,such as underwater and underground,is an essential technology for interconnecting various devices and enables data transmission and *** wireless technologies using electromagnetic(EM)waves face many known problems,such as high path loss,unpredictable multi-path fading,and large antenna size in the lossy *** this article,the magnetic induction(MI)based physical layer communication is introduced as a promising solution for wireless transmissions in extreme ***,the fundamentals of the MI-based communications are ***,with the goal of establishing reliable and low-power links between small-size devices,we review several key physical layer technologies for MI-based communications,including the MIbased signal modulations,magnetic beamforming,and relay transmissions,and summarize their state-of-theart research ***,the related open issues and challenges in each area are analyzed and presented for future investigations.

关键词： beamforming magnetic induction communications relay transmission signal modulation

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A violence detection method based on deep and shallow feature fusion

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Instrumentation 2025年

作者： Lin'en Liu Xuguang Zhang HangZhou Dianzi University The Communication Engineering Department

In the research of video-based violent behavior detection,the motion information in the video is vital for violence *** to highlight motion information in videos and integrate spatiotemporal information is an urgent problem that needs to be solved in violence *** this paper,we propose a deep learning architecture that integrates shallow features into deep features to strengthen the network's ability to express motion information at a deep *** enhance the weight of motion information in the network,we design a downsampling module to extract shallow features,fused with the deep features extracted by MobileNet's *** we constructed a channel attention module and introduced a Convolutional Long Short-Term Memory (ConvLSTM) *** two modules aim to redistribute network attention:the channel attention module focuses on channel-level information and the ConvLSTM module emphasizes temporal ***,we employ 3D convolution and global pooling to compress the feature sizes,fed into fully connected layers to perform violence *** are conducted on three publicly available standard datasets,achieving an accuracy rate of 91%on the surveillance video dataset RWF2000,97.5%on the Hockey fight dataset,and 100%on the movies ***,the proposed model demonstrates satisfactory performance in violence detection..

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