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An approach for identifying vulnerable nodes in power networks: Neighborhood compactness model based on differential electrical conductivity strength

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Chaos, Solitons and Fractals 2025年 198卷

作者： Min, Zhao Jiayun, Li Junhan, Ye Beijing Laboratory of Advanced Information Networks Beijing University of Posts and Telecommunications Beijing100876 China Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing100876 China School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing100876 China

The extensive scale and intricate connections of power networks have highlighted their vulnerability. The failure of a single vulnerable node can quickly bring down the system due to the networks’ sensitivity to interference. Therefore, it is crucial to efficiently and accurately identify the vulnerable nodes to enhance the safety and management of the power networks. The global information-based vulnerable node identification methods are time-consuming and do not meet the real-time requirements. Meanwhile, the existing local information-based methods lack the exploration of the interaction between neighbors. This paper concentrates on the essential characteristics of the power network topology and aims to mine the vulnerable nodes using broader and richer neighborhood information. A novel vulnerable node identification method is proposed, which combines the neighborhood compactness model and differential electrical conductivity strength (ECS). From the new perspective of the decentered neighborhood, we propose the kth order neighborhood ECS to dynamically quantify multipath connection strength across topological layers, and introduce differential ECS to model incremental connectivity gains from path redundancy and distance decay. Finally, the performance of the neighborhood compactness model is evaluated through average ECS, network efficiency, connectivity, vulnerability, capacity, ranking distribution, and complexity. The proposed algorithm demonstrates superior performance in the six dimensions in comparison experiments on nine power networks. © 2025 Elsevier Ltd

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Generation of Multi-Channel Co-axial Quasi-Perfect Vortex Electromagnetic Waves with Equal Divergence Radii Based on Aperture-Shared Metasurface

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IEEE Transactions on Antennas and Propagation 2025年

作者： Deng, Li Yang, Kaiqiao Yin, Kaiyue Chen, Jiawei Qu, Meijun Feng, Botao Beijing University of Posts and Telecommunications Beijing Laboratory of Advanced Information Networks Beijing Key Laboratory of Network System Architecture and Convergence Beijing100876 China Southeast University Institute of Electromagnetic Space State Key Laboratory of Millimeter Wave Nanjing211189 China Communication University of China School of Information and Communication Engineering Beijing Beijing100024 China Shenzhen University College of Electronics and Information Engineering Shenzhen518060 China

Vortex electromagnetic (EM) waves hold significant promise for next-generation wireless communication applications. However, their practical deployment is hindered by varying divergence characteristics across vortex modes with different mode numbers. To overcome this challenge and enable true spatial multiplexing of orbital angular momentum (OAM) waves, a dual-polarized shared-aperture metasurface is proposed. By leveraging both polarization and OAM multiplexing, quasi-perfect vortex (QPV) EM waves with co-axial beams and equal divergence radii are successfully generated at microwave frequencies. Initially, the properties of quasi-perfect vortex waves in the microwave band are analyzed, followed by the design of a dual-polarized metasurface unit. This unit integrates parasitic damping-coupled patches based on the traditional Jerusalem cross structure, providing polarization-independent control and approximately 360° phase-tuning capability. Furthermore, simulations validate the effectiveness of the dual-polarized single-mode metasurface design. Based on this, the concept is extended to a 4-channel multiplexing metasurface, operating at 15 GHz and capable of generating QPV waves. Finally, experimental results from the fabricated metasurface demonstrate the generation of QPV waves with OAM mode numbers 0, +2, +1, and -1, achieving simulated and measured OAM mode purities of 0.835 and 0.70, respectively. The experimental data closely aligns with simulations, confirming the effectiveness of the design. This study offers new insights into generating and applying perfect vortex EM waves, paving the way for high-capacity near-field wireless communication systems and advanced control of novel EM physical dimensions. © 1963-2012 IEEE.

关键词： Near field communication

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Continual Reinforcement Learning for Digital Twin Synchronization Optimization

arXiv

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arXiv 2025年

作者： Tong, Haonan Chen, Mingzhe Zhao, Jun Hu, Ye Yang, Zhaohui Liu, Yuchen Yin, Changchuan The Beijing Key Laboratory of Network System Architecture and Convergence The Beijing Advanced Information Network Laboratory Beijing University of Posts and Telecommunications Beijing China Singapore The Department of Electrical and Computer Engineering Frost Institute for Data Science and Computing University of Miami Coral GablesFL33146 United States The Department of Industrial and Systems Engineering University of Miami Coral GablesFL33146 United States The College of Information Science and Electronic Engineering Zhejiang University Zhejiang Hangzhou310027 China The Department of Computer Science North Carolina State University RaleighNC27695 United States The Beijing Key Laboratory of Network System Architecture and Convergence China The Beijing Advanced Information Network Laboratory Beijing University of Posts and Telecommunications Beijing100876 China

This article investigates the adaptive resource allocation scheme for digital twin (DT) synchronization optimization over dynamic wireless networks. In our considered model, a base station (BS) continuously collects factory physical object state data from wireless devices to build a real-time virtual DT system for factory event analysis. Due to continuous data transmission, maintaining DT synchronization must use extensive wireless resources. To address this issue, a subset of devices is selected to transmit their sensing data, and resource block (RB) allocation is optimized. This problem is formulated as a constrained Markov process (CMDP) problem that minimizes the long-term mismatch between the physical and virtual systems. To solve this CMDP, we first transform the problem into a dual problem that refines RB constraint impacts on device scheduling strategies. We then propose a continual reinforcement learning (CRL) algorithm to solve the dual problem. The CRL algorithm learns a stable policy across historical experiences for quick adaptation to dynamics in physical states and network capacity. Simulation results show that the CRL can adapt quickly to network capacity changes and reduce normalized root mean square error (NRMSE) between physical and virtual states by up to 55.2%, using the same RB number as traditional methods. © 2025, CC BY-NC-SA.

关键词： Markov processes

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Task-Oriented Multi-user Semantic Communication based on Deep Over-the-Air Computation

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IEEE Transactions on Vehicular Technology 2025年

作者： Wei, Shuangying Feng, Chunyan Guo, Caili Zhang, Biling Chen, Jiujiu Beijing University of Posts and Telecommunications Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication Engineering Beijing100876 China Nanchang Hangkong University Key Laboratory of Processing and Pattern Recognition of Jiangxi Province School of Information Engineering Nanchang330063 China

The presence of large-scale heterogeneous IoT devices and AI-based applications has brought significant transmission and computation pressure on the wireless communication system. In this paper, we propose a novel multi-user semantic communication framework based on deep over-the-air computation called SC-DAC to tackle this challenge. By integrating communication and computation through a deep over-the-air computation (AirComp) encoder, SC-DAC is able to utilize the superposition of multiple access channels, facilitating multi-user information fusion during transmission and eliminating the need for multi-user detection at the receiver. Further, to achieve the optimal task results, the semantic encoders, decoders, and AirComp encoder are jointly optimized, where stochastic gradient descent (SGD) algorithm and deep double-Q network (DDQN) are employed to optimize the encoder/decoder parameters. The simulation results demonstrate that as the number of users increased, the performance of the system remains relatively stable and shows potential in resource utilization. What's more, when applied to the AI-based tasks such as multi-user multimodal action recognition and semantic segmentation, SC-DAC enhances the accuracy of action recognition by 26% compared with traditional methods and by about 30%-50% compared with other multi-user semantic communication methods under conditions of low signal-to-noise ratio (SNR), while it enhances the accuracy of semantic segmentation by 0.22 to 0.32 compared to other methods © 1967-2012 IEEE.

关键词： Deep reinforcement learning

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A New Paradigm of User-Centric Wireless Communication Driven by Large Language Models

arXiv

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arXiv 2025年

作者： Ding, Kuiyuan Guo, Caili Yang, Yang Hu, Wuxia Eldar, Yonina C. Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing100876 China Beijing Laboratory of Advanced Information Net works School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing100876 China Faculty of Mathematics and Computer Science Weizmann Institute of Science Rehovot7610001 Israel

The next generation of wireless communications seeks to deeply integrate artificial intelligence (AI) with user-centric communication networks, with the goal of developing AI-native networks that more accurately address user requirements. The rapid development of large language models (LLMs) offers significant potential in realizing these goals. However, existing efforts that leverage LLMs for wireless communication often overlook the considerable gap between human natural language and the intricacies of real-world communication systems, thus failing to fully exploit the capabilities of LLMs. To address this gap, we propose a novel LLM-driven paradigm for wireless communication that innovatively incorporates the nature language to structured query language (NL2SQL) tool. Specifically, in this paradigm, user personal requirements is the primary focus. Upon receiving a user request, LLMs first analyze the user intent in terms of relevant communication metrics and system parameters. Subsequently, a structured query language (SQL) statement is generated to retrieve the specific parameter values from a high-performance real-time database. We further utilize LLMs to formulate and solve an optimization problem based on the user request and the retrieved parameters. The solution to this optimization problem then drives adjustments in the communication system to fulfill the user’s requirements. To validate the feasibility of the proposed paradigm, we present a prototype system. In this prototype, we consider user-request centric semantic communication (URC-SC) system in which a dynamic semantic representation network at the physical layer adapts its encoding depth to meet user requirements, such as improved data transmission quality or reduced data transmission latency. Additionally, two LLMs are employed to analyze user requests and generate SQL statements, respectively. Simulation results demonstrate the effectiveness of the prototype in personalizing and addressing user r

关键词： Structured Query Language

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A dual circularly polarized flower-shaped antenna for WiFi-6E basestation communications with low sidelobe level and high gain

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Results in Engineering 2025年 26卷

作者： Ding, Xiao Zhou, Zhengdong Feng, Botao Wu, Sulin Sim, Chow-Yen-Desmond Deng, Li Faculty of Humanities and Arts Macau University of Science and Technology Macau 999078 China College of Electronics and Information Engineering Shenzhen University Shenzhen518060 China Shenzhen518060 China Department of Electrical Engineering Feng Chia University Taichung40724 Taiwan Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing100876 China

This paper proposes a dual circularly polarized (CP) flower-shaped antenna with low sidelobe levels and high gain for WiFi-6E basestation communications. The antenna consists of two printed circuit board (PCB) substrates and a polyvinyl chloride (PVC) radome, and is excited by a pair of coaxial cables. Initially, a flower-shaped parasitic patch etched with slots is placed atop a square main radiated patch that is directly fed by two orthogonal "L"-shaped microstrip lines with constant amplitude in phase, achieving wideband, high gain, and dual CP characteristics. Furthermore, a three-level T-junction power divider network collaborates in conjunction with a dual-port electrical bridge to excite an array that is comprised of the proposed 4×4 antenna elements to achieve higher array gain. Finally, an open box-shaped PVC radome is selected for fixation and protection, contributing significantly to sidelobe level (SLL) reduction. The working mechanisms including precise phase control and SLL reduction, etc., are analyzed using equivalent circuit and E-field distribution, among other methods. Measured results demonstrate excellent performances, such as a low profile of 0.074λ0 (λ0 is the free-space wavelength at the starting frequency), a low SLL of less than -14.4 dB, a wide impedance bandwidth of 20% (5.85-7.15 GHz), a wide axial ratio (AR) bandwidth of 21% (5.83-7.4 GHz), a peak gain of larger than 19.4 dBic in left hand circular polarization (LHCP), another peak gain of better than 19.6 dBic in right hand circular polarization (RHCP), and a high radiation efficiency of larger than 72%. © 2025 The Author(s)

关键词： Wi-Fi

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Lightweight Task-Oriented Semantic Communication Empowered by Large-Scale AI Models

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IEEE Transactions on Vehicular Technology 2025年

作者： Liu, Chuanhong Guo, Caili Yang, Yang Chen, Mingzhe Quek, Tony Q. S. Beijing University of Posts and Telecommunications Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication Engineering Beijing100876 China Beijing University of Posts and Telecommunications Beijing Laboratory of Advanced Information Networks School of Information and Communication Engineering Beijing100876 China University of Miami Department of Electrical and Computer Engineering Institute for Data Science and Computing Coral GablesFL United States Singapore University of Technology and Design Dept. of Information Systems Technology and Design 487372 Singapore

Recent studies have focused on leveraging large-scale artificial intelligence (LAI) models to improve semantic representation and compression capabilities. However, the substantial computational demands of LAI models pose significant challenges for real-time communication scenarios. To address this, this paper proposes utilizing knowledge distillation (KD) techniques to extract and condense knowledge from LAI models, effectively reducing model complexity and computation latency. Nevertheless, the inherent complexity of LAI models leads to prolonged inference times during distillation, while their lack of channel awareness compromises the distillation performance. These limitations make standard KD methods unsuitable for task-oriented semantic communication scenarios. To address these issues, we propose a fast distillation method featuring a pre-stored compression mechanism that eliminates the need for repetitive inference, significantly improving efficiency. Furthermore, a channel adaptive module is incorporated to dynamically adjust the transmitted semantic information based on varying channel conditions, enhancing communication reliability and adaptability. In addition, an information bottleneck-based loss function is derived to guide the fast distillation process. Simulation results verify that the proposed scheme outperform baselines in term of task accuracy, model size, computation latency, and training data requirements. © 1967-2012 IEEE.

关键词： NP-hard

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Temperature stability of magnetic field for periodic permanent-magnet focusing system

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Rare Metals 2014年第2期33卷 180-184页

作者： Li Li Jian-Ya Chen Yun-Jie Liu Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications

In this study, finite element analysis based on an Ansoft Maxwell software was used to reveal the temperature stability of a magnet ring and the equivalent structural periodic permanent-magnet（PPM） focusing system. It is found that with the temperature increasing, the decrease rate of magnetic induction peak（Bz）maxof single magnet ring is greater than that of remanence Brof magnet in the range from room temperature to 200 °C, however,the PPM focusing system do have the same temperature characteristics of permanent-magnet materials. It indicates that the magnetic temperature properties of the PPM system can be effectively controlled by adjusting the temperature properties of the magnets. Moreover, the higher permeability of the magnets indicates the less Hcb, giving rise to lower magnetic induction peak （Bz）′max： Finally, it should be noted that the magnetic orientation deviation angle θ（／15°） of permanent magnets has little effect on the focusing magnetic field of the PPM system at different temperatures and the temperature stability. The obtained results are beneficial to the design and selection of permanent magnets for PPM focusing system.

关键词： Periodic permanent-magnets focusing system Rare earth permanent magnets Finite element simulation Temperature stability Wireless underground sensor network

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Pre-scan based fast handoff scheme for enterprise IEEE 802.11 networks

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The Journal of China Universities of Posts and Telecommunications 2016年第6期23卷 60-67页

作者： Zhang Biao Wen Xiangming Lu Zhaoming Lei Tao Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications

In IEEE 802.11 networks, many access points（APs） are required to cover a large area due to the limited coverage range of APs, and frequent handoffs may occur while a station（STA） is moving in an area covered by several APs. However, traditional handoff mechanisms employed at STAs introduce a few hundred milliseconds delay, which is far longer than what can be tolerated by some multimedia streams such as voice over Internet protocol（Vo IP）, it is a challenging issue for supporting seamless handoff service in IEEE 802.11 networks. In this paper, we propose a pre-scan based fast handoff scheme within an IEEE 802.11 enterprise wireless local area network（EWLAN） environment. The proposed scheme can help STA obtain the best alternative AP in advance after the pre-scan process, and when the handoff is actually triggered, STA can perform the authentication and reassociation process toward the alternative AP directly. Furthermore, we adopt Kalman filter to minimize the fluctuation of received signal strength（RSS）, thus reducing the unnecessary pre-scan process and handoffs. We performed simulations to evaluate performance, and the simulation results show that the proposed scheme can effectively reduce the handoff delay.

关键词： fast handoff IEEE 802.11 networks handoff delay enterprise WLAN

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Best-effort service QoE assessment using visual information based Weber-Fechner law

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The Journal of China Universities of Posts and Telecommunications 2016年第2期23卷 38-45页

作者： Guan Wanqing Wang Luhan Lu Zhaoming Wen Xiangming Chen Xin Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications

Quality of experience（QoE） has been one of the most important factors for service providers and operators to develop and deploy services. Previous works have shown that Weber-Fechner law（WFL） can be used to promote the accuracy of best-effort（BE） services＇ QoE assessment. In this paper, based on WFL, we take a deep insight into the visual information of BE services and its role in WFL, especially in web browsing services, and propose an enhanced QoE assessment model for BE services by taking the visual information into account. Both images and texts visual information are extracted and combined to get the visual information for web pages. Finally, a subjective experiment is performed to validate performance of proposed QoE assessment model, which shows that it performs better than traditional WFL based model.

关键词： QoE assessment Weber-Fechner law best-effort service visual information

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