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International Conference on Computer and communications (ICCC)

作者： Zhiping Lu Ruxin Zhi Weiguo Ma School of Information and Communication Engineering Beijing University of Posts and Telecommunications State Key Laboratory of Wireless Mobile Communications China Academy of Telecommunications Technology (CATT) Beijing China Key Laboratory of Information and Communication Systems Ministry of Information Industry Beijing Information Science and Technology University Key Laboratory of Modern Measurement and Control Technology Ministry of Education Beijing Information Science and Technology University Beijing China

Low earth orbit satellite communication systems are attractive for provisioning global, high-speed and low latency Internet access services. In order to achieve global continuous multiple coverage, the number of satellites is tremendous. But Low earth orbit satellite networks are prone to instability due to unpredictable link failures and frequent topology changes. Therefore, in this paper, a novel routing schemes with quick response to link failures is first proposed. Based on Dijkstra algorithm, a scalable routing algorithm is proposed to minimize the end-to-end transmission delay. It takes advantage of the predictable constellation trajectory, and changes dynamically according to the changes of network topology. It provides the shortest routing path and an alternative path simultaneously. When a link failure is detected by one satellite, notification packets will be sent to its neighbors for adjustment to the alternative routing path. Notification packets also will be sent to the head node for the recalculation of routing table. Finally, extensive simulations have been conducted, and the results show that the proposed scheme is able to produce desired performance.

关键词： Satellites Network topology Heuristic algorithms Dynamics Low earth orbit satellites Packet loss Routing

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Effect of Kinetic Properties of Zeolites on the Gas-Sensing Performance of Zeolite-Covered Sno2 Sensors

SSRN

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SSRN 2022年

作者： Sun, Yanhui Hou, Tengyue Sun, Shupeng Fu, Shouhang Du, Haiying Wang, Xue College of information &communication Engineering Dalian Minzu University Dalian116600 China School of Mechanical Engineering Dalian University of Technology Dalian116023 China School of Microelectronics Dalian University of Technology Liaoning Dalian116024 China College of Mechanical and Electronic Engineering Dalian Minzu University Dalian116600 China KEDE Numerical Control Co. Ltd Dalian116600 China

Zeolite additional layers coating on metal oxide surfaces to improve the selectivity and response values of the sensors are effective and widely used. The specific adsorption and diffusion of gas molecules in the zeolite are recognized to play an important role in gas sensing improvement. In this work, the adsorption and diffusion behaviors of formaldehyde and acetone in H-Y and H-A zeolites were calculated by Monte Carlo and molecular dynamics simulations. The loading of acetone is greater than formaldehyde in these two kinds of zeolites under the same temperature and pressure, and the water load is lower. The simulation results show that the effects of the nature of the guest molecule and steric hindrance of the diffusing molecule on diffusivity is significant. The diffusivity in H-A zeolite decreases by several orders of magnitude than that in H-Y zeolite However, in H-A zeolite, the internal diffusion dominates, and only the smaller diameter formaldehyde can diffuse between the pores, which is beneficial to improving the sensing properties of formaldehyde. In addition, in the competition diffusion with water molecules, formaldehyde dominates than acetone. The H-Y/SnO2 and H-A/SnO2 sensors were prepared to verify the reliability of the molecular simulations. © 2022, The Authors. All rights reserved.

关键词： Zeolites

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Optimal control of linear Gaussian quantum systems via quantum learning control

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Physical Review A 2024年第6期109卷 063508-063508页

作者： Yu-Hong Liu Yexiong Zeng Qing-Shou Tan Daoyi Dong Franco Nori Jie-Qiao Liao Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Key Laboratory for Matter Microstructure and Function of Hunan Province Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications Theoretical Quantum Physics Laboratory Cluster for Pioneering Research Quantum Computing Center Key Laboratory of Hunan Province on Information Photonics and Freespace Optical Communication College of Physics and Electronics School of Engineering and Information Technology Department of Physics Institute of Interdisciplinary Studies

Efficiently controlling linear Gaussian quantum (LGQ) systems is a significant task in both the study of fundamental quantum theory and the development of modern quantum technology. Here, we propose a general quantum-learning-control method for optimally controlling LGQ systems based on the gradient-descent algorithm. Our approach flexibly designs the loss function for diverse tasks by utilizing first- and second-order moments that completely describe the quantum state of LGQ systems. We demonstrate both deep optomechanical cooling and large optomechanical entanglement using this approach. Our approach enables the fast and deep ground-state cooling of a mechanical resonator within a short time, surpassing the limitations of sideband cooling in the continuous-wave driven strong-coupling regime. Furthermore, optomechanical entanglement could be generated remarkably fast and surpass several times the corresponding steady-state entanglement, even when the thermal phonon occupation reaches one hundred. This work will not only broaden the application of quantum learning control, but also open an avenue for optimal control of LGQ systems.

关键词： Optomechanics Quantum optics

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An abundance estimation algorithm based on orthogonal bases for hyperspectral image

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Optoelectronics Letters 2019年第5期15卷 396-400页

作者： ZHAO Yan ZHOU Zhen WANG Dong-hui School of Measurement and Communication Engineering Harbin University of Science and Technology Harbin 150080 China College of Information and Communication Engineering Harbin Engineering University Harbin 150001 China

An abundance estimation algorithm based on orthogonal bases is proposed to address the problem of high computational complexity faced by most abundance estimation algorithms that are based on a linear spectral mixing model(LSMM) and need to perform determinant operations and matrix inversion operations. The proposed algorithm uses the Gram-Schmidt method to calculate the endmember vector set to obtain the corresponding orthogonal basis set and solve the unmixing equations to obtain the eigenvector of each endmember. The spectral vector to be decomposed is projected onto the eigenvector to obtain projection vector, and the ratio between the length of the projection vector and the length of the orthogonal basis corresponding endmember is calculated to obtain an abundance estimation of the endmember. After a comparative analysis of different algorithms, it is concluded that the proposed algorithm only needs to perform vector inner product operations, thereby significantly reducing the computational complexity. The effectiveness of the algorithm was verified by experiments using simulation data and actual image data.

关键词： linear spectral mixing model(LSMM) perform determinant operations matrix inversion operations

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Broadband Chaos Generation from Relaxation Oscillation-Free Polarization Mode of Vertical-Cavity Surface-Emitting Laser

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Guangxue Xuebao/Acta Optica Sinica 2025年第10期45卷

作者： Di, Chengzhen Liu, Qi Wang, Longsheng Zhao, Qingchun Guo, Yuanyuan Chang, Pengfa Jia, Zhiwei Wang, Anbang Key Laboratory of Advanced Transducers and Intelligent Control System Ministry of Education Taiyuan University of Technology Shanxi Taiyuan030024 China College of Electronic Information and Optical Engineering Taiyuan University of Technology Shanxi Jinzhong030600 China Key Laboratory of Precision Measurement Physics Ministry of Shanxi Province Taiyuan University of Technology Shanxi Taiyuan030024 China School of Computer and Communication Engineering Northeastern University at Qinhuangdao Hebei Qinhuangdao066004 China Key Laboratory of Photonic Technology for Integrated Sensing and Communication Ministry of Education Guangdong University of Technology Guangdong Guangzhou510006 China

Objective Secure communication based on chaotic lasers has gained significant attention in recent years due to its high speed and compatibility with existing fiber-optic networks. Vertical-cavity surface-emitting lasers (VCSELs) are promising candidates, offering a compact structure and low power consumption. However, VCSELs are constrained by chaotic bandwidth limitations induced by relaxation oscillations, which reduce the secure transmission rate. Existing methods for broadening the chaos bandwidth often rely on complex external perturbations, which may hinder system synchronization. We propose a simplified method for generating broadband chaos by utilizing the relaxation-oscillation-free polarization mode of VCSELs. Methods We present a novel approach for generating broadband chaos by utilizing the relaxation-oscillation-free polarization mode of VCSELs. The experimental setup (Fig. 1) employs a custom single-mode VCSEL with a wavelength of 1550 nm and no internal isolator. The laser is powered by a low-noise current source and is equipped with precise temperature control to ensure stable operation. Optical feedback is provided via a fiber mirror, with its intensity regulated by a variable optical attenuator. Polarization controllers are used to align the feedback polarization, directing X mode feedback to the X mode and Y mode feedback to the Y mode. The output signals are separated into X+Y, X, and Y modes using polarization beam splitters. The spectral, temporal, and dynamic properties of the VCSEL are analyzed using an optical spectrum analyzer, a high-speed oscilloscope, and an electrical spectrum analyzer. Key parameters, including bias current and feedback strength, are systematically varied and optimized to investigate their effects on chaos generation, with the aim of identifying the optimal conditions for achieving broadband chaos with the desired characteristics. Results and Discussions We begin with an in-depth analysis of the free-running VCSEL to e

关键词： Optical feedback

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Spreading dynamics of information on online social networks

arXiv

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arXiv 2025年

作者： Meng, Fanhui Xie, Jiarong Sun, Jiachen Xu, Cong Zeng, Yutian Wang, Xiangrong Jia, Tao Huang, Shuhong Deng, Youjin Hu, Yanqing School of Systems Science and Engineering Sun Yat-sen University Guangzhou510275 China Center for Computational Communication Research Beijing Normal University Zhuhai519087 China School of Journalism and Communication Beijing Normal University Beijing100875 China School of Computer Science and Engineering Sun Yat-sen University Guangzhou510006 China Department of Statistics and Data Science College of Science Southern University of Science and Technology Shenzhen518055 China College of Mechatronics and Control Engineering Shenzhen University Shenzhen518060 China College of Computer and Information Science Chongqing Normal University Chongqing401331 China College of Computer and Information Science Southwest University Chongqing400715 China Institute of Neuroscience Technical University of Munich Munich80802 Germany Department of Modern Physics University of Science and Technology of China Hefei230026 China MinJiang Collaborative Center for Theoretical Physics College of Physics and Electronic Information Engineering Minjiang University Fuzhou350108 China Center for Complex Flows and Soft Matter Research Southern University of Science and Technology Shenzhen518055 China

Social media is profoundly changing our society with its unprecedented spreading power. Due to the complexity of human behaviors and the diversity of massive messages, the information spreading dynamics are complicated, and the reported mechanisms are different and even controversial. Based on data from mainstream social media platforms, including WeChat, Weibo, and Twitter, cumulatively encompassing a total of 7.45 billion users, we uncover a ubiquitous mechanism that the information spreading dynamics are basically driven by the interplay of social reinforcement and social weakening effects. Accordingly, we propose a concise equation, which, surprisingly, can well describe all the empirical large-scale spreading trajectories. Our theory resolves a number of controversial claims and satisfactorily explains many phenomena previously observed. It also reveals that the highly clustered nature of social networks can lead to rapid and high-frequency information bursts with relatively small coverage per burst. This vital feature enables social media to have a high capacity and diversity for information dissemination, beneficial for its ecological development. © 2025, CC BY.

关键词： Tweets

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Exploiting Active RIS in NOMA Networks with Hardware Impairments

arXiv

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arXiv 2023年

作者： Yue, Xinwei Song, Meiqi Ouyang, Chongjun Liu, Yuanwei Li, Tian Hou, Tianwei The Key Laboratory of Information and Communication Systems Ministry of Information Industry China The Key Laboratory of Modern Measurement & Control Technology Ministry of Education Beijing Information Science and Technology University Beijing100101 China The School of Electrical and Electronic Engineering University College Dublin DublinD04 V1W8 Ireland The School of Electronic Engineering and Computer Science Queen Mary University of London LondonE1 4NS United Kingdom The 54th Research Institute of China Electronics Technology Group Corporation Hebei Shijiazhuang050081 China The School of Electronic and Information Engineering Beijing Jiaotong University Beijing100044 China Erlangen91054 Germany

Active reconfigurable intelligent surface (ARIS) is a promising way to compensate for multiplicative fading attenuation by amplifying and reflecting event signals to selected users. This paper investigates the performance of ARIS assisted non-orthogonal multiple access (NOMA) networks over cascaded Nakagami-m fading channels. The effects of hardware impairments (HIS) and reflection coefficients on ARIS-NOMA networks with imperfect successive interference cancellation (ipSIC) and perfect successive interference cancellation (pSIC) are considered. More specifically, we develop new precise and asymptotic expressions of outage probability and ergodic data rate with ipSIC/pSIC for ARIS-NOMA-HIS networks. According to the approximated analyses, the diversity orders and multiplexing gains for couple of non-orthogonal users are attained in detail. Additionally, the energy efficiency of ARIS-NOMA-HIS networks is surveyed in delay-limited and delay-tolerant transmission schemes. The simulation findings are presented to demonstrate that: i) The outage behaviors and ergodic data rates of ARIS-NOMA-HIS networks precede that of ARIS aided orthogonal multiple access (OMA) and passive reconfigurable intelligent surface (PRIS) aided OMA;ii) As the reflection coefficient of ARIS increases, ARIS-NOMA-HIS networks have the ability to provide the strengthened outage performance;and iii) ARIS-NOMA-HIS networks are more energy efficient than ARIS/PRIS-OMA networks and conventional cooperative schemes. Copyright © 2023, The Authors. All rights reserved.

关键词： Energy efficiency

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Performance Analysis of Reconfigurable Intelligent Surface Assisted Two-Way NOMA Networks

arXiv

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arXiv 2022年

作者： Liu, Ziwei Yue, Xinwei Zhang, Chao Liu, Yuanwei Yao, Yuanyuan Wang, Yafei Ding, Zhiguo The Key Laboratory of Modern Measurement & Control Technology Ministry of Education and also The School of Information and Communication Engineering Beijing Information Science and Technology University Beijing100101 China The School of Electronic Engineering and Computer Science Queen Mary University of London LondonE1 4NS United Kingdom The Department of Electrical Engineering Princeton University Princeton United States The School of Electrical and Electronic Engineering The University of Manchester Manchester United Kingdom

This paper investigates the performance of reconfigurable intelligent surface assisted two-way non-orthogonal multiple access (RIS-TW-NOMA) networks, where a pair of users exchange their information through a RIS. The influence of imperfect successive interference cancellation on RIS-TW-NOMA is taken into account. To evaluate the potential performance of RIS-TW-NOMA, we derive the exact and asymptotic expressions of outage probability and ergodic rate for a pair of users. Based on the analytical results, the diversity orders and high signal-to-noise ratio (SNR) slopes are obtained in the high SNR regime, which are closely related to the number of RIS elements. Additionally, we analyze the system throughput and energy efficiency of RIS-TW-NOMA networks in both delay-limited and delay-tolerant transmission modes. Numerical results indicate that: 1) The outage behaviors and ergodic rate of RIS-TW-NOMA are superior to that of RIS-TW-OMA and two-way relay OMA (TWR-OMA);2) As the number of RIS elements increases, the RIS-TW-NOMA networks are capable of achieving the enhanced outage performance;and 3) By comparing with RIS-TW-OMA and TWR-OMA networks, the energy efficiency and system throughput of RIS-TW-NOMA has obvious advantages. © 2022, CC BY-NC-ND.

关键词： Energy efficiency

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Cascade of pressure-driven phase transitions in the topological nodal-line superconductor PbTaSe2

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Physical Review B 2022年第6期106卷 L060501-L060501页

作者： Tahir Murtaza Haiyang Yang Jiajia Feng Yi Shen Yongheng Ge Yi Liu Chunqiang Xu Wenhe Jiao Yaokang Lv Christopher J. Ridley Craig L. Bull Pabitra K. Biswas Raman Sankar Wei Zhou Bin Qian Xuefan Jiang Zhenjie Feng Yonghui Zhou Ziming Zhu Zhaorong Yang Xiaofeng Xu Key Laboratory of Quantum Precision Measurement of Zhejiang Province Department of Applied Physics Zhejiang University of Technology Hangzhou 310023 China College of Information Engineering Zhejiang University of Technology Hangzhou 310023 China Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field Laboratory Chinese Academy of Sciences Hefei 10 230031 China School of Physics and Key Laboratory of MEMS of the Ministry of Education Southeast University Nanjing 211189 China Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha 410081 China College of Chemical Engineering Zhejiang University of Technology Hangzhou 310014 China ISIS Pulsed Neutron and Muon Source STFC Rutherford Appleton Laboratory Harwell Campus Didcot Oxfordshire OX11 0QX United Kingdom School of Chemistry University of Edinburgh David Brewster Road Edinburgh EH9 3FJ United Kingdom Institute of Physics Academia Sinica Nankang Taipei 11529 Taiwan Department of Physics Changshu Institute of Technology Changshu 215500 China Materials Genome Institute Shanghai University Shanghai 200444 China

We report a succession of pressure-tuned structural transitions in the topological nodal-line superconductor PbTaSe2, evidenced from synchrotron x-ray diffraction, elastic neutron scattering, Raman spectroscopy, and electrical transport measurements up to 56 GPa, accompanied by first-principles calculations to uncover the evolution of the underlying electronic structure. In contrast to the previously proposed small shift of the Pb Wyckoff coordinate in the sub-GPa regime, our study reveals that it is rather a transition from P6¯m2 (α phase) to P63mc (β phase), subsequently followed by a transition to P6/mmm (γ phase) at ∼7.5 GPa and to Pmmm (δ phase) at ∼44 GPa. In addition, the first-principles calculations unambiguously demonstrate the multiple types of topological fermions associated with these different pressure-driven structures. Collectively, our results not only present the intriguing structural transitions in this topological PbTaSe2 superconductor, they also provide the impetus to study topological phase transitions and their physical consequences in a broader class of topological materials.

关键词： Phase transitions by order Superconducting phase transition Superconductivity Topological superconductors

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Surface crack characterization using laser nonlinear ultrasonics based on the bispectrum

Surface crack characterization using laser nonlinear ultraso...

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作者： Liu, Hui Wang, Zhaoba Zheng, Bin National Key Lab for Electronic Measurement Technology North University of China Taiyuan030051 China School of Information and Communication Engineering North University of China Taiyuan030051 China School of Electrical and Control Engineering North University of China Taiyuan030051 China

Laser nonlinear wave modulation spectroscopy (LNWMS) has been used to detect nonlinear ultrasonic signatures caused by fatigue cracks in materials. The nonlinear feature extraction from the spectral plot plays a significant role in LNWMS. This paper uses the bispectrum to distinguish harmonically related signals which result from nonlinear interactions and to remove those which do not. A feature called bispectrum damage factor (BDF), which is defined as the ratio of the bispectrum peak difference value of the damage and intact signals to the bispectrum peak value of intact signals at frequencies F 1, F 2, is extracted from the bispectral plot to characterize the crack features. The basic premise of the proposed laser nonlinear wave modulation bispectrum (LNWMBS) is that this BDF value will vary regularly as the level of crack-induced nonlinearity increases. A finite element model and a noncontact laser ultrasonic system have been built for LNWMBS measurement. The simulation results show that the BDF value is sensitive to crack depth and angle, and is insensitive to crack length and detecting position. BDF values of reflected Rayleigh waves are positive and approximately linearly increase with an increase of the crack depths in the range of 0.1 λ ∼ 0.6 λ (λ is the corresponding wavelength of adopted frequency);meanwhile, the values of the transmitted waves are negative and decreasing. The BDF values are larger than the crack angle at 90° when they are less than 90°, which is beneficial for crack detection. The proposed LNWMBS technique has been successfully tested for detecting artificial sub-millimeter surface-breaking cracks in aluminum alloy plates and closed fatigue cracks of torque load simulator connection blocks. © 2020 IOP Publishing Ltd.

关键词： Finite element method

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