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Numerical simulation for the initial state of avalanche in polydisperse particle systems

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Chinese Physics B 2024年第2期33卷 405-412页

作者：韩韧李亭迟志鹏杨晖李然 School of optical-electrical and computer engineering University of Shanghai for Science and TechnologyShanghai 200093China

Numerical simulation is employed to investigate the initial state of avalanche in polydisperse particle *** and propagation processes are illustrated for pentadisperse and triadisperse particle systems,*** these processes,particles involved in the avalanche grow slowly in the early stage and explosively in the later stage,which is clearly different from the continuous and steady growth trend in the monodisperse *** examining the avalanche propagation,the number growth of particles involved in the avalanche and the slope of the number growth,the initial state can be divided into three stages:T1(nucleation stage),T2(propagation stage),T3(overall avalanche stage).We focus on the characteristics of the avalanche in the T2 stage,and find that propagation distances increase almost linearly in both axial and radial directions in polydisperse *** also consider the distribution characteristics of the average coordination number and average velocity for the moving *** results support that the polydisperse particle systems are more stable in the T2 stage.

关键词： avalanche initial state polydisperse particle systems propagation

Switching,explosion,and chaos of multi-wavelength soliton states in ultrafast fiber lasers

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 82-90页

作者： Zhi-Zeng Si Yue-Yue Wang Chao-Qing Dai college of optical Mechanical and Electrical EngineeringZhejiang A&F UniversityLin’an 311300China

Because of the complexity and difficulty of realizing a multi-wavelength soliton state,reports on its internal dynamic characteristics are *** this study,the switching and periodic soliton explosion processes of the multi-wavelength soliton state in a negative dispersion passively mode-locked fiber laser are *** generation of the multi-wavelength soliton state undergoes the process of noise,oscillation,and stable mode-locking,and the splitting and annihilation of solitons with different group velocities directly impact the generation and disappearance of three *** and negative dispersion lead to different group velocities of *** presence and displacement of solitons with different group velocities cause soliton collisions,which lead to soliton explosions.A soliton experiences relative phase oscillation,chaos,and oscillation,as well as convergence and separation before and after an *** an increase in parameters related to pump power,single-soliton oscillation,multi-wavelength solitons,and chaos are found in experiments and simulations,proving the relevance and reliability between simulation and experimental *** work promotes the dynamical study of multi-soliton collisions in nonlinear science and the development of chaos theory in multi-comb lasers.

关键词： multi-wavelength fiber laser soliton explosion chaos state switching real-time dynamics

Solitons and Their Biperiodic Pulsation in Ultrafast Fiber Lasers Based on CB/GO

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Chinese Physics Letters 2024年第8期41卷 28-32页

作者： Zhen-Tao Ju Zhi-Zeng Si Xin Yan Chao-Qing Dai college of optical Mechanical and Electrical EngineeringZhejiang A&F UniversityLin’an 311300China

The carbon black(CB)is introduced to manufacture CB/graphene oxide(GO)composite material to mitigate limitations of GO as a saturable absorber with the excellent performance in ultrafast fiber *** a central wavelength of 1555.5 nm,the stable mode-locked pulse with width of 656 fs,repetition rate of 20.16 MHz,and high signal-to-noise ratio of 82.07 dB is experimentally ***,experimental observations for pulsation phenomena of vector biperiodic solitons combining period-1 and period-17,period-2 and period-32,period-3 and period-36 are verified via simulations.

关键词： fiber periodic absorber

Measurement of acceleration and angular velocity of particles during a 3D silo discharge

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Particuology 2024年第9期92卷 61-71页

作者： Tongtong Mu Yiming Li Quan Chen Ran Li Hui Yang college of Medical Instrument Shanghai University of Medicine and Health SciencesShanghai201318China School of optical-electrical and computer engineering University of Shanghai for Science and TechnologyShanghai200093China

Accurate measurement of the three-dimensional(3D)movement of discrete particles is crucial for comprehending complex granular rheology in *** this paper,the acceleration and angular velocity of particles in 3D silos are measured by using a spherical detector based on inertial technology and magnetic positioning *** acceleration of particles is the largest in the center of silos,which suggest that the resistance generated by friction and extrusion is the ***,the angular velocity distribution follows lognormal function except for particles near the *** correlation between acceleration and angular velocity is opposite in different flow *** reveals for the first time that the extent to which the resultant force on the particles affects their rotational motion is related to the flow *** results have practical significance for regulating the granular flow pattern and optimizing the structural design of silos.

关键词： Granularflow Silo Angular velocity Acceleration

Winding Function Model-based Performance Evaluation of a PM Transverse Flux Generator for Applications in Direct-drive Systems

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CES Transactions on electrical Machines and Systems 2024年第2期8卷 216-226页

作者： Mehrage Ghods Jawad Faiz Ali A Pourmoosa IEEE School of electrical and computer engineering College of Engineeringthe University of Tehran

The magnetic flux in a permanent magnet transverse flux generator(PMTFG) is three-dimensional(3D), therefore, its efficacy is evaluated using 3D magnetic field analysis. Although the 3D finite-element method(FEM) is highly accurate and reliable for machine simulation, it requires a long computation time, which is crucial when it is to be used in an iterative optimization process. Therefore, an alternative to 3DFEM is required as a rapid and accurate analytical technique. This paper presents an analytical model for PMTFG analysis using winding function method. To obtain the air gap MMF distribution, the excitation magneto-motive force(MMF) and the turn function are determined based on certain assumptions. The magnetizing inductance, flux density, and back-electro-magnetomotive force of the winding are then determined. To assess the accuracy of the proposed method, the analytically calculated parameters of the generator are compared to those obtained by a 3D-FEM. The presented method requires significantly shorter computation time than the 3D-FEM with comparable accuracy.

关键词： Index Terms—Permanent magnet transverse flux generator Winding function 3D-FEM Cogging torque Prototyping

Performance Analysis of ZF and RZF in Low-Resolution ADC/DAC Massive MIMO Systems

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China Communications 2024年第8期21卷 115-126页

作者： Talha Younas Shen Jin Muluneh Mekonnen Gao Mingliang Saqib Saleem Sohaib Tahir Mahrukh Liaqat School of electrical and Electronic engineering Shandong University of TechnologyZibo 255000China Department of electrical and computer engineering COMSATS University IslamabadSahiwal Campus Department of electrical and computer engineering College of EngineeringDhofar UniversitySalalah 211Oman Department of electrical and computer engineering Addis Ababa Science and Technology UniversityAddis AbabaEthiopia Department of electrical engineering College of Electrical and Mechanical EngineeringNUSTIslamabadPakistan

Large number of antennas and higher bandwidth usage in massive multiple-input-multipleoutput(MIMO)systems create immense burden on receiver in terms of higher power *** power consumption at the receiver radio frequency(RF)circuits can be significantly reduced by the application of analog-to-digital converter(ADC)of low *** this paper we investigate bandwidth efficiency(BE)of massive MIMO with perfect channel state information(CSI)by applying low resolution ADCs with Rician *** start our analysis by deriving the additive quantization noise model,which helps to understand the effects of ADC resolution on BE by keeping the power constraint at the receiver in *** also investigate deeply the effects of using higher bit rates and the number of BS antennas on bandwidth efficiency(BE)of the *** emphasize that good bandwidth efficiency can be achieved by even using low resolution ADC by using regularized zero-forcing(RZF)combining *** also provide a generic analysis of energy efficiency(EE)with different options of bits by calculating the energy efficiencies(EE)using the achievable *** emphasize that satisfactory BE can be achieved by even using low-resolution ADC/DAC in massive MIMO.

关键词： low-bit analog-digital converter massive(multiple-input-multiple-output)MIMO minimum mean square error(MMSE) regularized zero forcing zero forcing

Liquid lens based holographic camera for real 3D scene hologram acquisition using end-to-end physical model-driven network

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Light(Science & Applications) 2024年第3期13卷 488-497页

作者： Di Wang Zhao-Song Li Yi Zheng You-Ran Zhao Chao Liu Jin-Bo Xu Yi-Wei Zheng Qian Huang Chen-Liang Chang Da-Wei Zhang Song-Lin Zhuang Qiong-Hua Wang School of Instrumentation and Optoelectronic engineering Beihang UniversityBeijing 100191China School of optical-electrical and computer engineering University of Shanghai for Science and TechnologyShanghai 200093China

With the development of artificial intelligence,neural network provides unique opportunities for holography,such as high fidelity and dynamic *** to obtain real 3D scene and generate high fidelity hologram in real time is an urgent ***,we propose a liquid lens based holographic camera for real 3D scene hologram acquisition using an end-to-end physical model-driven network(EEPMD-Net).As the core component of the liquid camera,the first 10 mm large aperture electrowetting-based liquid lens is proposed by using specially fabricated *** design of the liquid camera ensures that the multi-layers of the real 3D scene can be obtained quickly and with great imaging *** EEPMD-Net takes the information of real 3D scene as the input,and uses two new structures of encoder and decoder networks to realize low-noise phase *** comparing the intensity information between the reconstructed image after depth fusion and the target scene,the composite loss function is constructed for phase optimization,and the high-fidelity training of hologram with true depth of the 3D scene is realized for the first *** holographic camera achieves the high-fidelity and fast generation of the hologram of the real 3D scene,and the reconstructed experiment proves that the holographic image has the advantage of low *** proposed holographic camera is unique and can be used in 3D display,measurement,encryption and other fields.

关键词： calculation solution holographic

Bifurcation analysis and control study of improved full-speed differential model in connected vehicle environment

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Chinese Physics B 2024年第7期33卷 245-266页

作者：艾文欢雷正清李丹洋方栋梁刘大为 college of computer Science and engineering Northwest Normal UniversityLanzhou 730070China college of electrical engineering Lanzhou Institute of TechnologyLanzhou 730050China

In recent years, the traffic congestion problem has become more and more serious, and the research on traffic system control has become a new hot spot. Studying the bifurcation characteristics of traffic flow systems and designing control schemes for unstable pivots can alleviate the traffic congestion problem from a new perspective. In this work, the full-speed differential model considering the vehicle network environment is improved in order to adjust the traffic flow from the perspective of bifurcation control, the existence conditions of Hopf bifurcation and saddle-node bifurcation in the model are proved theoretically, and the stability mutation point for the stability of the transportation system is found. For the unstable bifurcation point, a nonlinear system feedback controller is designed by using Chebyshev polynomial approximation and stochastic feedback control method. The advancement, postponement, and elimination of Hopf bifurcation are achieved without changing the system equilibrium point, and the mutation behavior of the transportation system is controlled so as to alleviate the traffic congestion. The changes in the stability of complex traffic systems are explained through the bifurcation analysis, which can better capture the characteristics of the traffic flow. By adjusting the control parameters in the feedback controllers, the influence of the boundary conditions on the stability of the traffic system is adequately described, and the effects of the unstable focuses and saddle points on the system are suppressed to slow down the traffic flow. In addition, the unstable bifurcation points can be eliminated and the Hopf bifurcation can be controlled to advance, delay, and disappear,so as to realize the control of the stability behavior of the traffic system, which can help to alleviate the traffic congestion and describe the actual traffic phenomena as well.

关键词： bifurcation analysis vehicle queuing bifurcation control Hopf bifurcation

SwiftTheft: A Time-Efficient Model Extraction Attack Framework Against Cloud-Based Deep Neural Networks

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Chinese Journal of Electronics 2024年第1期33卷 90-100页

作者： Wenbin YANG Xueluan GONG Yanjiao CHEN Qian WANG Jianshuo DONG School of Cyber Science and engineering Wuhan University School of computer Science Wuhan University college of electrical engineering Zhejiang University

With the rise of artificial intelligence and cloud computing, machine-learning-as-a-service platforms,such as Google, Amazon, and IBM, have emerged to provide sophisticated tasks for cloud applications. These proprietary models are vulnerable to model extraction attacks due to their commercial value. In this paper, we propose a time-efficient model extraction attack framework called Swift Theft that aims to steal the functionality of cloud-based deep neural network models. We distinguish Swift Theft from the existing works with a novel distribution estimation algorithm and reference model settings, finding the most informative query samples without querying the victim model. The selected query samples can be applied to various cloud models with a one-time selection. We evaluate our proposed method through extensive experiments on three victim models and six datasets, with up to 16 models for each dataset. Compared to the existing attacks, Swift Theft increases agreement(i.e., similarity) by 8% while consuming 98% less selecting time.

关键词： Performance evaluation Cloud computing Analytical models Computational modeling Estimation Artificial neural networks Artificial intelligence