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Three-dimensional spin Hall effect of light in tight focusing

Physical Review A 2020年第2期101卷 023819-023819页

作者： Weixing Shu Chuyang Lin Jun Wu Shizhen Chen Xiaohui Ling Xinxing Zhou Hailu Luo Shuangchun Wen Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices School of Physics and Electronics Hunan University Changsha 410082 China Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education Hunan Normal University Changsha 410081 China College of Computer Science and Electronic Engineering Hunan University Changsha 410082 China Hunan Provincial Key Laboratory of Intelligent Information Processing and Application College of Physics and Electronic Engineering Hengyang Normal University Hengyang 421002 China

We theoretically propose the realization of a three-dimensional (3D) spin Hall effect (SHE) of light by tightly focusing a linearly polarized light. Owing to the spin-orbital interaction in focusing, the left and right circularly polarized components of light are partly converted into each other, acquiring opposite vortex phases. As the superposition of the vortex and the initial vortex-free light, the two polarized components exhibit spiral intensity patterns which rotate oppositely around the propagation axis. Consequently, the two spin components are distributed alternatively in both the azimuthal and the longitudinal directions, leading to a 3D array of split spin components, and the transverse intensity is also spit asynchronously. Moreover, that array is rotatable by the incident polarization, and the longitudinal spacing in the array can be controlled by the numerical aperture of the lens. The 3D SHE of light finds an additional degree of freedom available to control the spin state of the photon, which may be valuable in optical manipulation and quantum information.

关键词： Classical optics

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Vibration measurement using a low-cost imaging sensor and image processing techniques 22

Vibration measurement using a low-cost imaging sensor and im...

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22nd World Congress of the International Measurement Confederation, IMEKO 2018

作者： Wang, T. Yan, Y. Wang, L. School of Control and Computer Engineering North China Electric Power University Beijing102206 China School of Engineering and Digital Arts University of Kent Canterbury KentCT2 7NT United Kingdom

Vibration measurement is essential for the monitoring of rotational machineries in a variety of industries. This paper presents a novel method using a low-cost imaging sensor and image processing techniques to measure the vibration of a rotor. A series of regions of interest in the captured images is selected to extract useful information for vibration measurement. Digital image correlation is applied to evaluate the similarity level of the regions of interest between sequential images and the reference image. Vibration measurement of a rotor is achieved through the spectral analysis of the signal indicating image similarity level. Experimental assessments of the proposed method were conducted on a purpose-built test rig where a commercial eddy current sensor was used to provide reference data. Experimental results demonstrate that the vibration frequencies and their relative amplitudes from the proposed measurement system agree well with those from the reference sensor. Meanwhile, the rotor vibrates at several distinct frequencies that increase with the rotational speed and hence agrees the expected vibration characteristics. © 2018 Institute of Physics Publishing. All rights reserved.

关键词： Costs

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Profiling of pulverized fuel flow in a square-shaped pneumatic conveying pipe using electrostatic sensor arrays 22

Profiling of pulverized fuel flow in a square-shaped pneumat...

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22nd World Congress of the International Measurement Confederation, IMEKO 2018

作者： Zhang, S. Wu, S. Qian, X. Yan, Y. School of Control and Computer Engineering North China Electric Power University Beijing102206 China School of Engineering and Digital Arts University of Kent Canterbury KentCT2 7NT United Kingdom

Quantitative profiling of pulverized fuel flow in a pneumatic conveying pipe is essential to balance the fuel distribution and improve the operation flexibility of a coal-fired boiler. In this study, an electrostatic sensing head comprising square-loop shaped electrodes and strip-shaped electrodes is used to characterize the particle flow in a square-shaped pipe under various flow conditions. Cross-correlation and data fusion algorithms are also proposed to process and combine the multi-channel signals from the sensor arrays in the sensing head. Dynamic characteristics of the particle flow in a vertical square-shaped pipe on an experimental platform are presented. Experimental results demonstrate that the cross-sectional profiles of the velocity and volumetric concentration of particles in a square-shaped pneumatic conveying pipe are highly non-uniform. © 2018 Web Portal IOP. All rights reserved.

关键词： Electrostatics

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Flicker measurement of burner flames through electrostatic sensing and spectral analysis 22

Flicker measurement of burner flames through electrostatic s...

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22nd World Congress of the International Measurement Confederation, IMEKO 2018

作者： Wu, J. Hu, Y. Yan, Y. Qian, X. Gu, S. School of Control and Computer Engineering North China Electric Power University Beijing102206 China School of Engineering and Digital Arts University of Kent Canterbury KentCT2 7NT United Kingdom

Measurement of the flicker frequency of a burner flame is desirable to achieve an in-depth understanding of the dynamics of combustion processes. This paper presents a novel method based on electrostatic sensing to measure the flicker frequency of a hydrocarbon flame. The flame flickering behaviour is determined by measuring the concentration changes of ions in the flame and characterized by processing the signals from an electrostatic sensor. Power spectral analysis of the sensor signals is performed to obtain their frequency components. Experimental tests were conducted on a laboratory-scale combustion test rig for different equivalence ratios. Flame images were simultaneously acquired using a high-speed camera to provide a direct comparison between the results from the electrostatic sensors and those from the imaging approach. It is found that the flickering frequency of the burner flame decreases with the equivalence ratio. The results obtained demonstrate that the electrostatic sensing method can measure the flickering frequency of the flame and is useful for the assessment of flame stability. © 2018 Institute of Physics Publishing. All rights reserved.

关键词： Electrostatics

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Improved DFIG-WPGS Efficiency via the tuned PI-Resonant Unit controller based on BAT Algorithm

Improved DFIG-WPGS Efficiency via the tuned PI-Resonant Unit...

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International Conference on computer, control, Electrical, and Electronics engineering (ICCCEEE)

作者： Omar Busati Alzain Xiangiie Liu Xiaobing Kong Alhassan Busati Alzain Mohammed.A. Abdalla Dhaifallah Ahmed Ali School of Control and Computer Eng. North China Electric Power Univ. Beijing China Department of Control Engineering Karary Univ. Khartoum Sudan School of E.Power Eng. North China Electric Power Univ. Beijing China

ISBN: (数字)9781728110066

ISBN: (纸本)9781728110073

This study introduces rotor-edge current control concerning stator-edge power behavior based on the online tuned Resonant Proportional-Integral Regulator using Discrete-BAT optimization Algorithm (DPIR-ON-DBAT) for the DFIG-WPGS as a Recurrent Artificial Neural Network (RANN). The DPIR-ON-DBAT is designed to control the distorted system with several dynamic positions and control goals. The +dq rotor-edge current components, swings of electromagnetic torque and stator-edge power, are regulated by the proposed control with a resonant part oscillated at 6-times the main system frequency. Consequently, these variables are instantly regulated by the DPIR-ON-DBAT technique without extra succession disassembling the segments. The simulation results are implemented using Matlab-Simulink for the introduced control of a 2MW DFIG-WPGS, which gave a better dynamic behavior than the customary PIR-Naslin and PI control principle.

关键词： Doubly fed induction generators Voltage control Mathematical model Power systems Heuristic algorithms Stator windings

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The Swimmers Motion Detection Using Improved VIBE Algorithm

The Swimmers Motion Detection Using Improved VIBE Algorithm

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International Conference on Robotics and Artificial Intelligence (ICRAI)

作者： Muhammad Aftab Hayat Goutian Yang Atif Iqbal Adeel Saleem Adil hussain Muhammad Mateen School of Control & Computer Engineering North China Electric Power University Beijing China School of Renewable Energy & Clean Energy North China Electric Power University Beijing China Department of Electrical Engineering The University of Lahore Lahore Pakistan School of Electrical & Electronics Engineering North China Electric Power University Beijing China

this paper proposed a novel method for drowning person detection in the swimming pool using video images. For background extraction and to update the exact motion area from the whole video using frame by frame difference vibe algorithm is used. Static and dynamic features are detected to recognize the normal swimmer and drowning person. The present invention discloses video-based swimming pools drowning event detection method. In the detection process Time of map(Tom), the method is used to improve the traditional VIBE result. The sequence of video images of the swimming pool is collected in real-time by using a camera installed above the water surface, which mainly includes three steps of swimmers detection, swimmers tracking and drowning person behavior analysis. In the aspect of swimmer detection, an improved VIBE swimmer detection algorithm is proposed, and the algorithm is used to determine the swimmer's position. The swimmer tracking and particle filter based on the color distribution model which is combined with the nearest neighbor data association algorithm to achieve tracking of multiple swimmers. In the analysis of drowning behavior, three characteristics of drowning behavior are proposed to determine whether the swimmer is drowning. The invention can monitor the swimming pool in real-time through the camera installed above the water surface in a real public swimming place, and automatically detect the drowning person, which has great engineering application value.

关键词：

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Reliability analysis of web server cluster systems based on proportional hazards model

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Journal of Southeast University(English Edition) 2018年第2期34卷 187-190页

作者： Hou Chunyan Wang Jinsong Chen Chen School of Computer Science and Engineering Tianjin University of TechnologyTianjin 300384China College of Computer and Control Engineering Nankai UniversityTianjin 300071China

An approach for web server cluster(WSC)reliability and degradation process analysis is *** reliability process is modeled as a non-homogeneous Markov process(NHMH)composed of several non-homogeneous Poisson processes(NHPPs).The arrival rate of each NHPP corresponds to the system software failure rate which is expressed using Cox s proportional hazards model(PHM)in terms of the cumulative and instantaneous load of the *** cumulative load refers to software cumulative execution time,and the instantaneous load denotes the rate that the users requests arrive at a *** result of reliability analysis is a time-varying reliability and degradation process over the WSC ***,the evaluation experiment shows the effectiveness of the proposed approach.

关键词： web server cluster load-sharing proportional hazards model reliability software aging

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When autonomous systems meet accuracy and transferability through AI: A survey

arXiv

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arXiv 2020年

作者： Zhang, Chongzhen Wang, Jianrui Yen, Gary G. Zhao, Chaoqiang Sun, Qiyu Tang, Yang Qian, Feng Kurths, Jürgen Key Laboratory of Advanced Control and Optimization for Chemical Process Ministry of Education East China University of Science and Technology Shanghai200237 China School of Electrical and Computer Engineering Oklahoma State University StillwaterOK74075 United States Potsdam Institute for Climate Impact Research Potsdam14473 Germany Institute of Physics Humboldt University of Berlin Berlin12489 Germany

With widespread applications of artificial intelligence (AI), the capabilities of the perception, understanding, decision-making and control for autonomous systems have improved significantly in the past years. When autonomous systems consider the performance of accuracy and transferability, several AI methods, like adversarial learning, reinforcement learning (RL) and meta-learning, show their powerful performance. Here, we review the learning-based approaches in autonomous systems from the perspectives of accuracy and transferability. Accuracy means that a well-trained model shows good results during the testing phase, in which the testing set shares a same task or a data distribution with the training set. Transferability means that when a well-trained model is transferred to other testing domains, the accuracy is still good. Firstly, we introduce some basic concepts of transfer learning and then present some preliminaries of adversarial learning, RL and meta-learning. Secondly, we focus on reviewing the accuracy or transferability or both of them to show the advantages of adversarial learning, like generative adversarial networks (GANs), in typical computer vision tasks in autonomous systems, including image style transfer, image super-resolution, image deblurring/dehazing/rain removal, semantic segmentation, depth estimation, pedestrian detection and person re-identification (re-ID). Then, we further review the performance of RL and meta-learning from the aspects of accuracy or transferability or both of them in autonomous systems, involving pedestrian tracking, robot navigation and robotic manipulation. Finally, we discuss several challenges and future topics for using adversarial learning, RL and meta-learning in autonomous systems. Copyright © 2020, The Authors. All rights reserved.

关键词： Reinforcement learning

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Particle size estimation of pulverized fuel in pneumatic pipelines using electrostatic sensing techniques 22

Particle size estimation of pulverized fuel in pneumatic pip...

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22nd World Congress of the International Measurement Confederation, IMEKO 2018

作者： Qian, X. Wei, X. Yan, Y. Shi, D. School of Control and Computer Engineering North China Electric Power University Beijing102206 China School of Engineering and Digital Arts University of Kent Canterbury KentCT2 7NT United Kingdom

Particle size measurement of pulverized fuel (PF) provides useful data for efficiency improvement of a pulverizing system, optimization of fuel combustion and emission reduction on a fired power plant. This paper presents an experimental study of particle size estimation of pneumatically conveyed PF through electrostatic sensing. An electrostatic sensor head consisting of two narrow and one wide ring-shaped electrodes is designed and implemented to measure the PF velocity and quantify the features of the sensor signals. Experimental tests using particles with three different size ranges were conducted on the vertical pipe section of a 74 mm bore gas-solid two-phase flow test facility under various flow conditions. Test results show that the root-mean-square magnitude and power spectral density of electrostatic signals vary with particle size. For the same air velocity, the small change in particle velocity is an indication of particle size as the particle velocity decreases when the particle size is larger. The proposed method is capable of estimating PF particle size and has the potential to offer considerable advantages over its counterparts in power plant applications. © 2018 Institute of Physics Publishing. All rights reserved.

关键词： Particle size

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Coordinated Dispatching and Frequency control Strategy of Power Systems with Large Scale Wind Power Penetration

Coordinated Dispatching and Frequency Control Strategy of Po...

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Chinese Automation Congress (CAC)

作者： Jianhua Zhang Rui Shan Fei Xu Bo Hu Guiping Zhou Guolian Hou Congzhi Huang State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing China School of Control and Computer Engineering North China Electric Power University Beijing China Tsinghua University Beijing China State Grid Liaoning Electric Power Supply Co. Ltd. Shenyang China

ISBN: (数字)9781728176871

ISBN: (纸本)9781728176888

In this paper, a coordinated dispatching and frequency control strategy is presented for wind turbines (WTs) participating in frequency regulation from three levels. Firstly, the coordinated dispatching and frequency control strategy among multi-source power generation systems is given with the aid of the wind power installed capacity penetration rate; Secondly, the coordinated distribution strategy among the wind farms is presented by combing the incremental active power reference with parameters tuning method; Thirdly, the coordinated control is investigated by integrating droop control, inertia control and de-load control for each WT. Simulation results demonstrate that the proposed coordinated dispatching and frequency control strategy can obtain better frequency regulation performance for power systems with large scale wind power penetration.

关键词： Frequency control Wind turbines Wind power generation Dispatching Wind speed Wind farms Rotors

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