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A Survey of Abnormal Event Perception Research Based on Mobile Phone Location Big Data

Journal of Physics: Conference Series 2021年第1期1792卷

作者： Hu Yang Zhang Xiaoyong Xiao Di Beijing Information Science & Technology University Automated institute Beijing China Beijing Key Laboratory of High Dynamic Navigation Technology Beijing China Key Laboratory of Modern Measurement & Control Technology Beijing China

The perception of human behavior that is different from normal has always been a common concern in many fields. The widespread use of smartphones makes it possible to obtain a large amount of user activities at fine spatial scales. In this context, this article first systematically summarizes the research on human behavior patterns in the era of mobile phone big data. Although the current research has made certain research progress, there are certain limitations in data source selection and activity semantic analysis. Then it focuses on the relevant research on the perception of abnormal events by mobile phone positioning big data, including the research progress in abnormal event early warning and emergency response, and believes that there is more room for development in related research. The analysis of these studies provides reference value for handling similar emergencies in the future, especially for post-disaster emergency response and resource allocation. It provides strong theoretical support.

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A study of underwater transducers based on piezoelectric composites working at shear vibration modal

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Zhendong yu Chongji/Journal of Vibration and Shock 2019年第8期38卷 193-197and237页

作者： Jia, Junbo Qin, Lei Zhong, Chao Wang, Likun Research Center of Sensor Technology Beijing Information Science & Technology University Beijing100192 China Beijing Key Laboratory for Optoelectronic Measurement Technology Beijing Information Science & Technology University Beijing100192 China Key Laboratory of Modern Measurement & Control Technology Ministry of Education Beijing Information Science and Technology University Beijing100192 China

The shear vibration modes (d15 mode) of piezoelectric ceramics have many advantages, such as high electromechanical coupling coefficient, generally higher piezoelectric constant, low frequency constant, and dielectric constant. It thus has a good performance in piezoelectric energy collector and new structural composite transducers. The shear vibrations generated by the piezoelectric ceramics were converted into the thickness vibration of the composite with designing a transition layer with a special structure. At the same time, this transition layer meets the requirements to radiate underwater longitudinal wave, and thus improves the piezoelectric properties of composite materials. The impact of the transition layer material types on the overall performance of the composite material was studied through the finite element analysis and experiments. © 2019, Editorial Office of Journal of Vibration and Shock. All right reserved.

关键词： Finite element method

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The Design Factor Analysis of a Miniaturized Rotating Guided Ammunition Actuator

The Design Factor Analysis of a Miniaturized Rotating Guided...

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第三十八届中国控制会议

作者： Gao Hao Fan Jun-fang Beijing Key Laboratory of High Dynamic Navigation Technology Beijing Information Science & Technology University Key Laboratory of Modern Measurement & Control Technology Ministry of Education

The performance of actuator directly affects the overall performance index of guided munition and determines its dynamic flight quality and guidance precision. The design of actuator system needs to meet many constraints. In this paper,self-spin frequency and actuator hinge moment are listed for the design of the actuator of a miniaturized rotating guided munition. First, combining with the motion characteristics of guided munition and criterion of self-spin frequency design, the dynamic coefficient and natural frequency is calculated, the self-spin frequency which meets the design requirements is obtained, the relationship between actuator turn frequency and self-spin frequency is discussed;and then, aiming at the hinge moment of actuator surface, the calculating criterion is discussed and the engineering calculating method is *** to the performance index of a certain actuator, the calculating result of the hinge moment of the actuator surface is finally obtained, which can be of great guiding significance to the test of the hinge moment of the actuator surface.

关键词： Miniaturized rotating guided munition Self-spin frequency Actuator Hinge moment

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Simultaneously Transmitting and Reflecting Reconfigurable Intelligent Surface Assisted NOMA Networks

arXiv

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arXiv 2021年

作者： Yue, Xinwei Xie, Jin Liu, Yuanwei Han, Zhihao Liu, Rongke Ding, Zhiguo 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 Electronic Engineering and Computer Science Queen Mary University of London LondonE1 4NS United Kingdom The School of Electronic and Information Engineering Beihang University Beijing100191 China The Department of Electrical Engineering Princeton University Princeton United States The School of Electrical and Electronic Engineering The University of Manchester Manchester United Kingdom

Simultaneously transmitting/refracting and reflecting reconfigurable intelligent surface (STAR-RIS) has been introduced to achieve full coverage area. This paper investigate the performance of STAR-RIS assisted non-orthogonal multiple access (NOMA) networks over Rician fading channels, where the incidence signals sent by base station are reflected and transmitted to the nearby user and distant user, respectively. To evaluate the performance of STAR-RIS-NOMA networks, we derive new approximate expressions of outage probability and ergodic rate for a pair of users, in which the imperfect successive interference cancellation (ipSIC) and perfect SIC (pSIC) schemes are taken into consideration. Based on the asymptotic expressions, the diversity orders of the nearby user with ipSIC/pSIC and distant user are achieved carefully. The high signal-to-noise ratio slopes of ergodic rates for nearby user with pSIC and distant user are equal to one and zero, respectively. In addition, the system throughput of STAR-RIS-NOMA is discussed in delay-limited and delay-tolerant modes. Simulation results are provided to verify the accuracy of the theoretical analyses and demonstrate that: 1) The outage probability of STAR-RIS-NOMA outperforms that of STAR-RIS assisted orthogonal multiple access (OMA) and conventional cooperative communication systems;2) With the increasing of reflecting elements K and Rician factor κ, the STAR-RIS-NOMA networks are capable of attaining the enhanced performance;and 3) The ergodic rates of STAR-RIS-NOMA are superior to that of STAR-RIS-OMA. Copyright © 2021, The Authors. All rights reserved.

关键词： Signal to noise ratio

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NURBS interpolation for tangential point tracing grinding of eccentric shaft

NURBS interpolation for tangential point tracing grinding of...

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7th International Symposium on Test Automation and Instrumentation, ISTAI 2018

作者： Li, Zhonggang Han, Qiushi Peng, Baoying Li, Qiguang Zuo, Yunbo China Academy of Machinery Science and Technology Haidian Shouti Nanlu No.2 Beijing China Key Laboratory of Modern Measurement and Control Technology Beijing Information Science and Technology University Haidian Qinghe Xiaoying Donglu No.12 Beijing China

The sine eccentric shaft is one of the most important parts for industrial robot RV reducer, and its machining quality has immediate effect on the overall device performance. The eccentric shaft X-C linkage grinding model is built based on the tangential point tracing machining principle, and the method of calculating the roundness error for eccentric circle grinding is proposed here. The research is performed on non-uniform rational B-spline (NURBS) interpolation for the coordinates’ densification of eccentric shaft X-C linkage grinding, and the algorithm process is put forward. The process of eccentric grinding is simulated and analysed by wheel inversion envelope method. The results show that the eccentric tangent point tracking model proposed is correct. Compared with the linear interpolation, NURBS interpolation can remarkably improve the accuracy of eccentric shaft tangent point tracking grinding. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Grinding (machining)

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Study on Underwater Performance of Underwater Transducer Manufactured by 1-1-3 Piezoelectric Composite

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Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 2019年第2期37卷 386-392页

作者： Du, Haibo Qin, Lei Zhong, Chao Wang, Likun Research Center of Sensor Technology Beijing Information Science & Technology University Beijing100192 China Key Laboratory of Modern Measurement & Control Technology Ministry of Education Beijing Information Science and Technology University Beijing100192 China

A novel kind of underwater transducer with trapezoidal matching layer manufactured by 1-1-3 piezoelectric composite has been proposed to improve the underwater performance of high frequency transducer. In this paper, the finite element method has been used to analyze the influence of the matching layer on the electrical properties of the composite materials and vibration displacement of the radiation area. Two kinds of underwater transducers with and without matching layers have been fabricated. The experimental results show that the transmission voltage response of the underwater transducer with matching layer reaches 169.4 dB at 360 kHz, and the receiving voltage sensitivity reaches-190 dB, the bandwidth is up to 70 kHz and the maximum sound source level is 208 dB. Comparing with transducer without matching layer, the transmission voltage response is increased by 3.8 dB. Meanwhile the sound source level is increased by 6 dB. The received bandwidth is increased by 1.45 times. © 2019 Journal of Northwestern Polytechnical University.

关键词： Bandwidth

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Fault Evolution Parameter Extraction Method Faced to Wind Turbine Gearbox System 57

Fault Evolution Parameter Extraction Method Faced to Wind Tu...

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57th Annual Conference of the Society of Instrument and control Engineers of Japan, SICE 2018

作者： Zhanglei, Jiang Yapeng, Wu Xiaoli, Xu Liyong, Wang Xiuli, Liu Ministry of Education Beijing Information Science and Technology University Key Laboratory of Modern Measurement Control Technology Beijing China

ISBN: (纸本)9784907764609

Rotating machinery is the most widely used mechanical equipment in production, and wind turbines are typical large rotating machinery, whether the equipment running in safe and stable state has an important impact on the economy and society. The wind turbine gear running in variable conditions and variable speed state, so traditional method which studying fault mechanism through fault feature frequency under certain speed is no longer applicable. This paper describes the evolutionary trajectory of spalling fault of wind turbine gearbox transmission system. Deterioration evolutionary matrix has been proposed based on higher-order cumulant method, and the mapping mechanism is established between the fault evolution and fault state migration. Fault evolution parameter such as mean value and variance of normal distribution has been extracted and used to depict fault evolutionary track. Finally, the graphical representation of fault evolution process is explored. Concerning the fault of gearbox transmission system, this research mainly emphasizes on fault evolution. It will provide scientific means to implement predictive maintenance, and avoid occurrence of fatal accidents. © 2018 The Society of Instrument and control Enginners - SICE.

关键词： Wind turbines

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Fitting algorithm for interferometric spectrum of fiber Fabry-Perot cavity acoustic sensors

Fitting algorithm for interferometric spectrum of fiber Fabr...

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作者： Changkun Yu Jin Cheng Yangmeng Tian Xiaoping Zou Research Center for Sensor Technology Beijing Key Laboratory for Sensor Ministry of Education Key Laboratory for Modern Measurement and Control TechnologySchool of Applied Sciences Beijing Information Science and Technology University

Fiber Fabry-Perot cavity acoustic sensors have been widely used in some fields recently due to its advantages such as high sensitivity, resistance to electromagnetic interference, etc. In order to control the performance of the sensors, it is necessary to precisely adjust the cavity length. In order to obtain the cavity length efficiently and accurately, a fitting algorithm for interference spectrum is proposed in this paper. The base of the algorithm is the principle of light interference and the key of the algorithm is to find the peaks and valleys of the interference spectrum. Experimental results show that the algorithm has a high fitting degree.

关键词： Fitting algorithm for interferometric spectrum of fiber Fabry-Perot cavity acoustic sensors

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Performance analysis of intelligent reflecting surface assisted NOMA networks

arXiv

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arXiv 2020年

作者： Yue, Xinwei Liu, Yuanwei Key Laboratory of Modern Measurement and Control Technology Ministry of Education School of Information and Communication Engineering Beijing Information Science and Technology University Beijing100101 China School of Electronic Engineering and Computer Science Queen Mary University of London LondonE1 4NS United Kingdom

Intelligent reflecting surface (IRS) is a promising technology to enhance the coverage and performance of wireless networks. We consider the application of IRS to non-orthogonal multiple access (NOMA), where a base station transmits superposed signals to multiple users by the virtue of an IRS. The performance of an IRS-assisted NOMA networks with imperfect successive interference cancellation (ipSIC) and perfect successive interference cancellation (pSIC) is investigated by invoking 1-bit coding scheme. In particular, we derive new exact and asymptotic expressions for both outage probability and ergodic rate of the mth user with ipSIC/pSIC. Based on analytical results, the diversity order of the m-th user with pSIC is in connection with the number of reflecting elements and channel ordering. The high signal-to-noise radio (SNR) slope of ergodic rate for the m-th user is obtained. The throughput and energy efficiency of nonorthogonal users for IRS-NOMA are discussed both in delaylimited and delay-tolerant transmission modes. Additionally, we derive new exact expressions of outage probability and ergodic rate for IRS-assisted orthogonal multiple access (IRS-OMA). Numerical results are presented to substantiate our analyses and demonstrate that: i) The outage behaviors of IRS-NOMA are superior to that of IRS-OMA and relaying schemes;ii) With increasing the number of reflecting elements, IRS-NOMA is capable of achieving enhanced outage performance;and iii) The M-th user has a larger ergodic rate compared to IRS-OMA and benchmarks. However, the ergodic performance of the m-th user exceeds relaying schemes in the low SNR regime. Copyright © 2020, The Authors. All rights reserved.

关键词： Signal to noise ratio

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Fault Diagnosis Method of Wind Turbine Gearbox Based on Deep Belief Network and Vibration Signal 57

Fault Diagnosis Method of Wind Turbine Gearbox Based on Deep...

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57th Annual Conference of the Society of Instrument and control Engineers of Japan, SICE 2018

作者： Xiuli, Liu Xueying, Zhang Liyong, Wang Beijing Information Science and Technology University Key Laboratory of Modern Measurement Control Technology of Ministry of Education Beijing100192 China

ISBN: (纸本)9784907764609

With the development of wind power, the fault of wind turbine is increasing year by year. The gearbox is the fault multiple component of the wind turbine. The monitoring system gets massive data, and the health monitoring of the fan has also entered the era of 'big data'. The new problem in the field of health monitoring of mechanical equipment is to excavate information from these large data and to identify the health status of equipment efficiently and accurately. Deep learning is an effective tool for large data processing. Based on the strong perception and self-learning ability of deep learning theory, a fault diagnosis method of wind turbine gearbox based on deep belief network and vibration signal is proposed in this paper. The original fault sample vibration signal is input to the deep belief network to get the deep learning sample model. At the same time, Batch Normalization is added to reduce the overfitting probability and improve the convergence speed of the network. Then the trained deep neural network model is applied to the fault diagnosis of the planetary gear box of the wind turbine gearbox, and the results show that the method is more accurate than the DBN, the BPNN algorithm and the traditional fault diagnosis method. © 2018 The Society of Instrument and control Enginners - SICE.

关键词： Wind turbines

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