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The 8th International Symposium on Test Automation &Instrumentation (ISTAI 2020)

作者： Y. Fu Z. Luan F. Zhou S. Wang Key Laboratory of Modern Measurement & Control Technology Ministry of Education Beijing Information Science & Technology University Beijing China

There are common faults in planetary gearbox that it is not suitable for shutdown detection at the initial stage or there are many kinds of faults which are not easy to classify accurately. Based on the above reasons, this paper proposes a method combining multi population genetic algorithm (MPGA) and BP neural network. Traditional BP neural network uses a variety of genetic algorithms to optimize the initial weights between layers and the initial threshold corresponding to the single layer network. The traditional method greatly increases the global optimization ability of BP neural network when gradient drops, so we avoid the problem that the local optimal of selecting initial weight and initial threshold. This paper uses the tradition BP neural network and optimized MPGA BP neural network to classify the common faults of planetary gearbox. Then we compare the results of traditional BP neural network and MPGA BP neural network in planetary gearbox fault classification. The results show that: MPGA BP neural network has higher prediction accuracy than traditional BP neural network, so this method can be used for fault classification of planetary gearboxes.

关键词： backpropagation gears fault diagnosis neural nets genetic algorithms mechanical engineering computing

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OFDM Signal Design Based on Electrode-based Through-the-earth Communication

OFDM Signal Design Based on Electrode-based Through-the-eart...

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International Conference on Ubiquitous Computing and Communications and International Symposium on Cyberspace and Security (IUCC-CSS)

作者： Gan Zhang Zhan Xu Jinhui Chen Xiaowen Wen Key Laboratory of Modern Measurement and Control Technology Beijing Information Science and Technology University Beijing China School of Automation Beijing Information Science and Technology University Beijing China School of Information and Communication Engineering Beijing Information Science and Technology University Beijing China

ISBN: (纸本)9781665466684

Through-the-earth (TTE) communication is of great significance to establish the information transmission with the trapped people at the first time and ensure the smooth flow of information. The complex electromagnetic environment of the terrestrial channel brings many difficulties in wireless signal transmission. This paper proposes an orthogonal frequency division multiplexing (OFDM) signal design scheme of electrode-based TTE communication. The scheme, which has intense penetration and high reliability, designs the frequency and modulation mode of the subcarrier according to the electromagnetic characteristics of earth channel and noise interference. This paper also provides the results of field experiments to show the performance of this OFDM signal.

关键词： Earth Wireless communication Frequency modulation OFDM Low-pass filters Interference Ubiquitous computing

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REVIEW OF FAULT DIAGNOSIS METHODS FOR ROTATING MACHINERY BASED ON DEEP LEARNING

REVIEW OF FAULT DIAGNOSIS METHODS FOR ROTATING MACHINERY BAS...

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The 8th International Symposium on Test Automation &Instrumentation (ISTAI 2020)

作者： Y. L. Guo G. X. Wu X. L. Liu X. L. Xu The Ministry of Education Key Laboratory of Modern Measurement and Control Technology Beijing Information Science&Technology University Beijing China

Mechanical equipment fault diagnosis technology is a new research field with the development of modern science and technology In recent years, the deep learning has been applied into the field of mechanical equipment fault diagnosis by more and more researchers. Deep learning has been widely applied in various in dustries and fields with its unique advantages in feature extraction and pattern recognition. The development history of deep learning is first briefly reviewed. Then, four fault diagnosis methods based on deep learning model are emphatically analyzed com bined with the characteristics and requirements of fault diagnosis technology for large rotating machinery equipment, and the problems and challenges they face are discussed. Finally, the research direction worth to be carried out in the future is prospected.

关键词： fault diagnosis mechanical engineering computing feature extraction machinery learning (artificial intelligence)

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Computation simulation and experiment investigations of stable co-doping perovskite solar cells with TiO 2 /SnO 2 bilayer and CuSCN structures

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Journal of Alloys and Compounds 2025年 1032卷

作者： Guangdong Li Mingxiang Xu Qingwang Bai Xiaoping Zou Xiao Bai School of Physics Southeast University Nanjing 211189 China Beijing Advanced Innovation Center for Materials Genome Engineering Research Center for Sensor Technology Beijing Key Laboratory for Sensor MOE Key Laboratory for Modern Measurement and Control Technology School of Applied Sciences Beijing Information Science and Technology University Jianxiangqiao Campus Beijing 100101 China

The charge transport layers play a momentous role in facilitating the extraction and injection of carriers in perovskite solar cells (PSCs). Unfortunately, the performance of PSCs fabricated with conventional charge transport materials exhibits significant hysteresis and instability. Here we utilise the composite TiO₂/SnO₂ with superior electron mobility and stability and the low-cost CuSCN as bilayer electron transport layer (ETL) and hole transport layer (HTL) materials, respectively. The PSCs with the p-n-n (p-type FA x MA 1-x PbI x Br y Cl 3-x-y (FA=CH(NH 2 ) 2 ), MA=CH 3 NH 3 )-n-type SnO 2 -n-type TiO 2 ) construction of FTO/TiO 2 /SnO 2 /FA x MA 1-x PbI x Br y Cl 3-x-y /CuSCN/C/FTO have been investigated via the computation simulation and experiment. It has been observed that the PSCs performance of p-n-n structure surpasses that of n-n-p (n-type SnO 2 -n-type TiO 2 -p-type FA x MA 1-x PbI x Br y Cl 3-x-y ) structure, benefiting from the existence of the bilayer ETL with p-n-n structure, which improves the collection ability, and the lifetime and mobility of photogenerated carriers. The perovskite thin film can be uniformly covered by the CuSCN HTL with 25 μL CuSCN drop-coating solution, which effectively reducing the hysteresis of the device under the atmosphere conditions during the experiment. Furthermore, we further demonstrate that the thickness of functional layers, conduction band offset, doping concentration, and operating temperature play crucial roles in determining the photophysical and photoelectric properties of PSCs. The simulation results imply that the PSCs we designed and optimized not only have high power conversion efficiency (PCE) (17.7619 %) at 295 K but also maintain ascendant stability. This work shall provide up an effective strategy for the realization of high efficiency and long-term stable carbon-based PSCs.

关键词： Bilayer ETL Carbon-based PSCs Co-doped CuSCN Low-cost Stability

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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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Research on acquisition and recognition of Naxi speaker's speech information

Research on acquisition and recognition of Naxi speaker's sp...

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

作者： Wu, Guoxin Xu, Xiaoli Wang, Shanghong Jia, Xu Key Laboratory of Modern Measurement and Control Technology Ministry of Education Beijing Information Science and Technology University Beijing China

The human–machine dialogue system allows people and the machine to communicate basically. This technology is also attracting more and more attention. It is conducive to the realisation of resource sharing, inheritance, and protection of Dongba culture worldwide to analyse the Naxi speech recognition for the protection and inheritance needs of Naxi Dongba culture. The model was established for Naxi speaker recognition, and the method is studied with text-independent speaker speech voice recognition. The practical analysis method was used to compare the application effect of Gaussian mixture model (GMM) and hidden Markov model (HMM) in the processing of speaker recognition in Naxi speaker's pronunciation. It is very useful to provide a theoretical basis for the establishment of a Naxi language-based human–computer interaction system to find out the speaker's voice characteristics, personality differences, and different regions. This is a theoretically necessary analysis of ethnic minority languages and the protection of ethnic and folk cultures. It can also provide practical significance for carrying out ethnic cultural differences analysis. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Hidden Markov models

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Rolling bearing fault diagnosis based on EEMD sample entropy and PNN

Rolling bearing fault diagnosis based on EEMD sample entropy...

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

作者： Liu, Xiuli Zhang, Xueying Luan, Zhongquan Xu, Xiaoli Beijing Information Science and Technology University Ministry of Education Key Laboratory of Modern Measurement and Control Technology Beijing China

A fault diagnosis method for rolling bearing based on ensemble empirical mode decomposition (EEMD) sample entropy and probabilistic neural network (PNN) is proposed for non-steady and non-linear signals. First, the rolling bearing signals are decomposed into intrinsic mode function (IMF) using EEMD. Then, the kurtosis of each component is calculated. Five components with large kurtosis are selected and the sample entropy is extracted to form the feature vectors. Finally, the feature vectors are input to the PNN for fault diagnosis. The method is used to classify the type of the rolling bearing fault. The results show that the accuracy of fault diagnosis of the proposed method is 100%, which proves the effectiveness of the proposed method. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Roller bearings

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Fault diagnosis of rolling bearing based on kurtosis criterion VMD and modulo square threshold

Fault diagnosis of rolling bearing based on kurtosis criteri...

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

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

Aiming at the problem that fault signals of rolling bearing are easily submerged by the strong background noise, which makes it difficult to extract fault information, so a method based on kurtosis criterion variational mode decomposition (VMD) and modulo square threshold is proposed and applied to fault diagnosis of rolling bearing. First, the vibration signals of rolling bearing are processed by VMD. Second, the signals are reconstructed by selecting the intrinsic mode function (IMF) components with the largest kurtosis and the second largest kurtosis. Finally, the reconstruction signals are de-noised by the modulo square threshold. Through the test of the inner ring and outer ring of the rolling bearing, the feasibility and effectiveness of the proposed method are verified. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Roller bearings

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Dynamic testing and analysis of turbine generator shafting

Dynamic testing and analysis of turbine generator shafting

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

作者： Tang, Changliang Wang, Liyong Chen, Tao Key Laboratory of Modern Measurement and Control Technology Ministry of Education Beijing Information Science and Technology University Beijing China

With the world's energy shortage, the scholars all over the world have done a lot of research work on the efficient use of energy, energy-saving emission reduction, and the development of new energy. Turbine generators have a wide range of applications in energy recovery. In this study, a new type of turbine generator structure is proposed. Four disc-type permanent magnet motors are symmetrically mounted on the shafting, and are supported by gas hydrostatic bearing. The vibration tests of the shafting were carried out. The vibration characteristics of the shafting were analysed by using the bode diagram, the time-waterfall map, the bifurcation diagram, the shaft orbits at the typical speeds, and the Poincare maps, which can provide references for developing high-speed turbine generators. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Energy conservation

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Development of fault diagnosis system for wind power planetary transmission based on labview

Development of fault diagnosis system for wind power planeta...

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

作者： Yang, Zhihan Wang, Shaohong Ma, Chao Huang, Jingnan Beijing Information Science and Technology University Ministry of Education Key Laboratory of Modern Measurement and Control Technology Beijing China

The article uses LabView to develop a fault diagnosis system for wind power planetary transmissions. First, use LabView software to create a signal acquisition system. Then, the built wind turbine planetary transmission experiment platform was combined with the NI9171 data acquisition card and the upper computer. The hysteresis brake was used in the laboratory to simulate the external wind environment, and the planetary gear transmission planetary gear crack fault diagnosis and testing experiments were performed. The frequency domain signal is obtained from the initial time domain signal obtained by the experiment through the EMD and envelope demodulation method. The frequency of the corresponding planetary gear crack in the frequency domain signal is compared with the theoretical calculation of the planetary gear crack failure frequency. The results show that the frequency of the corresponding planetary gear cracks in the frequency domain spectra obtained by the experiment is basically consistent with the theoretical calculation of the frequency of cracks in planetary gears. The fault diagnosis system developed by LabView is reliable. The experiment provides a theoretical basis for fault diagnosis, optimisation design, and life prediction of wind turbine planetary transmissions. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Failure analysis

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