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Your search keyword '"YANG Lei"' showing total 399 results
Start Over Author "YANG Lei" Publication Year Range Last 50 years Publisher hindawi limited
399 results on '"YANG Lei"'

1. Operational Risk Assessment for International Transport Corridor: A Case Study of China-Pakistan Economic Corridor

Author

Yang Lei, Chengfeng Huang, and Yuan Wu

Subjects
Mathematics, QA1-939
Abstract

The international transport corridor is the basis and carrier of economic and trade exchanges between countries and regions. International transport corridors span different countries and regions, coupled with the long distance, complicated transportation environment and process, which determines the potential risks of the operation of the transport corridors. Therefore, accurately identifying and assessing the risk of international channels are an important prerequisite for ensuring its safe and stable operation. The expert scoring method is used to collect the basic data of risk identification, and the hesitant fuzzy decision theory is introduced. The dependent linguistic ordered weighted geometric (DLOWG) operator and the Failure Mode and Effect Analysis (FMEA) method are used in combination. Taking the China-Pakistan Economic Corridor (CPEC) as an example, evaluate the operational risks of the international transport corridor. The research results show that corruption, terrorism, and policy stability are the top three risk factors in the operation of the China-Pakistan transport corridor. The risk management and control should focus on these three types of risks and strengthen the security management along the route. Strengthen policy docking and communication, maintain political stability, and strengthen antiterrorism cooperation.

Published
2019
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5. A Low-Cost Wideband Digital Array Antenna Based on Stretch Processing Technique.

Author

Yu, Daqun, Hao, Zhangcheng, Yang, Lei, Wang, Yang, Sun, Lei, and Mao, Jianjun

Subjects
ANTENNA arrays, PHASED array radar, PHASED array antennas, SIGNAL processing, ANTENNAS (Electronics), MIMO radar, ARRAY processing
Abstract

Wideband digital phased array radar offers the advantages of high range resolution, which improves the recognition ability for multiple targets, group targets, and high-speed targets. Traditional wideband phased arrays use true time delay to compensate for aperture fill time; however, the cost increases significantly. In this paper, a wideband elemental digital array architecture based on the stretch processing method is proposed. By utilizing the time-domain and frequency-domain translation equivalence of the LFM (Linear Frequency Modulation) signal waveform, the equivalent aperture fill time is compensated for through frequency shift and phase shift after stretch processing. Compared to traditional wideband digital arrays, this method can dramatically reduce the required sampling rate and lower the requirements on antenna hardware, thereby reducing the manufacturing cost of system. A comprehensive analysis of the signal processing process and stretch processing method is provided. And an antenna array prototype is developed to verify the T/R channel compensation and wideband beamforming. Measured results show that the antenna is capable of ±60° scanning in azimuth plane and ±40° scanning in elevation plane, with a bandwidth of 500 MHz in S-band. The results demonstrate excellent wideband beam performance and accurate lobe scanning, which confirms the validity of the proposed wideband architecture for stretch processing, frequency shift, and phase shift. This method can be widely applied to the low-cost design and wideband performance improvement of wideband digital array radar. [ABSTRACT FROM AUTHOR]

Published
2024
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6. Tracking and Disturbance Suppression of the Radio Telescope Servo System Based on the Equivalent-Input-Disturbance Approach.

Author

Yang, Lei, Wang, Na, Liu, Zhiyong, and Li, Ning

Subjects
*VERY large array telescopes, *RADIO telescopes, *LINEAR matrix inequalities, *COST functions, *STATE feedback (Feedback control systems), *RADIO control
Abstract

This paper presents a composite control algorithm for the radio telescope servo control system to address the target tracking and matched/mismatched disturbance suppression problems. The algorithm consists of the equivalent-input-disturbance (EID) approach and the optimal control method. An EID estimator is developed using the difference between the estimated output of the state observer and the measurement output and then the estimate of the EID is fed forward into the control input to reject the disturbance. A cost function with clear physical meaning is selected and the weighting parameters are adjusted for the optimal controller to improve tracking performance. Considering the nonminimum phase characteristics of the radio telescope system, the state observer gain is computed using the linear matrix inequality (LMI) method. The system stability is analyzed using the small gain theorem, and the linear quadratic regulator (LQR) control method is utilized to determine the state feedback gain. Finally, the composite controller is designed for an identified telescope model. Simulation results show that for the tracking performance, the settling time of proposed method is 1.13 s and reduces by about 0.32 s and 0.87 s than that of the ADRC controller and PI controller, respectively. For the antidisturbance performance, the RMS value and the maximum error of the proposed method are 0.0039 and 0.0128, which are 42.86% and 40.38% of the ADRC controller and 30.71% and 27.77% of the PI controller, respectively, which indicates that the proposed method has better control performance. In addition, the proposed controller has certain robustness to systematic parameter perturbations. [ABSTRACT FROM AUTHOR]

Published
2024
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20. Multisource Information Risk Evaluation Technology of Mine Water Inrush Based on VWM: A Case Study of Weng’an Coal Mine

Author

Zijie Liu, Tao Li, Bo Li, Zhang Wenping, and Yang Lei

Subjects
QE1-996.5, Hydrogeology, Article Subject, business.industry, Computer science, 0211 other engineering and technologies, Coal mining, Geology, 02 engineering and technology, Factor analysis of information risk, 010502 geochemistry & geophysics, computer.software_genre, 01 natural sciences, Inrush current, Field (computer science), Hotspot (Wi-Fi), General Earth and Planetary Sciences, Data mining, business, Constant (mathematics), Cwm, computer, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences
Abstract

The use of multisource information fusion technology to predict the risk of water inrush from coal floor is a research hotspot in recent years, but the current evaluation method is mainly based on a constant weight evaluation model. Using constant weights to reflect the control effect of changing factor state values on water inrush evaluation has obvious limitations, and it is unable to describe the control effect of the hydrogeological condition mutation on the water inrush from the floor. In order to solve the above problems, this manuscript introduces the idea of variable weight into the field of water inrush evaluation, expounds on the significance of variable weight theory for water inrush evaluation, analyzes the characteristics of mine water inrush variable weight evaluation, and, on this basis, further combines GIS-based multisource information fusion technology and typical engineering case to compare with the evaluation effect map, evaluation unit, and comprehensive evaluation values. The differences between the variable weight model (VWM) and the constant weight model (CWM) are analyzed, which proves that the evaluation process of the variable weight evaluation model is more reasonable and can effectively improve the evaluation accuracy.

Published
2021

22. Hui Medicine Moxibustion Promotes the Absorption of Lumbar Disc Herniation and the Recovery of Motor Function in Rats through Fas/FasL Signaling Pathway

Author

Xu, Jianfeng, primary, Luo, Qiang, additional, Song, Junyao, additional, Zhang, Yanming, additional, Wang, Yingxu, additional, Yang, Lei, additional, Sha, Yinyin, additional, Sun, Bowen, additional, You, Na, additional, Tian, Xinbao, additional, Lin, Ruizhu, additional, and Wu, Yongli, additional

Published
2022
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40. Evaluation of Novel Tranexamic Acid/Montmorillonite Intercalation Composite, as a New Type of Hemostatic Material

Author

Ma, Fei, primary, Sui, Shujing, additional, Yang, Zhiyuan, additional, Ye, Tong, additional, Yang, Lei, additional, Han, Peng, additional, Gan, Hui, additional, Wu, Zhuona, additional, Gu, Ruolan, additional, Zhu, Xiaoxia, additional, Li, Fei, additional, Meng, Zhiyun, additional, Jiang, Zhiping, additional, and Dou, Guifang, additional

Published
2022
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43. Experimental and Numerical Investigation of Flow Measurement Mechanism and Hydraulic Performance of Portable Pillar-Shaped Flumes in Rectangular Channels

Author

Jinping Zhang, Shun Zhu, Bin Sun, Chao Zhang, Quan Liu, and Yang Lei

Subjects
Airfoil, Accuracy and precision, Article Subject, QC1-999, 0207 environmental engineering, 02 engineering and technology, 01 natural sciences, Flow measurement, 010305 fluids & plasmas, symbols.namesake, Hydraulic head, 0103 physical sciences, Froude number, 020701 environmental engineering, Choked flow, Civil and Structural Engineering, Turbulence, Physics, Mechanical Engineering, Mechanics, Geotechnical Engineering and Engineering Geology, Condensed Matter Physics, Flume, Mechanics of Materials, symbols, Geology
Abstract

Based on the principle of the critical flow and standard k-ε three-dimensional turbulence model, experiments and simulations were performed on a portable pillar-shaped flume with three contraction ratios under 12 working conditions. By combining the numerical simulations with the experiments, the theoretical stage-discharge formula of the portable pillar-shaped flume was developed, and the variations in the Froude number, backwater height, critical submergence, head loss, and velocity distribution were examined. The simulation data obtained from the standard k-ε three-dimensional turbulence model are in good agreement with the experimental results, with a maximum error of 8.65%. The maximum error in the difference between the theoretical stage-discharge formula and the measured value is 4.74%. The upstream Froude number is less than 0.5, and critical submergence is between 0.73 and 0.96. Compared to airfoil pillar-shaped flumes, the portable pillar-shaped flume had a significantly smaller head loss and backwater height. Finally, the portable pillar-shaped flume can be used for flow measurement and has the advantages of high measurement accuracy, low backwater height, and small head loss.

Published
2020

46. Association between Phenotypic Age and Mortality in Patients with Multivessel Coronary Artery Disease

Author

Ma, Qiong, primary, Li, Bo-Lin, additional, Yang, Lei, additional, Zhang, Miao, additional, Feng, Xin-Xin, additional, Li, Qian, additional, Liu, Hui, additional, Gao, Ya-Jie, additional, Ma, Wen-Zhuo, additional, Shi, Rui-Juan, additional, Xue, Yan-Bo, additional, Zheng, Xiao-Pu, additional, Gao, Ke, additional, and Mu, Jian-Jun, additional

Published
2022
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