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4 results on '"Ma, Zhengying"'

2. Damage Analysis of Urban Comprehensive Pipe Gallery Caused by Internal Gas Explosion Based on HHT.

Author

Li, Linna, Ma, Zhengying, Zhong, Dongwang, Li, Tengfei, and Zhang, Qi

Subjects
*GAS explosions, *PIEZOELECTRIC detectors, *PIEZOELECTRIC ceramics, *TIME-frequency analysis, *PIPE, *SIGNAL processing
Abstract

In this paper, the method of embedding piezoelectric ceramic sensors is used to test the damage of the materials and models of the urban comprehensive pipe gallery. The monitoring signal is processed by HHT method, and the frequency and energy changes of the piezoelectric signal before and after the explosion were analyzed, thus the damage characteristics of the urban comprehensive pipe gallery under the internal gas explosion are determined. The results show that in the gas explosion test inside the pipe gallery model, the waveform and peak value of the piezoelectric signal before and after the explosion did not change significantly, indicating that there was no obvious damage to the side wall of the integrated pipe gallery. However, after further time-frequency analysis of the piezoelectric signal by HHT, it is found that the dominant frequency of the piezoelectric signal after explosion has a downward trend, so it is judged that there is a small damage in the pipe gallery after explosion. [ABSTRACT FROM AUTHOR]

Published
2024
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3. DRFM jamming suppression for radar exploiting linear frequency modulation transmission

Author

Feng Wang, Ma Zhengying, Zhang Chi, Defu Jiang, and Wei Shuang

Subjects
020301 aerospace & aeronautics, Pulse-Doppler radar, 020206 networking & telecommunications, Jamming, 02 engineering and technology, law.invention, Constant false alarm rate, Continuous-wave radar, 0203 mechanical engineering, law, Radar jamming and deception, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, Digital radio frequency memory, Radar, Frequency modulation, Mathematics
Abstract

Digital radio frequency memory (DRFM) jamming is difficult to eliminate if it enters a radar system from the main lobe. A novel processing scheme for radar using linear frequency modulation waveform is proposed to accomplish target detection in asynchronous false target scenarios in accordance with the incoherent characteristic of the jamming signals. The technique of fractional Fourier transformation is adopted to transform the received signals with different time delays into single frequencies, then the target is estimated by a type of modified multiple signal classification approach. The difference of the estimated frequencies among the multiple transmitting period is used to discriminate the true and false echoes. In the end, order statistic constant false alarm rate approach is applied to target detection. The results of computer simulations show that the performance of the proposed scheme is superior to the conventional pulse compression processing in radar.

Published
2016

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