Time frequency characteristic analysis and simulation of VFTO waveform generated by disconnector switch in GIS

2016 ◽  
Author(s):  
Kaifeng Zhou ◽  
Yue Hu ◽  
Haitao Li ◽  
Feng Xue
Keyword(s):  
Frequency Characteristic ◽  
Characteristic Analysis ◽  
Time Frequency

scholarly journals Time-Frequency Analysis and Application of a Vibration Signal of Tunnel Excavation Blasting Based on CEEMD-MPE-HT

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Chen-yang Ma ◽  
Li Wu ◽  
Miao Sun ◽  
Qing Yuan
Keyword(s):  
Empirical Mode Decomposition ◽  
Frequency Band ◽  
Frequency Analysis ◽  
Frequency Characteristic ◽  
Permutation Entropy ◽  
Natural Vibration Frequency ◽  
Characteristic Parameters ◽  
Time Frequency Analysis ◽  
Time Frequency ◽  
Mode Decomposition

The traditional empirical mode decomposition method cannot accurately extract the time-frequency characteristic parameters contained in the noisy seismic monitoring signals. In this paper, the time-frequency analysis model of CEEMD-MPE-HT is established by introducing the multiscale permutation entropy (MPE), combining with the optimized empirical mode decomposition (CEEMD) and Hilbert transform (HT). The accuracy of the model is verified by the simulation signal mixed with noise. Based on the project of Loushan two-to-four in situ expansion tunnel, a CEEMD-MPE-HT model is used to extract and analyze the time-frequency characteristic parameters of blasting seismic signals. The results show that the energy of the seismic wave signal is mainly concentrated in the frequency band above 100 Hz, while the natural vibration frequency of the adjacent existing tunnel is far less than this frequency band, and the excavation blasting of the tunnel will not cause the resonance of the adjacent existing tunnel.

Hardware Trojan Detection Technique Using Frequency Characteristic Analysis of Path Delay in Application Specific Integrated Circuits

2020 ◽  
Vol 10 (2) ◽  
pp. 36-43
Author(s):  
Ha Thai Tran ◽  
Phuc Van Hoang ◽  
Tuan Ngoc Do ◽  
Duong Hai Nguyen
Keyword(s):  
Integrated Circuits ◽  
Frequency Characteristic ◽  
Integrated Circuit ◽  
Hardware Security ◽  
Hardware Trojan ◽  
Path Delay ◽  
Characteristic Analysis ◽  
Hardware Trojan Detection ◽  
Ic Manufacturing ◽  
Application Specific

 Abstract—  Since the last decade, hardware Trojan (HT) have become a serious problem for hardware security because of outsourcing trends in Integrated Circuit (IC) manufacturing. As the fabrication of IC is becoming very complex and costly, more and more chipmakers outsource their designs or parts of the fabrication process. This trend opens a loophole in hardware security, as an untrusted company could perform malicious modifications to the golden circuit at design or fabrication stages. Therefore, assessing risks and proposing solutions to detect HT are very important tasks. This paper presents a technique for detecting HT using frequency characteristic analysis of path delay. The results show that measuring with the frequency step of 0.016 MHz can detect a HT having the size of 0.2% of the original design.Tóm tắt— Từ thập niên 2010, Trojan phần cứng (HT) đã trở thành một vấn đề nghiêm trọng đối với bảo mật phần cứng, do xu hướng thuê sản xuất mạch tích hợp (Integrated Circuit - IC). Khi quá trình chế tạo IC trở nên phức tạp và tốn kém, ngày càng nhiều nhà sản xuất chip lựa chọn phương án thuê lại một phần hoặc toàn bộ thiết kế IC. Xu hướng này tạo ra lỗ hổng trong bảo mật phần cứng, vì một công ty không đáng tin cậy có thể thực hiện các sửa đổi độc hại vào trong mạch nguyên bản ở giai đoạn thiết kế hoặc chế tạo. Do đó, đánh giá rủi ro và đề xuất giải pháp phát hiện HT là một trong những nhiệm vụ hết sức quan trọng. Bài báo này trình bày một giải pháp phát hiện HT sử dụng phân tích đặc tính tần số của độ trễ đường truyền tín hiệu. Kết quả cho thấy, thực hiện khảo sát với bước tần số 0,016 MHz có thể phát hiện được HT có kích thước 0,2% so với thiết kế ban đầu. 

Denoising Vibration Signals of Food Refrigerant Air Compressor Based on Wavelet Transform

2010 ◽  
Vol 439-440 ◽  
pp. 1037-1041 ◽  
Author(s):  
Yan Jue Gong ◽  
Zhao Fu ◽  
Hui Yu Xiang ◽  
Li Zhang ◽  
Chun Ling Meng
Keyword(s):  
Wavelet Transform ◽  
Frequency Characteristic ◽  
Vibration Signal ◽  
Wavelet Denoising ◽  
Signal Denoising ◽  
Denoising Method ◽  
Vibration Signals ◽  
Air Compressor ◽  
Time Frequency ◽  
Soft Threshold

On the basis of wavelet denoising and its better time-frequency characteristic, this paper presents an effective vibration signal denoising method for food refrigerant air compressor. The solution of eliminating strong noise is investigated with the combination of soft threshold and exponential lipschitza. The good denoising results show that the presented method is effective for improving the signal noise ratio and builds the good foundation for further extraction of the vibration signals.

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