Trial Study on Methods of Damage Extent Identification Based on Wavelet Transform of Strain Signal

2010 ◽  
Vol 163-167 ◽  
pp. 2543-2548
Author(s):  
Jin Fan ◽  
Hong Po Liu
Keyword(s):  
Wavelet Transform ◽  
Wavelet Coefficient ◽  
Maximum Modulus ◽  
Steel Beam ◽  
Simply Supported ◽  
Relative Damage ◽  
Damage Extent ◽  
Strain Signal

Wavelet transform of strain signal can be used in the damage relative damage extent identification. The proposed method is validated by trial on a simply supported steel beam. And meanwhile the relative damage extent can be identified by drawing the curve of the maximum modulus of the wavelet coefficient and damage extent.

A Feature Extracting Method for Chinese Character Recognition of License Plate Based on Elastic Mesh and Wavelet Transform

2013 ◽  
Vol 760-762 ◽  
pp. 1452-1456
Author(s):  
Chao Zheng ◽  
Hua Yang ◽  
Xing Yang ◽  
Chao Chao Huang ◽  
Xiao Di Wu
Keyword(s):  
Wavelet Transform ◽  
Character Recognition ◽  
Chinese Character ◽  
Wavelet Coefficient ◽  
Difficult Problem ◽  
License Plate ◽  
Structure Information ◽  
Feature Extracting ◽  
Chinese Character Recognition ◽  
Character Feature

Low-resolution Chinese character recognition of license plate is always a difficult problem. For solving it, we must think about the distinctiveness of character feature and the counting speed of method simultaneously. In this paper, we proposed a simple and effective feature extraction algorithm. First, extract the statistical feature of Chinese character based on decomposing stroke with wavelet transform. Second, apply Elastic Mesh Algorithm into extracting wavelet coefficient of decomposing stroke to get the structure information of Chinese character. The experimental results show the method is robust against low quality Chinese characters, such as skew, fuzzy, glue, distorted character, and easy to be used in actual projects with simple advantage.

Aeroacoustic analysis of slat tones

2021 ◽  
Vol 263 (1) ◽  
pp. 5650-5663
Author(s):  
Hasan Kamliya Jawahar ◽  
Syamir Alihan Showkat Ali ◽  
Mahdi Azarpeyvand
Keyword(s):  
Wavelet Transform ◽  
Surface Pressure ◽  
Wavelet Coefficient ◽  
Pressure Fluctuations ◽  
Low Frequency ◽  
Stream Velocity ◽  
High Lift ◽  
Unsteady Surface Pressure ◽  
Slat Noise ◽  
Generation Mechanisms

Experimental measurements were carried out to assess the aeroacoustic characteristics of a 30P30N high-lift device, with particular attention to slat tonal noise. Three different types of slat modifications, namely slat cove filler, serrated slat cusp, and slat finlets have been experimentally examined. The results are presented for an angle of attack of α = 18 at a free-stream velocity of U = 30 m/s, which corresponds to a chord-based Reynolds number of Re = 7 x 10. The unsteady surface pressure near the slat region and far-field noise were made simultaneously to gain a deeper understanding of the slat noise generation mechanisms. The nature of the low-frequency broadband hump and the slat tones were investigated using higher-order statistical approaches for the baseline 30P30N and modified slat configurations. Continuous wavelet transform of the unsteady surface pressure fluctuations along with secondary wavelet transform of the broadband hump and tones were carried out to analyze the intermittent events induced by the tone generating resonant mechanisms. Stochastic analysis of the wavelet coefficient modulus of the surface pressure fluctuations was also carried out to demonstrate the inherent differences of different tonal frequencies. An understanding into the nature of the noise generated from the slat will help design the new generation of quite high-lift devices.

Digital Watermarking for 3D Polygonal Model Based on Wavelet Transform

1999 ◽  
Author(s):  
Hiroaki Date ◽  
Satoshi Kanai ◽  
Takeshi Kishinami
Keyword(s):  
Wavelet Transform ◽  
Digital Watermarking ◽  
Copyright Protection ◽  
Affine Transformation ◽  
Wavelet Coefficient ◽  
Original Data ◽  
Geometric Error ◽  
Digital Data ◽  
Cad Cam ◽  
Polygonal Model

Abstract Recently, much interest is being taken in a method to protect the copyright of digital data and prevent illegal duplication of it. However, in the area of CAD/CAM and CG, there are no effective ways to protect the copyright of the 3D geometric models. As a first step to solve this problem, a new digital watermarking method for 3D polygonal models is introduced in this paper. Watermarking is one of the copyright protection methods where an invisible watermark is secretly embedded into the original data. The proposed watermarking method is based on the wavelet transform (WT) and multi-resolution representation (MRR) of the polygonal model. The watermark can be embedded in the large wavelet coefficient vectors at various resolution levels of the MRR. This makes the embedded watermark imperceptible and invariant to the affine transformation, and also makes the control of the geometric error caused by the watermarking reliable.

The Meaning of Wavelet Transform in High Resolution Sequence Stratigraphy Study

2013 ◽  
Vol 411-414 ◽  
pp. 3035-3038
Author(s):  
Zhan Dong Li ◽  
Meng Li ◽  
Yan Liu
Keyword(s):  
Wavelet Transform ◽  
High Resolution ◽  
Sequence Stratigraphy ◽  
Wavelet Coefficient ◽  
Scale Factor ◽  
Sequence Stratigraphic ◽  
Natural Gamma ◽  
Set Up ◽  
Morlet Wavelet Transform ◽  
High Resolution Sequence Stratigraphy

Taking the division of Gao3 reservoir group strata sequence in Songliao basin of Daqing Changyuan Xingbei for example, this paper analyzed the applicability of the one-dimensional continuous wavelet transform in high resolution sequence division. By means of making morlet wavelet transform on the natural gamma logging curve, the connection between well curve signal and depth is transformed to the alter relationship between depth and the domains of scale, which obtains the wavelet coefficient curve. Then set up the corresponding relations between periodic oscillations characteristics of wavelet coefficient curve and sequence interface at all levels under the optimal scale factor. And the wavelet coefficients curve in best scale factor will eventually be used for the identification and division of the sequence. Practice has proved that the wavelet coefficient curve in the best factor can accurately identify the sequence interface at all levels, and the result is more accurate, objective and effective than manual calibration. So take advantage of wavelet transform in sequence stratigraphic classification provides a new way for high resolution sequence stratigraphy studies.

Method of Footprint Image Stitching Based on Multiscale SIFT Feature Matching

2013 ◽  
Vol 303-306 ◽  
pp. 1056-1059
Author(s):  
Sen Wang ◽  
Yin Hui Zhang ◽  
Zhong Hai Shi ◽  
Zi Fen He
Keyword(s):  
Wavelet Transform ◽  
Feature Matching ◽  
Wavelet Coefficient ◽  
Low Frequency ◽  
Original Method ◽  
Inverse Transformation ◽  
Image Stitching ◽  
Image Splicing ◽  
Sift Feature ◽  
Matching Pair

The image stitching method is widely used into the suspect's footprint information extraction. In order to improve the image detail and the matching precision, the Footprint map image stitching method which is based on the wavelet transform and the SIFT feature matching is put forward. The wavelet transform in this method is perform based on the pretreatment of image, move the low frequency wavelet coefficient to zero, adjusting thresholds of the high frequency wavelet coefficient and inverse transformation, then, use the SIFT to extract and match the key-points of the processed images. For the error matching pair of coarse match, you can use the RANSAC to filter them out. This article demonstrates its advantage through to the original image splicing comparisons. The experimental results show that the method display more clear detail and the precision of matching than the original method.

Experimental Research of Performance of a New Fabricated Lightweight Steel-Concrete Composite Floor

2014 ◽  
Vol 501-504 ◽  
pp. 787-790
Author(s):  
Xin Tang Wang ◽  
Bing Shao ◽  
Zheng Jue Huang
Keyword(s):  
Static Load ◽  
Lightweight Aggregate ◽  
Main Beam ◽  
Lightweight Aggregate Concrete ◽  
Steel Beam ◽  
Bottom Flange ◽  
Simply Supported ◽  
Concrete Panels ◽  
Vertical Displacements ◽  
Thin Walled

For study of mechanical property of a fabricated composite floor consisting of thin-walled steel I beams and lightweight aggregate concrete panels, the static load experiment of the new composite floor was presented and the results was discussed. The specimen was simply supported at the two shorter sides and the other two longer sides free. The equivalent uniform loads are applied to the floor through setting the load blocks on the supper surface of the floor. The vertical displacements, slips between steel beam and concrete panel and strains of the specimen were measured. It was shown that the strain at the bottom of the concrete panel is quite close to the strain at the top flange of the main beam and the strain at bottom flange of the main beam is much larger than the value at top flange.

Denoising Algorithm Based on Correlation of Inter Scales Wavelet Coefficient for Damage Signal of Wire Rope

2011 ◽  
Vol 328-330 ◽  
pp. 2027-2031 ◽  
Author(s):  
Wei Xia Zhan ◽  
Ji Wen Tan ◽  
Yan Wen
Keyword(s):  
Wavelet Transform ◽  
Strong Correlation ◽  
Wavelet Coefficient ◽  
Wire Rope ◽  
Correlation Factor ◽  
Original Signal ◽  
Signal Noise ◽  
Processing Effect ◽  
Noise Ratio

In order to remove noise in the broken wire signal of wire rope, a new denoising algorithm based on the correlation of inter scales wavelet coefficient was proposed. Because the wavelet coefficient of signal has strong correlation and the wavelet coefficient of noise does not has obvious correlation, in the process of calculating threshold, an inter scales correlation factor was constructed considering the part specialty of next scale on the same position after wavelet transform. The proposed factor can adaptively adjust threshold on the position of signal and noise, thereby otaining good denoising effect and holding the break information in original signal. The actual processing effect of simulation and damage signal of wire rope shows that the proposed method, compared with the classical threshold, not only effectively removes noise in original signal and improve the signal noise ratio(SNR),but also retains the break information of inspected damage signal of wire rope.

scholarly journals Modal Analysis of a Simply Supported Steel Beam with Cracks under Temperature Load

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Yijiang Ma ◽  
Guoping Chen ◽  
Fan Yang
Keyword(s):  
Modal Analysis ◽  
Transfer Matrix ◽  
Analytical Method ◽  
Natural Frequencies ◽  
Steel Beam ◽  
Simply Supported ◽  
Local Flexibility ◽  
Temperature Load ◽  
Different Temperatures ◽  
Torsion Springs

Based on the transfer matrix method, an analytical method is proposed to conduct the modal analysis of the simply supported steel beam with multiple transverse open cracks under different temperatures. The open cracks are replaced with torsion springs without mass, and local flexibility caused by each crack can be derived; the temperature module is introduced by the mechanical properties variation of the structural material, and the temperature load is caused by the temperature variation, which can be transformed to the axial force on the cross-section. The transfer matrix of the whole beam with the temperature and geometric parameters of cracks can be obtained. According to boundary conditions of the simply supported beam, natural frequencies of the beam can be calculated, which are compared with the finite element results. Results indicate that the analytical method proposed has a high accuracy; the natural frequencies of the simply supported steel beam are mostly affected by the temperature load, which cannot be ignored.

Experimental Study on Moving Train Loads Identification from Bridge Responses

2010 ◽  
Vol 143-144 ◽  
pp. 32-37
Author(s):  
Yi Wang ◽  
Wei Lian Qu
Keyword(s):  
Genetic Algorithm ◽  
Experimental Studies ◽  
Steel Beam ◽  
Beam Model ◽  
Moving Loads ◽  
Simply Supported ◽  
Simulated Annealing Genetic Algorithm ◽  
Bridge Responses ◽  
Moving Train ◽  
Moving Speed

This paper describes a method for multi-axle moving train loads identification based on simulated annealing genetic algorithm by minimizing the errors between the measured displacements and the reconstructed displacements from the identified moving loads. Experimental studies were carried out to investigate the effect of the proposed method on moving loads identification. A simply supported steel beam model and a model train with three carriages were constructed in laboratory. A series of comparative researches for moving loads identification have been conducted. Effects of moving speed and measurement station numbers on the accuracy of the proposed method are investigated. The results show that the proposed method is accurate and feasible for multi-axle moving train loads identification.

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