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High-resolution Rayleigh wave phase velocity maps from ambient noise tomography in North China

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Earthquake Science 2012年第3期25卷 241-251页

作者： Jiatie Pan Institute of Geophysics, China Earthquake Administration, Beijing 100081, China 1. Institute of Geophysics China Earthquake Administration Beijing 100081 China

We presented high-resolution Rayleigh wave phase velocity maps at periods ranging from 5 s to 30 s in the northeast part of the North China Craton (NNCC). Continuous time-series of vertical component between October 2006 and December 2008, recorded by 187 broadband stations temporarily deployed in the NNCC region, have been cross-correlated to obtain estimated fundamental mode Rayleigh wave Green’s functions. Using the frequency and time analysis technique based on continuous wavelet transformation, we measured 3 667 Rayleigh wave phase velocity dispersion curves. High-resolution phase velocity maps at periods of 5, 10, 20 and 30 s were reconstructed with grid size 0.25°× 0.25°, which reveal lateral heterogeneity of shear wave structure in the crust and upper mantle of NNCC. For periods shorter than 10 s, the phase velocity variations are well correlated with the principal geological units in the NNCC, with low-speed anomalies corresponding to the major sedimentary basins and high-speed anomalies coinciding with the main mountain ranges. Within the period range from 20 s to 30 s, high phase velocity observed in eastern NCC is coincident with the thin crust, whereas low phase velocities imaged in central NCC is correlated to the thick crust. However, the low-velocity anomaly in the Beijing-Tianjin-Tangshan region displayed in the 20 s and 30 s phase maps may be associated with fluids.

关键词： Rayleigh wave phase velocity ambient noise tomography wavelet transformation North China Craton

Research on Digital Dynamic Testing Technique for Electrohydraulic Servovalve

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Journal of Beijing Institute of Technology 2003年第4期12卷 357-361页

作者：汪首坤王军政赵江波张宇河 Department of Automatic Control

The digital testing technique based on computers for dynamic characteristics of electrohydraulic servovalves via frequency scan method is researched. The no-load piston which measures the servo's transient output flow is designed properly. The velocity testing method by which the speed signal can be obtained indirectly by means of a piezoelectral accelerometer is given. High speed sampling has been realized in Windows OS. wavelet denoising and Fourier transform are adopted in data processing and analyses. The testing technique discussed has been applied to actual testing systems and the experimental results have proved it to be correct.

关键词： electrohydraulic servovalve frequency response no-load piston wavelet transformation frequency scan

A Biblock wavelet Zero Tree Coding for Hyperspectral Imagery Data Compression

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Chinese Journal of Lasers 2001年第4期 23-30页

作者： YAN Jingwen SHEN Guiming HU Xiaoyi XU Fang (The Dept. of Electronic Engineering, Xiamen University, Xiamen 361005, China) Received Aug. 14, 2000 Revised manuscript received Nov. 6, 2000

In this paper, a biblock zero tree compression coding (BBZTC) method, based on wavelet zero tree compression coding (ZTC), is used to exploit redundancy in hyperspectral imagery data. Because of ZTC scanning every wavelet zero tree coefficients with low efficiency, BBZTC method outperforms ZTC in the aspects of high compression ratio, simple real time implementing, and higher coding/decoding speed, and convenient real time transmission. The experimental results show that this method can obtain the compression ratio 17～40 times of 224 spectral bands to remove the spectral correlation without any coding by using KLT, and the total compression performance of KLT+BBZTC method is better than the method of KLT and other one dimensional transformation (such as DCT) to remove the spectral correlation. To compare with the total compression ratio of KLT+JPEG method and SFCVQ method, this method reaches 180 at the PSNR of 33.6 db. This method is superior to the present any other method at compression rate.

关键词： wavelet transformation zero tree coding biblock zero tree coding spectral feature coding vector quantization (SFCVQ)

Relations Between wavelet Network and Feedforward Neural Network

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Journal of Southwest Jiaotong University(English Edition) 2002年第2期10卷 179-184页

作者：刘志刚何正友钱清泉 Institute of Railway Electrification & Automation Southwest Jiaotong University Chengdu 610031 China

A comparison of construction forms and base functions is made between feedforward neural network and wavelet network. The relations between them are studied from the constructions of wavelet functions or dilation functions in wavelet network by different activation functions in feedforward neural network. It is concluded that some wavelet function is equal to the linear combination of several neurons in feedforward neural network.

关键词： wavelet transformation feedforward neural network wavelet network

The Coherence Cube Computing Method with Self-adaptive Time Window Based on wavelet Transform

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Computer Aided Drafting,Design and Manufacturing 2014年第2期24卷 10-14页

作者： LI Ying-qi CHE Xiang-jiu College of Computer Science and Technology Jilin University

The coherence cube technology has become an important technology for the seismic attribute interpretation, which extracts the discontinuities of the events through analyzing the similarities of adjacent seismic channels to identify the fault form. The coherence cube technology which uses constant time window lengths can not balance the shallow layers and the deep layers, because the frequency band of seismic data varies with time. When analyzing the shallow layers, the time window will crossover a lot of events, which will lead to weak focusing ability and failure to delineate the details. While the time window will not be long enough for analyzing deep layers, which will lead to low accuracy because the coherences near the zero points of the events are heavily influenced by noise. For solving the problem, we should make a research on the coherence cube technology with self-adaptive time window. This paper determines the sample points＆#39; time window lengths in real time by computing the instantaneous frequency bands with wavelet transformation, which gives a coherence computing method with the self-adaptive time window lengths. The result shows that the coherence cube technology with self-adaptive time window based on wavelet transformation improves the accuracy of fault identification, and supresses the noise effectively. The method combines the advantages of long time window method and short time window method.

关键词： coherence cube time window length wavelet transformation seismic attribute

Image interpolation based on wavelet Transform

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International English Education Research 2013年第12期 156-158页

Image interpolation is widely studied and used in digital image processing. In this paper, a method of image magnification according to the properties of fi＇actal interpolation and wavelet transformation are presented. We focus the development of edge forming methods to be applied as a post process of standard image zooming methods for grayscale images, with the hope of retaining edges. Experiments make sure it valid.

关键词： wavelet transformation Image magnification Fractal interpolation

A Novel Approach for Iris Recognition System Using Genetic Algorithm

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Journal of Artificial Intelligence and Technology 2024年第1期4卷 9-17页

作者： Jayesh Mohanrao Sarwade Sandip Bankar Surekha Janrao Kishor Sakure Rohini Patil Shudhodhan Bokefode Nilesh Kulal School of Computing MIT-ADT University PuneIndia School of Technology Management and Engineering SVKM’sNMIMSNaviMumbaiIndia K.J.Somaiya Institute of Technology SionMumbaiIndia Terna Engineering College NaviMumbaiIndia

In a brand new era,with chaotic scenario that exists within the world,people are undermined with diverse psychological *** have been numerous sensible approaches on the way to understand and lessen those *** developments have verified to be one of the beneficial approaches for intercepting these *** recognition through human iris organ is said as one of the well-known biometric strategies because of its reliability and higher accurate return in comparison to different *** beyond literatures,terrible imaging condition,low flexibility of version,and small length iris image dataset are the constraints desiring *** these kinds of developments,the iris popularity structures are suitable gear for the human *** popularity has been an energetic studies location for the duration of previous couple of decades,due to its extensive packages in the areas,from airports to native land protection border *** the past,various functions and methods for iris recognition have been *** of the very fact that there are many approaches published in this field,there are still liberal amount of problems in this methodology like tedious and computational *** suggest an all-encompassing deep learning architecture for iris recognition supported by a genetic algorithm and a wavelet transformation,which may jointly learn the feature representation and perform recognition to realize high *** just a few training photos from each class,we train our model on a well-known iris recognition dataset and demonstrate improvements over prior *** think that this architecture can be frequently employed for various biometric recognition jobs,assisting in the development of a more scalable and precise *** exploratory aftereffects of the proposed technique uncover that the strategy is effective inside the iris acknowledgment.

关键词： biometrics genetics algorithm(GA) iris recognition machine learning wavelet transformation

Study of wavelet transform type high-current transformer

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Journal of Coal Science & Engineering(China) 2002年第2期8卷 75-79页

作者：卢文科朱长纯刘君华张建军 Institute of Vaccum Microelectronics & Microelectromechanical System School of Electronics and Information EngineeringXi'an Jiaotong UniversityXi'an 710049China

The wavelet transformation is applied to the high current *** high current transformer elaborated in the paper is mainly applied to the measurement of AC/DC high *** principle of the transformer is the Hall direct measurement *** transformer has the following three characteristics:firstly, the effect of the remnant field of the iron core on the measurement is decreased;secondly,because the temperature compensation is adopted,the transformer has good temperature charactreristic;thirdly,be cause the wavelet transfomation technology is adopted,the transformer has the capacity of good antijanming.

关键词： wavelet transformation high current sensor Hall direct measurement transformer

Object-Oriented wavelet-Layered Digital Watermarking Technique

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Journal of Electronic Science and Technology of China 2005年第2期3卷 116-119页

作者：刘晓云虞厥邦李明玉 School of Automation Engineering University of Electronic Science and Technology of China Chengdu 610054 China School of Electronic Engineering University of Electronic Science and Technology of China Chengdu 610054 China

In this paper, an object-oriented digital watermarking technique is proposed in the wavelet domain for still images. According to the difference of recognition degree of the human eye to the different region of the image, the image is divided into the interested region and uninterested region of human eye vision in this scheme. Using the relativity of position and the difference to ocular sensitivity of the multiresolution wavelet among each subband, the image is processed with layered watermarking append technique. Experimental results show that the proposed technique successfully survives image processing operations, additive noise and JPEG compression.

关键词： digital watermarking object-oriented wavelet transformation ocular masking