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Dynamic responses of unsaturated half-space soil to a moving harmonic rectangular load

INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS 2018年第9期42卷 1057-1077页

作者： Lu, Zheng Fang, Ran Yao, Hailin Dong, Cheng Xian, Shaohua Chinese Acad Sci Inst Rock & Soil Mech State Key Lab Geomech & Geotech Engn Wuhan 430071 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China Hunan Commun Res Inst Changsha 410015 Hunan Peoples R China

The problem of the dynamic responses of a semi-infinite unsaturated poroelastic medium subjected to a moving rectangular load is investigated analytical/numerically. The dynamic governing equations are obtained with consideration of the compressibility of solid grain and pore fluid, inertial coupling, and viscous drag as well as capillary pressure in the unsaturated soil, and they can be easily degraded to the complete Biot's theory. Using the Fourier transform, the general solution for the equations is derived in the transformed domain, and then a corresponding boundary value problem is formulated. By introducing fast Fourier transform algorithm, the unsaturated soil vertical displacements, effective stresses, and pore pressures induced by moving load are computed, and some of the calculated results are compared with those for the degenerated solution of saturated soils and confirmed. The influences of the saturation, the load speed, and excitation frequency on the response of the unsaturated half-space soil are investigated. The numerical results reveal that the effects of these parameters on the dynamic response of the unsaturated soil are significant.

关键词： dynamic response fft algorithm Fourier transform moving load saturation unsaturated soil

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Implementation of Quadrilateral Relay for Three Zone Protection of Transmission Line 7

Implementation of Quadrilateral Relay for Three Zone Protect...

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7th IEEE India International Conference on Power Electronics (IICPE)

作者： Verma, Manish Sinha, Amrita Thapar Univ EIED Patiala Punjab India

ISBN: (纸本)9781509045303

The quadrilateral relayhas been implemented at the generating end of a 5 bus system in Simulink. The three phase voltage and current signals have been sampled for different faults with varying distance, fault resistance and inception angle. These sampled and rationalized signals are transferred to microcontroller for implementation of quadrilateral relay. The DC offset has been filtered from the current signal using full cycle window. The fundamental component of voltage and current signals has been extracted using fft algorithm full cycle window. The fault resistance (R) and reactance (X) have been calculated using sine and cosine coefficients of voltages and currents for LG and LL faults. These values of R and X have been used for implementation of three zone protection scheme of transmission line. The effect of arc resistance and power swing on the quadrilateral relay has also been studied. The impedance seen by the relay has been calculated for location of the fault after its classification.

关键词： Quadrilateral Relay Transmission Line Protection Microcontroller DC offset removal fft algorithm

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Research on Multi-target Signal Separation and Processing Method

Research on Multi-target Signal Separation and Processing Me...

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作者： Hong Lv Jun Li Hongfeng Xu Quanling Sun AnHui JianZhu University

Nowadays,intelligent cities and transportation are being implemented in major cities around the *** unmanned vehicles,autonomous identification and separation of moving targets is the essential and important part of intelligent *** paper proposes a multi-object separation algorithm in order to solve the security problems that can promote smart *** paper deals with multi-target signals based on *** terms of distance,between the cars(targets) that can be separated,multiple targets are separated by matched filter and fft algorithm,then the performance of the research is expressed by distance *** separable target distance is up to 200 m,and the resolution is up to 0.6 m;in the terms of speed,multiple targets are separated by the Doppler transform,then the performance of the research is reflected in the form of speed *** speed at which the separated target can be identified is up to 200 km/h,and the resolution is up to 1.8 km/h,otherwise,both stationary and moving targets can be ***,all the results are obtained by MTALAB simulation.

关键词： Multi-object separation Matched filter fft algorithm

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Fast and Adaptive Blind Audio Source Separation Using Recursive Levenberg-Marquardt Synchrosqueezing

Fast and Adaptive Blind Audio Source Separation Using Recurs...

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IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Dominique Fourer Geoffroy Peeters UMR STMS (IRCAM - CNRS - UPMC)

ISBN: (纸本)9781538646595

This paper revisits the Degenerate Unmixing Estimation Technique (duet) for blind audio separation of an arbitrary number of sources given two mixtures through a recursively computed and adaptive time-frequency representation. Recently, synchrosqueezing was introduced as a promising signal disentangling method which allows to compute reversible and sharpen time-frequency representations. Thus, it can be used to reduce overlaps between the sources in the time-frequency plane and to improve the sources' sparsity which is often exploited by source separation techniques. Furthermore, synchrosqueezing can also be extended using the Levenberg-Marquardt algorithm to allow a user to adjust the energy concentration of a time-frequency representation which can be efficiently implemented without the fft algorithm. Hence, we show that our approach can improve the quality of the source separation process while remaining suitable for real-time applications.

关键词： blind source separation time-frequency analysis synchrosqueezing Levenberg-Marquardt algorithm l-m algorithm Blind source separation Time frequency analysis Audio fft algorithm Source separation real-time application program Fasting

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Vector-Radix-2~2×2~2 Fast Fourier Transform algorithm

Vector-Radix-2~2×2~2 Fast Fourier Transform Algorithm

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IEEE International Conference on Electronics, Circuits and Systems

作者： Monir T. Hamood Said Boussakta School of Electrical Electronic and Computer Engineering Newcastle University

ISBN: (纸本)9781424481552

In this paper, a new decimation-in-time vector-radix-2~2×2~2 fast Fourier transform (VR-2~2×2~2-fft) algorithm for computing the two dimensional discrete Fourier transform (2-D DFT) is presented. The algorithm is derived by applying a two-stage decomposition approach and by introducing an efficient technique for grouping the twiddle factors. The arithmetic complexity of the proposed algorithm is analyzed and the number of real multiplications and additions are computed for different transform sizes. Moreover, a comparison with the existing 2-D vector-radix fft algorithms has shown that the presented algorithm can be considered as a good compromise between the structural and computational complexities.

关键词： 2-D fft Vector-radix algorithms Radix-2~2 algorithm fft algorithm complexity classes Fast Fourier transform algorithms discrete Fourier transform

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European Signal Processing Conference

作者： D. Schwingshackl D. Straeussnigg University of Pisa

In this paper we propose a method for suppressing discrete disturbers in data communication systems where the modulation scheme is implemented using the fft (Fast Fourier Transform) algorithm. Similar to radio frequency interference (RFI) cancelation in the frequency domain, the compensation is performed after the fft in the receiver. As opposed to the RFI methods it is not necessary to reserve some of the subchannels for the compensation purpose. However, the new method requires at least one reference tone and all discrete disturbers impairing the data transmission performance must be related to it. For example, this is the case for harmonics where the fundamental acts as reference tone. A detailed derivation of the compensation method is presented and illustrated by means of an example.

关键词： fft algorithm Radiofrequency interference compensation method COMMUNICATION SYSTEMS DATA TRANSMISSION SYSTEMS Fast Fourier transform Transmission Characteristics subchannel Frequency-domain analysis compensated

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A Comparison Between fft and MCT for Period Measurement with an ARM Microcontroller

A Comparison Between FFT and MCT for Period Measurement with...

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IEEE International Instrumentation and Measurement Technology Conference

作者： S. S. Guia A. Espirito-Santo V. Paciello F. Abate A. Pietrosanto Electromechanical Engineering Department University of Beira Interior UBI Covilha Portugal Industrial Engineering Department University of Salerno UNISA Salerno Italy

ISBN: (纸本)9781479961153

A comparison between two different algorithms to measure the period of a signal is performed on this work. One of the algorithms is based on the Fast Fourier Transformation (fft) measurement procedure, whereas the other is based on the Segmentation and Labeling algorithm (MCT). Both algorithms have been prepared for implementation in a microcontroller with ARM architecture. The measurement operation of each one of the algorithms is described in detail. Experimental results are reported, with the purpose of demonstrating both performance and output format for signal analysis.

关键词： Signal Processing fft algorithm MCT algorithm IEEE 1451 Period Measurement Microcontroller

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GEARBOX FAULT DIAGNOSIS BASED ON WAVELET-AR MODEL

GEARBOX FAULT DIAGNOSIS BASED ON WAVELET-AR MODEL

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2007 International Conference on Machine Learning and Cybernetics(IEEE第六届机器学习与控制论国际会议)

作者： GUI-HONG ZHOU CHUN-CHENG ZUO SHU-XIA LIU JIA-ZHONG WANG College of Mechanical Science and Engineering Jilin University Changchun 130025 China College of I College of Mechanical Science and Engineering Jilin University Changchun 130025 China College of Information Science and Technology Agricultural University of Hebei071000 China

A fault diagnosis technique for gearbox that uses a Wavelet-AR model spectrum estimation method is presented in this *** the experimental work, the wavelet transform was used for original signal decomposition and de-noising to obtain fault signals, and the fault type was confirmed using AR model spectrum estimation method for gearbox fault signal *** experimental results indicated that the proposed wavelet-AR model spectrum estimation method, compared with fft algorithm, is effective in fault signal diagnosis for gearbox.

关键词： Wavelet-AR model Gearbox Fault diagnosis fft algorithm

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Double Factors algorithm for Computing DFT

Double Factors Algorithm for Computing DFT

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International Conference on Image Analysis and Signal Processing

作者： Haijun Li Caojun Yan Wenbiao Peng Electrical and Information College China Three Gorge University

ISBN: (纸本)9781424439874

A fast Fourier transform algorithm for computing N=N_1×N_2-point DFT, where both factors N_1 and N_2 are smaller positive integer, said to be a double factors algorithm (DFA), is developed. The DFA subdivides a DFT of length N=N_1×N_2 into smaller transforms of length N_1 and N_2 and takes the following steps:(1) computes N_1 N_2-point DFTs, (2) multiplies the values of DFT by twiddle factors, (3) computes N_2 N_1-point DFTs. The structure of the DFA is similar to those of the most simple PFA and WFTA, but N_1 and N_2 are not necessarily relatively prime. When N=2~M or 4~M, the total number of computations of DFT in the DFA is less than those in the radix-2 and radix-4 fft algorithm but slightly more than that in the split-radix fft algorithm. When N is other values, the total number of computations of DFT in the DFA is less than those in the PFA and WFTA.

关键词： Double factors algorithm Prime factor algorithm Radix-4 fft Splix-radix fft Smaller-length DFT DELAYED FLAP APPROACH Doped fiber amplifiers Deferoxamine discrete Fourier transform fft algorithm Fly ash

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Fast 3D Nonlinear Inversion Method for Airborne Electromagnetic Exploration

Fast 3D Nonlinear Inversion Method for Airborne Electromagne...

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IEEE International Symposium on Antennas and Propagation

作者： Yu Jia Qing Liu Dept. of Electr. & Comput. Eng. Duke Univ. Durham NC USA

ISBN: (纸本)9781479978168

This paper presents an efficient three-dimensional nonlinear inversion method for airborne electromagnetic exploration. The stabilized biconjugate-gradient fast Fourier transform (BCGS-fft) is used as the forward solver, and the distorted Born iterative method (DBIM) combined with the conjugate-gradient iterative solver is utilized in the inversion. Because of the usage of the fft algorithm and the recursive matrix method combined with an interpolation technique to evaluate the layered media Greens functions rapidly, this method is highly efficient, and requires very low time and memory, O(NlogN) and O(N) respectively. Numerical examples for both 3D forward modeling and conductivity inversion are presented to show the accuracy and efficiency of the method.

关键词： fft algorithm Inversion airborne Matrix methods Solvers nonlinearity

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