检索结果-南通市图书馆

fast fourier transform-based Support Vector Machine for Prediction of G-protein Coupled Receptor Subfamilies

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Biochimica et Biophysica Sinica 2005年第11期37卷 759-766页

作者： Yan-Zhi GUO Meng-Long LI Ke-Long WANG Zhi-Ning WEN Min-Chun LU Li-Xia LIU Lin JIANG College of Chemistry,Sichuan University,Chengdu 610064,China College of Chemistry Sichuan UniversityChengdu 610064China

Although the sequence information on G-protein coupled receptors(GPCRs)continues togrow,many GPCRs remain orphaned(*** specificity unknown)or poorly characterized with littlestructural information available,so an automated and reliable method is badly needed to facilitate the identifi-cation of novel *** this study,a method of fast fourier transform-based support vector machinehas been developed for predicting GPCR subfamilies according to protein’s *** classifyingClass B,C,D and F subfamilies,the method achieved an overall Matthew’s correlation coefficient andaccuracy of 0.95 and 93.3%,respectively,when evaluated using the jackknife *** method achieved anaccuracy of 100% on the Class B independent *** results show that this method can classify GPCRsubfamilies as well as their functional classification with high accuracy.A web server implementing theprediction is available at http://***/blast/Pred-GPCR.

关键词： G-protein coupled receptor subfamily fast fourier transform support vector machine prediction

Identification of faults through wavelet transform vis-a-vis fast fourier transform of noisy vibration signals emanated from defective rolling element bearings

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Mechanical Engineering 2014年第2期9卷 130-141页

作者： Deepak PALIWAL Achintya CHOUDHURY T. GOVANDHAN Department of Mechanical Engineering Sir Padampat Singhania University Udaipur 313601 Rajasthan India

Fault diagnosis of rolling element bearings requires efficient signal processing techniques. For this purpose, the performances of envelope detection with fast fourier transform （FFT） and continuous wavelet transform （CWT） of vibration signals produced from a bearing with defects on inner race and rolling element, have been examined at low signal to noise ratio. Both simulated and experimental signals from identical bearings have been considered for the purpose of analysis. The bearings have been modeled as spring-mass-dashpot systems and the simulated signals have been obtained considering transfer functions for the bearing systems subjected to impulsive loads due to the defects. Frequency B spline wavelets have been applied for CWT and a discussion on wavelet selection has been presented for better effectiveness. Results show that use of CWT with the proposed wavelets overcomes the short coming of FFT while processing a noisy vibration signals for defect detection of bearings.

关键词： Fault detection spline wavelet continuous wavelet transform fast fourier transform

fast fourier transform Approximation of Foreign Currency Option Pricing Based on Exponential Lévy Model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Southwest Jiaotong University(English Edition) 2007年第3期15卷 261-270页

作者：陈旭万建平 Department of Mathematics Huazhong University of Science and Technology

To study the approximation of foreign currency option prices when the underlying assets＇ price dynamics are described by exponential Lévy processes, the convolution representations for option pricing formulas were given, and then the fast fourier transform （FFT） algorithm was used to get the approximate values of option prices. Finally, a numerical example was given to demonstrate the calculate steps to the option price by FFT.

关键词： Exponential Lévy model Bilateral Laplace transformation Measure change Foreign currency options fast fourier transform

维普期刊数据库

A sapphire fibre thermal probe based on fast fourier transform and phase-lock loop

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2006年第5期15卷 975-979页

作者：王平田王冬生葛文谦崔立超 Department of Electrical Engineering Yanshan University Qinhuangdao 066004 China

A sapphire fibre thermal probe with Cr^3＋ ion-doped end is developed by using the laser heated pedestal growth method. The fluorescence thermal probe offers advantages of compact structure, high performance and ability to withstand high temperature in a detection range from room temperature to 450℃. Based on the fast fourier transform （FFT）, the fluorescence lifetime is obtained from the tangent function of phase angle of the non-zeroth terms in the FFT result. This method has advantages such as quick calculation, high accuracy and immunity to the background noise. This FFT method is compared with other traditional fitting methods, indicating that the standard deviation of the FFT method is about half of that of the Prony method and about 1/6 of that of the log-fit method. And the FFT method is immune to the background noise involved in a signal. So, the FFT method is an excellent way of processing signals. In addition, a phase-lock amplifier can effectively suppress the noise.

关键词： fluorescence thermometer fast fourier transform phase-lock loop sapphire optical fibre

Reconstruction and fitting of second-harmonic signals by wavelength modulation spectroscopy method based on fast fourier transform

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Optics Letters 2022年第9期20卷 68-72页

作者： Linquan Lai Yue Chen Kongtao Chen Jiale Tang Kaiwen Yin Fuqiang Jia Dun Qiao Yuanlong Fan Kang Li Nigel Copner Fujian Key Laboratory of Ultrafast Laser Technology and Applications School of Electronic Science and TechnologyXiamen UniversityXiamen 361005China Wireless&Optoelectronics Research&Innovation Centre Faculty of ComputingEngineering&ScienceUniversity of South WalesWales CF371DLUK

Conventional wavelength modulation spectroscopy(WMS)is vulnerable to the influence of low-frequency *** of the method highly depends on the performance of the costly lock-in *** this article,we report a new and effective method for reconstructing second-harmonic signals through WMS based on fast fourier transform(FFT).This method is less disturbed by low-frequency noise because it does not use a low-frequency ramp *** and detection procedures were *** discrete second-harmonic waveform can be obtained by continuously changing the DC signal and FFT analysis in this ***-harmonic waveforms acquired by the two means are generally *** experimental study validates the obtained gas concentration from 5% to 30%,showing a good linear relationship by the proposed *** maximum relative error on concentration extraction is 2.87%;as for conventional WMS,this value is 4.50%.The developed measurement method may have potential in computed tomography.

关键词： fast fourier transform wavelength modulation spectroscopy second-harmonic waveform

维普期刊数据库

A high performance fast-fourier-transform spectrum analyzer for measuring spin noise spectrums

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第9期29卷 259-266页

作者： Yu Tong Lin Wang Wen-Zhe Zhang Ming-Dong Zhu Xi Qin Min Jiang Xing Rong Jiangfeng Du Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics University of Science and Technology of ChinaHefei 230026China CAS Key Laboratory of Microscale Magnetic Resonance University of Science and Technology of ChinaHefei 230026China Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China

A high performance fast-fourier-transform (FFT) spectrum analyzer, which is developed for measure spin noise spectrums, is presented in this paper. The analyzer is implemented with a field-programmable-gate-arrays (FPGA) chip for data and command management. An analog-to-digital-convertor chip is integrated for analog signal acquisition. In order to meet the various requirements of measuring different types of spin noise spectrums, multiple operating modes are designed and realized using the reprogrammable FPGA logic resources. The FFT function is fully managed by the programmable resource inside the FPGA chip. A 1 GSa/s sampling rate and a 100 percent data coverage ratio with non-dead-time are obtained. 30534 FFT spectrums can be acquired per second, and the spectrums can be on-board accumulated and averaged. Digital filters, multi-stage reconfigurable data reconstruction modules, and frequency down conversion modules are also implemented in the FPGA to provide flexible real-time data processing capacity, thus the noise floor and signals aliasing can be suppressed effectively. An efficiency comparison between the FPGA-based FFT spectrum analyzer and the software-based FFT is demonstrated, and the high performance FFT spectrum analyzer has a significant advantage in obtaining high resolution spin noise spectrums with enhanced efficiency.

关键词： fast fourier transform spectrum analyzer field-programmable-gate-arrays(FPGA) spin noise spectrum

维普期刊数据库

Gait Recognition Based on the fast fourier transform and SVM

在线全文

学校读者我要写书评

暂无评论

Gait Recognition Based on the Fast Fourier Transform and SVM

A Deepfake Detection Algorithm Based on fourier transform of Biological Signal

2011 Chinese Control and Decision Conference（CCDC）

作者： Fei Wang,Shiguang Wen are with the College of Information Science and Engineering,Northeastern University,Shenyang,China,Chengdong Wu,Yuzhong Zhang,Hao Wang

Gait recognition is a new type of biometric identification *** the preliminary study of biped robot with heterogeneous legs,we detect road information by classify of subject’s gait data by measurement using *** we can make bionic leg’s movement to follow artificial leg’s movement *** gait recognition is a very important step in *** paper adopted the fast fourier transform to the feature selection of time-series sequence of measurement gait data,and reduces the characteristic number of the samples into *** we detected the situation of road by gait recognition of different gait data on the different roads based support vector *** experiment shows a good result,and the method reduces the computing time significantly.

关键词： Gait recognition Feature selection fast fourier transform Support vector machine.

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第6期79卷 5295-5312页

作者： Yin Ni Wu Zeng Peng Xia Guang Stanley Yang Ruochen Tan School of Electrical and Electronic Engineering Wuhan Polytechnic UniversityWuhan430023China School of Mathematics and Computer Science Wuhan Polytechnic UniversityWuhan430048China Paul G.Allen School of Computer Science and Engineering University ofWashingtonSeattleWA98195USA School of Computer Science and Engineering University of CaliforniaSanDiegoCA92093USA

Deepfake-generated fake faces,commonly utilized in identity-related activities such as political propaganda,celebrity impersonations,evidence forgery,and familiar fraud,pose new societal *** current deepfake generators strive for high realism in visual effects,they do not replicate biometric signals indicative of cardiac *** this gap,many researchers have developed detection methods focusing on biometric *** methods utilize classification networks to analyze both temporal and spectral domain features of the remote photoplethysmography(rPPG)signal,resulting in high detection ***,in the spectral analysis,existing approaches often only consider the power spectral density and neglect the amplitude spectrum—both crucial for assessing cardiac *** introduce a novel method that extracts rPPG signals from multiple regions of interest through remote photoplethysmography and processes them using fast fourier transform(FFT).The resultant time-frequency domain signal samples are organized into matrices to create Matrix Visualization Heatmaps(MVHM),which are then utilized to train an image classification ***,we explored various combinations of time-frequency domain representations of rPPG signals and the impact of attention *** experimental results show that our algorithm achieves a remarkable detection accuracy of 99.22%in identifying fake videos,significantly outperforming mainstream algorithms and demonstrating the effectiveness of fourier transform and attention mechanisms in detecting fake faces.

关键词： Deepfake detector remote photoplethysmography fast fourier transform spatial attention mechanism

Exploring the correlation between temperature and crime:A case-crossover study of eight cities in America

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Safety Science and Resilience 2024年第1期5卷 13-36页

作者： Jinming Hu Xiaofeng Hu Xin’ge Han Yan Lin Huanggang Wu Bing Shen School of Information Technology and Cyber Security People’s Public Security University of ChinaBeijing 100038China Center for Capital Social Safety People’s Public Security University of ChinaBeijing 100038China China Association for Public Safety Beijing 100084China School of Emergency Management and Safety Engineering China University of Mining and TechnologyBeijing 100083China School of International Police Studies People’s Public Security University of ChinaBeijing 100038China

Recent years have seen increasing academic interest in exploring the correlation between temperature and ***,it is uncertain whether similar long-term trends or seasonality(rather than causal effect)of temper-ature and crime is the major reason for the observed correlation between *** explore whether there is still a correlation between temperature and crime when long-term trends and seasonal cycles are filtered out,we use the Kalman filter to decompose the time series of temperature and crimes,and then the fast fourier transform is used to calculate the exact circle of their seasonality *** on that,the box-plot method and linear regression are used to explore the correlation between temperature residuals and crime *** results show that more than half of the crime types have similar seasonal cycles(approximately 1 year)to that of ***,the daily residual analyses show that temperature residuals have a positive correlation with assault and robbery residuals in all cities,whose average slopes are more than *** other four types of crimes vary greatly from case to *** temperature residuals show a weak correlation with the residuals of some crime types.

关键词： Time series decomposition Crime Temperature Kalman filter fast fourier transform