期刊文献+
共找到12篇文章
< 1 >
每页显示 20 50 100
The optimal fractional Gabor transform based on the adaptive window function and its application 被引量:4
1
作者 陈颖频 彭真明 +2 位作者 贺振华 田琳 张洞君 《Applied Geophysics》 SCIE CSCD 2013年第3期305-313,358,共10页
We designed the window function of the optimal Gabor transform based on the time-frequency rotation property of the fractional Fourier transform. Thus, we obtained the adaptive optimal Gabor transform in the fractiona... We designed the window function of the optimal Gabor transform based on the time-frequency rotation property of the fractional Fourier transform. Thus, we obtained the adaptive optimal Gabor transform in the fractional domain and improved the time-frequency concentration of the Gabor transform. The algorithm first searches for the optimal rotation factor, then performs the p-th FrFT of the signal and, finally, performs time and frequency analysis of the FrFT result. Finally, the algorithm rotates the plane in the fractional domain back to the normal time-frequency plane. This promotes the application of FrFT in the field of high-resolution reservoir prediction. Additionally, we proposed an adaptive search method for the optimal rotation factor using the Parseval principle in the fractional domain, which simplifies the algorithm. We carried out spectrum decomposition of the seismic signal, which showed that the instantaneous frequency slices obtained by the proposed algorithm are superior to the ones obtained by the traditional Gabor transform. The adaptive time frequency analysis is of great significance to seismic signal processing. 展开更多
关键词 FrFT generalized time bandwidth product optimal rotation factor search adaptive optimal Gabor transform spectral decomposition seismic signals
下载PDF
FM interference suppression for PRC-CW radar based on adaptive STFT and time-varying filtering 被引量:9
2
作者 Zhao Zhao Xiangquan Shi 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2010年第2期219-223,共5页
The influence of frequency modulation (FM) interfer- ence on correlation detection performance of the pseudo random code continuous wave (PRC-CW) radar is analyzed. It is found that the correlation output deterior... The influence of frequency modulation (FM) interfer- ence on correlation detection performance of the pseudo random code continuous wave (PRC-CW) radar is analyzed. It is found that the correlation output deteriorates greatly when the FM inter- ference power exceeds the anti-jamming limit of the radar. Accord- ing to the fact that the PRC-CW radar echo is a wideband pseudo random signal occupying the whole TF plane, while the FM in- terference only concentrates in a small portion, a new method is proposed based on adaptive short-time Fourier transform (STFT) and time-varying filtering for FM interference suppression. This method filters the received signal by using a binary mask to excise only the portion of the TF plane corrupted by the interference. Two types of interference, linear FM (LFM) and sinusoidal FM (SFM), under different signal-to-jamming ratio (S JR) are studied. It is shown that the proposed method can effectively suppress the FM interference and improve the performance of target detection. 展开更多
关键词 interference suppression frequency modulation in- terference adaptive short-time Fourier transform (STFT) time- varying filtering pseudo random code continuous wave (PRC-CW) radar.
下载PDF
High-frequency compensation for seismic data based on adaptive generalized S transform 被引量:2
3
作者 Li Hui-Feng Wang Jin +1 位作者 Wei Zheng-Rong Yang Fei-Long 《Applied Geophysics》 SCIE CSCD 2020年第5期747-755,902,共10页
The low-pass fi ltering eff ect of the Earth results in the absorption and attenuation of the high-frequency components of seismic signals by the stratum during propagation.Hence,seismic data have low resolution.Consi... The low-pass fi ltering eff ect of the Earth results in the absorption and attenuation of the high-frequency components of seismic signals by the stratum during propagation.Hence,seismic data have low resolution.Considering the limitations of traditional high-frequency compensation methods,this paper presents a new method based on adaptive generalized S transform.This method is based on the study of frequency spectrum attenuation law of seismic signals,and the Gauss window function of adaptive generalized S transform is used to fi t the attenuation trend of seismic signals to seek the optimal Gauss window function.The amplitude spectrum compensation function constructed using the optimal Gauss window function is used to modify the time-frequency spectrum of the adaptive generalized S transform of seismic signals and reconstruct seismic signals to compensate for high-frequency attenuation.Practical data processing results show that the method can compensate for the high-frequency components that are absorbed and attenuated by the stratum,thereby eff ectively improving the resolution and quality of seismic data. 展开更多
关键词 seismic data time-frequency analysis adaptive generalized S transform high-frequency compensation
下载PDF
Multi-Label Chinese Comments Categorization: Comparison of Multi-Label Learning Algorithms 被引量:4
4
作者 Jiahui He Chaozhi Wang +2 位作者 Hongyu Wu Leiming Yan Christian Lu 《Journal of New Media》 2019年第2期51-61,共11页
Multi-label text categorization refers to the problem of categorizing text througha multi-label learning algorithm. Text classification for Asian languages such as Chinese isdifferent from work for other languages suc... Multi-label text categorization refers to the problem of categorizing text througha multi-label learning algorithm. Text classification for Asian languages such as Chinese isdifferent from work for other languages such as English which use spaces to separate words.Before classifying text, it is necessary to perform a word segmentation operation to converta continuous language into a list of separate words and then convert it into a vector of acertain dimension. Generally, multi-label learning algorithms can be divided into twocategories, problem transformation methods and adapted algorithms. This work will usecustomer's comments about some hotels as a training data set, which contains labels for allaspects of the hotel evaluation, aiming to analyze and compare the performance of variousmulti-label learning algorithms on Chinese text classification. The experiment involves threebasic methods of problem transformation methods: Support Vector Machine, Random Forest,k-Nearest-Neighbor;and one adapted algorithm of Convolutional Neural Network. Theexperimental results show that the Support Vector Machine has better performance. 展开更多
关键词 Multi-label classification Chinese text classification problem transformation adapted algorithms
下载PDF
IMPROVED METHOD FOR HILBERT INSTANTANEOUS FREQUENCY ESTIMATION 被引量:3
5
作者 BO Lin LIU Xiaofeng QIN Shuren 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2007年第6期94-98,共5页
In the mechanical fault detection and diagnosis field, it is more and more important to analyze the instantaneous frequency (IF) character of complex vibration signal. The improved IF estimation method is put forwar... In the mechanical fault detection and diagnosis field, it is more and more important to analyze the instantaneous frequency (IF) character of complex vibration signal. The improved IF estimation method is put forward aiming at the shortage of traditional Hilbert transform. It is based on Hilbert transform in wavelet domain. With the help of relationship between the real part and the imaginary part obtained from the complex coefficient of continuous wavelet transform or the analyti- cal signal reconstructed in wavelet packet decomposition, the instantaneous phase function of the subcomponent is extracted. In order to improve the precise of IF estimated out, some means such as Linear regression, adaptive filtering, resampling are applied into the instantaneous phase obtained, then, the central differencing operator is used to get desired IF. Simulation results with synthetic and gearbox fault signals are included to illustrate the proposed method. 展开更多
关键词 Instantaneous frequency Hilbert transform Wavelet transform Linear regression Adaptive filtering Resampling
下载PDF
Evolved Urban Form to Respond to Extreme Sea Level Events in Coastal Cities
6
作者 Wang Liangling Han Jie 《Journal of Civil Engineering and Architecture》 2016年第6期726-735,共10页
Along with climate change and global warming, ESLEs (extreme sea level events) are seriously threatening coastal cities' development. In order to respond to such events, transformational adaptation strategy in urba... Along with climate change and global warming, ESLEs (extreme sea level events) are seriously threatening coastal cities' development. In order to respond to such events, transformational adaptation strategy in urban planning might play an important role. For instance, it has been proposed that BCR (building coverage ratio) should be minimized to a certain range in order to enhance coastal areas' resiliency. For the purpose of urban planning practices, the main objective of this research is to develop a method which could formulate the proper BCR range in vulnerable coastal areas. The research is conducted through simulating storm surge floods in simplified waterfront settlements with different BCRs. Data representing the impact of ESLEs collected through CFD (computational fluid dynamic) simulations has been examined. This research has proved that in dense coastal areas, ESLEs may cause serious damage to the built environment if their protective structures fail. It showed that controlling BCR is an effective way to enhance their resiliency. When the BCR is low, the pressure caused by storm surge floods and wave height can be greatly reduced. However, decreased BCR may also reduce land utilization efficiency. Simulation results indicated that controlling the BCR to around 36% might be the most effective scenario which balances resiliency and land use efficiency. They also showed that under the same storm surge flood scenario, the pressures caused by flood waves could be reduced if the length of the building is increased. This study might be considered as transformational adaptation measures that contributes some knowledge for waterfront development in vulnerable locations, and it also provides scientific and useful proof for sustainable strategies in coastal cities and reveals that particular urban design tools, such as BCR control, could play an essential role in responding to ESLEs. 展开更多
关键词 ESLEs BCR transformational adaptation CFD simulation.
下载PDF
A NEW ADAPTIVE FILTERING SCHEME BASED ON WAVELET TRANSFORM
7
作者 Wang Yongde He Peiyu Wang Chunxia(Dept. of Radio Electronics, Sichuan University, Chengdu 610064) 《Journal of Electronics(China)》 1999年第3期257-262,共6页
Based on the scale function representation for a function in L2(R), a new wavelet transform based adaptive system identification scheme is proposed. It can reduce the amount of computation by exploiting the decimation... Based on the scale function representation for a function in L2(R), a new wavelet transform based adaptive system identification scheme is proposed. It can reduce the amount of computation by exploiting the decimation properties and keep the advantage of quasi-orthogonal transform of the discrete wavelet, transform (DWT). The issue has been supported by computer simulations. 展开更多
关键词 IIR SP NLMS A NEW ADAPTIVE FILTERING SCHEME BASED ON WAVELET TRANSFORM DWT IEEE
下载PDF
The Translation of Neologisms From the Perspective of Eco-Translatology
8
作者 ZHU Yu 《Sino-US English Teaching》 2022年第2期65-73,共9页
Based on relevant theories of eco-translatology,this paper analyzes the translation of neologisms in the English book,The Money Is Coming from the perspective of adaptive transformation from three basic dimensions-the... Based on relevant theories of eco-translatology,this paper analyzes the translation of neologisms in the English book,The Money Is Coming from the perspective of adaptive transformation from three basic dimensions-the linguistic,cultural,and communicative dimensions. 展开更多
关键词 the translation of neologisms ECO-TRANSLATOLOGY adaptive transformation from three dimensions translation strategy
下载PDF
AN IMPROVED ALGORITHM OF GMM VOICE CONVERSION SYSTEM BASED ON CHANGING THE TIME-SCALE
9
作者 Zhou Ying Zhang Linghua 《Journal of Electronics(China)》 2011年第4期518-523,共6页
This paper improves and presents an advanced method of the voice conversion system based on Gaussian Mixture Models(GMM) models by changing the time-scale of speech.The Speech Transformation and Representation using A... This paper improves and presents an advanced method of the voice conversion system based on Gaussian Mixture Models(GMM) models by changing the time-scale of speech.The Speech Transformation and Representation using Adaptive Interpolation of weiGHTed spectrum(STRAIGHT) model is adopted to extract the spectrum features,and the GMM models are trained to generate the conversion function.The spectrum features of a source speech will be converted by the conversion function.The time-scale of speech is changed by extracting the converted features and adding to the spectrum.The conversion voice was evaluated by subjective and objective measurements.The results confirm that the transformed speech not only approximates the characteristics of the target speaker,but also more natural and more intelligible. 展开更多
关键词 Gaussian Mixture Models(GMM) Speech transformation and Representation using Adaptive Interpolation of weiGHTed spectrum(STRAIGHT) TIME-SCALE Voice conversion
下载PDF
Adaptive self-assembly and induced-fit transformations of anion-binding metal-organic macrocyclic receptors
10
《Science Foundation in China》 CAS 2017年第3期34-34,共1页
Subject Code:B01With the financial support from the National Natural Science Foundation of China,the research group led by Prof.Sun Qingfu(孙庆福)from the Fujian Institute of Research on the Structure of Matter,Chines... Subject Code:B01With the financial support from the National Natural Science Foundation of China,the research group led by Prof.Sun Qingfu(孙庆福)from the Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences has recently reported a dynamic anion-adaptive self-assembly system 展开更多
关键词 Adaptive self-assembly and induced-fit transformations of anion-binding metal-organic macrocyclic receptors
原文传递
The Performance Comparisons between the Unconstrained and Constrained Equalization Algorithms 被引量:2
11
作者 HE Zhong-qiu,LI Dao-ben(School of Information Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, P. R. China) 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2003年第4期50-58,共9页
This paper proposes two unconstrained algorithms, the Steepest Decent (SD)algorithm and the Conjugate Gradient (CG) algorithm, based on a superexcellent cost function. At thesame time, two constrained algorithms which... This paper proposes two unconstrained algorithms, the Steepest Decent (SD)algorithm and the Conjugate Gradient (CG) algorithm, based on a superexcellent cost function. At thesame time, two constrained algorithms which include the Constrained Steepest Decent (CSD) algorithmand the Constrained Conjugate Gradient algorithm (CCG) are deduced subject to a new constraincondition. They are both implemented in unitary transform domain. The computational complexities ofthe constrained algorithms are compared to those of the unconstrained algorithms. Resultingsimulations show their performance comparisons. 展开更多
关键词 transform domain adaptive equalization constrained equalization algorithm
原文传递
An approach for parameter estimation of combined CPPM and LFM radar signal 被引量:3
12
作者 Zhang Wei Xiong Ying +2 位作者 Wang Pei Wang Jun Tang Bin 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2013年第4期986-992,共7页
In this paper, the problem of parameter estimation of the combined radar signal adopting chaotic pulse position modulation (CPPM) and linear frequency modulation (LFM), which can be widely used in electronic count... In this paper, the problem of parameter estimation of the combined radar signal adopting chaotic pulse position modulation (CPPM) and linear frequency modulation (LFM), which can be widely used in electronic countermeasures, is addressed. An approach is proposed to estimate the initial frequency and chirp rate of the combined signal by exploiting the second-order cyclostationarity of the intra-pulse signal. In addition, under the condition of the equal pulse width, the pulse repetition interval (PRI) of the combined signal is predicted using the low-order Volterra adaptive filter. Simulations demonstrate that the proposed cyclic autocorrelation Hough transform (CHT) algorithm is theoretically tolerant to additive white Gaussian noise. When the value of signal noise to ratio (SNR) is less than 4 dB, it can still estimate the intra-pulse parameters well. When SNR = 3 dB, a good prediction of the PRI sequence can be achieved by the Volterra adaptive filter algorithm, even only 100 training samples. 展开更多
关键词 Chaotic pulse position modulation Combined radar signal Cyclic autocorrelation Electronic countermeasures Hough transform Linear frequency modulation Volterra adaptive filter
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部