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1.
Complex wavelet transform can characterize the partial feature of the PD signal in time-domain and frequency-domain,and provides the unique phasic information.In this paper,the PD pulse waveforms which are created by 4 typical insulated defects are transformed by complex wavelet,and then the complex wavelet coefficient's real part,imaginary part and compound coefficient are clustered by the Fuzzy c-means,the energy of the cluster is the feature of pattern recognition.Discharge samples are got through large number of experiments,and BPNN can identify the PD created by 4 typical insulated defects effectively.The results show that the feature extracted from compound coefficient is better than the feature extracted form the real part and imaginary part of complex wavelet coefficient or wavelet coefficient.  相似文献   

2.
A virtual wavelet transform analyzer for the signal analysis based on the direct algorithm is introduced so that the discrete wavelet transform and continuous wavelet transform is maken to signal in the direct algorithm. The authors first introduce the direct algorithm of the WT, which is numerical algorithm obtained from the original formula of the wavelet transform by directly numericalizing. Then some conclusions are drawn on the direct algorithm. The examples are the sampling principle and technology for the wavelets, the limitation of the scale range of the wavelets and the measures to solve the edge phenomenal in the direct algorithm of the discrete wavelet transform, and some conclusions in the direct algorithm of the continuous wavelet transform. The virtual wavelet transform analyzer for the signal analysis based on the direct algorithm explored based on these studies and combined with virtual instrument technique can make the discrete wavelet transform and continuous wavelet transform to signal with any basic wavelet. It can be applied in studying the property of any basic wavelet and learning the theory on the wavelet transform, and also in making some engineering signal analysis. In the end, the authors give some typical examples for the application of the virtual analyzer. These examples show that the analyzer can be applied in many situations.  相似文献   

3.
The method to carry out time frequency analysis of engineering signal using wavelets transform is discussed and the formuli of quantitative relationship between the position & width of time frequency window of wavelet transform and the scale & sampling interval is put forward.  相似文献   

4.
EEG signal is a kind of very complex non stationary signal. It is of important clinical values for using EEG most efficiently to distinguish all kinds of components in EEG or getting needed components to judge some pathology features effectively. The phase moving of the system can change the relative phase relation between the components in the inputed signal, so there can be a great change of the feature in time domain of inputed signal. The FRR and RRF digital filtering methods and their realization are discussed. By using these methods, the system can be of the feature of zero phase error, and the filtering of EEG signals with zero phase error can be realized. Based on the definition of sleep spindles, we can detect sleep spindles in time domain directly by using digital filtering with zero phase error.  相似文献   

5.
Multirate filter banks and wavelet transform are closely related theoretically and practically. This paper researches the wavelet transform of discrete-time sequences basing on dendriform filer banks in the signal processing field, analyses the theory and design method of two channel conjugate quadrature mirror filter banks and fast implement of discrete orthogonal wavelet transform and generation of orthogonal wavelets, and points out the internal relationship between them.  相似文献   

6.
The complex non-stationary signals are most often used in modem radar and communication systems. It must perform the tasks of envelope detection and intra-pulse feature analysis for radar pulse classification and identification. Time-frequency analysis is an effective tool for modem signal processing, and often applied to analyze and process non-stationary signals. Several methods of time-frequency analysis are presented, reconnaissance are also discussed and simulated. Simulation results show the and their applications in the radar signal effectiveness of these methods.  相似文献   

7.
An control algorithm with goed robustness has been developed,based on the combination of poletassignment self- tuning control algorithm with robust estimation and control al-gorithms,while the input signal and process parameters are varied on a large scale. The design of controller based on presented algorithm is simple,with good robustness for parameter changes and a strong ability for overcoming determined disturbance.The simulating research results proved the ef-fectiveness of the pole- assienment self-tuning robust control algorithm.  相似文献   

8.
Wavelets have been widely applied in such research areas as image processing, computer vision, network management and data mining. Wavelets have many favorable properties, which are hierarchical and multiresolution decomposition structure, linear time and space complexity of the transformations. The paper presents wavelet application on the algorithms of data mining, in cluding as clustering, classification, distributed data mining, similarity search, approximate query processing, visualization and so on. Finally, the paper concludes by discussing the impact of wavelets on data mining research and outlining potential future research directions and applications.  相似文献   

9.
生态旅游兴起和繁荣的同时,带来了一系列的景观干扰问题。本文从景观生态学的角度来分析和探讨生态旅游的景观干扰问题,探讨了生态旅游对景观(主要是景观格局)和景观要素的干扰,探讨了不同的景观干扰形式,并对景观干扰进行了评价方面的概述,在此基础上提出了相应的对策,为解决当前存在的生态旅游与景观保护这一矛盾提供借鉴与参考。  相似文献   

10.
The web documents classification is an important research content of web mining. Document vector space model is the foundation of automatic classification of documents, while it is difficult to eliminate redundant attributes and reduce the dimension of the vector space. The Rough Sets Theory is applied to generalize the information system comprised by document samples set, and to compute the best reducing properties set. So dimension of document feature space is reduced greatly, and disturbance to document classification is decreased too, which improve the efficiency of classification. In addition, using the advantage of adaptive classification and incremental learning of Fuzzy ARTMAP neural network, the online adaptive classification of web document is achieved.  相似文献   

11.
The properties of fault signals of motors are studied using dyadic wavelets transform in this paper,which can be treated as signals with sigularities.The method of removing white noises is presented by using the difference between the wavelets transforms of white noises and those of fault signals of motors in this paper."Denoised" signals can be reconstructed by using this practical algorithm.  相似文献   

12.
鉴于小型养猪场废水污染成分复杂、处理能力有限等特点,选择生物生态组合工艺作为小型养猪场废水处理的关键技术和工艺。本研究以江西某养猪场为研究对象,基于目前推广的干清粪工艺,设计了一套以“源分离-氧化塘-立体生物滤池-人工湿地”组合工艺处理养猪废水的工程技术方案,并进行效果评价,以满足小型养猪场废水处理经济性和高效性要求。研究结果认为该生物生态组合工艺具有良好的污染物去除效能,出水水质达到《畜禽养殖业污染物排放标准》(GB18596-2001)的一级排放标准。  相似文献   

13.
In order to protect the copyright of digital audio and video in Internet, we propose a novel audio blind watermarking scheme combined discrete wavelets transform, discrete cosine transform, QR decomposition and audio characteristics. In this algorithm, the audio are split into blocks, and each block are decomposed on two dimensional discrete wavelet transform (DWT), then the approximate sub band coefficients are decomposed on discrete cosine transform (DCT), and the first quarter of the DCT coefficients are decomposed on QR decomposition and get a triangle matrix. At last, the watermarking information is embedded into the triangle matrix. The experiments show that the algorithm can get better balance between transparency and robustness of watermark, and it has strong robustness against the common audio signal processing such as additive white Gaussian noise, re sampling, re quantization, low pass filter, MP3 compression and cutting replacement.  相似文献   

14.
The robust control theory is used to solve the uncertainty of the optical extra-precise vibration isolation system. The wavelet theory is used to analyze the random vibration signal in the time-frequency domain and get the low frequency signal from the random vibration signal. The robust controller designed by the robust control theory is used to restrain the low frequency vibration. The active vibration isolation exploits the theory of robust control, which overcomes the uncertainty of model and the disturbance, and makes the control system to restrain the uncertainty of the model and the disturbance of the vibration. The simulation results prove that this method has shown good robustness and control precision in the vibration isolation of the optical extra-precise instrument and have good performance on restraining the low frequency vibration.  相似文献   

15.
The metabolism and development of plants are controlled through interplay between genetic and environmental cues.For optimal growth plants require the ability to coordinate complex developmental processes and at the same time sense and respond to environmental stimuli.The responses can be divided into three main events: stimulus perception,generation and transmission of a signal,and subsequent changes in downstream biochemical processes.Because of space limitation this review does not provide an exhaustive account of plant signal transduction.Rather,the authors intention is to cover new and important results in this field,including the mechanochemical transform mediated by integrin and integrin-like protein,the change of membrane fluidity respond to stimulus,and the wide accepted transduction pathway of calcium signaling system.The research emphasis and tendency are prospected.  相似文献   

16.
植物营养缺素研究进展   总被引:4,自引:1,他引:3  
营养缺素症是植物体内营养失调的外部表现,研究植物营养缺素可作为进行形态诊断合理施肥的重要依据。此文综述了近年来在粮食作物、经济作物、药用植物、园艺作物、林木等多个领域间营养缺素方面的相关研究,并对今后的研究方向提出展望。  相似文献   

17.
By CD ROM and Internet Service System,lots of references on wavelet are searched.These references are analysed in the paper,a new viewpoint is put forward by the authors.Recent studies by the authors on wavelets are also introduced.  相似文献   

18.
A new image reconstruction algorithm is presented, based on orthogonal wavelets derived from symmetric scale functions. The analysis and practice show that the method lessens greatly the computational time,and improves the reconstruction quality.  相似文献   

19.
In this paper, some problems such as circuit jam, mutual disturbance of signals, bad operation reliability and so on were analyzed, which resulted from the deficiency of integral electric and computer systems design and installation. It discusses mainly such problems as power supply, separation of alternating and direct currents, ground connection, undisturbed signal lines and so on. Then it puts forward a reference model for computer room's synthetical power distribution.  相似文献   

20.
With the development and application of information and internet and virtual instrument technology ,the virtual globular company based on internet arises .To study remote state monitoring, remote fault detection and diagnosis about large scale, complicated and integrative equipment become very important. In the whole fault diagnosis system , the detecting ,data acquisition is original ,processing; transform and extracting features with the signal detected is a key factor. The theories and methods used in mechanical fault diagnosis is stated. The application of signal process and its feature extracting methods is introduced which are time domain, frequency domain and time frequency domain analysis, in state monitoring and fault diagnosis with its signal analysis. The processing method of random time variant special signal is given also.  相似文献   

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