نتایج جستجو برای: cyclic wavelet system
تعداد نتایج: 2344889 فیلتر نتایج به سال:
Embedded wavelet codes are very sensitive to channel noise because a single bit error can lead to an irreversible loss of synchronization between the encoder and the decoder. Sherwood and Zeger protected a zero-tree based embedded wavelet code sent through a memoryless noisy channel by using cyclic redundancy detection codes (CRC) and channel correction codes. Chande and Farvardin proposed an o...
An adaptive watermarking method based on the human visual system model and the fuzzy inference system in wavelet domain is proposed. Fuzzy logic is used for data fusion and builds a HVS model for spatial masking in wavelet domain. Modeling spatial masking is a complicated task and there is no single theoretical formulation to precisely compute the perceptual value for a corresponding wavelet co...
An ecient method, based on the Legendre wavelets, is proposed to solve thesecond kind Fredholm and Volterra integral equations of Hammerstein type.The properties of Legendre wavelet family are utilized to reduce a nonlinearintegral equation to a system of nonlinear algebraic equations, which is easilyhandled with the well-known Newton's method. Examples assuring eciencyof the method and its sup...
This paper presents the wavelet domain theoretical basis for rms value and total harmonic distortion measurements. It provides a systematic method for analyzing power system disturbances in the wavelet domain. The wavelet domain capabilities in detection, classification, and measurements of different power system disturbances are presented. The distortion event is mapped into the wavelet domain...
During their service life, marine pipelines continually accumulate damage as a result of the action of various environmental forces. Clearly, the development of robust techniques for early damage detection is very important to avoid the possible occurrence of a disastrous structural failure. Most of vibration-based damage detection methods require the modal properties that are obtained from mea...
Orthogonal Frequency Division Multiplexing (OFDM) is of the strong prospects as a future wireless communication system. Improved spectral efficiency has been found in OFDM based on DFT, has a good orthogonality but inter symbol interference (ISI) and inter carrier interference (ICI) degrade the performance. ISI and ICI can be improved by using cyclic prefix (CP). About 20% of bandwidth is consu...
in the past few decades, increasing growth of wind power plants causes different problems for the power quality in the grid. normal and transient impacts of these units on the power grid clearly indicate the need to improve the quality of the electricity generated by them in the design of such systems. improving the efficiency of the large-scale wind system is dependent on the control parameter...
In this paper, a fault diagnosis system based on discrete wavelet transform (DWT) and artificial neural networks (ANNs) is designed to diagnose different types of fault in gears and bearings. DWT is an advanced signal-processing technique for fault detection and identification. Five features of wavelet transform RMS, crest factor, kurtosis, standard deviation and skewness of discrete wavelet co...
An application of wavelet neural network/wavenet in control problems of nonlinear systems is investigated in this study. A wavelet neural network is constructed as an alternative architecture to a neural network to approximate a nonlinear system. Based on approximation capability of wavelet network, a suitable adaptive control law and parameter updating algorithm as applied to nonlinear system ...
Spectral singularities at non-zero frequencies play an important role in investigating cyclic or seasonal time series. The publication [2] introduced the generalized filtered method-of-moments approach to simultaneously estimate singularity location and long-memory parameters. This paper continues studies of these simultaneous estimators. A wide class Gegenbauer-type semi-parametric models is c...
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