Wavelet transformation has been widely used in geophysical and geochemical exploration, the fractal feature of wavelet coefficients recently stood out from many threshold methods. We introduced wavelet–fractal method to analyze polarizability resistivity graphite deposits. Due unique nature graphite-bearing gneiss, characterized by high low resistivity, we concluded that background mode is bett...

We attempt to recover a function of unknown smoothness from noisy, sampled data. We introduce a procedure, SureShrink, which suppresses noise by thresholding the empirical wavelet coe cients. The thresholding is adaptive: a threshold level is assigned to each dyadic resolution level by the principle of minimizing the Stein Unbiased Estimate of Risk (Sure) for threshold estimates. The computatio...

1 Facultatea de Electronică şi Telecomunicaţii, Departamentul Comunicaţii Bd. V. Pârvan Nr. 2, 300223 Timişoara, e-mail [email protected] Abstract – This paper presents an in-depth investigation of DWTbased OFDM, by analyzing the influence of the wavelets mother choice on the BER performance for the transmission in a flat fading channel. Simulations made show the importance of this param...

This paper introduces the use of adaptive multichannel discrete wavelet transforms (AMDWTs), allowing for a customized design of optimum mother wavelets, for the detection of a constituent absorption band within a hyperspectral curve. Even when the target’s amplitude is only 3% of the background signal’s amplitude, the AMDWT approach produces target detection rates of 90%.

For the significance test of the unknown parameter distributions, a non-parametric method, such as wavelet transformation analysis, is a reasonable choice. A wavelet is a waveform of effectively limited duration that has an average value of zero, and wavelet analysis is the breaking up of a signal into shifted and scaled versions of the original (or mother) wavelet. It provides a multi-scale re...

In Image Compression, the researchers’ aim is to reduce the number of bits required to represent an image by removing the spatial and spectral redundancies. Recently discrete wavelet transform and wavelet packet has emerged as popular techniques for image compression. The wavelet transform is one of the major processing components of image compression. The result of the compression changes as p...

The coherent secondary flow structures (i.e., swirling motions) in a curved artery model possess a variety of spatio-temporal morphologies and can be encoded over an infinitely-wide range of wavelet scales. Wavelet analysis was applied to the following vorticity fields: (i) a numerically-generated system of Oseen-type vortices for which the theoretical solution is known, used for bench marking ...

Nowadays, most analytical instruments in modern laboratories are computerized, partly owing to the rapid development of advanced micro-electronic technology. Digitalized spectroscopic data can be exported from these instruments very easily for subsequent signal processing. Raman Spectroscopy is widely recognized as powerful, non-destructive techniques for characterizing materials. The key to re...

This paper presents a diagnosis technique to detect and identify faults in AC servo motors. The first phase of stator currents among three phases is digitized and stored in the time domain. Wavelet transform is employed to convert the signals onto time-frequency domain because the time domain based approach is not suitable for detecting state features of the current signals. Pre-processing algo...

Applying a wavelet analysis based on the Morlet mother function, we previously demonstrated the presence of both Al and Zn atoms in the first metal shell (r ≈ 3 Å from the central Zn atom) of Zn-Al layered double hydroxide (LDH). However, this approach was not suited to resolve the second and third metal shells (r ≈ 5 6 Å) in r and k space independently. Therefore, we developed a new FEFF-Morle...