نتایج جستجو برای: time frequency analysis

تعداد نتایج: 4548791  

2009
Binh Phu Nguyen Masato Akagi

Aims of voice transformation are to change styles of given utterances. Most voice transformation methods process speech signals in a time-frequency domain. In the time domain, when processing spectral information, conventional methods do not consider relations between neighboring frames. If unexpected modifications happen, there are discontinuities between frames, which lead to the degradation ...

Journal: :TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C 2013

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علامه طباطبایی - دانشکده اقتصاد 1389

this thesis is a study on insurance fraud in iran automobile insurance industry and explores the usage of expert linkage between un-supervised clustering and analytical hierarchy process(ahp), and renders the findings from applying these algorithms for automobile insurance claim fraud detection. the expert linkage determination objective function plan provides us with a way to determine whi...

2004
L. Ferro-Famil A. Reigber E. Pottier

In this paper, a fully polarimetric time-frequency analysis method is introduced to decompose synthesized polarimetric and interferometric SAR images into range-frequency and azimuth-frequency domain. This 4-D representation permits to characterize the frequency response of the scene reflectivity, observed under different azimuth look-angles. A statistical analysis of polarimetric parameters pe...

Journal: :CoRR 2016
Pushpendra Singh

The nonstationary nature of signals and nonlinear systems require the time-frequency representation. In time-domain signal, frequency information is derived from the phase of the Gabor’s analytic signal which is practically obtained by the inverse Fourier transform. This study presents time-frequency analysis by the Fourier transform which maps the time-domain signal into the frequency-domain. ...

2013
Jiajun Han Mirko van der Baan

Time-frequency analysis plays a significant role in seismic data processing and interpretation. Complete ensemble empirical mode decomposition decomposes a seismic signal into a sum of oscillatory components, with guaranteed positive and smoothly varying instantaneous frequencies. Analysis on synthetic and real data demonstrates that this method promises higher spectral-spatial resolution than ...

Journal: :فیزیک زمین و فضا 0
محمد صادق پرکان دانشجوی کارشناسی ارشد مؤسسة ژئوفیزیک دانشگاه تهران حمیدرضا سیاه کوهی استاد، گروه فیزیک زمین، موسسه زئوفیزیک دانشگاه تهران، ایران علی غلامی دانشیر، گروه فیزیک زمین، موسسه ژئوفیزیک دانشگاه تهارن، ایران

in this paper some new applications of empirical mode decomposition (emd) and hilbert spectrum in seismic ground-roll attenuation, random noise attenuation and spectral decomposition are introduced. hilbert spectrum is a time-frequency representation for hilbert-huang transform which is obtained by combination of instantaneous frequency (if) concept and intrinsic mode function of empirical mode...

1999
Xiang-Gen Xia Leon Cohen

In this paper, we characterize all analytic signals with band-limited amplitudes and polynomial phases. We show that a signal with band-limited amplitude and polynomial phase is analytic if and only if it has nonneg-ative constant instantaneous frequency, i.e., the derivative of the phase is a nonnegative constant, and the constant is greater than or equal to the minimum bandwidth of the amplit...

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