نتایج جستجو برای: frequency transforms generate high volume of spectral components

تعداد نتایج: 21389038  

Journal: :فیزیک زمین و فضا 0
سمیرا محمدی کارشناس ارشد ژئوفیزیک (لرزه شناسی)، دانشگاه آزاد اسلامی واحد ساوه، ایران حمیدرضا سیاه کوهی دانشیار، گروه فیزیک زمین، موسسه ژئوفیزیک دانشگاه تهران، ایران

obtaining a seismic section with high temporal and spatial resolution was always one of the goals of seismic data processors and interpreters. accurate estimation of the thicknesses of thin beds is an important tool in this regard. the basic problem is that the wavelength of the signal must be similar in dimention to that of the bed thinness. if it is much longer than the bed thinness, the dete...

پایان نامه :0 1392

it is definitely necessary to understand the concept and behavior of causation of life insurance policies and its determinants for insurance managers, regulators, and customers. for insurance managers, the profitability and liquidity of insurers can be increasingly influenced by the number of causation through costs, adverse selection, and cash surrender values. therefore, causation is a materi...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده مهندسی 1388

در این پایان نامه، به کمک نرم افزار flow-3d میدان جریان عبوری از سریز اوجی بررسی می گردد. همچنین اثر هندسه سرریز و بلندای آب بالا دست سرریز بر میدان جریان و توزیع فشار بررسی شده و تاثیر مدل های مختلف آشفتگی (renormalizd group) rng, k-e, prandtl در میدان جریان نیز مورد توجه بوده است. نرم افزار flow-3d یک برنامه تحلیلی میدان جریان است که معادلات حاکم بر میدان جریان عبوری از روی سرریز که همان معاد...

Journal: :فیزیک زمین و فضا 0
احسان ذبیحی نائینی حمیدرضا سیاهکوهی

spectral decomposition is a powerful tool for analysis of seismic data. fourier transform determines the frequency contents of a signal. but for analysis of non-stationary signals, 1-d transform to frequency domain is not sufficient. in early years, transforming of seismic traces into time and frequency domain was done via windowed fourier transform, called a short time fourier transform (stft)...

Journal: :فیزیک زمین و فضا 0
محمد رداد دانشجوی دکتری ژئوفیزیک، گروه فیزیک زمین، مؤسسة ژئوفیزیک دانشگاه تهران، ایران عبدالرحیم جواهریان استاد بازنشسته، گروه فیزیک زمین، مؤسسه ژئوفیزیک، دانشگاه تهران و استاد دانشکده مهندسی نفت دانشگاه صنعتی امیرکبیر، تهران، ایران

most geologic changes have a seismic response but sometimes this is expressed only in certain spectral ranges hidden within the broadband data. spectral decomposition is one of the methods which can be utilized to help interpreting such cases. there are several time-frequency methods including: short-time fourier transform (stft), continuous wavelet transform (cwt), wigner-ville distribution (w...

2017
Koichiro OHNuKi Tohru FusHiKI

We assessed the sympatho-vagal actiyities of the heart after administration of capsalcin by measuring the pewer spectral analysis in rats. There were major two frequency components of heart rate variability, which we defined as high (1.0 Hz < , HF) and low (LF, <1.0 Hz) frequency components. Vagal blockade by atropine abo)ished the high frequency component, and lowered the amplitude of the low ...

2013
CHRISTIAN SCHÖRKHUBER

Pitch shifting of polyphonic music is usually performed by manipulating the time-frequency representation of the input signal. Most approaches proposed in the past are based on the Fourier transform although its linear frequency bin spacing is known to be inadequate to some degree for analyzing and processing music signals. Recently invertible constant-Q transforms (CQT) featuring high Q-factor...

In this paper, we present an analytical method for solving a well-posed boundary value problem of mathematical physics governing the vibration characteristics of an internal flow propelled fluid-structure interaction where the pipeline segment is idealized as an elastic hollow beam conveying an incompressible fluid on a viscoelastic foundation. The effect of Coriolis and damping forces on the o...

2017
Fuqi Liao Jianling Peng Rujin Chen

Diverse leaf forms ranging from simple to compound leaves are found in plants. It is known that the final leaf size and shape vary greatly in response to developmental and environmental changes. However, changes in leaf size and shape have been quantitatively characterized only in a limited number of species. Here, we report development of LeafletAnalyzer, an automated image analysis and classi...

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