نتایج جستجو برای: huang transform is a time consuming process while by using instantaneous frequency separately

تعداد نتایج: 16116937  

Journal: :فیزیک زمین و فضا 0
محمد رداد دانشجوی دکتری لرزه شناسی، گروه فیزیک زمین، مؤسسة ژئوفیزیک، دانشگاه تهران، ایران علی غلامی دانشیار، گروه فیزیک زمین، مؤسسة ژئوفیزیک، دانشگاه تهران، ایران حمیدرضا سیاه کوهی استاد، گروه فیزیک زمین، مؤسسة ژئوفیزیک، دانشگاه تهران، ایران

seismic attribute is a quantitative measure of an interested seismic characteristic. there are several seismic attributes. in recent years, time-frequency (tf) attributes have been developed which to reach them, tf analyzing of seismic data is required. a high resolution tf representation (tfr) can yield more accurate tf attributes. there are several tfr methods including short-time fourier tra...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده ریاضی 1390

به طور کلی در فرآیندهای مارکوف ارگودیک دو بعدی یافتن فرم بسته توزیع ایستا، تنها برای حالات خیلی خاص امکان پذیر است. با توجه به این مشکل و نیز با توجه به اهمیت توزیع ایستا، بررسی و مطالعه رفتار مجانبی توزیع ایستای این فرآیندها مورد توجه قرار گرفته است. زنجیر قدم زدن تصادفی دو بعدی که در برخی متون به آن، فرآیند qbd دو طرفه نیز می گویند، یکی از این فرآیندها است. یک فرآیند qbd زمان گسسته یک زنجیر م...

A. ‎Naderi Saatlo‎ N. ‎Romooz‎ S. ‎Sheykhivand‎ T. ‎Yousefi ‎R‎ezaii‎

‎There are different feature extraction methods in brain-computer interfaces (BCI) based on Steady-State Visually Evoked Potentials (SSVEP) systems‎. ‎This paper presents a comparison of five methods for stimulation frequency detection in SSVEP-based BCI systems‎. ‎The techniques are based on Power Spectrum Density Analysis (PSDA)‎, ‎Fast Fourier Transform (FFT)‎, ‎Hilbert‎- ‎Huang Transform (H...

پایان نامه :0 1391

uncertainty in the financial market will be driven by underlying brownian motions, while the assets are assumed to be general stochastic processes adapted to the filtration of the brownian motions. the goal of this study is to calculate the accumulated wealth in order to optimize the expected terminal value using a suitable utility function. this thesis introduced the lim-wong’s benchmark fun...

پایان نامه :دانشگاه امام رضا علیه اسلام - دانشکده ادبیات و علوم انسانی 1393

this research aims at answering the questions about translation problems and strategies applied by translators when translating cultural concepts. in order to address this issue, qualitative and quantitative study were conducted on two groups of subjects at imam reza international university of mashhad. these two groups were assigned as beginner and advanced translation students (10 students). ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تبریز 1390

learning a second or foreign language requires the manipulation of four main skills, namely, listening, reading, speaking, and writing which lead to effective communication. it is obvious that vocabulary is an indispensible part of any communication, so without a vocabulary, no meaningful communication can take place and meaningful communication relies heavily on vocabulary. one fundamental fac...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده شیمی 1389

in this thesis, a new optically active poly(amide-imide) (pai) was synthesized by the indirect polycondensation reaction of the l-phenylalanine based diacid chloride and 4,4?-diaminodiphenylether in the presence of triethylamine in n-methyl-2-pyrrolidone. the formation of pai was confirmed by ftir, 1h nmr and elemental analysis. in next step, the surface of titanium dioxide (tio2) nanoparticles...

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)...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده زبانهای خارجی 1391

this thesis seeks to present a critical reading of virginia woolf’s mrs. dalloway and michael cunningham’s the hours in terms of an intertextual approach, concentrating on dialogic imagination, negativity, transposition and allusion. this study attempts to evaluate cunninghams perception of woolfs life and work by adopting kristevas conception of intertextuality and her consideration of the hou...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه ارومیه 1377

‏‎applications such as high definition viedeo reproduction, portable computers, wireless, and multimedia demand, and ever-increasing need for ligh-frequency high-resolution and low-power analog-to-digital converters. flash, two-step flash, and pipeline convertors are fast but consume large amount of power and require large area. to overcome these problems, successive approximation converter blo...

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