نتایج جستجو برای: frequency and spatial domain

تعداد نتایج: 16961384  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه یزد - دانشکده زبانهای خارجی 1392

abstract since heubners (1985) pioneering study, there have been many studies on (mis) use/ non-use of articles by l2 learners from article-less and article languages. the present study investigated how persian l2 learners of english produce and interpret english definite descriptions and demonstrative descriptions. it was assumed that definite and demonstrative descriptions share the same cen...

Fereidoun Nowshiravan-Rahatabad, Omid Khayat,

Purpose: The aim of this study was to characterize prolonged standing and its effect on postural control in elderly individuals in comparison to adults.Materials and Methods: The elderly individuals’ behavior during standing and how demanding such a task is for them, is still unknown. We recorded the center of pressure (COP) position of 12 elder and 15 young participants while they were standin...

ژورنال: فیزیک زمین و فضا 2018

Time-frequency filtering is an acceptable technique for attenuating noise in 2-D (time-space) and 3-D (time-space-space) reflection seismic data. The common approach for this purpose is transforming each seismic signal from 1-D time domain to a 2-D time-frequency domain and then denoising the signal by a designed filter and finally transforming back the filtered signal to original time domain. ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده ادبیات و علوم انسانی 1393

as far as bandura’s (1977) conceptualization of the sense of self-efficacy is concerned, it is argued to be context- and even task-specific, compared to other concepts like self-esteem (brown, 2000); therefore, upon the previous research studies, related theories and definitions, and the ideas and views obtained from the interviews conducted with the scholars, the current research study aimed a...

1997
D. G. Bailey

Donald G. Bailey Physics Department, Massey University Palmerston North, New Zealand D.G.Bailey @ massey . ac.nz Filtering is often used in image processing to smooth noise, and to enhance or detect features within an image. Images which have regular patterns in the spatial domain have peaks in the frequency domain corresponding to the spatial frequencies of the regular patterns. When processin...

Journal: :فیزیک زمین و فضا 0
مریم خاکی فیروز کارشناس ارشد پردازش داده های لرزه ای، شرکت کدکم حمیدرضا سیاهکوهی دانشیار، گروه فیزیک زمین، مؤسسة ژئوفیزیک دانشگاه تهران

the stolt (f-k) migration algorithm is a direct (i.e. non-recursive) fourier-domain technique based on a change of variables (or equivalently, a mapping) that converts the input spectrum to the output spectrum. the algorithm is simple and efficient but limited to constant velocity. a v(z)(f-k) migration method, capable of very high accuracy for vertical variations of velocity, can be formulated...

The present paper is aimed at introducing a new algorithm for image encryption using chaotic tent maps and the desired key image. This algorithm consists of two parts, the first of which works in the frequency domain and the second, in the time domain. In the frequency domain, a desired key image is used, and a random number is generated, using the chaotic tent map, in order to change the phase...

Journal: :iranian journal of astronomy and astrophysics 2014
iraj gholami

given the sensitivity of current ground-based gravitational wave (gw) detectors, any continuous-wave signal we can realistically expect will be at a level or below the background noise. hence, any data analysis of detector data will need to rely on statistical techniques to separate the signal from the noise. while with the current sensitivity of our detectors we do not expect to detect any tru...

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