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

تعداد نتایج: 21389038  

Journal: :journal of tethys 0

in the form of passive seismic methods, broadband seismometers have been used in hydrocarbon exploration. the frequency bandwidth typically studied is in the range of 1–6 hz. the observations on low frequency band of microtremors are used to calculate the spectral ratio of vertical and horizontal components (v/h) and power spectral density (psd). attributes based on the v/h ratio and the psd ha...

2015
Zeeshan Hashmi Khateeb

Assessment of clean speech from a noisy speech signal has been a research topic for a long time. This research finds its variety of applications, which includes the present mobile communication also. The most important outcome of this research is the improved quality and reduced listening effort in the presence of an interfering noise signal. In this paper the performance of various noise reduc...

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...

2015
J W Silverstone R Santagati D Bonneau M J Strain M Sorel J L O'Brien M G Thompson

Entanglement--one of the most delicate phenomena in nature--is an essential resource for quantum information applications. Scalable photonic quantum devices must generate and control qubit entanglement on-chip, where quantum information is naturally encoded in photon path. Here we report a silicon photonic chip that uses resonant-enhanced photon-pair sources, spectral demultiplexers and reconfi...

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

in this thesis, a better reaction conditions for the synthesis of spirobarbiturates catalyzed by task-specific ionic liquid (2-hydroxy-n-(2-hydroxyethyl)-n,n-dimethylethanaminium formate), calcium hypochlorite ca(ocl)2 or n-bromosuccinimide (nbs) in the presence of water at room temperature by ultrasonic technique is provided. the design and synthesis of spirocycles is a challenging task becaus...

2009
Yongwei Miao Jieqing Feng Jinrong Wang Xiaogang Jin

Due to different shape modeling applications, partitioning a given complex 3D mesh model into some patches or meaningful subparts is one of the fundamental problems in digital geometry processing. By using the high-dimensional mean-shift clustering scheme in shape signature space, a new method is proposed which can generate user-specified segmentation results automatically for different applica...

Journal: :NeuroImage 2005
Ville T Mäkinen Patrick J C May Hannu Tiitinen

Using available signal (i.e., spectral and time-frequency) analysis methods, it can be difficult to detect neural oscillations because of their continuously changing properties (i.e., nonstationarities) and the noise in which they are embedded. Here, we introduce fractally scaled envelope modulation (FSEM) estimation which is sensitive specifically to the changing properties of oscillatory acti...

Journal: :Applied sciences 2023

Feature extraction is a collection of the necessary detailed information from given source, which holds for further analysis. The quality fused image depends on many parameters, particularly its directional selectivity and shift-invariance. On other hand, traditional wavelet-based transforms produce ringing distortions artifacts due to poor directionality shift invariance. Dual-Tree Complex Wav...

2000
C.-B. Huang Z. Jiang D. E. Leaird A. M. Weiner

Introduction: High repetition rate optical pulses in a few picosecond range and below are playing an increasingly important role in high speed optical fibre communication systems. Such high repetition rate short pulses are routinely generated by harmonically modelocked lasers [1], but with the following limitations: (i) complicated feedback control is required; (ii) the modelocked frequency com...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده مهندسی عمران 1391

deployable scissor type structures are composed of the so-called scissor-like elements (sles), which are connected to each other at an intermediate point through a pivotal connection and allow them to be folded into a compact bundle for storage or transport. several sles are connected to each other in order to form units with regular polygonal plan views. the sides and radii of the polygons are...

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