نتایج جستجو برای: wavelet

تعداد نتایج: 38198  

Journal: :International Journal of Mathematics and Mathematical Sciences 2005

Extended Abstract. Forecasting is one of the most important purposes of time series analysis. For many years, classical methods were used for this aim. But these methods do not give good performance results for real time series due to non-linearity and non-stationarity of these data sets. On one hand, most of real world time series data display a time-varying second order structure. On th...

In ‎the present ‎paper, ‎we ‎introduce the ‎two-wavelet ‎localization ‎operator ‎for ‎the square ‎integrable ‎representation ‎of a‎ ‎homogeneous space‎ with respect to a relatively invariant measure. ‎We show that it is a bounded linear operator. We investigate ‎some ‎properties ‎of the ‎two-wavelet ‎localization ‎operator ‎and ‎show ‎that ‎it ‎is a‎ ‎compact ‎operator ‎and is ‎contained ‎in‎ a...

Journal: :journal of medical signals and sensors 0
alireza shirazi nodeh hossein ahmadi noubari hossein rabbani alireza mehri dehnavi

recent studies on wavelet transform and fractal modeling applied on mammograms for the detection of cancerous tissues indicate that microcalcifications and masses can be utilized for the study of the morphology and diagnosis of cancerous cases. it is shown that the use of fractal modeling, as applied to a given image, can clearly discern cancerous zones from noncancerous areas. in this paper, f...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سمنان - دانشکده برق و کامپیوتر 1394

در این پایان‎نامه روشی جدید برای تعیین مکان خطا در خطوط انتقال سه ترمیناله ارائه شده است. این روش در دسته روش های مکان یابی مبتنی بر امواج سیّار طبقه بندی می‎شود. روش‎های پیشنهادی با استفاده از اطلاعات سنکرون از ابزارهای تبدیل s، hyperbolic s، time‎-time، wavelet و hilbert برای استخراج ویژگی های سیگنال‎های جریان و ولتاژ بهره گرفته‎اند. مطالعات شبیه‎سازی گسترده‎ای جهت ارزیابی عملکرد الگوریتم پیشن...

Journal: :Entropy 2014
Jikai Chen Guoqing Li

As a novel data mining approach, a wavelet entropy algorithm is used to perform entropy statistics on wavelet coefficients (or reconstructed signals) at various wavelet scales on the basis of wavelet decomposition and entropy statistic theory. Shannon wavelet energy entropy, one kind of wavelet entropy algorithm, has been taken into consideration and utilized in many areas since it came into be...

This paper presents a new multi-sensor data fusion method based on the combination of wavelet transform (WT) and extended Kalman filter (EKF). Input data are first filtered by a wavelet transform via Daubechies wavelet “db4” functions and the filtered data are then fused based on variance weights in terms of minimum mean square error. The fused data are finally treated by extended Kalman filter...

Journal: :مدیریت آب و آبیاری 0
طاهر رجایی استادیار، گروه مهندسی عمران، دانشکدۀ فنی و مهندسی، دانشگاه قم، قم، ایران هادی ابراهیمی کارشناس ارشد سازه های هیدرولیکی، گروه مهندسی عمران، دانشکدۀ فنی و مهندسی، دانشگاه قم، قم، ایران

simulation of groundwater fluctuations plays a crucial role in management of watersheds and water demand balancing. recently, wavelet analysis has been used widely in time series decomposition and coupling with neural networks for hydrological modeling. in this paper, the ability of the wavelet-dynamic artificial neural networks (w-ann) model was applied in forecasting one-month-ahead of ground...

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