نتایج جستجو برای: ville distribution wvd is another method that has superior tfr resolution

تعداد نتایج: 9485128  

Journal: :Chinese Journal of Systems Engineering and Electronics 2021

Recent advances in electronics have increased the complexity of radar signal modulation. The quasi-linear frequency modulation (quasi-LFM) waveforms (LFM, Frank code, P1-P4 code) similar time-frequency distributions, and it is difficult to identify such signals using traditional analysis methods. To solve this problem, paper proposes an algorithm for automatic recognition quasi-LFM based on fra...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز 1379

‏‎for the first time nakayama introduced qf-ring. in 1967 carl. faith and elbert a. walker showed that r is qf-ring if and only if each injective right r-module is projective if and only if each injective left r-modules is projective. in 1987 s.k.jain and s.r.lopez-permouth proved that every ring homomorphic images of r has the property that each cyclic s-module is essentialy embeddable in dire...

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...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده علوم انسانی 1389

there are two major theories of measurement in psychometrics: classical test theory (ctt) and item-response theory (irt). despite its widespread and long use, ctt has a number of shortcomings, which make it problematic to be used for practical and theoretical purposes. irt tries to solve these shortcomings, and provide better and more dependable answers. one of the applications of irt is the as...

پایان نامه :وزارت علوم، تحقیقات و فناوری - پژوهشگاه شیمی و مهندسی شیمی ایران - پژوهشکده شیمی تجزیه و معدنی 1390

hydrochlorothiazide (hct) is a diuretic agent which is shown to be effective in the treatment of hypertension. literature reports have demonstrated that urinary excretion data may be used to assess the bioavailability of various formulations containing this thiazide. also hct consumption by the athletes is one of the drugs which should be regulated by world anti-doping agency (wada), because of...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده اقتصاد و علوم اجتماعی 1390

abstract deviation or in other words committing a crime is literally a social problem. this research that was conducted in 1389 and 1390 has tried to investigate the causes of crimes committed by young male inmates qazvin central prison and effective variables on their tendency to deviation. accordingly after collecting theoretical framework and offering theoretical model including both hirsch...

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

the methods which are used to analyze microstrip antennas, are divited into three categories: empirical methods, semi-empirical methods and full-wave analysis. empirical and semi-empirical methods are generally based on some fundamental simplifying assumptions about quality of surface current distribution and substrate thickness. thses simplificatioms cause low accuracy in field evaluation. ful...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده برق و کامپیوتر 1392

abstract nowadaysphotovoltaic solar cells (pvs) areacknowledged the fastest growing energy technology in the word, however, they only account for only fraction of current global renewable energy capacity. it isrecognized that this incomplete market penetration has been largely a result of the technology’sexcessive cost. so researchers are trying to find innovative, economic way with theaim of ...

2015
Ying-Pei Liu Hai-Ping Liang Zhong-Ke Gao Xiaosong Hu

In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC) system, we propose an improved auto-disturbance rejection control (ADRC) method based on least squares support vector machines (LSSVM) in the rectifier side. Firstly, we deduce the high frequency transient mathematical model of VSC-HVDC system. Then we investigate the ADRC and LSSVM principles...

2010
E. Sejdić

Introduction: Time-frequency representations (TFRs) indicate variations of the signal spectral characteristics with time, and they are the natural choice as an analysis tool for the non-stationary signals [1]. The main objectives of the various types of time-frequency distribution functions (e.g. Wigner-Ville distribution (WVD) [1], short-time Fourier transform (STFT) [1], the S-transform [2]) ...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید