scholarly journals The Real-time Forecast of Photovoltaic Output Based on Empirical Mode Decomposition

Author(s):  
Cui Du ◽  
Zongqi Liu
2010 ◽  
Vol 02 (04) ◽  
pp. 509-520 ◽  
Author(s):  
SY-SANG LIAW ◽  
FENG-YUAN CHIU

Real nonstationary time sequences are in general not monofractals. That is, they cannot be characterized by a single value of fractal dimension. It has been shown that many real-time sequences are crossover-fractals: sequences with two fractal dimensions — one for the short and the other for long ranges. Here, we use the empirical mode decomposition (EMD) to decompose monofractals into several intrinsic mode functions (IMFs) and then use partial sums of the IMFs decomposed from two monofractals to construct crossover-fractals. The scale-dependent fractal dimensions of these crossover-fractals are checked by the inverse random midpoint displacement method (IRMD).


Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1637
Author(s):  
Saiqiang Xia ◽  
Jun Yang ◽  
Wanyong Cai ◽  
Chaowei Zhang ◽  
Liangfa Hua ◽  
...  

In order to suppress the strong clutter component and separate the effective fretting component from narrow-band radar echo, a method based on complex variational mode decomposition (CVMD) is proposed in this paper. The CVMD is extended from variational mode decomposition (VMD), which is a recently introduced technique for adaptive signal decomposition, limited to only dealing with the real signal. Thus, the VMD is extended from the real domain to the complex domain firstly. Then, the optimal effective order of singular value is obtained by singular value decomposition (SVD) to solve the problem of under-decomposition or over-decomposition caused by unreasonable choice of decomposition layer, it is more accurate than detrended fluctuation analysis (DFA) and empirical mode decomposition (EMD). Finally, the strongly correlated modes and weakly correlated modes are judged by calculating the Mahalanobis distance between the band-limited intrinsic mode functions (BLIMFs) and the original signal, which is more robust than the correlation judgment methods such as computing cross-correlation, Euclidean distance, Bhattachryya distance and Hausdorff distance. After the weak correlation modes are eliminated, the signal is reconstructed locally, and the separation of the micro-motion signal is realized. The experimental results show that the proposed method can filter out the strong clutter component and the fuselage component from radar echo more effectively than the local mean decomposition (LMD), empirical mode decomposition and moving target indicator (MTI) filter.


2019 ◽  
Author(s):  
Vinícius R. Carvalho ◽  
Márcio F.D. Moraes ◽  
Antônio P. Braga ◽  
Eduardo M.A.M. Mendes

AbstractSignal processing and machine learning methods are valuable tools in epilepsy research, potentially assisting in diagnosis, seizure detection, prediction and real-time event detection during long term monitoring. Recent approaches involve the decomposition of these signals in different modes or functions in a data-dependent and adaptive way. These approaches may provide advantages over commonly used Fourier based methods due to their ability to work with nonlinear and non-stationary data. In this work, three adaptive decomposition methods (Empirical Mode Decomposition, Empirical Wavelet Transform and Variational Mode Decomposition) are evaluated for the classification of normal, ictal and inter-ictal EEG signals using a freely available database. We provide a previously unavailable common methodology for comparing the performance of these methods for EEG seizure detection, with the use of the same classifiers, parameters and spectral and time domain features. It is shown that the outcomes using the three methods are quite similar, with maximum accuracies of 97.5% for Empirical Mode Decomposition, 96.7% for Empirical Wavelet Transform and 98.2% for Variational Mode Decomposition. Features were also extracted from the original non-decomposed signals, yielding inferior, but still fairly accurate (95.3%) results. The evaluated decomposition methods are promising approaches for seizure detection, but their use should be judiciously analysed, especially in situations that require real-time processing and computational power is an issue. An additional methodological contribution of this work is the development of two python packages, already available at the PyPI repository: One for the Empirical Wavelet Transform (ewtpy) and another for Variational Mode Decomposition (vmdpy).


2020 ◽  
Vol 91 (5) ◽  
pp. 2851-2861
Author(s):  
Yuchen Wang ◽  
Kenji Satake ◽  
Takuto Maeda ◽  
Masanao Shinohara ◽  
Shin’ichi Sakai

Abstract We propose a method of real-time tsunami detection using ensemble empirical mode decomposition (EEMD). EEMD decomposes the time series into a set of intrinsic mode functions adaptively. The tsunami signals of ocean-bottom pressure gauges (OBPGs) are automatically separated from the tidal signals, seismic signals, as well as background noise. Unlike the traditional tsunami detection methods, our algorithm does not need to make a prediction of tides. The application to the actual data of cabled OBPGs off the Tokohu coast shows that it successfully detects the tsunami from the 2016 Fukushima earthquake (M 7.4). The method was also applied to the extremely large tsunami from the 2011 Tohoku earthquake (M 9.0) and extremely small tsunami from the 1998 Sanriku earthquake (M 6.4). The algorithm detected the former huge tsunami that caused devastating damage, whereas it did not detect the latter microtsunami, which was not noticed on the coast. The algorithm was also tested for month-long OBPG data and caused no false alarm. Therefore, the algorithm is very useful for a tsunami early warning system, as it does not require any earthquake information to detect the tsunamis. It detects the tsunami with a short-time delay and characterizes the tsunami amplitudes accurately.


2013 ◽  
Vol 73 (1) ◽  
pp. 43-58 ◽  
Author(s):  
Amir Eftekhar ◽  
Christofer Toumazou ◽  
Emmanuel M. Drakakis

2019 ◽  
Author(s):  
Lucas J. Morales Moya ◽  
Charlotte S. L. Bailey ◽  
J. Kim Dale ◽  
Philip J. Murray

AbstractPreviously we showed, using fixed tissue techniques, that treatment of chick embryos with a family of pharmacological inhibitors yields increased levels of NICD, an increased NICD half life and longer segments (Wiederman et al., 2015). Here we measure the effect of one of the pharmacological perturbations (Roscovtine) using a real time reporter of the somitogenesis clock. After processing the reporter signal using empirical mode decomposition, we measure the oscillator period in mPSM explants and find, in agreement with the previous study, that the period of the segmentation clock increases upon Roscovitine treatment. However, we also make the novel discovery that the differentiation rate of the mPSM tissue also increases upon Roscovitine treatment. Returning to the previous study, we find that the measured increases in somite size and oscillator period are only consistent with the clock and wavefront model if the wavefront velocity also increased.


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