Sleep spindles are brief bursts of brain activity in the sigma frequency range (11-16 Hz) measured by electroencephalography (EEG) mostly during non-rapid eye movement (NREM) stage 2 sleep. These oscillations are of great biological and clinical interests because they potentially play an important role in identifying and characterizing the processes of various neurological disorders. Convention...

Most of signals in engineering are nonstationary and time-varying. The Fourier transform as a traditional approach can only provide the feature information in frequency domain. The time-frequency techniques may give a comprehensive description of signals in time-frequency planes. Based on some typical nonstationary signals, five time-frequency analysis methods, i.e., the short-time Fourier tran...

Modal analysis is a well-established method for of linear systems, but its extension to non-linear structures has proven be much more problematic. Several competitive definitions modes and variety experimental methods have been introduced. In this paper, the definition complex (CNMs) mechanical systems adopted possibility their identification from free decay responses using Hilbert-Huang transf...

Tracking of low-visibility targets in complex backgrounds is an important research field, where existing methods struggle to image with irregular changes moving direction and speed. Move contrast imaging can greatly improve the sensitivity target tracking, which has achieved applications field X-ray imaging, including high-resolution microvessels living rats help agents, <i>in-situ</i&...

The Hilbert-Huang-Transform (HHT) has proven to be an appropriate multiscale analysis technique specifically for nonlinear and nonstationary time series on non-equidistant grids. It is empirically adapted to the data: first, an additive decomposition of the data (empirical mode decomposition, EMD) into certain multiscale components is computed, denoted as intrinsic mode functions. Second, to ea...

An understanding of physiological time series such as the heart-beat intervals is important to many areas, like heart-attack prediction, cardiovascular health, sport and exercise, etc. The study of time series can reveal underlying mechanisms of the physiological system, which usually contains both deterministic and stochastic components. Therefore the analysis of time series is very complicate...

To solve the difficulty of eigenvalue extraction on-load tap-changer (OLTC) vibration signals, an method time-frequency matrix based on Hilbert energy spectrum and spectral entropy is proposed in this study. By optimizing Hilbert-Huang transform (HHT) algorithm, signal distribution obtained. The was extracted to characterize chaotic degree distribution, avoided problem inaccurate feature quanti...

The violent fluctuation of hydrodynamic pressure in stilling basins is an important factor threatening the safety bottom plates basins, and plays role safe operation basins. In order to deeply understand fluctuating characteristics signal a basin plate processed by Hilbert-Huang transform method through hydraulic model test. this paper, three decomposition methods are used decompose pulsating s...

OBJECTIVE The diagnosis of labor is currently one of the most difficult problems encountered by obstetrical healthcare providers. A major health problem is the increase in the rate of preterm delivery, which is responsible for 75% of all deaths in newborns. In addition, preterm delivery is associated with several cognitive and health problems in later life and enormous costs for the health syst...