Suppose that we have a set of numbers x1, . . . , xn which have nonnegative sum. How many subsets of k numbers from {x1, . . . , xn} must have nonnegative sum? Manickam, Miklós, and Singhi conjectured that for n ≥ 4k the answer is ( n−1 k−1 ) . This conjecture is known to hold when n is large compared to k. The best known bounds are due to Alon, Huang, and Sudakov who proved the conjecture when...

Fourier transform, wavelet transformation, and Hilbert-Huang transformation (HHT) can be used to discuss the frequency characteristics of linear and stationary signals, the time-frequency features of linear and non-stationary signals, the time-frequency features of non-linear and non-stationary signals, respectively [1-6]. HHT is a combination of empirical mode decomposition (EMD) and Hilbert s...

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Since blood pressure is a significant parameter to examine people’s physical attributes and it is useful to indicate cardiovascular diseases, the measurement/estimation of blood pressure has gained increasing attention. The continuous, cuff-less and non-invasive blood pressure estimation is required for the daily health monitoring. In recent years, studies have been focusing on the ways of bloo...

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...

This paper presents an application of the Hilbert–Huang transform (HHT) and ensemble correlation for detection of the transient evoked otoacoustic emissions (TEOAEs), and high resolution time–frequency mapping. The HHT provides a powerful tool for nonlinear analysis of nonstationary signals such as TEOAEs. Since the HHT itself does not distinguish between signal and noise it was used with ensem...

In the empirical mode decomposition (EMD) for the Hilbert–Huang transform (HHT), a nonlinear and non-stationary signal is adaptively decomposed by an HHT into a series of intrinsic mode functions (IMFs) with the lowest one as the trend. At each step of the EMD, the low-frequency component is mainly determined by the average of the upper envelope (consisting of local maxima) and the lower envelo...

A number of wave energy controllers tune the power take-off (PTO) system to the frequency of incident waves. Since real ocean waves are non-stationary by nature and not defined by a single frequency component, the PTO can be either tuned at a constant frequency characterized by the local spectrum, or continuously tuned to a representative wave frequency. In either case, a time-frequency represe...