Presented here is an amplitude and frequency modulation method (AFMM) for extracting damage-induced nonlinear characteristics and intermittent transient responses by processing steady-state/transient responses using the empirical mode decomposition, Hilbert-Huang transform (HHT), and nonlinear dynamic characteristics derived from perturbation analysis. A sliding-window fitting (SWF) method is d...

In this study, vibration based non-destructive testing (NDT) technique is adopted for assessing the condition of in-service timber pole. Timber a natural material, and hence captured broadband signal (induced from impact using modal hammer) greatly affected by uncertainty on wood properties, structure, environment. Therefore, advanced processing essential in order to extract features associated...

Combing the stress wave signals with Synthetic Aperture Focusing Technique (SAFT) to inspect and image the interior defect of concrete structural has shown its feasibility by some researchers. However, some bright zones displayed in the image plot are not corresponding to the Rayleigh waves and reflection signals from the bottom surface of the structural component or the embedded defect. This t...

The Empirical Mode Decomposition is a process for signals which produces Intrinsic Mode Functions from which instantaneous frequencies may be extracted by simple application of the Hilbert transform. The beauty of this method to generate redundant representations is in its simplicity and its effectiveness. Our study has two objectives: first, to provide an alternate characterization of the Intr...

Through numerical simulations, it is predicted that the gravitational waves (GWs) reflect characteristics of core-collapse supernova (CCSN) explosion mechanism. There are multiple GW excitation processes occur inside a star before its explosion, and suggested GWs originating from CCSN have mode for each process in terms time-frequency representation. Therefore, we propose an application Hilbert...

This paper uses the Hilbert–Huang transform (HHT) method to make time–frequency diagnostic analyses of four monthly time series of the global precipitation: MERG (1900– 2008), REOF (1900–2008), GPCP (1979–2009), and CMAP (1979–2009). All these data are the global land and ocean average of precipitation anomalies with respect to the mean of the entire data period. The MERG and REOF are spectral ...

This study conducts a detailed analysis of multiscale periodic features involved in the annual and seasonal precipitation signals at the typical coastal reclamation region in China by selecting the suitable continuous wavelet transform (CWT) and innovatively combining the improved Hilbert–Huang transform (HHT), and further deduces the precipitation trend and its impacts on the future soil hydro...

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...

A novel approach to fault detection and diagnosis of gearbox based on Ensemble Empirical Mode Decomposition (EEMD) and Teager Kaiser Energy Operator (TKEO) technique is presented. The time-domain vibration signal of the gearbox with gear crack fault is measured. EEMD can adaptively decompose the vibration signal into a series of zero mean Amplitude Modulation-Frequency Modulation (AM-FM) Intrin...