The empirical mode decomposition (EMD) was a method pioneered by Huang et al, as an alternative technique to the traditional Fourier and wavelet techniques for nonlinear and non-stationary signals. It decomposes a signal into several components called intrinsic mode functions (IMFs), which have shown to admit better behaved instantaneous frequencies via Hilbert transforms. In this talk we prese...

in this paper coupled nonlinear equations of motion of a suspended cable with time dependent tension and velocity are derived by using hamilton’s principal. a modal analysis for a stationary sagged cable is initially carried out in order to identify the dynamic system. the natural solution is directed to compute the natural frequencies and mode shapes of the free vibration of a suspended cable....

it is well known that ground-shaking site effect caused by an earthquake can vary significantly within a small distance. this is because at sites having soft soil and/or topographic and basement undulations, seismic energy gets trapped, leading to amplification of vibration that may cause considerable damage to man-made structures. theoretical analysis and observational data have shown that eac...

Dynamic Analysis of an axially moving cable with time dependent tension and velocity isstudied in this paper. Tension force and the moving speed are assumed to be harmonic.It is found that there exists a specific value of speed in which natural frequency of the system approacheszero. This specific speed for such a critical condition is called critical speed and it will be proved thatincreasing ...

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 ...

The Hilbert transform is one of the most successful approaches to tracking the varying nature of vibration of a large class of nonlinear systems, thanks to the extraction of backbone curves from experimental data. Because signals with multiple frequency components do not admit a well-behaved Hilbert transform, this transform is inherently limited to the analysis of single-degree-of-freedom syst...