future design procedures for civil structures, especially those to be protected from extreme and blast relatedloads, will need to account for temporal evolution of their frequency content. there are, however, several instanceswhere acceleration time histories are required as seismic input. for example, to determine the ultimate resistance andto identify modes of structures’ failure, a nonlinear...

Short Time Fourier Transform (STFT) is an important technique for the time-frequency analysis of a time varying signal. The basic approach behind it involves the application of a Fast Fourier Transform (FFT) to a signal multiplied with an appropriate window function with fixed resolution. The selection of an appropriate window size is difficult when no background information about the input sig...

The TT-transform stands for time-time transform and has been derived as an inverse Fourier transform of the time-frequency S-transform. So far, it has been proposed that the diagonal of the TT-transform can be used for signal characterisation. We show here an alternative and simplified derivation of the TT-transform which enables a better understanding of this transform.

Development of robust and efficient front-end is crucial for robust ASR. Proper time and frequency resolution of the TFR of speech, motivated by the auditory models is considered an important factor for robustness. An efficient method of realizing a variable resolution TFR using DTFT/Goertzel algorithm is proposed instead of the standard FFT based approach. It is shown that the new representati...

A new four-parameter atomic decomposition of chirplets is developed for compact representation of signals with chirp components. The four-parameter atom is obtained by scaling the Gaussian function, and then applying the fractional Fourier transform (FRFT), timeshift and frequency-shift operators to the scaled Gaussian. The decomposition is realized by extending the matching pursuit algorithm t...

A new rough-wavelet granular space based model for land cover classification of multispectral remote sensing image, is described in the present article. In this model, we propose the formulation of classdependent (CD) granules in wavelet domain using shift-invariant wavelet transform (WT). Shift-invariant WT is carried out with properly selected wavelet base and decomposition level(s). The tran...

The S transform is variable window of short time Fourier transform (STFT) or an extension of wavelet transform (WT). It is based on a scalable localizing Gaussian window and supplies the frequency dependent resolution. In this tutorial, we introduce the fundamental function of S transform and the generalized S transform. Furthermore, we present some applications of S transform: seismogram analy...

A new signal-adaptive joint time-frequency distribution for the analysis of nonstationary signals is proposed. It is based on a fractionalFourier-domain realization of the weighted Wigner distribution producing auto-terms close to the ones in the Wigner distribution itself, but with reduced cross-terms. Improvement over the standard time-frequency representations is achieved when the principal ...

This paper proposes two new approaches for formant tracking using Fourier and wavelet ridges. The speech signal is decomposed into Time-Frequency representations issued from windowed Fourier transform and wavelet transform. Formant tracking is achieved by exploring ridges from time-frequency representation and imposing continuity constraints on formant trajectories. These approaches are validat...