We propose a new method called incremental Fourier synthesis to generate 2-D self-similar images based on a 2D fractional Brownian motion (fBm) model. With this method, the stationary increments of fBm are created by a Fourier synthesis method and the increments are added up to generate the nonstationary 2D fBm process. Since the new method takes advantage of the FFT, its computational complexi...

Analysis of non stationary signals like audio, speech and biomedical signals require good resolution both in time and frequency as their spectral components are not fixed. There are many applications of time-frequency analysis in non stationary signals like source separation, signal denoising etc. This paper presents an application of time frequency analysis using STFT, Short Time Fourier Trans...

We study the Hamiltonian system made of weakly coupled anharmonic oscillators arranged on a three dimensional lattice Z2N × Z2, and subjected to a stochastic forcing mimicking heat baths of temperatures T1 and T2 on the hyperplanes at 0 and N . We introduce a truncation of the Hopf equations describing the stationary state of the system which leads to a nonlinear equation for the two-point stat...

Envelope Detection (ED) is traditionally always used with Fast Fourier Transform (FFT) to identify the rolling element bearing faults. The inability of FFT to detect non-stationary signals makes Wavelet Analysis (WA) an alternative for machinery fault diagnosis as WA can detect both stationary and non-stationery signals. A comparative study of ED with FFT and WA techniques for bearing fault dia...

Coupled-mode systems are used in physical literature to simplify the nonlinear Maxwell and Gross-Pitaevskii equations with a small periodic potential and to approximate localized solutions called gap solitons by analytical expressions involving hyperbolic functions. We justify the use of the one-dimensional stationary coupled-mode system for a relevant elliptic problem by employing the method o...