A highly non-gaussian cosmological perturbation with a flat spectrum has unusual stochastic properties. We show that they depend on the size of the box within which the perturbation is defined, but that for a typical observer the parameters defining the perturbation ‘run’ to compensate for any change in the box size. Focusing on the primordial curvature perturbation, we show that an un-correlat...

We describe a higher-order spectral analysis-based approach for detecting people by recognizing human motion such as walking or running. The periodic attribute of human motion lends itself to efficient spectral inspection. In the proposed method, the stride length is determined in every frame as the image sequence evolves. The bispectrum which is the Fourier transform of the triple correlation ...

We investigated whether autonomic nervous system imbalance imposed by pharmacological blockades and associated with acute myocardial infarction (AMI) is manifested as modifications of the nonlinear interactions in heart rate variability signal using a statistically based bispectrum method. The statistically based bispectrum method is an ideal approach for identifying nonlinear couplings in a sy...

In this paper we pursue the origin of the non-Gaussianity determined by a bispec-trum analysis of the COBE-DMR 4-year sky maps. The robustness of the statistic is demonstrated by the rebinning of the data into 12 coordinate systems. By computing the bispectrum statistic as a function of various data partitions – by channel, frequency, and time interval, we show that the observed non-Gaussian si...

We address the issue of setting up generic non-Gaussian initial conditions for N-body simulations. We consider inflationary-motivated primordial nonGaussianity where the perturbations in the Bardeen potential are given by a dominant Gaussian part plus a non-Gaussian part specified by its bispectrum. The approach we explore here is suitable for any bispectrum, i.e. it does not have to be of the ...

This paper presents a new technique which exploits constrained optimization methods to derive optimal two dimensional filters in the cumulant domain for processing signals in non Gaussian noise, or signals with corrupting interferences which have non symmetrical probability density functions. The approach proposed here for enhancing signals in such noise is important, as increasingly practical ...

We present the first calculation of the bispectrum of the matter perturbations induced by cosmic strings. The calculation is performed in two different ways: the first uses the unequal time correlators (UETCs) of the string network computed using a Gaussian model previously employed for cosmic string power spectra. The second approach uses the wake model, where string density perturbations are ...

Arc fault is one of the most critical reasons for electrical fires. Due to the diversity, randomness and concealment of arc faults in low-voltage circuits, it is difficult for general methods to protect all loads from series arc faults. From the analysis of many series arc faults, a large number of high frequency signals generated in circuits are found. These signals are easily affected by Gaus...