Fuel cells have the potential to provide environmentally-friendly sources of energy for transportation, portable, and stationary applications. Because fuel cells convert chemical energy directly to electrical energy, high efficiencies can be realized. Production of electrical power from fuel cells has several other advantages. There are no moving parts. Fuel cells operate noiselessly with no fr...

We propose the Wasserstein-Fourier (WF) distance to measure (dis)similarity between time series by quantifying displacement of their energy across frequencies. The WF operates calculating Wasserstein (normalised) power spectral densities (NPSD) series. Yet this rationale has been considered in past, we fill a gap open literature providing formal introduction distance, together with its main pro...

Fourier-based spectral analysis methods have been widely used for studying random waves. One major weakness of the Fourier-based spectral analysis methods is the assumption of linear superposition of wave components. As a result, the energy of a nonlinear wave is spread into many harmonics, which are phase-coupled via the nonlinear dynamics inherent in nearshore wave propagation. In addition to...

Circulant embedding is a technique that has been used to generate realizations from certain real-valued Gaussian stationary processes. This technique has two potential advantages over competing methods for simulating time series. First, the statistical properties of the generating procedure are exactly the same as those of the target stationary process. Second, the technique is based upon the d...

For nonstationary time series the fixed Fourier basis is no longer canonical. This article shows how the choice of analysis basis influences the detection of nonstationarities within time series. Rather than limit our basis choice to wavelet or Fourier functions we develop a new stationarity test using a (multiple) bootstrap hypothesis test based on non-decimated wavelet packets. Non-decimated ...

Power Spectral Density (PSD) of quasi-stationary processes can be efficiently estimated using the short time Fourier series (STFT). In this paper, an algorithm has been proposed that computes the PSD of quasi-stationary process efficiently using offline autoregressive model order estimation algorithm, recursive parameter estimation technique and modified sliding window discrete Fourier Transfor...

Introduction A 2D analytical cardiac magnetic resonance imaging (MRI) phantom in the Fourier domain was introduced by Brummer et al. [1] to compare acceleration strategies based on a reduction of the field of view. In related work by our group and others the value of a standardized simulation phantom to test and compare reconstruction methods for cardiac imaging has become evident. In this work...