Dimension reduction techniques for multivariate time series decompose the observed into a few useful independent/orthogonal univariate components. A spectral domain method is developed second-order stationary that linearly transforms several groups of lower-dimensional subseries. These subseries have non-zero coherence among components within group but zero across groups. The expressed as sum f...

In this paper, an approach to lossy image compression using 1-D wavelet transforms is proposed. The analyzed image is divided in little subimages and each one is decomposed in vectors following a fractal Hilbert curve. A Wavelet Transform is thus applied to each vector and high frequency components are suppressed. The Huffman coding algorithm is then applied in order to reduce image weight. The...

Introduction: The central-governor model explains the mechanism of endurance exercise-induced central fatigue, but high-intensity exercise-induced central fatigue has not been investigated yet. This study aimed to research how central fatigue during high-intensity intermittent pedaling alters the neural response, which results in electroencephalography (EEG) recordings. Methods: We assessed ne...

This paper describes a novel analysis-synthesis method based on estimation and comparison between spectral methods that are specifically designed for modeling of random signals. These methods are an alternative to the discrete Fourier transform, providing high-resolution, smooth and easily interpretable spectral estimation over short signal frames. It is generally acknowledged that musical sign...

A generalized S transform based on energy normalized windows is presented, which avoids the weighting effect of existing S transform influenced by the time-frequency spectral energy. The transform can reflect the spectral energy distribution of different frequency components while maintaining the excellent time-frequency resolution. While TT transform is a new approach to process non-stationary...

climate is a multivariate system. every change in every climate variable could result in different changes in climate. recently, experts have paid extensive attention to frequency distribution sequence of climate elements. accordingly, many different indices have been defined. precipitation extremes can exhibit the phase space of climate system. a technique that can be used to analyze climate p...

OBJECTIVE To test the hypothesis that components of heart period variability track autonomic function during simulated hemorrhage in humans. DESIGN Prospective experimental laboratory intervention. SETTING Human physiology laboratory. SUBJECTS A total of 33 healthy, nonsmoking, volunteer subjects (23 men, ten women). INTERVENTIONS Progressive lower body negative pressure was applied in ...