Frequency Analysis Of Oscillations Research Articles

Frequency Analysis of Oscillations of External Respiration Parameters and Heart Rate in the VLF Range

Frequency Analysis of Oscillations of External Respiration Parameters and Heart Rate in the VLF Range

Frequency analysis of oscillations in cerebral hemodynamics measured by time domain near infrared spectroscopy.

In this paper, we propose the application of time-domain near-infrared spectroscopy to the assessment of oscillations in cerebral hemodynamics. These oscillations were observed in the statistical moments of the distributions of time of flight of photons (DTOFs) measured on the head. We analyzed the zeroth and second centralized moments of DTOFs (total number of photons and variance) to obtain their spectra to provide parameters for the frequency components of microcirculation, which differ between the extracerebral and intracerebral layers of the head. Analysis of these moments revealed statistically significant differences between a control group of healthy subjects and a group of patients with severe neurovascular disorders, which is a promising result for the assessment of cerebral microcirculation and cerebral autoregulation mechanisms.

Digital Image Processing based Fire Flame Color and Oscillation Frequency Analysis

Abstract Two distinctive fire flame characteristics, i.e., color information and flickering are discussed in this paper to provide basic criteria to improve the anti-jamming ability and reliability of the video flame detection technology in complex scenes. An effective real-time flame color detection criterion is firstly proposed by the method of two-dimensional color space reconstruction and saturation fitting for the manually collected flame-pixel sample database. The flame size and accumulated gray value are then extracted to construct the time series of video sequences of four combustion experiments. At last, the oscillation frequency of the flame flickering is calculated by performing the Fourier Transform for these time series. It is found that oscillation frequencies are in good agreement with the ones calculated by Pagni's law. The results of this paper can be used as bases of multi-feature fusion video flame detection method.