scholarly journals A study of acoustic characteristics of voluntary expiratory sounds produced before and immediately after swallowing

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Shoma Hattori ◽  
Shinji Nozue ◽  
Yoshiaki Ihara ◽  
Koji Takahashi
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Time Window ◽  
Maximum Amplitude ◽  
Comparison Method ◽  
Window Length ◽  
Acoustic Characteristics ◽  
The Mean ◽  
Time Waveform ◽  
The Relationship

AbstractTo evaluate the expiratory sounds produced during swallowing recorded simultaneously with videofluorographic examination of swallowing (VF) using fast Fourier transform (FFT), and to examine the relationship between dysphagia and its acoustic characteristics. A total of 348 samples of expiratory sounds were collected from 61 patients with dysphagia whose expiratory sounds were recorded during VF. The VF results were evaluated by one dentist and categorized into three groups: safe group (SG), penetration group (PG), and aspiration group (AG). The duration and maximum amplitude of expiratory sounds produced were measured as the domain characteristics on the time waveform of these sounds and compared among the groups. Time window-length appropriate for FFT and acoustic discriminate values (AD values) of SG, PG, and AG were also investigated. The groups were analyzed using analysis of variance and Scheffé's multiple comparison method. The maximum amplitude of SG was significantly smaller than those of PG and AG. The mean duration in SG (2.05 s) was significantly longer than those in PG (0.84 s) and AG (0.96 s). The AD value in SG was significantly lower than those in PG and AG. AD value detects penetration or aspiration, and can be useful in screening for dysphagia.

An analysis of the variation between dairy-sire progeny-groups for milk yield and fat content

1958 ◽  
Vol 1958 ◽  
pp. 19-29 ◽  
Author(s):  
Alan Robertson ◽  
S. S. Khishin
Keyword(s):  
Milk Yield ◽  
Comparison Method ◽  
Fat Content ◽  
Fat Percentage ◽  
Simple Method ◽  
Factors Affecting ◽  
Special Cases ◽  
The Mean ◽  
Milk Marketing ◽  
The Relationship

The past few years have seen the development in Great Britain of the ‘contemporary comparison’ method for evaluating progeny tests of dairy sires (Macarthur, 1954; Robertson, Stewart and Ashton 1956). The final overall figure attached to a sire is the mean difference between the yield of his daughters and that of other heifers milking in the same herd in the same year, with due regard for the numbers of animals in the two groups. Although it has some imperfections in special cases, this is probably the most informative simple method of evaluating a sire for yield and, fortunately, one which could be easily integrated with the existing recording system. The method has been turned into a simple routine in the Bureau of Records of the Milk Marketing Board and several thousand bulls have now been evaluated. In this paper, we shall be mostly concerned to use this material to investigate the heritabilities of milk yield and fat content and the relationship between the two in the different breeds. The information that we shall use consists, for each bull, of the mean contemporary comparison, with its effective ‘weight’, and the average fat percentage of the daughters. Before we deal with the observed results, we should go into rather more detail into the nature of these two figures and into the factors affecting them.

scholarly journals Periodic Noise Removal in Strain and Natural Images Using 2-D Fast Fourier Transform

2013 ◽  
pp. 90-94
Author(s):  
Mandeep Kaur ◽  
Dinesh Kumar ◽  
Ekta Walia ◽  
Manjit Sandhu
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Frequency Domain ◽  
Noise Removal ◽  
Natural Images ◽  
Periodic Pattern ◽  
Periodic Noise ◽  
Mean Filter ◽  
The Mean

This paper presents a 2-D FFT removal algorithm for reducing the periodic noise in natural and strain images. For the periodic pattern of the artifacts, we apply the 2-D FFT on the strain and natural images to extract and remove the peaks which are corresponding to periodic noise in the frequency domain. Further the mean filter applied to get more effective results. The performance of the proposed method is tested on both natural and strain images. The results of proposed method is compared with the mean filter based periodic noise removal and found that the proposed method significantly improved for the noise removal.

scholarly journals A Recognition Algorithm of VGPO Jamming Based on Discrete Chirp-Fourier Transform

2020 ◽  
Author(s):  
Chuanzhang Wu ◽  
Baixiao Chen
Keyword(s):  
Fourier Transform ◽  
Recognition Performance ◽  
Tracking System ◽  
Recognition Algorithm ◽  
Chirp Rate ◽  
Echo Signal ◽  
The Mean ◽  
Analytical Result ◽  
The Relationship ◽  
Scaling Characteristic

Abstract We address the recognition problem of velocity gate pull-off (VGPO) jamming from the target echo signal for the velocity automatic tracking system. To this end, we resort to the discrete chirp-Fourier transform (DCFT) to jointly estimate the chirp rates and frequencies of the target and jamming signals. Firstly, the scaling characteristic of the DCFT algorithm is explored. Then we highlight the quantitative effect of the VGPO jamming signal by analyzing the jointly estimated result in each pulse. The effective effect indicates that the relationship between the estimated chirp rate and the pulse is similar to that between the frequency offset of VGPO jamming and the time when the estimated frequency is unchanged. Finally, by utilizing the analytical result and extracting the feature of the mean square to variance ratio (MSVR) of the normalized estimated chirp rate, the VGPO jamming can be recognized. Simulation results show that, for a time when the estimated frequency is unchanged, the MSVR of VGPO jamming decreases with the pulse numbers increases, and is always larger than that of a target which is steady. Comparing to other methods, the proposed method can correctly recognize the jamming signal with jamming-to-noise ratio (JNR) 5dB which shows better recognition performance, and is also effective within a shorter period.

scholarly journals The Relationship Between Penumbral Tissue and Blood-Brain Barrier Disruption in Acute Stroke Patients Presenting in an Extended Time Window

2020 ◽  
Vol 11 ◽  
Author(s):  
Parisa Heidari ◽  
Sarah Blayney ◽  
Jarrhett Butler ◽  
Emi Hitomi ◽  
Marie Luby ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Time Window ◽  
Brain Barrier ◽  
Extended Time ◽  
Stroke Patients ◽  
Ischemic Lesion ◽  
Blood Brain ◽  
The Mean ◽  
Target Profile ◽  
The Relationship

Background: Penumbral brain tissue identified with multimodal imaging can be salvaged with reperfusion in an extended time window. The risk of severe hemorrhagic complications after reperfusion therapy increases with worsening disruption of the blood-brain barrier (BBB). The relationship between penumbral tissue and BBB disruption has not been previously studied.Methods: Stroke patients presenting in an extended time window without a large vessel occlusion who underwent diffusion-perfusion MRI within 24 h of last-seen-normal were included. The volume of penumbral tissue was calculated using mismatch on MRI. Mean permeability derangement (MPD) of the BBB was measured within the ischemic lesion. A target profile (TP) for treatment was defined based on the EXTEND trial.Results: 222 patients were included with a median age of 73 and 55% women. The median NIHSS was 6, the mean core volume was 14 ml, the mean ischemic volume was 47 mL and the mean mismatch volume was 33 mL. Higher MPD was significantly associated with less mismatch volume (p = 0.001). A target profile was associated with lower MPD (OR 0.97; CI 0.96:0.99; p < 0.001). Of the 105 patients who had a TP, 31 (30%) had a MPD > 20% suggesting an increased risk of hemorrhage. Thus, 33% (74/222) of patients had a favorable profile for benefit and safety.Conclusions: Patients presenting in an extended time window with a favorable penumbral profile for treatment have less severe BBB disruption. Up to a third of patients who currently go untreated could be considered for enrollment in a clinical trial of thrombolysis in an extended time window.

Multi-Symplectic Fourier Pseudospectral Method for the Kawahara Equation

2014 ◽  
Vol 16 (1) ◽  
pp. 35-55 ◽  
Author(s):  
Yuezheng Gong ◽  
Jiaxiang Cai ◽  
Yushun Wang
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Pseudospectral Method ◽  
Kawahara Equation ◽  
Fourier Pseudospectral Method ◽  
Numerical Examples ◽  
Fourier Pseudospectral ◽  
Energy And Momentum ◽  
The Relationship ◽  
Pseudospectral Scheme

AbstractIn this paper, we derive a multi-symplectic Fourier pseudospectral scheme for the Kawahara equation with special attention to the relationship between the spectral differentiation matrix and discrete Fourier transform. The relationship is crucial for implementing the scheme efficiently. By using the relationship, we can apply the Fast Fourier transform to solve the Kawahara equation. The effectiveness of the proposed methods will be demonstrated by a number of numerical examples. The numerical results also confirm that the global energy and momentum are well preserved.

The Effect of Anisotropy on the Percolation Threshold of Sealing Surfaces

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Zhimeng Yang ◽  
Jianhua Liu ◽  
Xiaoyu Ding ◽  
Feikai Zhang
Keyword(s):  
Fourier Transform ◽  
Theoretical Result ◽  
Fast Fourier Transform ◽  
Percolation Threshold ◽  
Rough Surface ◽  
Conjugate Gradient ◽  
Surface Anisotropy ◽  
Sealing Performance ◽  
The Relationship ◽  
Theoretical Results

The percolation threshold strongly affects sealing performance. This paper investigates the relationship between the percolation threshold and the rough surface anisotropy, which is represented by the Peklenik number, γ. A series of anisotropic rough surfaces were generated and the conjugate gradient-fast Fourier transform (CG-FFT) method was used to determine the percolation threshold. The percolation threshold was found to be A/A0≈0.484±0.009 (averaged over 45 surfaces) was established for an isotropic rough surface (γ=1). Furthermore, it was also found that the percolation threshold decreased from A/A0≈0.528±0.011 to A/A0≈0.431±0.008 as 1/γ increased from 0.6 to 2. Our results differ from the theoretical result of Persson et al., where A/A0=γ/(1+γ). Comparing our calculated results with the theoretical results established the presence of an intersection value of 1/γ that was related to the effect of elastic deformation on the percolation threshold. When 1/γ was smaller than the intersection value, our calculated results were lower than the theoretical ones; and when 1/γ was greater than the intersection value, our calculated results were higher than the theoretical ones.

scholarly journals Method for measuring the azimuth of an aerial target for a meter-range radar

2021 ◽  
pp. 26-31
Author(s):  
V. I. Ermoshkin ◽  
S. B. Shatkovsky ◽  
A. V. Shcherbinko ◽  
E. E. Fenyuk
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Antenna Array ◽  
New Method ◽  
Test Results ◽  
Radio Waves ◽  
Statistical Estimates ◽  
Pulse Processing ◽  
The Mean ◽  
Further Development

The purpose of the study is to develop a new method that increases the accuracy of measuring the azimuth of an air target for stationary radars of the meter range of radio waves with a fixed antenna array and a small number of antenna elements. For this, the known methods are considered and their disadvantages are revealed. The new method proposed by the authors uses a digital radiation pattern with a fast Fourier transform after intra-pulse processing of signals from the receiving elements of the antenna array at a given frequency. To refine the azimuth, an inverse fast Fourier transform is used, followed by signal processing and repeated measurement for each target with a small step. Calculations and test results are presented. Comparisons of statistical estimates of the mean and standard deviation of azimuth measurement tests by various methods are presented. The scientific novelty and directions for further development of the topic with the use of the results obtained have been established.

Noise and Finite Register Effects in Infrared Fourier Transform Spectroscopy

1976 ◽  
Vol 30 (5) ◽  
pp. 531-539 ◽  
Author(s):  
C. T. Foskett
Keyword(s):  
Fourier Transform ◽  
Data Acquisition ◽  
Fast Fourier Transform ◽  
Fourier Transform Spectroscopy ◽  
Noise Sources ◽  
Additional Noise ◽  
The Impact ◽  
The Relationship

Finite registers used in computations act as additional noise sources in infrared Fourier transform spectroscopy. The relationship between these noise sources and classical noise sources is examined. The impact of finite register lengths on data acquisition, computation of the fast Fourier transform (FFT), and post-FFT spectral manipulations leads to the conclusion that the minimum recommended register length is 27 bits.

Study on Effect of Shipborne Missile Launch Position Based on Fast Fourier Transform

2013 ◽  
Vol 427-429 ◽  
pp. 1653-1657
Author(s):  
Zhou Zhong ◽  
Yi Jiang ◽  
Chong Zhang ◽  
Yong Yuan Li
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Spectrum Analysis ◽  
Research Result ◽  
Integrative Model ◽  
Weapon System ◽  
Flexible Coupling ◽  
Scripting Language ◽  
Motion Characteristics ◽  
The Relationship

In allusion to the problem of launching precision, it carried on the research of the effect of shipborne missile launch position based on the spectrum analysis technology. A rigid-flexible coupling integrative model of ship movement and missile launch was built by use of virtual prototype technology. Simulation analyses on a variety of conditions were automatic conducted by launch time parameterized scripting language, and missile muzzle attitude parameters of different launch position were gained. By using of spectrum analysis which is based on FFT, the missile dynamic responsive was analyzed, and the relationship between launch position and accuracy was established. Then the position of the weapon system can be designed according to the specific motion characteristics of ship. The research result is also constructive to the selecting of suitable launch position.

scholarly journals ACCURACY VERSUS SPEED IN FLUCTUATION-ENHANCED SENSING

2012 ◽  
Vol 11 (02) ◽  
pp. 1250010 ◽  
Author(s):  
P. MAKRA ◽  
Z. TOPALIAN ◽  
C. G. GRANQVIST ◽  
L. B. KISH ◽  
C. KWAN
Keyword(s):  
Time Window ◽  
Measurement Data ◽  
Statistical Error ◽  
Window Size ◽  
Practical Case ◽  
Activation Temperature ◽  
Stochastic Signal ◽  
Different Types ◽  
The Mean ◽  
The Relationship

Fluctuation-enhanced sensing (FES) comprises the analysis of the stochastic component of the sensor signal and the utilization of the microscopic dynamics of the interaction between the agent and the sensor. We study the relationship between the measurement time window and the statistical error of the measurement data in the simplest case, when the output is the mean-square value of the stochastic signal. This situation is relevant at any practical case when the time window is finite, for example, when a sampling of the output of a fluctuation-enhanced array takes place; or a single sensor's activation (temperature, etc.) is stepped up; or a single sensor's output is monitored by sampling subsequently in different frequency windows. Our study provides a lower limit of the relative error versus data window size with different types of power density spectra: white noise, 1/f(flicker, pink) noise, and 1/f2 (red) noise spectra.

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