Correlation Analysis Between Low-Frequency Shock Oscillation and Liutex in SBLI

The aim of the paper is to assess the phenomena of EEG frequency modulation while performing real and imaginary movements necessary for BCI control. Materials and Methods. The study enrolled a group of 30 volunteers of both sexes, aged 17 to 23. The subjects had to execute four commands and to run them randomly following the program instruction. The experiment was carried out in two ways: physically and mentally. Firstly, each command corresponded to a certain subject’s movement. Secondly, the same commands were not performed, they were only imaginary. The command was considered successfully executed if a volunteer was able to follow the program instruction and to hold the position for 2 seconds. The analysis of the results was carried out for five frequency ranges: 7–10 Hz, 9–12 Hz, 12–15 Hz, 15–20 Hz, 20–25 Hz. Results. Correlation analysis and exploratory statistics (namely, correspondence analysis and cluster analysis) were used to process the generated electroencephalographic parameters. The actually performed subjects’ movements were associated with a high number of low-frequency modulations in the 12–20 Hz range in the absence of modulating influences in the range below 12 Hz. Pronounced patterns of high-frequency modulation were peculiar for unexecuted commands. Conclusion. The results of the correlation analysis demonstrate a positive relationship between the number of cases of high-frequency modulation in the range of 9–12 Hz with the number of cases of low-frequency modulation in all other studied signal ranges in case of successful command execution. Key words: brain-computer interface, μ-rhythm, frequency modulation, EEG. Цель – оценка феноменов частотной модуляции ЭЭГ в условиях выполнения реальных и воображаемых движений, необходимых для управления ИМК. Материалы и методы. Для получения данных была сформирована группа из 30 добровольцев обоих полов в возрасте от 17 до 23 лет. Участники эксперимента должны были выполнить четыре команды и повторить их в неизвестном для них порядке, заданном программой. Эксперимент проводился двумя способами: физически и мысленно. То есть при первом способе каждая команда соответствовала определенному движению человека, при втором те же команды выполнялись воображаемо, движение представлялось мысленно. Команда считалась успешно исполненной, если добровольцу удавалось повторить и удержать заданное программой положение в течение 2 с. Анализ результатов проводился для пяти частотных диапазонов: 7–10 Гц, 9–12 Гц, 12–15 Гц, 15–20 Гц, 20–25 Гц. Результаты. Сгенерированные электроэнцефалографические показатели обрабатывались методом корреляционного анализа и методами разведочной статистики, такими как анализ соответствий и кластерный анализ. Реально выполняемые движения испытуемых связаны с высоким количеством низкочастотных модуляций в диапазоне 12–20 Гц при отсутствии модулирующих влияний в диапазоне ниже 12 Гц. Для случаев невыполнения команд характерны выраженные паттерны высокочастотной модуляции. Выводы. Результаты корреляционного анализа демонстрируют положительную связь между числом случаев высокочастотной модуляции в диапазоне 9–12 Гц с числом случаев низкочастотной модуляции во всех других исследуемых диапазонах сигнала в случае успешного выполнения команд. Ключевые слова: интерфейс «мозг – компьютер», μ-ритм, частотная модуляция, ЭЭГ.

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Identification and evaluation for the dynamic signals caused by pressure fluctuation of aerostatic slider

Industrial Lubrication and Tribology ◽

10.1108/ilt-11-2016-0271 ◽

2018 ◽

Vol 70 (6) ◽

pp. 927-934 ◽

Cited By ~ 2

Author(s):

Dongju Chen ◽

Jihong Han ◽

Xianxian Cui ◽

Jinwei Fan

Keyword(s):

Wavelet Transform ◽

Correlation Analysis ◽

Frequency Domain ◽

Low Frequency ◽

Measured Signal ◽

Analysis Method ◽

Content Type ◽

Correlation Analysis Method ◽

The Impact ◽

Signal Correlation

Purpose To identify the dynamic feature of the aerostatic slider caused by gas film, an evaluation system by a piezoelectric acceleration sensor is presented in time and frequency domain. Design/methodology/approach The dynamic pressure fluctuation is evaluated by the wavelet transform, cross correlation analysis and power spectral density (PSD). Wavelet transform is used to process the measured result of the aerostatic slider and the signal is decomposed into high-frequency and low-frequency signal. Correlation analysis method is used to evaluate the impact of the initial gas gap on the fluctuation in time domain. Findings According to the PSD analysis of the processed signal in the frequency domain, the natural frequency of the aerostatic slider is identified from the measured signal in frequency domain; this method provides a basis for the identification of guideway errors. Research limitations/implications The method can also be applied to the error identification of other components of the machine tool. Originality/value Wavelet transform is used to process the measured result of the aerostatic slider by acceleration sensor, and the signal is decomposed into high-frequency and low-frequency signal. Correlation analysis method is used to evaluate the impact of the initial gas gap on the fluctuation in time domain. According to the PSD analysis of the processed signal in the frequency domain, the natural frequency of the aerostatic slider is identified from the measured signal in frequency domain; this method provides a basis for the identification of slider errors.

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Correlation analysis of electrical and optical low frequency fluctuation in organic device degradation

Journal of Applied Physics ◽

10.1063/1.3086625 ◽

2009 ◽

Vol 105 (6) ◽

pp. 064504 ◽

Cited By ~ 1

Author(s):

Ke Lin ◽

Lai Szu Cheng ◽

Adelia Ramam ◽

Chua Soo Jin

Keyword(s):

Correlation Analysis ◽

Low Frequency ◽

Frequency Fluctuation

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Analysis of vibration signal of diamond roller grinding

E3S Web of Conferences ◽

10.1051/e3sconf/202124801062 ◽

2021 ◽

Vol 248 ◽

pp. 01062

Author(s):

Yong Liu ◽

TingBin Fu ◽

HuaDong Zhao ◽

ZhenWei Zhu

Keyword(s):

Correlation Analysis ◽

Internal Friction ◽

Machine Tool ◽

Manufacturing Process ◽

Low Frequency ◽

Vibration Signal ◽

Modal Decomposition ◽

Non Linear

According to the non-linear and non-stationary characteristics of the vibration signal in the roller grinding manufacturing process, the background signals, namely the vibration signal when the grinder is idling and the vibration signal during contact grinding, are collected separately, and the signal is decomposed into multiple by the method of CEEMDAN modal decomposition. Then several components are removed by correlation analysis. Finally, the signal is denoised and analyzed by wavelet threshold denoising, which lays the foundation for the digital and intelligent grinding of diamond rollers by curve grinders. The results show that most of the grinding noise is in the low frequency, which is mainly caused by the internal friction of the machine tool; the frequency of the grinding vibration signal is mainly distributed around the two frequencies of 250hz and 350hz.

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Resting-State Functional MRI Metrics in Patients With Chronic Mild Traumatic Brain Injury and Their Association With Clinical Cognitive Performance

Frontiers in Human Neuroscience ◽

10.3389/fnhum.2021.768485 ◽

2021 ◽

Vol 15 ◽

Author(s):

Faezeh Vedaei ◽

Andrew B. Newberg ◽

Mahdi Alizadeh ◽

Jennifer Muller ◽

Shiva Shahrampour ◽

...

Keyword(s):

Traumatic Brain Injury ◽

Brain Injury ◽

Correlation Analysis ◽

Cognitive Performance ◽

Mild Traumatic Brain Injury ◽

Resting State ◽

Temporal Cortex ◽

Low Frequency ◽

Angular Gyrus ◽

Superior Temporal Cortex

Mild traumatic brain injury (mTBI) accounts for more than 80% of people experiencing brain injuries. Symptoms of mTBI include short-term and long-term adverse clinical outcomes. In this study, resting-state functional magnetic resonance imaging (rs-fMRI) was conducted to measure voxel-based indices including fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), and functional connectivity (FC) in patients suffering from chronic mTBI; 64 patients with chronic mTBI at least 3 months post injury and 40 healthy controls underwent rs-fMRI scanning. Partial correlation analysis controlling for age and gender was performed within mTBI cohort to explore the association between rs-fMRI metrics and neuropsychological scores. Compared with controls, chronic mTBI patients showed increased fALFF in the left middle occipital cortex (MOC), right middle temporal cortex (MTC), and right angular gyrus (AG), and increased ReHo in the left MOC and left posterior cingulate cortex (PCC). Enhanced FC was observed from left MOC to right precuneus; from right MTC to right superior temporal cortex (STC), right supramarginal, and left inferior parietal cortex (IPC); and from the seed located at right AG to left precuneus, left superior medial frontal cortex (SMFC), left MTC, left superior temporal cortex (STC), and left MOC. Furthermore, the correlation analysis revealed a significant correlation between neuropsychological scores and fALFF, ReHo, and seed-based FC measured from the regions with significant group differences. Our results demonstrated that alterations of low-frequency oscillations in chronic mTBI could be representative of disruption in emotional circuits, cognitive performance, and recovery in this cohort.

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Abnormal Fractional Amplitude of Low-frequency Fluctuation Changes in Patients With Diabetic Optic Neuropathy: a Functional MRI Study

10.21203/rs.3.rs-550996/v1 ◽

2021 ◽

Author(s):

Wenfeng Liu ◽

Chen-Yu Yu ◽

Yi-Cong Pan ◽

Hui-Ye Shu ◽

Li-Juan Zhang ◽

...

Keyword(s):

Correlation Analysis ◽

Low Frequency ◽

Anterior Cingulate ◽

Frequency Fluctuation ◽

Anxiety And Depression ◽

Cingulate Gyrus ◽

Anterior Cingulate Gyrus ◽

Pearson's Correlation ◽

The Right ◽

Left Middle

Abstract The present study was to assess the spontaneous changes in brain activity in patients with DON using functional magnetic resonance imaging (fMRI). 14 DON patients and 14 healthy controls (HCs) were enrolled. All participants underwent resting-state fMRI (rs-fMRI). The fractional amplitude of low-frequency fluctuation (fALFF) method was applied to evaluate neural activity changes. The Hospital Anxiety and Depression Scale (HADS) was used to assess the anxiety and depression status of participants. The independent sample t test and chi-squared test were applied to analyze demographics of DON patients and HCs. Receiver operating characteristic (ROC) curves were applied to analyze the variation in mean fALFF values between DON patients and HCs. The relationships between the fALFF values of brain regions and clinical behaviors in the DON group were analyzed using Pearson’s correlation analysis. In contrast to HCs, the fALFF value of DON patients was significantly higher in the right precentral gyrus (RPCG). However, the fALFF values in right anterior cingulate gyrus (RACG) and left middle cingulate gyrus (LMCG) were markedly decreased in DON patients. The area under the curve (AUC) of ROCs for each brain region showed high accuracy. Pearson's correlation analysis showed that fALFF values of the right anterior cingulate gyrus and left middle cingulate gyrus were negatively correlated with HADS scores, while fALFF values of the left middle cingulate gyrus were negatively correlated with DON disease duration. To sum up, we found abnormal spontaneous brain activities in regions related to cognitive and emotional dysfunction, eye movement disorder, and vision loss in patients with DON. These results may indicate the underlying neuropathological mechanisms of DON, and show that fALFF may be an effective method by which to distinguish patients with DON from healthy individuals.

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