• Journal of Korean Medicine Rehabilitation
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• v.19 no.2
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• pp.241-250
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• 2009

Objectives : To study autonomic nervous system dysfunction of Low Back Pain(LBP) patients, using spectral analysis of Heart Rate Variability(HRV). Methods : HRV of 190 patients was measured and seperated into two groups, those with LBP(n=95) and healthy controls(n=95). HRV was measured by SA-6000(Medicore, Korea) for 5 minutes after 5 minutes' resting. Results : 1. Mean heart rate(MHRT) of the experimental group was slightly higher than that of the control group, but did not show significant difference(P=0.428). The square root of the mean squared differences of successive normal-to-normal intervals(RMSSD), logarithmic very low frequency power(Ln VLF) and low frequency power/high frequency power ratio(LH/HF ratio) were not significantly low between experimental group and control group(P=0.16, 0.130, 0.537). 2. The standard deviation of all the normal-to-normal intervals(SDNN), logarithmic total power(Ln TP), logarithmic low frequency power(Ln LF) and logarithmic high frequency power(Ln HF) were significantly low between experimental group and control group(P=0.03, 0.005, 0.001, 0.007). 3. Ln LF of acute group was significantly low compared with those of chronic group(P= 0.039). Conclusions : This study suggests the activity and imbalance of autonomic nervous system in LBP is low. Also sympathetic nervous system of acute LBP is lower than that of chronic LBP. Further study of HRV related to LBP is needed in the clinical medicine.

• Journal of Biomedical Engineering Research
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• v.18 no.3
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• pp.285-290
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• 1997

In this paper, the power spectral analysis and the fractal analysis of heart rate variability(HRV) were performed to evaluate the effects of brain lesion on cardiovascular system and autonomic function for 24 normal subjects and 22 hemiplegic patients. The ECG and respiration signals were recorded at tilt angles of $0^{\circ}$ and $70^{\circ}$ for 5 and 6 minutes successively under the condition of frequency controlled respiration (0.25Hz). For normal subjects, HR, LF component, HF component and fractral dimension of HRV were distinctly changed after orthostatic stress, whereas, for hemiplegic patients, those were little changed. Complexity and variability of heart rate of patients were smaller than those of normal subjects. Sympathetic tone of patients was higher than that in normal subjects. All of these results support that autonomic disorder and cardiovascular disturbance accompanied by brain lesion could be assessed by the power spectral analysis and fractal analysis of HRV.

• Korean Journal of Psychosomatic Medicine
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• v.21 no.1
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• pp.55-61
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• 2013

Objectives : Alzheimer's disease(AD) and mild cognitive impairment(MCI) affect several nervous structures involved with the autonomic nervous system. Association between neuropsychiatric deficits and heart rate variability has been observed. But cardiac autonomic function in AD has been scarcely studied and the results reported are conflicting. We investigated autonomic function in normal control, MCI, AD using heart rate variability(HRV) technique. Methods : Time and frequency-domain variability of 5-min R-R interval series was comparatively evaluated in 26 normal control subjects, 22 MCI subjects and 34 AD subjects. Analysis of variance(ANOVA) was used to compare the differences across groups. Correlations between MMSE-KC and HRV components were performed using Pearson's correlation coefficient. Results : No significant difference was observed among the groups in time, frequency-domain analysis of HRV(p>0.05). HRV were not found to be significantly correlated with the degree of cognitive impairment. Conclusions : There were no differences in HRV with MCI, AD subjects when compared with normal controls. Further investigation is required to use HRV technique as noninvasive parameters of MCI and AD.

• Smart Structures and Systems
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• v.3 no.3
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• pp.341-356
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• 2007

A good understanding of normal modal variability of civil structures due to varying environmental conditions such as temperature and wind is important for reliable performance of vibration-based damage detection methods. This paper addresses the quantification of wind-induced modal variability of a cable-stayed bridge making use of one-year monitoring data. In order to discriminate the wind-induced modal variability from the temperature-induced modal variability, the one-year monitoring data are divided into two sets: the first set includes the data obtained under weak wind conditions (hourly-average wind speed less than 2 m/s) during all four seasons, and the second set includes the data obtained under both weak and strong (typhoon) wind conditions during the summer only. The measured modal frequencies and temperatures of the bridge obtained from the first set of data are used to formulate temperature-frequency correlation models by means of artificial neural network technique. Before the second set of data is utilized to quantify the wind-induced modal variability, the effect of temperature on the measured modal frequencies is first eliminated by normalizing these modal frequencies to a reference temperature with the use of the temperature-frequency correlation models. Then the wind-induced modal variability is quantitatively evaluated by correlating the normalized modal frequencies for each mode with the wind speed measurement data. It is revealed that in contrast to the dependence of modal frequencies on temperature, there is no explicit correlation between the modal frequencies and wind intensity. For most of the measured modes, the modal frequencies exhibit a slightly increasing trend with the increase of wind speed in statistical sense. The relative variation of the modal frequencies arising from wind effect (with the maximum hourly-average wind speed up to 17.6 m/s) is estimated to range from 1.61% to 7.87% for the measured 8 modes of the bridge, being notably less than the modal variability caused by temperature effect.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.19 no.1
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• pp.35-45
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• 2015

Objective The aim of this study was to investigate stress-related factors. Method: The subjects were 22,937 persons who had received health examination by Korean Medicine and submitted questionnaires for 8 months from March to November in 2011. The stress was measured by heart rate variability in an automobile manufacturing industry. We analyzed the relationship between stress and other factors including ages, smoke amount, drinking frequency, exercise frequency, occupational category, conjugal condition by multivariate analysis with SPSS ver. 19.0. Results: Comparing "normal" to "very bad" and "bad" level of stress, ages, drinking frequency, conjugal condition are not significant difference(p>0.05). But smoking amount and occupational category are significant difference(p<0.05). Whereas comparing "normal" to "very good" and "good" level of stress, ages, occupational category, conjugal condition, smoking amount, drinking frequency are not significant difference(p>0.05). Exercise is significant difference(p<0.05). Conclusion: The results of this study suggest that smoke is affected to stress negatively, whereas exercise is affected to stress positively.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.8 s.179
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• pp.2074-2082
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• 2000

In this study, to investigate and to predict the crack growth behavior under variable amplitude loading, crack growth tests are conducted on 7075-T6 aluminum alloy. The loading wave forms are generated by normal random number generator. All wave forms have same average and RMS(root mean square) value, but different standard deviation, which is to vary the maximum load in each wave. The modified Forman's equation is used as crack growth equation. Using the retardation coefficient D defined in previous study, the load interaction effect is considered. The variability in crack growth process is described by the random variable Z which was obtained from crack growth tests under constant amplitude loading in previous work. From these, a statistical model is developed. The curves predicted by the proposed model well describe the crack growth behavior under variable amplitude loading and agree with experimental data. In addition, this model well predicts the variability in crack growth process under variable amplitude loading.

• Anxiety and mood
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• v.6 no.2
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• pp.102-108
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• 2010

Objective : Although studies have explored responses to fear had been assessed using various psychophysiological methods, results have been inconsistent. The present study examined psychophysiological responses in healthy subjects after viewing fear stimuli in a video clip for set up future fear related psychophysiological studies. Methods : We monitored three psychophysiological variables (electroencephalography, skin temperature, and heart rate variability) in adults who watched either a control stimulus movie clip or a fear-inducing movie clip. Results : In 16 healthy adults, theta activity decreased significantly after the fear stimulus as compared to the normal stimulus. However the participants showed no differences in heart rate variability or skin temperature between the fear and normal control stimulus situations. Conclusion : In the limbic area, theta activity corresponds with information processing, integration into previous memories and long-term potentiation. In this study, we suggest decreased theta activity represents amygdalo-hippocampal activity, associated with fear, short-term memory, and memory extinction in the healthy adults. Further studies are needed to evaluate the interaction of fear, memory, and the pathophysiology of anxiety disorder in patient with anxiety disorders.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.7
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• pp.1072-1077
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• 2017

Mean-reverting analysis refers to a way of estimating the underlining tendency after new data has evoked the variation in the equilibrium state. In this paper, we propose a new method to interpret the specular portraits of Premature Ventricular Contraction(PVC) arrhythmia by applying K-means unsupervised learning algorithm on electrocardiogram(ECG) data. Aiming at this purpose, we applied a mean-reverting model to analyse Heart Rate Variability(HRV) in terms of the modified poincare plot by considering PVC rhythm as the component of disrupting the homeostasis state. Based on our experimental tests on MIT-BIH ECG database, we can find the fact that the specular patterns portraited by K-means clustering on mean-reverting HRV data can be more clearly visible and the Euclidean metric can be used to identify the discrepancy between the normal sinus rhythm and PVC beats by the relative distance among cluster-centroids.

• Journal of Korean Traditional Oncology
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• v.26 no.1
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• pp.29-37
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• 2021

Objectives: The purpose of this study is to examine whether heart rate variability (HRV) and pulse wave of cancer patients can be used as indicators of their health status and prognosis. Methods: We retrospectively compared HRV, pulse wave and body mass index (BMI) of cancer patients and healthy individuals who visited W hospital from November of 2020 to October of 2021. Results: As a result of comparing HRV and pulse wave parameters between cancer patients and healthy subjects, among HRV indices, mean heart rate (MHR), standard deviation of normal to normal (SDNN) and total power (TP), very low frequency (VLF) showed significant differences between two groups. Cancer patients' pulse wave parameters showed more rapid and superficial than that of healthy subjects. Also, cancer patients weighed less and had lower BMI. Conclusion: For increased MHR, decreased SDNN, rapid and superficial pulse wave can be indicators of poor prognosis of cancer patients, keep monitoring HRV and pulse wave can help to manage patients efficiently.

• MALSORI
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• v.55
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• pp.119-130
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• 2005

The aim of this paper is to investigate some acoustical characteristics of the voice quality features from the emotional speech database. Six different parameters are measured and compared for 6 different emotions (normal, happiness, sadness, fear, anger, boredom) and from 6 different speakers. Inter-speaker variability and intra-speaker variability are measured. Some intra-speaker consistency of the parameter change across the emotions are observed, but inter-speaker consistency are not observed.