• Kosin Medical Journal
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• v.33 no.3
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• pp.369-379
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• 2018

Objectives: Analysis of heart rate variability (HRV) has been used as a measure of cardiac autonomic function. According to the pNN50 statistic, the percentage of differences between successive normal RR intervals (RRI) that exceed 50 ms, has been known to reflect cardiac vagal modulation. Relatively little is known about the validity of pNN50 during general anesthesia (GA). Therefore, we evaluated the correlation of pNN50 with other variables such as HF, RMSSD, SD1 of HRV reflecting the vagal tone, and examined the validity of pNN50 in anesthetized patients. Methods: We assessed changes in RRI, pNN50, root mean square of successive differences of RRI (RMSSD), high frequency (HF) and standard deviation 1 (SD1) of $Poincar{\acute{e}}$ plots after GA using sevoflurane anesthesia. We also calculated the probability distributions for the family of pNNx statistics (x: 2-50 ms). Results: All HRV variables were significantly decreased during GA. HF power was not correlated with pNN50 during GA (r = 0.096, P = 0.392). Less than pNN47 was shown to have a correlation with other variables. Conclusions: These data suggest that pNN50 can not reflect the level of vagal tone during GA.

• The Korea Journal of Herbology
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• v.31 no.4
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• pp.53-60
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• 2016

Objective : The purpose of this study was to investigate anti-aging and antioxidant effects of extracts of Nelumbo nucifera leaves (NN-L) using ethanol on skin .Methods : Each part of leaves(NN-L), flowers(NN-F) and stem(NN-S) was extracted with 70% ethanol. We performed radical scavenging assay(DPPH, ABTS+, Superoxide anion radical), elastase inhibition assay, collagenase inhibition assay. NN-L extracts were tested for cell viability(MTT assay), MMP-1 inhibition and MMP-1 protein expression on CCD-986sk cells (human fibroblast line).Results : Recently, many studies have reported that elastin is also involved in inhibiting or repairing wrinkle formation, although collagen is a major factor in the skin wrinkle formation. We measured its free radical scavenging activity, elastase inhibitory activity and expression of MMP-1 (matrix metalloprotease-1) in human fibroblast cells. Among the parts of Nelumbo nucifera, NN-L showed the highest antioxidant activities and in radical scavenging. DPPH, ABTS+ and Superoxide anion radical scavenging activity of NN-L at concentration of 1,000 μg/mL were 91.43%, 99.31% and 73.7% respectively. In vitro elastase and collagenase inhibition effects of NN-L at concentration of 1,000 μg/mL was 42.8% and 55.3% respectively. The ethanol extract of NN-L showed cell viability of 95.4% in 50 μg/mL concentration. In addition, The results from Western blot assay showed that NN-L decreased the expression of MMP-1 protein in a dose-dependent manner (by up to 35.0% at 50 μM).Conclusion : The findings suggest that the NN-L great potential as a cosmeceutical ingredient with antioxidant and anti-wrinkling effects.

• Sleep Medicine and Psychophysiology
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• v.25 no.1
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• pp.15-20
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• 2018

Objectives: This study was designed to assess the change of heart rate variability (HRV) at resting, upright, and psychological stress states in depressive disorder patients. Methods: HRV was measured at resting, upright, and psychological stress states in 62 depressive disorder patients. We used visual analogue scale (VAS) score to assess tension and stress severity. Beck depression inventory (BDI) and state trait anxiety inventories I and II (STAI-I and II) were used to assess depression and anxiety severity, respectively. Differences between HRV indices and VAS score were evaluated using paired t-tests. Gender difference analysis was conducted with ANCOVA. Results: SDNN (standard deviation of normal to normal intervals), LF/HF (low frequency/high frequency), and VLF (very low frequency) were significantly increased, while NN50 and pNN50 were significantly decreased in the upright position compared to resting state. SDNN, RMSSD (root mean square of the differences of successive normal to normal intervals), and VLF were significantly increased, while pNN50 was significantly decreased in the psychological stress state compared to resting state. SDNN, NN50, and pNN50 were significantly lower in an upright position compared to a state of psychological stress, and LF, HF, and LF/HF showed no significant differences Conclusion: The LF/HF ratio was significantly increased after physical stress in depressive disorder. However, the LF/HF ratio was not significantly increased after psychological stress, and the change in LF/HF ratio after physical stress and psychological stress did not significantly differ from each other. Significant increase in SDNN, NN50, and pNN50 in an upright posture compared to psychological stress suggests that depressive patients react more sensitively to physical stress than psychological stress.

• Annals of Clinical Neurophysiology
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• v.16 no.2
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• pp.49-54
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• 2014

Heart rate variability is significantly associated with cardiovascular complications in various neurological disorders with cardiac impairment. Measures of spontaneous heart rate variability might be different from provocating tests of heart rate variability such as deep breathing and Valsava maneuver. Methods for analysis are divided into time domain methods and frequency domain methods. There are standard deviation of NN interval, standard deviation of average NN interval, root mean square of the successive differences, NN50, and pNN50 in time domain methods. Frequency domain bands can be divided into very low, low, and high frequency. Each variables are influenced by sympathetic and/or parasympathetic activity.

• Sleep Medicine and Psychophysiology
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• v.21 no.2
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• pp.69-73
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• 2014

Objectives: This study was designed to assess the change of heart rate variability (HRV) at resting, upright, and psychological stress in anxiety disorder patients. Methods: HRV was measured at resting, upright, and psychological stress states in 60 anxiety disorder patients. We used visual analogue scale (VAS) score to assess tension and stress severity. Beck depression inventory (BDI) and state trait anxiety inventories I and II (STAI-I and II) were used to assess depression and anxiety severity. Differences between HRV indices were evaluated using paired t-tests. Gender difference analysis was accomplished with ANCOVA. Results: SDNN (Standard deviation of normal RR intervals) and low frequency/high frequency (LF/HF) were significantly increased, while NN50, pNN50, and normalized HF (nHF) were significantly decreased in the upright position compared to resting state (p < 0.01). SDNN, root mean square of the differences of successive normal to normal intervals, and LF/HF were significantly increased, while nHF was significantly decreased in the psychological stress state compared to resting state (p < 0.01). SDNN, NN50, pNN50 were significantly lower in upright position compared to psychological stress and nVLF, nLF, nHF, and LF/HF showed no significant differences between them. Conclusion: The LF/HF ratio was significantly increased after both physical and psychological stress in anxiety disorder, but did not show a significant difference between these two stresses. Significant differences of SDNN, NN50, and pNN50 without any differences of nVLF, nLF, nHF, and LF/HF between two stresses might suggest that frequency domain analysis is more specific than time domain analysis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.8
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• pp.1246-1250
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• 2015

The purpose of this paper is to investigate the autonomic nervous system activity in various ambient temperature situation. To evaluate autonomic function, we use the time domain analysis of heart rate variability. Electrocardiogram was recorded to derive heart rate variability in 3 different temperature room which temperature is controlled in 18℃(low), 25℃ (mid) and 38℃(high), respectively. Totally 22 subjects were participated in the experiment. The result shows that the time-domain variables such as AVNN, SDNN, SDSD, RMSSD, NN50, pNN50, NN20 and pNN20 show the significant difference between low and high temperature (p<0.01). However, these variables has no significance (p>0.05) between mid and high except on AVNN, RMSSD and pNN20. AVNN, RMSSD shows the highest significance (p<0.001) according to the various temperature environment.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.6
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• pp.37-46
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• 2015

The wireless electrocardiographic monitoring system(WDMS) is designed to be long term monitoring for the early detection of cardiac disorders. The current version of the WDMS can identify two types of cardiac rhythms in real-time, such as atrial fibrillation(AF) and normal sinus rhythm(NSR), which are very important to track cardiac-rhythm disorders. In this study, we proposed the analysis method to discriminate the characteristics statistically evaluated in both time and frequency domains between AF and NSR using various parameters in the heart rate variability(HRV). And we applied various ECG detection methods (e.g., difference operation method) and compared the results with those of the discrete wavelet transform(DWT) method. From the statistically results, we found that the parameters such as STD RR, STD HR, RMSSD, NN50, pNN50, RR Trian, and TNN(p<0.05) are significantly different between the AF and NSR patients in time domain. On the other hand, the frequency domain analysis results showed a significant difference in VLF power($ms^2$), LF power($ms^2$), HF power($ms^2$), VLF(%), LF(%), and HF(%). In particular, the parameters such as STD RR, RMSSD, NN50, pNN50, VLF power, LF power and HF power were considered as the most useful parameters in both AF and NSR patient groups. Our proposed method can be efficiently applied to early detection of abnormal conditions and prevent the such abnormals from becoming serious.

• Journal of Oriental Neuropsychiatry
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• v.19 no.3
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• pp.143-169
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• 2008

Objective: This study was to investigate the relation of what insomnia patients' symptoms with Heart Rate Variability(HRV), Pittsburgh Sleep Quality Index (PSQI) and Insomnia Questionaire(IQ). Methods: For this study, we carried out HRV, PSQI and IQ of 43 patients with insomnia who have come to Donguei oriental hospital of Donguei university from September 2007 to May 2008. We studied the relationship HRV with PSQI and IQ. For every symptom, this study classified the patients as none-symptom, symptom groups and analyzed each group's HRV, PSQI and IQ. Result : 1. The rate of xerostomia in female group is significantly higher than male group. 2. P1 (hypnagogic time), P3(awakening time), LF has negative correlation with age. The score of PI (hypnagogic time), P3(awakening time), P4(time of recoverable sleep) in the group whose age is more than 50 are higher than the group whose age is lesser than 50. 3. The frequency of using hypnotics(P6) in the group whose duration of onset are over 1 year was significantly higher than the score in the group whose duration of onset were below 1 year. 4. The accompanied symptoms in the group who started sleep disorder after stressor are higher than the number in the group whose duration of onset were poor-defined. 5. The drinking group have lower rate of anorexia, higher score of P1 (hypnagogic time) and TP than non-drinking group. 6. The score of P-total(general quality of sleep) have negative correlation with NNSO, HF, TP and positive correlation with LF/HF. 7. The score of P1(hypnagogic time) have negative correlation with LF. 8. The score of P5a(frequency of delayed hypnagogue) have positive correlation with LF/HF. 9. The score of P5e(frequency of cough or snoring) have negative correlation with RMSSD. 10. The score of I1a(degree of onset insomnia), I1b(degree of maintenance insomnia) have negative correlation with NN50, pNN50, HF. 11. The score of I1c(degree of termination insomnia) have negative correlation with RMSSD, NN50, pNN50, HF, TP and positive correlation with MHR, LF/HF. 12.. The score of P5i(frequency of night pain), LF/HF in the group with headache are higher than the group without headache. 13. The score of P5a(frequency of delayed hypnagogue), P5c(frequency of awakening for urine of stool) in the group with xerostomia are higher than the group without xerostomia. 14. The score of P9(degree of unrecoverable sleep) and I5a(degree of onset insomnia) in the group with chest discomfort are lower than the group without chest discomfort. 15. The score of P7(frequency of drowsiness for daytime) in the group with palpitation are lower than the group without palpitation. 16. The score of P5c(frequency of awakening for urine of stool), P5f(frequency of burning sensation), P5h(frequency of nightmare), I1c(degree of termination insomnia) in the group with burning sensation of upper trunk are higher than the group without burning sensation. 17. The score of NN50, pNN50, LF, TP in the group with anorexia are lower than the group without anorexia. 18. The score of P-total(general quality of sleep), P2(duration for sleep start) in the group with constipation are higher than the group without constipation. 19. The score of P4(recoverable sleep time) in the group with depression are higher than the group without depression. 20. In the group with anxiety, the score of P1(time of hypnagogue), P5a(frequency of onset insomnia) are lower and the score of I1b(degree of maintenance insomnia), I4(objective degree of impairment by insomnia) are higher than the group without anxiety. 21. The score of NN50, pNN50, HF, TP in the group with inertia are lower than the group without inertia. 22. The accompanied symptoms haver posirive correlation with P5f(frequency of burning sensation), P5h(frequency of nightmare), P5i(frequency of night pain) and LF/HF. Conclusion: This study provides insights into the complicated relations of the pattern of sleep disorder with many symptoms such as headache, chest discomfort, depression and any others. And this study showed that autonomic nervous system have important function in the regulation of sleep.

• Journal of Electrical Engineering and Technology
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• v.4 no.3
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• pp.389-395
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• 2009

Industrial motors are subject to incipient faults which, if undetected, can lead to motor failure. The necessity of incipient fault detection can be justified by safety and economical reasons. The technology of artificial neural networks has been successfully used to solve the motor incipient fault detection problem. This paper develops inexpensive, reliable, and noninvasive NN based incipient fault detection scheme for small and medium sized induction motors. Detailed design procedure for achieving the optimal NN model and Principal Component Analysis for dimensionality reduction is proposed. Overall thirteen statistical parameters are used as feature space to achieve the desired classification. GFFD NN model is designed and verified for optimal performance in fault identification on experimental data set of custom designed 2 HP, three phase 50 Hz induction motor.

• Journal of the Korea Convergence Society
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• v.4 no.3
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• pp.43-50
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• 2013

This paper presents a model predictive control (MPC) based on a neural network (NN) model for air/fuel ration (AFR) control of automotive engines. The novelty of the paper is that the severe nonlinearity of the engine dynamics are modelled by a NN to a high precision, and adaptation of the NN model can cope with system uncertainty and time varying effects. A single dimensional optimization algorithm is used in the paper to speed up the optimization so that it can be implemented to the engine fast dynamics. Simulations on a widely used mean value engine model (MVEM) demonstrate effectiveness of the developed method.