• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.43.1-43.1
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• 2021

In this study, we suggest a new method to estimate the mass of a halo coronal mass ejection (CME) using synthetic CMEs. For this, we generate synthetic CMEs based on two assumptions: (1) the CME structure is a full ice-cream cone, (2) the CME electron density follows a power-law distribution (ρ_cme=ρ₀r^-n). The power-law exponent n is obtained by minimizing the root mean square error between the electron number density distributions of an observed CME and the corresponding synthetic CME at a position angle of the CME leading edge. By applying this methodology to 57 halo CMEs, we estimate two kinds of synthetic CME mass. One is a synthetic CME mass which considers only the observed CME region (M_cme1), the other is a synthetic CME mass which includes both the observed CME region and the occulted area larger than 4 solar radii (M_cme2). From these two cases, we derive conversion factors which are the ratio of a synthetic CME mass to an observed CME mass. The conversion factor for M_cme1 ranges from 1.4 to 3.0 and its average is 2.0. For M_cme2, the factor ranges from 1.8 to 5.0 with the average of 3.0. These results imply that the observed halo CME mass can be underestimated by about 2 times when we consider the observed CME region, and about 3 times when we consider the region including the occulted area. Interestingly these conversion factors have a very strong negative correlation with angular widths of halo CMEs.We also compare the results with the CME mass estimated from STEREO observations.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.6
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• pp.449-456
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• 2009

The RMS(Root Mean Square) current stress reduction technique for the PFC link capacitor is proposed. Although the various parameter is exist for optimizing the link capacitor, the RMS current stress is the most weighty practical parameter. The proposed C-L filter can reduce effectively the RMS current stress by filtering the output current. And with the C-L-L-C filter proposed in this paper, the more RMS current stress can be reduce because it filters not only the output current, like C-L filter, but also the input current of DC/DC stage. The proposed filter is simple to design and have no effect on the control part of the PFC because of the very low crossover frequency. To confirm the validity of proposed filter, theoretical analysis, the design guide, verification of experimental results are presented.

• Journal of Korean Medicine Rehabilitation
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• v.23 no.1
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• pp.51-64
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• 2013

Objectives : This study was performed to evaluate the effect of dry cupping treatment applied to back-shu points on the autonomic nervous system. Methods : Two groups of sympathicotonia and normal with each 30 volunteers were set up for this experiment. The sympathicotonia group was selected by the criterion for sympathicotonia by the questionnaire composed of 11 items. After 10 minutes for environmental adaptation, the first HRV(heart rate variability) test was conducted, and then, dry cupping therapy was applied to back-shu points for 5 minutes to stimulate sympathetic ganglia lying along the spine. The second HRV test was carried out just after the cupping therapy under the same condition and then, the third test was repeated after two hours based on the first test time. Results : 1. In sympathicotonia group, SDNN(standard deviation of all normal R-R intervals), RMSSD(the square root of the mean of the sum of the squares of differences between adjacent normal R-R intervals), Ln(HF)(high frequency power), nmHF(normalized high frequency power) increased and mHR(mean heart rate), nmLF(normalized low frequency power) decreased significantly right after dry cupping therapy which means dry cupping affects on autonomic nervous system. The effect lasts in these items of nmLF, Ln(HF), nmHF, rLHF(rate ratio of LF/HF). 2. In normal group, SDNN, RMSSD increased and mHR decreased significantly right after dry cupping therapy, too. But, Ln(LF)(low frequency power), nmLF, rLHF unexpectedly increased and nmLF, rLHF stay increased up to 2 hours. Conclusions : The results suggest that the dry cupping therapy has effect on the autonomic nervous system. It is effective to stabilize hyper-sympathetic tone of people diagnosed as Sympathicotonia and activate parasympathetic tone.

• Journal of Korean Neurosurgical Society
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• v.47 no.5
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• pp.345-351
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• 2010

Objective : In this study, the Mindfulness Based Stress Reduction (MBSR) program was applied to patients presenting with depression and anxiety after surgery from spontaneous subarachnoid hemorrhage (SAH) and the effects were assessed. Methods : The subjects were patients admitted for cerebral aneurysm rupture and treated by means of surgery from March to December, 2007. More than 6 months had passed after surgery, without any special lesions showing up on computed tomography (CT), and the Glasgow outcome scale (GOS) was 5 points. Among patients with anxiety and depression symptoms, 11 patients completed the program. The MBSR program was conducted once a week, 2.5 hours each, for 8 weeks. The evaluation criteria were : 1) the Beck Depression Inventory (BDI): it measures the type and level of depression, 2) the State-Trait Anxiety Inventory : the anxiety state of normal adults without mental disorder, and 3) Heart Rate Variability (HRV) : the influence of the autonomous nervous system on the sinoarterial node varies continuously in response to the change of the internal/external environment. Results : The BDI value was decreased from 18.5 ${\pm}$ 10.9 to 9.5 ${\pm}$ 7.1 (p = 0.013) : it was statistically significant, and the depression level of patients was lowered. The state anxiety was decreased from 51.3 ${\pm}$ 13.9 to 42.3 ${\pm}$ 15.2; the trait anxiety was reduced from 50.9 ${\pm}$ 12.3 to 41.3 ${\pm}$ 12.8, and a borderline significant difference was shown (p = 0.091, p = 0.056). In other words, after the treatment, although it was not statistically significant, a decreased tendency in anxiety was shown. In the HRV measurement, standard deviation normal to normal (SDNN), square root of the square root of the mean sum of squared differences between adjacent normal to normal intervals (RMSSD), and total power (TP) showed significant increase, Physical Stress Index (PSI) showed a significant reduction, and thus an improvement in the homeostatic control mechanism of the autonomic nervous system was ween. Conclusion : The MBSR program was applied to the patients showing anxiety and depression reaction after SAH treatment, and a reduction in depression symptoms and physiological reactions were observed. The application of the MBSR program may be considered as a new tool in improving the quality of life for patients after surgery.

• Journal of Korea Water Resources Association
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• v.52 no.12
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• pp.975-984
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• 2019

As an essential prerequisite for systematic and integrated management of river water, it is necessary to secure the basic data such as discharge supplied to the river and released from the river. Under the current permit system for river water use, 59.1% of licensed facilities were found to have no discharge meters in 2017, especially for agricultural water, which makes it difficult to secure reliable data as a large portion of the reports are voluntarily reported by users. In this study, the indirect discharge measurement method of calculating the discharge through the power usage of the pumping station was applied to secure reliable discharge data. In particular, focusing on the fact that the discharge calculated by the power usage method differed with the actual discharge according to the level of the river, the study was conducted on improving the power usage method reflecting the river water level and improving the accuracy of discharge data. Analysis of the discharge calculated using the power usage method considering river water level using the correlation analysis method such as regression analysis, percent difference, root mean square error etc. confirmed that the results are not high compared to the conventional power usage method, but are slightly more approximated to the actual discharge. Therefore, although reliable discharge data can be obtained from the existing power usage method, it is expected that more accurate data on intaking water of river water can be obtained if the improved power usage method is used at points where the variation in the water level of the river is large.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.2
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• pp.57-63
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• 2003

To investigate the RMS SD(Root Mean Square Spot Diameter) in a back focal plane as the front surface power, the center thickness, and the refraction index vary, we use programs which are Cove V and LOSA 2.0, and consider a spectacle lens with back vertex power of -4.00D and diameter of 70 mm. We also consider the front surface power varied from 0.00 to 10.00D, the center thickness varied from 1.1 to 2.0 mm, and the indices which are $n_d$ = 1.498, 1.523, 1.586, and 1.660, respectively. As the front surface power increases the RMS SD in the back focal plane increase rapidly. When the refraction index increases, the RMS SD in the back focal plane decrease and the variation of RMS SD in the back focal plane decreases as the front surface power increases. When the center thickness of spectacle lens increases, the RMS SD in the back focal plane is constant and the edge thickness of that increases. We know from these results that the image in the back focal plane of a spherical spectacle lens improves as the front surface power increases and the refraction index decreases.

• Journal of Life Science
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• v.19 no.2
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• pp.271-276
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• 2009

The Purpose of this study was to examine the effects of boxing aerobic training on resting heart rate variability (HRV) in females. The subjects for this study were performed 16 female college students that aged 19-23. The subjects were divided into two groups; boxing aerobic exercise group (9 students) and control group (7 students). Boxing aerobic training program was performed three times a week for twelve weeks with $VO_{2max}$ 60-80% exercise intensity. The results of this study were following; 1. Mean HRT (mean heart rate) had no signigicant difference among the groups and exercise time. 2. SDNN (standard deviation of the normal to normal interval) had no significant difference among the group and exercise time. 3. RMS-SD (square root of the mean squared differences of successive normal to normal interval) had no significant difference among the groups and exercise time. 4. TP (total power) had no significant difference among the groups and exercise time. 5. LF (low frequency) had no significant difference among the groups and exercise time. 6. HF (high frequency) had no significant difference among the groups and exercise time. 7. LF/HF (low frequence/high frequency ratio) had no significant difference among the groups and exercise time. 8. VLF (very low frequency) had no significant difference among the groups and exercise time.

• Korean Journal of Biological Psychiatry
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• v.15 no.3
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• pp.186-193
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• 2008

Objectives : The authors tried to investigate the characteristics of Heart Rate Variability(HRV) among the subjects with metabolic syndrome for testing the possibility of clinical application of HRV in evaluating metabolic syndrome. Methods : We examined the difference of the means of HRV between 122 subjects of metabolic syndrome and 1057 healthy controls using T-test, and the change of means in HRV according to increasing risk factors of metabolic syndrome. Using multiple regression analysis, we examined the association of HRV with the risk factors of metabolic syndrome. Results : The HRV indices including SDNN(Standard Deviation of all normal NN intervals), RMSSD(the square Root of the Mean Squared Differences of successive all normal NN interval), TP(Total Power), LF(Low Freuency), and HF(High Frequency) were significantly lower in the metabolic syndrome group than in the normal control group, and the means of all HRV indices except LF/HF were decreased consistently according to increasing risk factors of metabolic syndrome. The fasting glucose, triglyceride, and waist circumference were dependent factors that contributed significantly to the change of HRV. Conclusion : These findings suggest metabolic syndrome adversely affects cardiac autonomic system and HRV could be a useful method for evaluating metabolic syndrome.

• 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 Journal of Korean Obstetrics and Gynecology
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• v.24 no.3
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• pp.109-115
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• 2011

Objectives: To characterize autonomic dysfunction in patients with Cold hypersensitivity, their heart rate variability(HRV) were measured and analyzed with cold hypersensitivity patients, compared with those of normal population. Methods: We studied 56 patients visiting Gangnam Kyung-hee korean hospital from 1st January 2010 to 31th December 2010. Heart rate variability were obtained from 28 female patients who suffer from cold hypersensitivity and 28 healthy female controls in resting state. We studied the difference of Heart rate variability between two groups by Independent T-test using SPSS for windows(version 17.0). Results: Standard deviation of NN interval(SDNN), total power(TP), Very low frequency(VLF) in patients with cold hypersensitivity were significantly different with those of controls. While no significant differences were observed in square root of mean squared differences of successive NN intervals (RMSSD), low frequency (LF) and high frequency(HF). Conclusions: The decreased values of heart rate variability(HRV) study means that they may have some kinds of imbalance in autonomic nervous system in cold hypersensitivity patients. heart rate variabiliry(HRV) study might be a tool of diagnosis and predictors in cold hypersensitivity patients.