• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.5
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• pp.391-399
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• 2020

KASI (Korea Astronomy and Space Science Institute) has been developing the multipurpose laser tracking system with three functions of satellite laser tracking, adaptive optics and space debris laser tracking for scientific research and national space missions. The space debris laser tracking system provides the distance to space debris without a laser retro-reflector array by using a high power pulse laser, which employs a spinning disk to change the optical path between the transmit and receive beams. The spinning disk causes the collision band which is unable to reflect the returned signal to a detector and then has an effect on the tracking coverage of space debris. This study proposed the mathematical model for tracking coverage by taking into account the various specifications of spinning disk such as disk size, spinning velocity and collision rate between the disk and hole. In addition, the spinning disk specifications were analyzed in terms of tracking coverage and collision band based on the mathematical model to investigate tracking requirements of the Geochang laser tracking system.

• Journal of Preventive Medicine and Public Health
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• v.32 no.4
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• pp.435-442
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• 1999

Objectives: The purpose of this study was to examine the twelve-year incidence of hypertension, and to find risk factors for the incidence in adult population in Kangwha County, Korea. Methods: In 1986, 413 males(mean age 37 years) and 434 females(mean age 33 years) were examined in the Kangwha Study, Among 764 non-hypertensive participants, 164 males and 214 females were reexamined in 1998. Blood pressure(BP) was measured with standard mercury sphygmomanometers. Multiple logistic regression analysis was used to estimate the relative risk of risk factors on the incidence of hypertension. Results: During the 12-year period, 68 of 164 males and 53 of 2f4 females developed hypertension. In a multiple logistic model adjusted for age and pulse rate, baseline BP, baseline body mass index(BMI) and BMI change during the follow-up period were significantly related to the incidence of hyperiension. Adjusted relative risk(RR)s of baseline high-normal BP were 3.90(95% CI: 1.81-7.84) in males, and 12.72(95% CI: 3.70-30.73) in females. Compared with lower baseline BMI group, adjusted RRs of middle baseline BMI group were 2.66(95% CI: 1.19-5.70) in males, and 2.33(95% CI: 0.95-5.55) in females. Adjusted RRs of upper baseline BMI group were 3.52(95% CI: 1.53-7.67) in males and 3.63(95% CI: 1.50-8.43) in females. Increase of BMI was positively related to the incidence in males(adjusted RR=2.71, 95% CI: 1.00-6.71) and females(adjusted RR=3.05, 95% CI: 1.29-6.88). Conclusions: The twelve-year incidence of hypertension was 41.5% in males, and 25.8% in females. Baseline BP, baseline BMI, and BMI change were strongly related to the incidence of hypertension.

• Korean Journal of Veterinary Research
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• v.41 no.3
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• pp.421-427
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• 2001

This study was performed to evaluate the embolized kidney and contralateral normal kidney using computed tomography (CT) and enhanced computed tomography. Experimental hydronephrosis was induced by ligation of unilateral ureter in Beagle dogs. Renal artery embolization was performed using selective catheterization in the hydronephrotic kidney of seven dogs and EKG, $SpO_2$, body temperature, pulse, and repiratory rate were within normal ranges during procedures. Iohexol-ethanol solution was used as embolic material. There were no dogs expired after TAE-Ra and no side effects associated with regurgitation of iohexol-ehtanol solution. Revascularization of renal artery was not found in angiography in dogs treated by TAE-RA at immediately after TAE-RA and 14 days after TAE-RA. CT showed dilation of urinary collection system and ventral displacement of spleen at 14 days after TAE-RA in one dog not treated by TAE-RA and experimental group treated by TAE-Ra. CT two month after TAE-RA showed the shrunken embolized kidney in experimental group. Transverse CT with contrast enhancement demonstrated the increase of signal intensity at thinned renal cortex in control group not treated by TAE-Ra at 30 days and 60 days, however, there was no increase of signal intensity at shrunken embolized kidney at 60 days after TAE-RA. CT was useful modality for evaluation of the morphology and the size of embolized kidney and contralateral normal kidney. Enhanced CT was availabel for the detection of revascularization of renal artery after TAE-RA in dogs with hydronephrosis. It is conclued that CT is useful modality for the monitoring of the revascularization of the renal artery after TAE-RA.

• Korean Journal of Veterinary Research
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• v.41 no.3
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• pp.413-419
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• 2001

This study was performed to evaluate the renal hemodynamics using color Doppler ultrasonography in dogs with unilateral experimental hydronephrosis treated with transarterial embolization of the renal artery (TAE-RA). Experimental hydronephrosis was induced by ligation of unilateral ureter in 12 dogs. The mean resistive index (RI) value of kidney was significantly increased at 4, 9, 17 days after ligation of ureter. Unilateral hydronephrosis was established in 12 dogs at 17 days after ligation of ureter. Renal artery embolization was performed using selective catheterization in the hydronephrotic kidney of seven dogs and EKG, $SpO_2$body temperature, pulse, and respiratory rate were within normal ranges during procedures. There were no dogs expired after TAE-RA and no side effects associated with regurgitation of iohexol-ethanol solution. In color Doppler ultrasonographic findings, there was no blood flow into the embolized kidneys treated by TAE-RA, however, blood flow signal was found in contralateral normal kidney of dogs treated with TAE-RA compared to that of normal kidney in normal control group. It is concluded that TAE-RA does not affect the hemodynamics of contralateral normal kidney in dogs with experimental hydronephrosis and color Doppler ultrasonography is simple and non-invasive modality for the monitoring of the revascularization of the renal artery after TAE-RA.

• Journal of the Korean Vacuum Society
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• v.5 no.4
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• pp.269-277
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• 1996

The vacuum systems of PLS linac provides average pressure of $2.6\times 10^{-6}$Pa under high power microwave of 54 MW peak with 4.1 $\mu \textrm s$ pulse width and 10 Hz repetition rates. The base pressure of system is$2.4\times 10^{-6}$Pa with 45$^{\circ}C$ cooling water. The outgassing rate of the system is decreased from $3.0\times 10^{-11}Torr-l/sec-\textrm{cm}^2$ at the initial stage after installation to $1\times 10^{-12}Torr-l/sec-\textrm{cm}^2$ at present. Total accumulated microwave energy dose is about 140 GJ per module. All ion pumps are working under saturated regime and effective pumping speeds of 60 I/s, 230 I/s ion pumps are 45 I/s, 65 I/s, 140 I/s under the operating range. Main problems occurred in recent year are troubles of ion pump controller and vacuum gauge controller, vacuum leak of energy doubler window and electron gun ceramic, and water leak in the dummy load of acceleraing columns. Total of 41 troubles with 140. 8 hours down time give good system availability of 98%. Down time can be reduced by high power waveguide valves and water dummy loads under development, and then availability is expected to be increased up to 99.5%.

• Journal of Energy Engineering
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• v.15 no.1 s.45
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• pp.52-59
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• 2006

This paper examined the conversion of methane to hydrogen and other higher hydrocarbons using dielectric barrier discharge with AC pulse power. Two metal electrodes of a coaxial-type plasma reactor were separated by gas gap and an alumina tube. The inner electrode was located inside the alumina tube. The alumina tube was located inside the stainless steel tube, which was used as the outer electrode. Effect of feed gas composition (methane, oxygen, argon, water and helium), flow rate, applied frequency, input volt-age on methane conversion and product distribution were studied. The major products of plasma chemical reactions were ethylene, ethane, propane, buthane, hydrogen, carbon monoxide and carbon dioxide. The increment of applied voltage and the usage of inert gas as the background (helium and argon) enhanced the selectivity of hydrocarbons and methane conversion. The addition of water in the feed stream enhanced the conversion of methane and yield of hydrogen. Higher voltage leads to higher yield of $C_2H_6,\;C_3H_8,\;C_4H_{10}$ and yield or $C_2H_2\;and\;C_2H_4$ appeared highly in lower voltage.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6B
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• pp.1134-1141
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• 1999

In this paper, we implement an optical code division multiple access(OCDMA) system and analyze the performance of the implemented system. In the implemented system, a transmitter encodes input data into optical pulses by using laser diode, and spreads the encoded pulses in an encoder which consists of 4 stage delay lines. The decoder which is the same structure as that of encoder delays and combines the spreaded pulses, and thus recovers the original data. At first, we discuss the auto- and cross-correlations of OCDMA signals under both environments of single user and multi-users, and then verify the simulation results with experimental results. We also evaluate the effect of a number of stages of delay line and code length on the system performance through computer simulations. As experimental results we can see that if the decoder have the same configuration as that of encoder, the peak auto-correlation characteristics can be achieved, and thus we can recover the original data from received data. As simulation results we can see that although bit error rate decreases as code length decreases or the number of stage of delay line increases, it is difficult to implement the system because the pulse width becomes narrow. From the results, we can apply CDMA technologies to optical communication networks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.93-102
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• 2016

This study examined effects of the communication accompanied with music therapy on the anxiety of patients during a MRI examination. In the experiment group consisting of thirty patients and the control group consisting of thirty patients, the experiment was performed from February 1st 2014 to March 31st 2014 in hospital C located in Daegu Korea. The research design was a non-equivalent control group quasi-experimental study. The results showed that the anxiety score (VAS score) on communication with music therapy of the experimental group was significantly lower (p=.001), than that of the control group. Among the vital signs, the blood pressure was similar in both groups. On the other hand, the pulse rate of the experiment group was significantly lower (p=.001). Four categories of the physical discomfort (perspiration, facial change, change in physical posture, and change in vocal sound) did not show any statistically significant difference between the control and experiment group. Among the mental discomforts, dizziness did not have a significant difference between the experiment group and the control group, but the experimental group had significantly low fear (p=.001) and anxiety (p=.001). From the above results, communication accompanying music therapy proves is an effective alternative examination method that reduces the anxiety of patients.

• The Journal of the Korea Contents Association
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• v.11 no.6
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• pp.289-301
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• 2011

This study is a research based on the non-equivalent control group pretest-posttest design whose purpose is to examine the effects of music therapy on the anxiety of patients who take the magnetic resonance imaging(MRI) test and their feeling of discomfort during the test. "The first hypothesis that the experimental group who receive music therapy will be lower in score for anxiety during the MRI test than the control group who do not was supported because after the therapy, the experimental group was found significantly decreased in that score in comparison to the control group. "The second hypothesis that the experimental group who receive music therapy will be fewer in vital signs after the MRI test than the control group who do not" was rejected in terms of both systolic and diastolic blood pressure. But the same hypothesis was partially supported because the two groups showed a significant difference in pulse rate after the test. "The third hypothesis that the experimental group who receive music therapy will be less in the feeling of subjective discomfort during the MRI test than the control group who do not" was verified to find that the two groups were significantly different from each other in the feeling. Specifically, there was a significant difference between the two groups in only one sub-area of that feeling, that is, tension. These findings suggest that music therapy could be an alternative method which can effectively reduce the state anxiety of patients during the magnetic resonace imaging(MRI) test.

• Science of Emotion and Sensibility
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• v.14 no.4
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• pp.503-512
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• 2011

Recently in HCI research, emotion recognition is one of the core processes to implement emotional intelligence. There are many studies using bio signals in order to recognize human emotions, but it has been done merely for the basic emotions and very few exists for the other emotions. The purpose of present study is to confirm the difference of autonomic nervous system (ANS) response in three emotions (boredom, pain, and surprise). There were totally 217 of participants (male 96, female 121), we presented audio-visual stimulus to induce boredom and surprise, and pressure by using the sphygmomanometer for pain. During presented emotional stimuli, we measured electrodermal activity (EDA), skin temperature (SKT), electrocardiac activity (ECG) and photoplethysmography (PPG), besides; we required them to classify their present emotion and its intensity according to the emotion assessment scale. As the results of emotional stimulus evaluation, emotional stimulus which we used was shown to mean 92.5% of relevance and 5.43 of efficiency; this inferred that each emotional stimulus caused its own emotion quite effectively. When we analyzed the results of the ANS response which had been measured, we ascertained the significant difference between the baseline and emotional state on skin conductance response, SKT, heart rate, low frequency and blood volume pulse amplitude. In addition, the ANS response caused by each emotion had significant differences among the emotions. These results can probably be able to use to extend the emotion theory and develop the algorithm in recognition of three kinds of emotions (boredom, surprise, and pain) by response measurement indicators and be used to make applications for differentiating various human emotions in computer system.