• Journal of IKEEE
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• v.26 no.4
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• pp.553-559
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• 2022

In this paper, RC snubber circuit design technology for oscillation suppression in half-bridge configuration of cascode gallium nitride (GaN) field effect transistors (FETs) is analyzed. A typical wide band-gap (WBG) device, cascode GaN FET, has excellent high-speed switching characteristics. However, due to such high-speed switching characteristics, a false turn-off problem is caused, and an RC snubber circuit is essential to suppress this. In this paper, the commonly used experimental-based RC snubber design technique and the RC snubber design technique using the root locus method are compared and analyzed. In the general method, continuous circuit changes are required until the oscillation suppression performance requirement is met based on experimental experience . However, in root locus method, the initial value can be set based on the non-oscillation R-C map. To compare the performance of the two aforementioned design methods, a simulation experiment and a switching experiment using an actual double pulse circuit are performed.

• The Journal of Internal Korean Medicine
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• v.44 no.2
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• pp.277-284
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• 2023

Objective: This study investigated the effects of Guibiondam-tang-gamibang on patients in the thyrotoxic phase of painless thyroiditis. Methods: A patient in the thyrotoxic phase of painless thyroiditis was treated with Guibiondam-tang-gamibang combined with Western medicine (i.e., beta blockers). The effect of treatment was evaluated according to the pulse rate, NRS, the frequency of subjective symptoms, and sleep time. In addition, the thyroid function was evaluated with TSH, Free T4, and T3 using blood tests. Results: After treatment, the pulse rate decreased, and the NRS and frequency of subjective symptoms disappeared after improvement. Sleep time increased. In the thyroid function test, a significant normalization of each value was observed. Conclusion: This study suggests that Guibiondam-tang-gamibang can be effectively treated in patients with painless thyroiditis in the thyrotoxic phase. However, further studies should be conducted.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.2
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• pp.91-102
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• 2008

Nondestructive testing techniques have been historically and commonly used to evaluate the quality of existing concrete structures. The techniques utilized included visual inspection, hammer sounding, Schmidt hammer rebounding, and ultrasonic pulse velocity testing including tomographic imaging. Results of the nondestructive tests were used to determine areas to be tested with local destructive tests. These tests included concrete compressive strengths, chloride testing, and petrographic testing. The overall results indicate that inside core of each of the pier caps are healthy. On all of the pier caps, extensive exterior concrete layer rehabilitation needs to be completed. This paper shows the application and interpretation of common nondestructive testing techniques and the consequent repair, rehabilitation, maintenance decisions and safety assesment.

• Women's Health Nursing
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• v.9 no.3
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• pp.224-234
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• 2003

Purpose: This study was to test the effects of a full body massage on labor pain and delivery stress reaction for primipara during labor. Method: This study employed a quasi- experimental method(nonequivalent control group, pre-post test design). The subjects of this study were 57 primipara hospitalized at the U OB & GYN hospital in Inchon from November 1. 2001 to July 31, 2002. 28 women were assigned to the experimental group and 29 to the control group. The experimental group was given 20 minutes full body massage for each of three delivery phases. The control group was given conventional delivery care. The levels of labor pain were measured by the Visual Analogue Scale and the expression scores of the labor pain and the levels of delivery stress reaction were measured by pulse rate, respiration rate, and blood pressure, and State-Anxiety Scale. Data were analyzed using the repeated measures analysis of covariance(ANCOVA), t-test, $X^2$- test, simple ANCOVA with SPSS program. Result: There was no interaction effect between time and group(F=.370, p=.693), but significant time effects were found for subjective labor pain(F=3.840, p=.028). There was no interaction effect between time and group(F=.112, p=.894), but significant group effects were found for objective labor pain(F=12.299, p=.001). There was no interaction effect between time and group for PR(F=.172, p=.843), RR(F=.626, p=.539), SBP(F=.089, p=.915), DBP(F=.748, p=.479), but significant group effects were found for SBP(F=7.547, p=.008). The level of status anxiety of the experimental group was significantly lower than the control group(F=11.787, p=.001). Conclusion: This study showed that the full body massage has partially positive effect on labor pain and delivery stress reaction. Therefore this study suggested that the full body massage might be used clinically to help primipara during labor.

• Journal of Advanced Navigation Technology
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• v.10 no.2
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• pp.173-180
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• 2006

An airborne radar is an essential aviation electronic system of the aircraft to perform various missions in all weather environments. This paper presents the design, development, and test results of the multi-mode pulsed Doppler radar system test model for helicopter-borne flight test. This radar system consists of 4 LRU units, which include ANTU(Antenna Unit), TRU(Tx Rx Unit), RSDU(Radar Signal & Data Processing Unit) and DISU(Display Unit). The developed technologies include the TACCAR processor, planar array antenna, TWTA transmitter, coherent I/Q detector, digital pulse compression, DSP based Doppler FFT filtering, adaptive CFAR, IMU, and tracking capability. The design performance of the developed radar system is verified through various helicopter-borne field tests including MTD (Moving Target Detector) capability for the Doppler compensation due to the moving platform motion.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.9
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• pp.831-837
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• 2015

Many persons and electronic devices are exposed to electromagnetic (EM) waves generated from magnetic resonance imaging (MRI) equipment, EM pulses (EMPs), and many other kinds of EM wave devices. Finger strips are used to provide shielding from these EM waves. Because of the high thermal conductivity of finger strips, they are used in the design of specialized doors that are installed in shielded rooms. In this study, we perform an accelerated life test using the load acceleration stress, which affects the main failure mode of finger strips. We predict the life of the finger strip under normal usage conditions based on the results of the accelerated life test. We compare the results with those predicted from the life test under normal usage conditions to evaluate the validity of accelerated life testing.

• The Journal of the Korea Contents Association
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• v.16 no.11
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• pp.623-632
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• 2016

The purpose of the present study was to evaluate the effect of an offered blanket on the anxiety of patients undergoing brain MRI. The participants were 52 patients who underwent brain MRI in C university hospital of G city. Blanket was applied to the experimental group (n=26) before MRI. Data were collected from May to December 2015, and analysed using the chi-squared test, the independent t-test, and repeated measures ANOVA. The results showed that there was no significant difference in the anxiety measured by STAI of the two groups. But, the level of anxiety measured by the visual analog scales was reduced in the experimental group (t=-2.75, p=0.008). There were no difference in the blood pressure and pulse rate in the experimental and control groups. Therefore, further study is needed to decrease the level of anxiety of patients undergoing brain MRI.

• Journal of Home Health Care Nursing
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• v.22 no.2
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• pp.206-215
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• 2015

Purpose: This study aimed to provide basic data to enhance self-nursing ability by investigating the symptoms of autonomic neuropathy and self-management activities in patients with diabetes accompanying hypertension. Methods: Subjects were 113 type-2 diabetic patients who were diagnosed as hypertensive in two primary medical institutions and taking anti-hypertensive treatments. The existence of postural hypotension was evaluated by blood pressure and pulse rate, and the subjective symptoms of autonomic neuropathy and self-management activities were checked by structured questionnaires. The collected data were analyzed by chi-square test, Fisher's exact test, t-test, Wilcoxon rank sum test and analysis of covariance. Results: Postural hypotension occurred in 4.4% of the subjects. Urinary frequency and dizziness during postural changes were the most frequent symptoms of autonomic neuropathy, and 57.5% of the subjects complained of symptoms in two or more domains. The group with autonomic neuropathy symptoms showed higher age, higher living stress, and fewer self-management activities in the diet and foot management domains as compared to the group without autonomic neuropathy symptoms. Conclusion: From these results, we learned that strengthening education on self-management for diet and foot management and customized interventions considering age and living stress are required through early identification of the symptoms of autonomic neuropathy in patients with diabetes accompanying hypertension.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.3
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• pp.196-201
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• 2000

It is very important not only to detect PD signal but also to locate PD source in power cable line including its accessories. In this paper, the PID localization technique using interruption of metal sheath of cable or accessory is described. By interruption of metal sheath, the polarity of PD pulse to be measured on each part can be compared. With this technique, the exact location of PD in the accessory which has some defects can be found. Although the 'Soft' interruption method, that is, cable sheath is divided by semi-conductive layer with the resistance of higher than 1 k$\Omega$, was used instead of 'Hard' interruption method, it is also possible to detect exact location of PD. This technique is considered to be very effective for detecting PD localization in the type test of cable and accessories.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1867-1870
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• 2003

The analysis and simulation are the method to study the behavior, response, and specification of the driver device. This paper proposes brushless DC drive which using the vector control technique. The encoder is used detect the rotor position and decode to Three-phase step signal. The step signal is modulated with triangle signal and change to the pulse width modulation (PWM) signal. The PWM signal is used for control the input power of the motor based on the vector control technique. The experimental results of the driver circuit and motor response performed under the following condition: as the motor was started, change the load torque, and vary the supply voltage. The experimental performs with a dynamometer and the test results are compared to the simulation method is the same result.