• Journal of the Korean Society for Precision Engineering
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• v.13 no.4
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• pp.53-60
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• 1996

In the conventional linear elasticity, sound speed is determined by only elastic modulus and density of the medium. In actual, however, sound speed depends on the stress and this dependency becomes nonlinear as the stress increases. These phenomena can be introducing nonlinear elastic modulus. In this paper, relationships between nonlinear elastic modulus up to 4th order and the internal status of materials are discussed through computer simulations and experiments. For the measurement of sound speed, a new type of measurement system using ultrasonic wave is proposed on the basis of ultrasonic pulse echo method which has been generally used in nondestructive ultrasonic test equipment. In order to confirm the stress dependency of sound speed, several experiments are carried out for alumina specimen.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.196-198
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• 2020

본 논문은 SiC MOSFET의 단락 검출을 위한 고정밀 Rogowski 코일 회로 설계 방법을 제안한다. 설계 방법을 제안하기 위해 먼저 Rogowski 코일의 기본 구성인 적분기를 실제 시스템 요구 사양에 맞추어 설계한다. 설계한 회로의 성능 확인을 위하여 DPT (double pulse test)를 실시하며, test 결과 분석을 통해 문제점을 파악하고 전류 센싱 정밀도 향상을 위해 입출력 필터 설계 및 Rogowski 코일 턴 수를 변경한다. 변경한 각 조건들에 대하여 DPT를 진행하고 각 test 결과를 기반으로 Rogowski 코일 회로 설계 방안을 제안한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.5
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• pp.548-558
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• 2014

EMP(Electromagnetic Pulse) protection facility was evaluated according to standard of shielding effectiveness. To comply with the standard, transmitting antenna was placed on outside of protection facility and receiving antenna was placed on inside of protection facility. However, measurement is impossible that place does not have enough space between protection facility and external concrete structure. In this paper, we performed a various of tests that put transmitting antenna inside the EMP protection facility in order to find out test method for measuring the shielding effectiveness of electromagnetic wave. Transmitting antenna was placed on inside of the EMP protection facility for measuring the shielding effectiveness to compare and analyze the impact of the position regarding to the transmitting and receiving antenna. As a result of test, in case that transmitting antenna was placed on inside of the EMP protection facility, it was found that test frequency range 10 kHz~1 GHz were occurred overall average difference of ${\pm}4$ dB level.

• Journal of the Korea Concrete Institute
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• v.14 no.6
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• pp.973-981
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• 2002

Recently, the use of high strength concrete (HSC) has increased dramatically md however, few studies have been conducted on the early-age properties of HSC such as setting. The penetration resistance test (specified by KS F 2436) that is the standard test method for determining initial and final setting times of concrete, may not be appropriate for HSC because of the high viscosity of the mortar mixture. To address this issue, an ultrasonic pulse velocity (UPV) monitoring system was used to investigate the setting behavior of mortar and concrete. The experimental study was carried out to measure the UPV's of mortars and concretes having various water/binder ratios (W/B) and various fly ash replacement levels, during the first 24 hours of testing. Test results showed that the UPV in concrete was developed faster than that of mortar with the same W/B, and that of ordinary concrete was greater than that of fly ash concrete. Typical values of UPV were suggested that correspond to the initial and final setting times, based on following criteria: (1) the penetration resistance method; (2) the instant when the UPV begins to develop; and (3) the instant when the UPV development rate is maximum. The method and UPV monitoring device used in this study is promising for the setting assessment of concrete, particularly for HSC.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.2
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• pp.98-106
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• 2003

Nondestructive test (NDT) provides much information on concrete without damage of structural functions. Of NDT methods, elastic wave propagation methods, such as ultrasonic pulse velocity (UPV) method and impact-echo (IE) method, have been successfully used to estimate the strength, elastic modulus, and Poisson's ratio of concrete as well as to detect the internal microstructural change and defects. In this study, the concretes with water-binder ratio ranging from 0.27 to 0.50 and fly ash content of 20% were made and then their longitudinal wave velocities were measured by UPV and IE method, respectively. Test results showed that the UPV is greater than the longitudinal wave velocity measured by the If method, i.e., rod-wave velocity obtained from the same concrete cylinder. It was found that the difference between the two types of velocities decreased with increasing the ages of concrete and strength level. Moreover, for the empirical formula, the dynamic Poisson's ratio, static and dynamic moduli of elasticity, and velocity-strength relationship were determined. It was observed that the Poisson's ratio and the modulus of elasticity determined by the dynamic method are greater than those determined by the static test. Consequently, for the more accurate estimation of concrete properties using the elastic wave velocities, the characteristics of these velocities should be understood.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.13 no.2
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• pp.45-77
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• 2009

Background : Eight-Constitution Medicine (ECM) devides the human body into eight constitutions. Up until now, checking the pulse types is only way to classify the eight constitution. Recently we try to make a questionnaire that is based on the Eight-Constitution characters and analyze the answer from patients who were classified into one of the eight constitutions according to their pulse types and their responses to constitution-acupuncture therapy Objective : This study intends to analyze each answer of the Eight-Constitution Questionnaire with independent sample t-test. Methods: Participants of this study were outpatients in ECM clinics located in Korea. The resources were collected from 925 patients who were classified into one of the eight constitutions according to their pulse types and their responses to constitution-acupuncture therapy. SPSS 13.0 for Windows was used for independent sample t-test. Results and Conclusions: 1. The proportion of participants' constitutions is in the order of Pancreotonia (28.0%), Colonotonia (17.3%), Pulmotonia (18.1%), Hepatonia (18.1%), Vesicotonia (8.5%), Cholecystotonia (7.0%), Renotonia (2.6%) and Gastrotonia (0.4%). 2. Eight-Constitution Questionnaire consists of 5 parts; Appearance, Character, Body reaction, Physiology & Pathology and Food reaction. 3. 44 items were chosen among 128 question about Body reaction, Physiology & Pathology and Food reaction. 4. Due to the deficiency of Gastrotonia examples, useful items have to be given up. If we can gather Gastrotonia examples, we can use meaningful items more than 44.

• Journal of Korean Biological Nursing Science
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• v.19 no.3
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• pp.151-157
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• 2017

Purpose: The purpose of this study was to identify the effects of hand and foot baths on sleep and body temperature of the elderly. Methods: The research was designed for a nonequivalent control group before and after the test design. The subjects of this study totaled 43, aged 65 and over (23 people in hand bath group and 20 people in a foot bath group), who received a written voluntary consent to participate in experimental treatment and are in the W care center, S Nursing Home, and H care center in Seoul. Data were collected with questionnaires and observations, and were analyzed on the basis of frequency, percentage, mean, standard deviation, ${\chi}^2-test$, Fisher exact test, t-test and paired t-test. Results: There are no significant differences in homogeneity test of a dependent variable between groups (hand bath, foot bath). The differences between 2 groups on the sleep quality score and systolic blood pressure, diastolic blood pressure temperature were not significant statistically except on the pulse. Conclusion: Based on the results of this study, hand bath is as efficient as foot bath. Therefore, a hand bath can be a nursing intervention in order to enrich sleep quality for the elderly because a hand bath is more convenient than foot bath.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.6
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• pp.491-496
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• 2005

In this paper, test on characteristics of 3-phase line-interactive UPS system, known as delta conversion UPS system, is studied. Delta conversion UPS system is new line-interactive UPS system using two series-parallel PWM converters instead of using series inductor in conventional single conversion line-interactive UPS system. It is known that the characteristics of input and output in delta conversion UPS system is much improved by controlling source current of AC lines directly. Here the results on load test, normal/backup mode test, and normal/bypass mode test, which are very important in the test on characteristics of UPS system, is presented. And finally overall evaluation on delta conversion UPS system is given.

• Journal of Home Health Care Nursing
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• v.13 no.1
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• pp.54-60
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• 2006

This study, a quasi-experimental study using a nonequivalent control group pretest-posttest design. conducted a survey on 30 patients test group and control group of IS patients sampling an adjacent population at random - who are operated on the breast cancer and are in the A University Hospital located in Suwon, to examine into the effects of foot reflex zone massage on their pain and sleep satisfaction through the nursing interventions. It gave them a foot reflex zone massage for the total 30 minutes-basic massage 10 minutes and reflex massage 20 minutes required to alleviate their pain day in day out covering a two-month period from the first of July to the first of September 2004. for the purpose of collecting data. It launched into a two-round foot reflex zone massage at 6 and 24 hours since mastectomy through a direct visit at the hospital room to measure pain intensity, physiological index(pulse and blood pressure) and sleep satisfaction of them. The results are as follows. First, it showed that there is all the difference between pain intensity of test group and that of control group. In result, the first hypothesis, pain of test group. which measure at 6(p=.000) and 24 hours(p=.001) since mastectomies, will be bigger than that of control group, was established. Second, it showed that there is all the difference between physiological index of test group and that of control group. In result. the second hypothesis, pulse(p= .025, p= .002), systolic blood pressure(p= .004, p=.012) and diastolic blood pressure(p=.004. p= .003) of test group, which investigate at 6 and 24 hours since mastectomies, will be bigger than that of control group, was established. Third, it showed that there is a significant difference between sleep satisfaction of test group and that of control group(p=.000). In result, the fourth hypothesis, sleep satisfaction of test group. which examine in the morning after mastectomies, will be bigger than that of control group, was established. In the result. a foot reflex zone massage is seen to be effective in the pain reduction and sleep promotion of patients who are operated on breast cancer, and in providing them with more qualitative care by improving confidence between them and nurses through a physical touch. Also, it can be applied to a clinical examination through an independent nursing intervention.

• Journal of the Korean Society of Radiology
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• v.13 no.6
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• pp.873-878
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• 2019

Cerebrovascular disease is one of the three major causes of death in Korea. Since these diseases are associated with atherosclerosis, the diagnosis of atherosclerotic factors should be presented. In this study, we evaluated the relationship between brachial-ankle arterial pulse wave velocity, cerebral artery vascular stenosis, blood pressure, obesity, and abdominal obesity by age group. The significance of cerebral artery stenosis and age group. The risk factors of atherosclerosis, such as blood pressure, obesity, and abdominal obesity, were significant in all age groups. When the pulse wave velocity of the brachial-ankle artery was increased, the cerebral artery stenosis was distributed in 57.3% of the total test subjects. If the arterial stiffness is suspected during the measurement of the pulse wave velocity of the brachial ankle artery, We recommend suspected vascular stenosis and perform a cerebral artery angiography. It is suggested that the data will be used as a baseline data for similar studies after evaluating the significance of blood pressure, obesity, and abdominal obesity as risk factors of atherosclerosis.