• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1996-1998
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• 2000

In this paper, the electric and magnetic field waveforms produced by cloud-to-groud lightning discharges were measured and statistically analyzed. The measuring system used to measure the electric and magnetic fields is consisted of the hemisphere electric field sensor, the loop magnetic field sensor and the data acquisition system. The stepped leader is appeared before the return stroke. Some parameters of the electric and magnetic fields produced by the stooped leaders in cloud-to-ground lightning discharges were investigated.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 춘계학술대회 논문집
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• pp.581-585
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• 2004

The wave shapes of electromagnetic pulses radiated from lightning discharges are significantly changeable one of the topics concerning on EMI/EMC of modern electronic systems is the efficient and economic protection of electronic circuits against transient voltages caused by not only by cloud-to-ground lightning but also by intracloud lightning discharges. In this work, in order to obtain the detailed information about lightning electromagenetic pulses, the electromagnetic pulses radiated from intracloud lightning discharge processes were measured and analyzed statistically.

• 대한전기학회논문지
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• 제37권1호
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• pp.63-68
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• 1988

The V-I characteristics of low pressure discharges occurring between each of three kinds of anode and a fixed hot cathode in several bi-cusp magnetic fields are investigated. The results are different from those in non-magnetic fields as follows` First, both breakdown and maintaining potentials of low pressure discharges in the fields are rather depend on the arrangement of the directions of magnetic lines of force and the directions between two electrodes than on the distance between two electrodes or the size of the electrodes. Second, the maintaining potentials of the discharges in the fields are lower than those in the non-fields, and the electrical conductivity in the fields are better than those in the non-fields. Third, the breakdown potertials in the fields when the direction of magnetic lines of force is perpendicular with the direction of discharging path between two electrodes are higher than those when the two directions are parallel with each other. But the maintaining patentials in the fields are shown the contrary phenomena with before. This results are particularily conspicuous as the separatrix of the fields pass across the discharging path between two electrodes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2126-2128
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• 2005

In this paper, it was investigated the applicability of TF analysis for the discrimination of air corona in on-site PD measurement. For the purpose, single and multiple discharges combined with oil discharges and air corona were generated and measured by use of artificial models and HFPD pulse detector. Through the TF analysis, data clusters could be classified each other in the TF Map, even in the case of multiple discharges. Therefore, it is known that TF analysis could be applied for the improvement of on-site PD measurement.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2135-2137
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• 2005

This paper describes the features of electric and magnetic fields produced by lightning discharges. The measuring system consists of fast electric field sensor, crossed-loop magnetic field sensors, signal processing circuit, A/D converter and data acquisition equipment with a 12bit resolution and 10[MS/s] sampling rate. The frequency bandwidth and responsitivity of the electric field measuring system were 40[Hz]${\sim}$2.6 [MHz] and 2.08 (V/m/mV) and those of the magnetic field measuring system were 400[Hz]${\sim}$1[MHz] and 2.78[nT/mV], respectively. The electric and magnetic fields produced by lightning discharges were observed, and the features and parameters of the waveforms were analyzed.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1999년도 추계학술대회논문집
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• pp.243-252
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• 1999

Recently several research groups using CORMIX, approved by EPA, have been working on the hydrodynamic mixing processes due to the ocean discharges. It provides a useful tool for analyzing near field mixing characteristics through the outfall system. This paper applies CORMIX 1 & 2 to the Pusan Jungang Effluent Outfall System, which is planned to be in the Gamchun harbour and will be completed in 2011. This model output shows the trajectoral variation of dilution and concentration for three cases of outfall system. Dilution differences have been simulated and found the highest dilution condition under the different displacement of outfall system. On the basis of these outputs it will be proposed the optimum outfall system type and location. This approach might contribute on protecting the serious water quality problem due to the ocean discharge.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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• pp.109-111
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• 2002

The fundamental principles of the operation of microwave discharges that are used to convert microwave energy to broad spectrum visual light are known. In this paper, emission dependance of microwave discharges in mixture content of sulfur with noble gases was studied. It is shown that the excitation of this gaseous mixture is carried out in two phases; (1) ionization of noble gas atoms by a microwave field and (2) the consequent maintenance of slightly ionized nonequilibrium plasma by the field. These two processes have essentially various thresholds for the microwave pump. The purpose of this work is to investigate spectral properties of the high frequency discharges in a mixture sulfur vapors with noble gases.

• Applied Science and Convergence Technology
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• 제26권4호
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• pp.74-78
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• 2017

The discharge characteristics of the radio frequency (RF) surface dielectric barrier discharge have been simulated for the investigation of the ratio of the ion transit time to the RF period. From one-dimensional particle-in-cell (PIC) simulation for a planar dielectric barrier discharge (DBD), it was observed that the high-frequency driving voltage confines the ions in the plasma because of a shorter RF period than the ion transit time. For two-dimensional surface dielectric barrier discharges, a fluid simulation is performed to investigate the characteristics of RF discharges from 1 MHz to 40 MHz. The ratio of the peak density to the average density decreases with the increasing frequency, and the spatiotemporal discharge patterns change abruptly with the change in the ratio of ion transit time to the RF period.

• 대한임상검사과학회지
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• 제49권3호
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• pp.294-299
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• 2017

이 연구의 목적은 중첩성 뇌전증을 발견하고, 처음 기록된 30분 뇌파 패턴을 통하여 경련 가능성을 알아보고자 한다. 국제표준 10~20법을 통하여 전극을 부착하였다. 2014년 1월부터 2015년 12월까지 중환자실에 입원한 경련 의심 환자를 대상으로 하였다. 뇌파의 패턴은 주기적 방전파, 전반적 주기적 방전파, 버스트 억제파, 초점 뇌전증파, 비대칭 배경파, 전반적 서파, 삼상성 형태의 일반화 된 주기적 방전파 등 7 가지 범주로 분류하였다. 원인별 분류는 5가지 범주로 구분하였다. 전체 128명 중 평균 나이는 $56.9{\pm}17.5$였고, 남:여 비율은 74:54명이였다. 평균 뇌파검사 기간은 $5.5{\pm}5.1$일 이었고 최장 33일 이였다. 주기적 방전파(N=7), 전반적 주기적 방전파(N=10), 버스트 억제파(N=6), 초점 뇌전증파(N=19), 비대칭 배경파(N=24), 전반적 서파(N=51), 3상 형태의 일반화 된 주기적 방전파(N=11)이었다. 중첩성 뇌전증 환자의 원인은 원발성 증상성(N=4), 급성원발성 증상성(N=9), 급성 증상성(N=6), 진행성 뇌병증(N=2), 열성경련(N=1)이었다. 지속적 뇌파모니터링 검사는 중첩성 뇌전증을 발견하는데 유용한 검사이고, 뇌파 패턴을 통하여 경련 발생 유무를 확인할 수 있었다.

• Journal of Preventive Medicine and Public Health
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• 제26권2호
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• pp.293-309
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• 1993

With expanded and extended coverage of the national medical insurance and fast growing health care expenditures, appropriateness of health service utilization and quality of care are concerns of both health care providers and insurers as well as patients. An accurate patient classification system is a basic tool for effective health care policies and efficient health services management. A classification system applicable to Korean medical information-Korean Diagnosis Related Groups (K-DRGs)-was developed based on the U.S. Refined DRGs, and the performance of the developed system was assessed in this study. In the process of the development, first the Korean coding systems for diagnoses and procedures were converted to the systems used in the definition of the U.S. Refined DRGs using the mapping tables formulated by physician panels. Then physician panels reviewed the group definition, and identified medical practice patterns different in two countries. The definition was modified for the differences in K-DRGs. The process resulted in 1,199 groups in the system. Several groups in Refined DRGs could not be differentiated in K-DRGs due to insufficient medical information, and several groups could not be defined due to procedures which were not practiced in Korea. However, the classification structure of Refined DRGs was retained in K-DRGs. The developed system was evaluated fur its performance in explaining variations in resource use as measured by charges and length of stay(LOS), for both all and non-extreme discharges. The data base used in this evaluation included 373,322 discharges which was a random sample of discharges reviewed and payed by the medical insurance during the five-month period from September 1990. The proportion of variance in resource use which was reduced by classifying patients into K-DRGs-r-square-was comparable to the performance of the U.S. Refined DRGs: .39 for charges and .25 for LOS for all discharges, and .53 for charges and .31 for LOS for non-extreme discharges. Another measure analyzed to assess the performance was the coefficient of variation of charges within individual K-DRGs. A total of 966 K-DRGs (87.7%) showed a coefficient below 100%, and the highest coefficient among K-DRGs with more than 30 discharges was 159%.