• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권12호
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• pp.567-572
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• 2005

Recently, application area of the thyristor is extends to power conversion systems, such as HVDC, BTB, SVC and FACTS. Therefore, reliability diagnostic technique on thyristor is needed to obtain stability and maintenance of power conversion systems. To measure the characteristics of the thyristor, test equipments which based on IEC 747-6 and KS C 7023 standard are needed. In this paper, we presents the design and manufacture of the test equipments for 6.5kV/4.2kA thyristor which used in thyristor valve of HVDC conversion systems by using test standard. Voltage, current, dv/dt and turn-off time test equipments were designed and manufactured. Each systems were made separately, but unity operation can possible.

• 한국대기환경학회지
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• 제11권4호
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• pp.315-321
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• 1995

The purpose of this report is to describe the lidar measurement of depolarization ratios of particulate matter (Depolarization Ratio of Yellow Sand) and to discuss the transformation of aerosols due to Yellow Sand event. The scattering profile shows high level during Yellow Sand event and scattering layers are thicker as compared to other seasons in about 3 .sim. 8km, and the values and mode height of scattering ratio corresponed with depolarization ratio. A distribution of total depolarization ratio during the observation period was 44.7 percent among total cases of 0.03 < Dt < 0.5 with scattering ratio > 30 and relative humidity < 30 was satisfied (popular Yellow Sand type).

• 대한소아치과학회지
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• 제23권4호
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• pp.925-930
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• 1996

The purpose of this study was to know whether the information of caries activity and caries experience of the children can be used to predict the behavior of the children during the dental treatment. The subjects of the study were one hundred and eighty-one preschool children, three to six years old. Salivary reductase activity was tested by the Resazurin Disc Test. Caries experience was examined. The children's behavior was observed using the rating scale of Frankl. Salivary reductase activity of the negative behavior group was slightly higher than that of the positive behavior goup, but the difference was not significant. dt index and ds index of the negative behavior group were significantly higher than those of the positive behavior group. There were no significant differences in ft index and fs index between the two behavior groups. The results suggest that the negative behavior of a child can be predicted when the child has many untreated dental caries.

• 대한조선학회지
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• 제19권4호
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• pp.19-29
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• 1982

Galerkin's finite element method is applied to a two-dimensional heat convection-diffusion problem arising in the hydrodynamic lubrication of thrust bearings used in naval vessels. A parabolized thermal energy equation for the lubricant, and thermal diffusion equations for both bearing pad and the collar are treated together, with proper juncture conditions on the interface boundaries. it has been known that a numerical instability arises when the classical Galerkin's method, which is equivalent to a centered difference approximation, is applied to a parabolic-type partial differential equation. Probably the simplest remedy for this instability is to use a one-sided finite difference formula for the first derivative term in the finite difference method. However, in the present coupled heat convection-diffusion problem in which the governing equation is parabolized in a subdomain(Lubricant), uniformly stable numerical solutions for a wide range of the Peclet number are obtained in the numerical test based on Galerkin's classical finite element method. In the present numerical convergence errors in several error norms are presented in the first model problem. Additional numerical results for a more realistic bearing lubrication problem are presented for a second numerical model.

• 대한소아치과학회지
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• 제25권1호
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• pp.152-156
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• 1998

The purpose of this study was to investigate the prevalence rate of the nursing caries in preschool children by retrospective epidemiological survey. 500 preschool children in Iksan city were examined for their dental caries experience (dt, mt, ft). Subjects were divided stepwise by the pattern of caries experience: Group 1-no caries, Group 2-no caries in the upper arch, Group 3-no caries among the upper incisors, Group 4-dmft in the lower arch $\geq$ mft in the upper arch, Group 5-dmft among the upper molars > dmft among the upper incisors, Group 6-dmft among the upper molars < dmft among the upper incisors+caries among the lower incisors, and Group 7-the rest. Groups 6 was regarded as the group which had experienced rampant caries, and the Group 7 was regarded as the group which had the typical pattern of nursing caries. The prevalence rate of nursing caries (Group 7) was 16.0%.

• 산업경영시스템학회지
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• 제18권35호
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• pp.1-8
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• 1995

Automatic inspection system software for display image characteristic of CRT is developed. There are two major contributions of this software development. One is that the data from measuring equipments which was usually collected manually is automatically collected through RS-232C port and is saved in computer, then, trend analysis graph and final reports are generated. The other is that evauation of characteristic of electron gun was automatically processed by CCD camera and image processing technique. The system is developed under MS-Windows environment utilizing Borland C++4.0 Compiler and DT 3852-8 image processor board. This system can save the time and man power to measure and to anayze the image characteristics relative to current method.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2023년도 추계학술발표대회
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• pp.1220-1223
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• 2023

폐기물을 처리하는데 있어 배출과 수거에 대한 프로세스 자동화를 위해 폐기물 객체 유사도 판별이 요구된다. 이를 위해 본 연구에서는 폐기물 데이터셋에서 SIFT(Scale-Invariant Feature Transform)와 HSV(Hue, Saturation, Value)기반으로 두 이미지의 공통된 특징을 추출해 융합하고, 기계학습을 통해 이미지 객체 간의 유사도를 측정하는 모델을 제안한다. 실험을 위해 수집된 폐기물 데이터셋 81,072 장을 활용하여 이미지를 학습시키고, 전통적인 임계치 기반 유사도 측정과 본 논문에서 제시하는 유사도 측정을 비교하여 성능을 확인하였다. 임계치 기반 측정에서 SIFT 와 HSV 는 각각 0.82, 0.89(Acc)가 측정되었고, 본 논문에서 제시한 특징 추출 방법을 사용한 기계학습의 성능은 DT(Decision Tree)와 SVM(Support Vector Machine) 모두 0.93 (Acc)로 4%의 정확도가 향상되었다.

• 한국식품위생안전성학회지
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• 제23권2호
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• pp.129-136
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• 2008

Three benzimidazole pesticides commonly used in korean lettuce were subjected to a field residue trial to ensure safety of terminal residue in the harvest. The residual patterns of three benzimidazole pesticides, which were carbendazim, benomyl and thiophanate-methyl were examined after applying with the recommended dose in two types of korean lettuce (Chima and Chuckmeon) and their DT50 were calculated. In Chima lettuce, biological half-lives of carbendazim, benomyl and thiophanate-methyl were 2.56, 1.37 and 2.54 days, respectively and their required time under MRL(5.0 mg/kg as carbendazim) were 4.5, 2.2 and 1.0days. In Chuckmeon lettuce, biological half-lives of them were 3.41, 1.70 and 4.20 days, respectively and their required time under MRL were 5.4, 1.9 and 0.5days.

• 한국동물위생학회지
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• 제24권1호
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• pp.69-82
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• 2001

The result of studying the pathogenicity of Salmonella typhimurium and S enteritidis isolated from domestic animals in Gyeongbuk province were summarized as follows. In Congo-red binding test, S typhimurium had much more rough types than S enteritidis. In colicin production test, 4 strains of S typhimurium were positive but all of S enteritidis were negative. In hemolysin production test, all of S typhimurium and S enteritidis were negative. In Guinea pig serum resistant test, all of S typhimurium and S enteritidis were positive. As a result of pathogenicity test to mice, 54.4% of mice were died. Therefore, S typhimurium and S enteritidis were considered as highly pathogenic. S typhimurium DT104 and S enteritidis PT4 were more pathogenic to mice than other phage types of same serovar. S typhimurium and S enteritidis were considered not so pathogenic for 6-day-old chickens. The recovery rates of Salmonella stains from mice and chickens inoculated were 96.8%, and 54%, respectively. In chickens, proportional to the time from 2 weeks after challenge inoculation, the recovery rates were noticeably decreased.

• 전기전자학회논문지
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• 제25권1호
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• pp.15-24
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• 2021

본 논문에서는 CDT(Conventional Double Trench) MOSFET보다 스위칭 시간과 손실이 적은 1700 V EPDT(Extended P+ shielding floating gate Double Trench) MOSFET 구조를 제안하였다. 제안한 EPDT MOSFET 구조는 CDT MOSFET에서 소스 Trench의 P+ shielding 영역을 늘리고 게이트를 N+와 플로팅 P- 폴리실리콘 게이트로 나누었다. Sentaurus TCAD 시뮬레이션을 통해 두 구조를 비교한 결과 온 저항은 거의 차이가 없었으나 Crss(게이트-드레인 간 커패시턴스)는 게이트에 0 V 인가 시에는 CDT MOSFET 대비 32.54 % 줄었고 7 V 인가 시에는 65.5 % 감소하였다. 결과적으로 스위칭 시간 및 손실은 각각 45 %, 32.6 % 줄어 스위칭 특성이 크게 개선되었다.