• 한국재료학회지
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• 제24권8호
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• pp.429-433
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• 2014

As the fabrication technology used in FPDs(flat-panel displays) advances, the size of these panels is increasing and the pattern size is decreasing to the um range. Accordingly, a cleaning process during the FPD fabrication process is becoming more important to prevent yield reductions. The purpose of this study is to develop a FPD cleaning system and a cleaning process using a two-phase flow. The FPD cleaning system consists of two parts, one being a cleaning part which includes a two-phase flow nozzle, and the other being a drying part which includes an air-knife and a halogen lamp. To evaluate the particle removal efficiency by means of two-phase flow cleaning, silica particles $1.5{\mu}m$ in size were contaminated onto a six-inch silicon wafer and a four-inch glass wafer. We conducted cleaning processes under various conditions, i.e., DI water and nitrogen gas at different pressures, using a two-phase-flow nozzle with a gap distance between the nozzle and the substrate. The drying efficiency was also tested using the air-knife with a change in the gap distance between the air-knife and the substrate to remove the DI water which remained on the substrate after the two-phase-flow cleaning process. We obtained high efficiency in terms of particle removal as well as good drying efficiency through the optimized conditions of the two-phase-flow cleaning and air-knife processes.

• 자원ㆍ환경경제연구
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• 제30권3호
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• pp.471-501
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• 2021

본 연구는 투입물 거리함수에 의한 메타확률 프런티어 방법을 사용하여 1998년부터 2018년까지 4개 소득그룹의 이산화탄소 기준의 환경효율성(EE)을 측정하였다. 에너지 소비가 이산화탄소 배출을 증가시키고, 노동과 자본투입을 증가하면 이산화탄소 배출을 감소시킬 것임을 보여주고 있다. 또한 그룹환경효율성(GEE: Group Environmental Efficiency), 메타환경효율성(MEE: Meta Environmental Efficiency) 및 환경격차(EGR: Environmental Gap Ratio)를 비교하였다. 결과는 GEE가 과대평가되고 MEE는 이 기간 동안 하향세를 보여주고 있다. 중하위 소득그룹의 EGR은 가장 높았다. 그리고 고소득 및 중상위 소득그룹의 MEE 및 EGR이 상대적으로 낮았다. 환경효율성을 높이려면 화석에너지를 저감하고 기준 환경 문제를 해결하는 방법이 보다 과학적이고 기술적인 방법을 찾아 필요가 있음을 시사한다.

• 디지털융복합연구
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• 제14권10호
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• pp.137-145
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• 2016

스마트기기 대중화에 따른 소셜 네트워크 서비스의 폭발적인 증가로 온라인상의 관계와 활동이 오프라인상의 실생활까지 영향을 미침에 따라 온라인상의 소셜 네트워크 활동에 대한 관심과 중요성이 지속적으로 증가하고 있다. 본 연구에서는 SNS 활동에 영향을 미치는 요소를 대상(object, 사용자(User), 영향력 방향(Influence direction), 영향력 강도(Influence distance) 4가지 요소로 정의하고 SNS 사용자 상호간 영향을 유기적 관점에서 측정하는 방법을 제안하였다. 기존 영향력 측정 요소를 반응횟수, 친구의 수, 접촉횟수 등 정형 데이터와 원인시간과 반응시간의 차이, 호감도, 반응의 유형 등 비정형 데이터까지 확대하여 영향력 방향(Influence Directio)과 영향력 강도(Influence Strength or Distance)의 측정 기법을 정교화 하였다. 또한, 영향력 측정을 위한 data를 수집하고 분석하는 시스템과 facebook으로 수집한 sample data를 이용한 영향력 측정 기법 프로세스를 실험하고 구현 가능성을 설명하였다.

• Journal of Forest and Environmental Science
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• 제37권1호
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• pp.62-68
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• 2021

Despite numerous efforts on reducing road-kill worldwide, the collisions have been occurring continuously. Many factors are affecting road-kill occurrences and the effect is various by species. We investigated Hydropotes inermis argyropus road-kill characteristics on the national highway. We examined 9,099 H. i. argyropus road-kill points with distance to the gaps on road (interchange and intersection) and distance to six natural land-cover types as explanatory variables. We also examined the number of road-kill occurrences according to temporal variation using chi-square test with 9,658 events. In general, H. i. argyropus road-kill location tended to occur close to the gaps on road, agricultural lands and forests. The average distance from road-kill to the gap was 694.7 m and 78.6% of the collisions were occurred within 1 km from the gaps. In addition, Kruskal-Wallis test showed the distance between road-kill points and each land cover and the gaps was significantly different. The temporal analyses showed that the differences of the H. i. argyropus road-kill frequency are significant in both month and season. Our results implies H. i. argyropus road-kill location tended to occur close to the gaps on road, agricultural lands and forests in general, especially during May and June, according to their seasonal behavior. Thus, we suggest there is a need of concentrated management on the roads with specific characteristics for both wildlife and human safety.

• 대한교통학회지
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• 제20권6호
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• pp.115-128
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• 2002

고속도로 합류부는 본선과 유입램프가 만나는 부분으로 유입교통에 의한 교통량의 증가로 빈번히 고속도로 상류부 혼잡의 원인이 되어 고속도로 운영관리에 있어 중요한 관심을 요구한다. 근래에 들어 이러한 합류부 교통류의 분석을 위하여 운전자의 다양한 운행행태를 고려하는 모의실험모형이 적용되어왔다. 그러나 현존하는 모의실험모형은 운전자의 운행행태가 주어진 교통상황에 따라 능동적으로 변하지 않아 상황에 따라 변하는 복잡한 합류부에서의 운전자 간격수락행태를 현실적으로 모사함에 문제가 있다. 본 연구에서 수행한 현장자료 분석을 통하여 진입차량의 간격수락행태는 정규분포를 따르며 '가속차로 상의 주행위치' 대 '가속차로 길이'의 비율에 의해 영향을 받아 그러한 정규분포의 평균과 분산이 변화하는 것으로 도출되었으며, 합류 운전자는 본선 주행 전방차량과의 간격보다 후방 차량과간의 간격에 더 많은 영향을 받는 것으로 도출되었다. 본 논문은 모의실험 전산모형으로의 적용을 위하여 현장자료를 토대로 개발된 새로운 합류 차량 간격 수락 행태 모형을 제시한다. 제시된 간격수락모형을 사용하여 수행된 모의실험 결과와 현장자료를 비교한 결과 합류 시(1)본선 밀도수준별 가속 차로에서 본선으로의 차로 변경 위치분포, (2)합류 시 본선 후방차량과의 간격분포, (3)본선 후방차량과의 상대속도가 95% 신뢰수준에서 현장자료(모형개발에 사용되지 않은 자료)와 통계적으로 동일한 것으로 분석되었다.

• 한국치위생학회지
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• 제7권4호
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• pp.405-418
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• 2007

The purpose of this study was to examine the interest level of mothers in oral health. The subjects in this study were 184 mothers whose children attended daycare centers in the city of K. A survey was conducted from March 15 through April 30, 2007, and SPSS WIN 11.5 program was employed to analyze their answer sheets. The findings of the study were as follows: 1. A group of mothers whose children brushed their teeth three times a day on the average made up 55.7 percent of those who were at the age of 35 and under. Among the mothers having three or more children, those mothers accounted for 59.1 percent. The daily mean toothbrushing frequency of children was higher among the better-educated mothers. 2. Concerning dietary and oral guidance, the mothers whose academic background was better curbed their children's excessive sugar intake more often, and the gap between them and the others was statistically significant(pE.05). As to the importance of oral health by the number of child and academic credential, those who had two children(36.0%) taught them the importance of oral health frequently(pE.01), and the better-educated mothers taught about it often(pE.05). The gap between the groups and the others was significant. 3. As for experience of visiting dental institutions, the working mothers visited dental institutions more often than the stay-at-home mothers, and the gap between them was statistically significant(pE.05). Regarding purpose of the visit, the largest group aimed to get treatment(64.6%), followed by having a dental checkup(14.6%) and receiving preventive treatment(13.5%). As to any inconveniences in using dental institutions, those who were working and who were in the upper income bracket found it more inconvenient to do that because of a long distance or time constraints. The gap between them and the others was significant. 4. In regard to concern for dental care, the mothers who were better educated(pE.001) and whose family income was 3 million won or more had their teeth scaled more often, and the gap between them and the others was statistically significant(pE.01). The rate of the regular visitors of dental institutions stood at 32.7 percent of the junior-college graduates, 31.0 percent of the mothers receiving college or higher education and 10.1 percent of the high-school graduates(pE.01). And those who earned larger income paid a visit to dental institutions more often and on a regular basis. The gap between them and the others was statistically significant(pE.05).

• 인지과학
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• 제25권2호
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• pp.109-133
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• 2014

관찰자가 대상이나 상황에 관해 느끼는 주관적인 간극을 심리적 거리라고 한다. 심리적 거리는 개인이 그 대상과 상황에 대해 취하는 의사결정과 행위에 영향을 끼친다. 본 연구는 친숙감의 수준이 심리적 거리의 형성에 끼치는 효과를 탐색하였다. 친숙한 자극이 덜 친숙한 자극에 비해 심리적으로 더 가깝게 느껴진다면, 자극이 유발하는 친숙감 수준이 자극의 지각된 공간적 거리와 상호작용할 것으로 예상하였다. 각 실험에서 참가자들은 먼저 사전 노출 단계에서 세 개의 무의미 단어를 경험하였다. 선행연구들에 따르면 친숙감은 자극의 노출 횟수와 지각적 유창성(perceptual fluency)의 영향을 받는다. 따라서 참가자들이 단어 판단 과제를 수행하는 동안, 무의미 단어들은 각기 다른 수준의 빈도(실험 1)와 선명도(실험 2)로 제시되었다. 그 다음 단계에서 참가자들은 가장 친숙한 무의미 단어와 가장 덜 친숙한 무의미 단어를 가지고 거리 스트룹 과제를 수행하였다. 각각의 단어들은 깊이 단서가 분명한 장면 사진들 속에서 지각적으로 가깝거나 먼 장소에 출현하였다. 그 결과, 두 실험 모두에서 단어의 친숙감과 공간적 거리 간 상호작용이 유의미하였다. 친숙한 단어는 가까운 위치에서 제시되었을 때 빠른 판단반응을 유발하였고 상대적으로 덜 친숙한 단어는 먼 위치에서 제시되었을 때 빠른 판단 반응을 유발하였다. 이러한 결과는 친숙감에 대한 상위인지적 평가(metacognitive evaluation)가 심리적 거리의 형성을 뒷받침하는 주요 요인임을 의미한다.

• 한국재료학회지
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• 제13권3호
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• pp.137-143
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• 2003

The air gap between the metal and mold, formed by shrinkage during solidification, causes surface and subsurface cracks in the continuous casting process. Molten crack on the surface might also occur due to improper heat transfer between them. In order to compensate the air gap in mold design, the thermal contraction is an essential factor. In this study, the thermal contraction and expansion behaviors were examined from the ($\alpha$ and pearlite)/${\gamma}$ to ${\gamma}$/$\delta$ transformations in continuous casting steels by the commercial dilatometer and the self- assembled dilatometer with laser distance measurement. It was found that the thermal contraction and expansion behaviors were very dependant on the phase transformation of the ${\gamma}$/$\delta$ as well as ($\alpha$ and pearlite)/${\gamma}$. The sudden volume change from $\delta$ to ${\gamma}$ which might cause cracks in the continuous casting process, was observed on cooling just below the melting temperature by the self-assembled dilatometer.

• 한국전기전자재료학회논문지
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• 제30권9호
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• pp.589-595
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• 2017

MOS-FET structured gas sensors were manufactured using MWCNTs for application as NOx gas sensors. As the gas sensors need to be heated to facilitate desorption of the gas molecules, heat dispersion plays a key role in boosting the degree of uniformity of molecular desorption. We report the desorption of gas molecules from the sensor at $150^{\circ}C$ for different sensor electrode gaps (30, 60, and $90{\mu}m$). The COMSOL analysis program was used to verify the process of heat dispersion. For heat analysis, structure of FET gas sensor modeling was proceeded. In addition, a property value of the material was used for two-dimensional modeling. To ascertain the degree of heat dispersion by FEM, the governing equations were presented as partial differential equations. The heat analysis revealed that although a large electrode gap is advantageous for effective gas adsorption, consideration of the heat dispersion gradient indicated that the optimal electrode gap for the sensor is $60{\mu}m$.

• 한국정밀공학회지
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• 제30권5호
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• pp.513-519
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• 2013

Line scan camera has been widely used in the area of inspection of glass, film, fabric, iron, PCB and etc. due to the high resolution and the high speed. We developed the line scan based vision system to inspect tangled and cut-off status of yarn in the manufacturing process. The original image is binarized with a proper threshold, and the gap distances in the yarn are measured in real time, so finally the status of the process is decided by the maximum value of the gap distance. All procedures are executed in real time by realization of multi-processed threads. By implementation of this system, the error of the yarn in manufacturing process can be precedently monitored and the loss of the yarn is decreased efficiently.