• The Korean Journal of Applied Statistics
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• v.22 no.5
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• pp.981-993
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• 2009

It would cause a serious problem in the panel data when panel attrition is concentrated on certain socioeconomic groups. Using the GOMS, this study investigates whether there exists non-random attrition bias in the data and seeks for feasible solutions to minimize the bias. The results of logit analyses show that panel attrition in the GOMS results mainly from surveying system but not from the surveyed. Therefore, the result suggests to develop well-organized management skill and systems as well as to construct weighting methods.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.1
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• pp.1-8
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• 2005

This paper presents the experimental results measured by photoelastic 4-step phase shifting method for the isochromatic fringe distribution in a TV glass panel. In the conventional photoelastic method, the isochromatic fringe orders are measured manually point by point. The 4-step phase shifting method uses four images obtained from a circular polariscope by rotating the analyzer to $0^{\circ},\;45^{\circ},\;90^{\circ}$, and $135^{\circ}$. In order to use the 4-step phase shifting method, the elements of a polariscope should be aligned to isoclinic direction at a point and/or along a line where isochromatic fringe distribution is measured. Experimental results obtained from the 4-step phase shifting method are compared with those measured by the Senarmont compensation method. Both results are well agreed. Then, isochromatic fringe distributions in the TV glass panel that is heat-treated before and after are compared. Maximum and minimum isochromatic fringe orders in the TV glass panel with before- and after-heat treatment are changed approximately two times.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.103.2-103.2
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• 2015

10-3 Pa 이하의 고진공 환경과 $180^{\circ}C$ 이하의 극저온 환경에서 대형정지궤도위성의 고온 열평형 환경구현을 위한 열제어패널이 설계되었다. 열제어패널은 가로 2.2 m, 세로 2.6 m, 두께 2 mm의 구리판에 구리 튜브가 브레이징되어 있는 형태로 설계되었으며, 지상에서 6 m 이상의 높이에 설치되고 위성의 위치에 따라 이동이 가능해야 하기 때문에, 별도의 지지 구조물이 함께 설계되었다. 따라서, 열제어패널 설치 및 고정을 위한 지지구조물의 경우 160 kg의 무게를 견뎌내야 하며 이동 및 설치에 있어 구조적인 안전성이 확보 되어야 한다. 이에 본 연구에서는 상용유한요소해석 프로그램을 사용하여 열평형시험 시 위성체 상단부의 고온 환경모사를 위한 열제어패널 지지구조물에 대한 구조 안전성을 확인 하였다.

• Information Display
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• v.8 no.3
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• pp.12-17
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• 2007

유기박막트랜지스터(OTFT)는 지난 십 수년 간 개발되어 상용화의 단계에 도달하여 우선적으로 플렉시블 디스플레이에 적용될 것으로 예상된다. 본 논문에서는 EPD와 OLED의 구동소자로서 OTFT를 사용한 플렉시블 디스플레이 패널 제작에 대해서 살펴본다. EPD와 OLED는 소자의 구조와 특성이 다르기 ��문에 OTFT 어레이와 집적화 시 고려해야 할 요소들도 다르다. EPD는 문턱전압이 없으므로 스위칭 소자로서 OTFT가 반드시 필요하다. 또한 전압구동소자이고 동작이 느리기 ��문에 OTFT의 이동도가 $0.01cm^2/V.sec$ 이상만 되어도 사용 가능하고 쌍안정 소자임에도 불구하고 저장 캐패시터를 사용하여야 한다. 그리고 OTFT 패널과 EPD 패널을 상호 부착해야 하므로 OTFT 어레이에 영향을 주지 않는 중간층이 중요한 요소이다. OLED는 전류구동소자이므로 OTFT의 이동도가 최소 $0.1cmcm^2/V.sec$ 이상이어야 하고, OTFT 어레이와 동일한 패널을 사용하므로 제조 공정의 호환성이 필수 요건이다.

• Proceedings of the Korean Association for Survey Research Conference
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• 2000.11a
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• pp.171-200
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• 2000

한국노동패널조사(Korea Labor and Income Panel Study)는 비농촌지역에 거주하는 한국의 가구와 가구원을 대표하는 패널표본구성원(5,000가구에 거주하는 가구원)을 대상으로 1년에 1회 경제활동 및 노동시장 이동, 소득 활동 및 소비, 교육 및 직업훈련, 사회생활 등에 관하여 추적 조사하는 종단면 조사(longitudinal survey)이다. 매년 반복적인 조사를 통해 표본가구구성원들에 대한 다양한 내용의 정보를 수집하는 가운데 조사년수가 늘어가면서 표본가구원 개인들의 생애과정(Life Course)에 걸친 단계별 변화와 이동의 이력, 특히 학교교육력(Schooling History), 취업력(Work History) 혹은 노동시장이동(Labor Market Transitions) 과정이 구축될 수 있을 것이다. 조사구의 추출방법은 계통추출방법을 사용하였으며, 제주도를 제외한 전국의 시부만을 대상으로 1,000개의 조사구를 선정하고, 각 조사구내에서는 97년 고 3965;의 조사대상가구 중에서 5가구를 임의 선정(random sampling)하였다.다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1376-1380
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• 2007

The charged particle type display have characteristics of high contrast ratio and wide viewing angle, quick response time. We used the yellow(-) and the black(+) colored particles, which is respectively addressed to the cells of upper and rear panel by using electric field. Our independent addressing method has strong points compared to the mixed particle putting method. After addressing, we packaged two panels and did aging process, and then panel is driven by matrix method of four channel electrodes. Layers of particles are controlled by height of cell barriers and needed minimum two layers. When positive voltage is applied to the upper electrode, the yellow particles with negative charge move toward the upper substrate and the black particles with positive charge move toward opposite direction.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.4
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• pp.45-52
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• 2009

We proposed a new pixel circuit and driving method for the large-area, high-luminance AMOLED applications in this study. We designed with the low-temperature poly-silicon(LTPS) thin film transistors(TFTs) that has poor uniformity but stable characteristic. To improve the uniformity of an image, the threshold voltage($V_{TH}$) and the mobility of the TFTs can be compensated together. The proposed method overcomes the previous methods for mobility compensation, and that is profitable for large-area applications. Black data insertion was introduced to improve the characteristics for moving images. AMOLED panel can operate in two compensation mode, so the luminance degradation by mobility compensation can be released. The scan driver for controlling the pixel circuits were optimized, and the compensation mode can be controlled simply by that. Final driving signal has large timing margin, and the panel operates stably. The pixel circuit was designed for 14.1" WXGA top-emission ANGLED panel. The non-uniformity of the designed panel was estimated under 5% for the mobility compensation time of 1us.

• Journal of Labour Economics
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• v.35 no.2
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• pp.25-41
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• 2012

This paper estimates the intergenerational income mobility of Korea by applying the new errors-in-variable correction methods to recent waves of the Korea Labor and Income Panel Study. The intergenerational income elasticity estimates ranged from 0.24 to 0.34 show a substantial intergenerational income association in Korea and an upward trend over time.

• Korea Real Estate Review
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• v.28 no.3
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• pp.79-94
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• 2018

This study analyzed the factors associated with residential mobility based on the data from the 11th to the 19th wave of the Korean Labor & Income Panel Study (KLIPS). After grouping low-income households within the first to the fourth income bracket into households that exhibited no income bracket change and those with income bracket changes during the research period, this study examined the effects of the income situation of each group on residential mobility. According to the results of the analysis, in the group of households that showed no low-income bracket change, significant effects were found only in the age of the head of the household, housing cost, and rental deposit (Jeonse) and monthly rental of the household. In the group of households that showed low-income bracket changes, findings were generally in line with those of the whole household, where total income and the number of full-time employees in the household were the same as those of the whole household, indicating that it would be necessary to improve the employment stability of low-income households. Based on the findings of this study, housing inequality is intensifying within low-income households, and, thus, housing policies, based on continuing surveys, must be implemented to enhance income opportunities and stabilize the housing needs of low-income households.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.672-680
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• 2017

A solar photovoltaic system is composed of a module mounting structure, supporting trunk, and a control unit that supplies generated electrical power to an external power grid or a load. The efficiency of the system depends on the incident solar light, so the mounting structure is installed to face the sun. However, because the sun always moves, systems that track the sun have better efficiency than fixed systems. The structure experiences wind pressure, snow load, seismic load, and structure weight. The wind pressure has the most serious effect on the structure. The pressure was obtained using finite element method for various gaps between modules and angles between the panel and the ground. The wind pressure is lowest when the gap is zero, and it increases with the inclination angle. Based on the results, a mounting structure module was designed.