• Journal of the Korean Data and Information Science Society
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• v.27 no.1
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• pp.101-110
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• 2016

Depression is a mental symptoms that accompany psychological symptoms such as anxiety, gloom, a sense of failure, helplessness as well as a physical symptoms that shows in the adaption process of stress. Depression may result in cognitive, emotional, and behavioral disorders in accordance with individual experience. In particular, the depression when growing lowers the concentration on studies of children and adolescents and also increases the violence and interpersonal problems causes a serious loss to individuals and society. This study analyzed the longitudinal data using mixed models to investigate how depression affects girls who experienced violence in home or at school.

• Korea journal of population studies
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• v.28 no.1
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• pp.47-71
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• 2005

본 연구는 사망원인통계의 질과 밀접한 관련이 있는 사망진단서 첨부율이 지역간 큰 격차를 보인다는 사실에 기초하여 어떤 요인이 이 현상에 영향을 미치는지 파악하는 데 목적이 있다. 이를 위해 1991년부터 2000년까지 10개 년 간 6개 대도시 및 9개 시도의 지역별 사망진단서 첨부율과 각 지역의 사망자, 신고자 및 기타 지역 특성을 사망신고자료와 지역통계연보를 통하여 수집하였다. 이 패널자료를 분석함에 있어서 진단서 첨부율에 영향을 미치되 불가피하게 누락된 요인의 영향은 가변수를 사용하는 고정효과모형을 이용하여 보정하였다. 분석에 포함된 변수 중에서는 사망자의 교육수준과 병원사망자 비율이 사망진단서 첨부율의 지역별 차이를 낳는 주요 요인인 것으로 나타났다. 따라서 사망원인통계의 추가적인 질 제고를 위해서는 국가정책수립에 있어서 사망원인통계의 중요성에 대한 홍보 및 교육과 농어촌 벽지 및 도서 지역 등 의료이용이 여전히 어려운 지역에서의 의료기관 이용률 제고를 위한 노력을 기울여야 할 것이다.

• Proceedings of the KSRS Conference
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• 2009.03a
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• pp.202-206
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• 2009

본 논문에서는 X-band GB-SAR 시스템을 이용하여 지상을 모니터링 하였으며, 대기 중의 습도와 거리의 영향을 받는 대기보정 상수를 산출하였다. 시스템에서 X-band 안테나는 중심주파수 9.65 GHz, 밴드 폭 600 MHz이며, 신호의 증폭과 다편파 측정 및 분석을 위해 각각 마이크로파 앰프와 마이크로파 스위치를 이용하였다. Azimuth step과 length는 5 cm와 5 m로 최대 관측 거리는 약 200 m 이다. phase 분석에 쓰인 산란체는 총 5개의 trihedral corner reflector로서, 시스템으로부터의 거리를 각각 다르게 설정하였다. 실험은 3일간 연속적으로 수행되었으며, 실험간 상대습도는 최소 50 %에서 최대 90 %까지로 약 40 %의 변화를 보였다. 고정된 상태의 reflector는 마치 이동한 것과 같은 현상을 보였는데 이는 마이크로화의 전파과정에서 발생하는 거리와 습도에 따른 지연효과라고 판단하였으며, 이를 배제하기 위하여 대기보정식을 산출하였다. 산출과정에서 temporal coherence가 0.98 이하인 reflector의 신호는 제외하였는데 이 경우 시스템 및 reflector의 안정성에 문제가 있다고 판단하였기 때문이다. 산출된 대기보정식은 C-band 안테나를 사용한 실험과 비교하여 보았다.

• Journal of Labour Economics
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• v.32 no.3
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• pp.1-26
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• 2009

Using panel data from the Korean Labor and Income Panel Study(KLlPS), we examine the wage differentials between standard and Don-standard workers. To control for unobserved individual heterogeneities, we estimate the fixed effect models. Our results show that the OLS estimates are upwardly biased. We also find that labor unions and firm size are important determinants of the wage differentials.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.143-143
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• 2010

다결정 실리콘 (Poly-Si)은 LPCVD를 이용하여 $750^{\circ}C$에서 증착하였다. 증착된 실리콘 박막은 실란, 수소 및 헬륨 가스를 이용하여 증착하였다. 성장된 poly-Si의 특성은 Raman spectroscopy 및 SEM을 이용하여 분석하였다. 헬륨 가스의 양을 15 sccm으로 고정하고 실란과 수소의 가스비를 60:0에서 20:40까지 가변시켰다. 활성화 에너지는 전류-전압 측정을 통해 Arrhenius plot을 이용하여 계산하였다. 박막 트랜지스터는 quartz 기판 위에 제작되었다. 게이트 절연막으로 TEOS $SiO_2$를 이용하였으며 source 및 drain 전극으로 Al을 이용하였다. 이 때 제작된 박막 트랜지스터의 전류 점멸비, 전계 효과 이동도, SS 및 문턱 전압은 각각 $10^5$, $76\;cm^2/V-s$, 167 mV/decade 및 1.43 V이었다.

• Environmental and Resource Economics Review
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• v.27 no.3
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• pp.463-493
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• 2018

As the population structure of Korea changes with the increase of single households and elderly households, this may have effect on domestic energy consumption pattern. Our study analyzes whether the energy consumption of single and elderly households are distinguishable from those of general households. For empirical analysis, Household Energy Standing Survey panel data and regional fixed effect model are employed. The result strongly shows that single households consume more energy than other households. The consumption of single households from 40s to 60s was the highest. On the other hand, the effect of aging was different from energy sources. Electricity consumption of elderly household was more than other age groups, while oil consumption of elderly household was less than others. Gas and total energy consumptions turned out to be not much different among different age groups.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.26-32
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• 2019

The purpose of this study is to improve the running speed on a small-radius curved section on an existing train line. When the transition curve was extended, and the amount of movement in the horizontal direction tended to increase as the curve radius increased. The amount of increase in the transition curve extension was lowest when extending the curve radius, and the amount of horizontal movement was the lowest when changing the curve radius to a cosinusoidal curve. As a result of applying the pass rate after improvement to the Kyeongbu line, there was a time-shortening effect of 9.4 to 11.6% and a facial expression speed increasing effect when the curve radius was fixed and the transition curve was changed to a sinusoidal curve. In conclusion, the most effective way to improve the running speed on an existing train route is to change the image to concrete and to change the relaxation curve to a cosinusoidal curve. The amount of horizontal movement of the track is small, and the speed improvement effect is excellent.

• The Korean Journal of Applied Statistics
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• v.24 no.2
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• pp.373-381
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• 2011

This paper discusses how to get the sums of squares due to treatment factors when Type I Analysis is used by projections for the analysis of data under the assumption of a two-way ANOVA model. The suggested method does not need to calculate the residual sums of squares for the calculation of sums of squares. There-fore, the calculation is easier and faster than classical ANOVA methods. It also discusses how eigenvectors and eigenvalues of the projection matrices can be used to get the calculation of sums of squares. An example is given to illustrate the calculation procedure by projections for unbalanced data.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.5
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• pp.126-133
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• 2003

High performance induction motor drives are driven by two advanced control methods: vector control and direct torque control (DTC). In order to apply the control methods to the speed/position control systems, the informations on rotor speed and rotor or stator flux are required. The speed is measured by encoder, and the rotor or stator flux is estimated by using the motor parameters and measured currents. The control input generated on the basis of the information that is provided by abnormal sensors should be far from the desired value and deteriorates the overall control perfonnance. In this paper, the effects of sensor faults on the motor variables and the control performance of induction motor drives are analyzed by both theoretical approach and simulation study. The presented analysis results could be utilized for the purpose of developing a fault detection and isolation scheme in induction motor drives.

• International Area Studies Review
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• v.14 no.2
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• pp.79-105
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• 2010

This paper investigates empirically the impact of foreign investors on a firm's dividend and investment decision making in Korean stock market. Empirical results using the sample firms in non-financial firms listed in Korean stock market whose settlement month are December, we find that foreign investors who declared participation in management didn't exert significant impact on dividend increase. In the case of investment, foreign investors exerts significant impact on R&D investments. Using Hausman-Taylor Instrumental Variable method, we controlled endogeneity problem related with foreign ownership and dividend and investment policy. The contribution of this paper is that the purpose of foreign investors whether or not participate in management is the most critical point and the impacts of foreign investors on dividends and investment are different whether they participate in management or not.