• Journal of the Korean Data and Information Science Society
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• v.18 no.2
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• pp.327-344
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• 2007

Ridge partial least squares regression (RPLS) is a regression method which can be obtained by combining ridge regression and partial least squares regression and is intended to provide better predictive ability and less sensitive to overfitting. In this paper, explicit expressions for the shrinkage factor of RPLS are developed. The structure of the shrinkage factor is explored and compared with those of other biased regression methods, such as ridge regression, principal component regression, ridge principal component regression, and partial least squares regression using a near infrared data set.

• Journal of the Korean Data and Information Science Society
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• v.28 no.1
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• pp.1-10
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• 2017

Longitudinal data of Korean child academic achievement have been used to find the significant exploratory variables under the assumption of independent repeated measured data. Using the exploratory variables in previous research works, we analyze the linear mixed model incorporating the fixed and random effects for child academic achievement to detect the significant exploratory variables. Korea welfare panel study data observed three times between 2006 and 2012 by additional survey for children. The child academic achievement is evaluated by the sum of academic achievements of Korean, English and Mathematics. We also investigate the multicollinearity and the missing mechanism and select some popular correlation matrices to analyze the linear mixed model.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.412-427
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• 2016

댐의 건설은 자연하천에서 퇴적과 침식의 유사 순환과정에 영향을 주고 저수지 퇴사(reservoir sedimentation)를 야기한다. 이러한 현상은 댐의 건설 이후 장기간 축적되면서 이수와 취수에 대한 영향을 가져오기 때문에 댐 관리와 설계를 위해 정확한 추정이 필요하다. 퇴사량을 산정하는 방법에는 실측자료를 방법과 실제 유사량 자료를 이용하는 방법 그리고 경험공식을 이용하는 방법 등이 있으나, 가용한 자료의 부족으로 주로 경험 공식에 의존하고 있다. 이에 본 연구에서는 국내 대규모 다목적댐에 적합한 비퇴사량 산정 경험 공식을 제안하고자 하였다. 이를 위해 먼저 기존의 공식을 조사 및 검토하여 비퇴사량에 영향을 미칠 만한 여러 인자들을 선정하였다. 총 8개 국내 대규모 다목적댐의 비퇴사량 자료와 제원을 이용하여 다중 회귀분석을 실시하여 최종적인 식을 제안하였다. 그 결과, 대규모 다목적댐의 비퇴사량에 영향을 미치는 인자로 연평균 강우량(P, mm),연평균 유입량(I, cms), 유역 평균경사(S, %),저수지 길이(L, km),저수용량/유역면적(C/A, $m^3/km^2$)을 채택하였으며, 제안된 식을 이용하여 산정한 비퇴사량과 실측 비퇴사량의 상관계수와 결정계수는 각각 0.985, 0.970으로 확인되었다. 아울러, 다중 공선성 분석에서도 모두 일반적인 기준치를 범위 안에 존재함을 확인하면서, 선정된 독립변수들이 통계적으로 유의함을 확인하였다. 허나, 가용 자료의 부족과 불확실성으로 인해 여전히 한계점이 존재한다. 충분한 비퇴사량 실측 자료가 구축된다면, 보다 신뢰도 높고 발전된 형태의 경험 공식의 제안이 가능할 것이다.

• Industry Promotion Research
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• v.2 no.1
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• pp.69-75
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• 2017

In this study, 62 questionnaires were surveyed from November 3 to November 25, 2016 for workers who received more than one skill improvement training at Korea Polytechnic University. Factor analysis was done by removing 11 items out of 27 items and using the final 16 items, five factors were derived and the validity was confirmed with significance probability p = .000. Durbin-Watson values were 1.787 and 1.780, respectively. The results of this study were as follows: First, the effects of skill enhancement training on job attitude of Korea Polytechnic University were found as follows. First, the effects on job satisfaction were consistency of contents (p <.05, ${\beta}=.434$) (P <.05, p = .328), and the sense of belonging was significant (p <.05, p = .338). Second, the correlation between the skill improvement training and the turnover attitude shows that the efficiency of method - job satisfaction (.311), efficiency of method - clarity of purpose (.350), efficiency of method - suitability of content (.771) - content fit (.467), job satisfaction - content fit (.191), but the sense of belonging was not correlated. Third, the results of the difference in perception of turnover attitude according to years of service of technical improvement training at Korea Polytechnic University did not have a statistically significant effect. In this study, it is meaningful to investigate the effect of the skill improvement training on the attitude of turnover and its effectiveness.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.4
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• pp.255-262
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• 2018

In order to determine the three-dimensional position in photogrammetry, a spatial resection is a pre-requisite step to determine exterior orientation parameters. The existing spatial resection method is a non-linear equation that requires initial values of exterior orientation parameters and has a problem that a gimbal lock phenomenon may occur. On the other hand, the spatial resection using quaternion is a closed form solution that does not require initial values of EOP (Exterior Orientation Parameters) and is a method that can eliminate the problem of gimbal lock. In this study, to analyze the stability of the quaternion-based spatial resection, the exterior orientation parameters were determined according to the different layout of control points and were compared with the determined values using existing non-linear equation. As a result, it can be seen that the quaternionbased spatial resection is affected by the layout of the control points. Therefore, if the initial value of exterior orientation parameters could not be obtained, it would be more effective to estimate the initial exterior orientation values using the quaternion-based spatial resection and apply it to the collinearity equation-based spatial resection method.

• Journal of the Korean association of regional geographers
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• v.11 no.6
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• pp.559-570
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• 2005

The purpose of this paper is to estimate the effect of population change on waste emission in the case of Busan City. The results are as follows : First, population and waste emission in Busan City Show decreasing pattern since 1995. According to increase or decrease of population and waste emission, The 16 Gus in Busan City are categorited into 5 types. Comparing the difference of population and waste emission between 1995 and 2003, we find out a similar trend by 16 Gus in Busan City. Second, the waste emission shows the positive relation with the number of population and the land by use. But there exists multicollinearity between population and the land by use, and the population is considered the main factor of waste emission. Third, the population causes 92% or more of the waste emission in Busan City, and future researches are required for the additional causes of waste generation.

• Journal of Korea Entertainment Industry Association
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• v.14 no.2
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• pp.97-107
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• 2020

This Study designed to examine the effects of participation motivation of Dance Sports Activation. The dance sports club participants were selected by systematic stratifies cluster random sampling method. The questionnaire was given to 320 members of badminton club members and engaging in the range activity from March 2019 to April 2019. After collecting the questionnaires, I exclude 20 unreliable questionnaires which were incomplete, incorrectly marked or double marked, and used 300 questionnaires for the study. The conclusion of this research was as follows: First, Participation motivation had a effect on enjoyment factor in dance sports club participants. Second, Participation motivation had a effect on exercise dependence in dance sports club participants. Third. Enjoyment factor had a effect on exercise dependence in dance sports club participants. It was concluded that participation motivation would be beneficial for enjoyment factor and exercise dependence in dance sports club participants.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.91-94
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• 2012

본 논문에서는 3D 콘텐츠 제작에 있어 입체피로를 최소화하기 위한 영상의 수직시차 제거과정에 있어 사진측량기반의 강인기법을 제안하고자 한다. 영상의 수직시차 제거 과정은 크게 기하추정 단계와 에피폴라 변환 단계로 구성된다. 본 논문에서는 기하추정을 위해 사진측량에서 널리 활용되고 있는 공면조건 기반 상대표정 알고리즘을 적용한다. 이 때 상대표정 알고리즘에는 자동 정합점 추출에 따른 오정합과 위치오차에 강인성을 확보하기 위해 제약조건을 도입한 베이지안 접근방식을 적용하고자 하며, 이를 바탕으로 수행되는 에피폴라 변환에는 영상의 왜곡과 원 영상 대비 변형을 최소화하기 위해 공선조건기반의 중심투영변환기법을 적용하고자 한다. 알고리즘의 성능검증을 위한 비교 알고리즘으로, 기하추정에는 8점 알고리즘과 스테레오 캘리브레이션 기법이 사용되었으며 에피폴라 변환에는 Hartley 방법과 Bouguet 방법이 사용되었다. 실험결과는 제안알고리즘의 높은 정확도와 강인성, 그리고 활용적 가치를 보여주었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.212-212
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• 2010

최근 차세대 반도체 메모리 소자로 대두된 magnetic random access memory(MRAM)에 대한 연구가 활발히 진행되고 있다. 특히 MRAM의 magnetic tunnel junction(MTJ) stack을 구성하는 자성 재료의 건식 식각에 대한 연구에서는 좋은 profile을 얻고, 재층착의 문제를 해결하기 위한 노력이 계속해서 진행되고 있다. 본 연구에서는 photoresist(PR)과 Ti 하드 마스크로 패턴 된 배리어(barrier) 층인 MgO 박막의 식각 특성을 유도결합 플라즈마를 이용한 고밀도 반응성 이온 식각(inductively coupled plasma reactive ion etching-ICPRIE)을 통해서 연구하였다. PR 및 Ti 마스크를 이용한 자성 박막들은 HBr/Ar, HBr/$O_2$/Ar 식각 가스의 농도를 변화시키면서 식각되었다. HBr/Ar 가스를 이용 식각함에 있어서 좋은 식각 조건을 얻기 위한 parameter로서 pressure, bias voltage, rf power를 변화시켰다. 각 조건에서 Ti 하드마스크에 대한 터널 배리어층인 MgO 박막에 selectivity를 조사하였고 식각 profile을 관찰하였다. 식각 속도를 구하기 위해 alpha step(Tencor P-1)이 사용되었고 또한 field emission scanning electron microscopy(FESEM)를 이용하여 식각 profile을 관찰함으로써 최적의 식각 가스와 식각 조건을 찾고자 하였다.

• Journal of Preventive Medicine and Public Health
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• v.34 no.2
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• pp.103-108
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• 2001

Recently, numerous studies have focused on the health effects of ambient particulate pollutants. Compared to earlier studios that focused on severe air pollution episodes, recent studies are more relevant to understanding the health effects of air pollution at levels common to contemporary cities. We reviewed recent epidemiologic studies that evaluated health effects of particulate air pollution and concluded that respirable particulate air pollution is an important contributing factor to acute mortality and morbidity. We observed increased respiratory and cardiovascular deaths, increased hospital admissions and visits, and decreased lung function. We also observed increased mortality and morbidity in a Korean population. Theses health effects were observed at levels below the current Ambient Air Quality Standard for particulate air pollution.