• Industrial Engineering and Management Systems
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• 제1권1호
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• pp.73-78
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• 2002

In this paper, we propose a constrained optimization model for conjoint analysis (a preference decomposition technique) to improve parameter estimation by restricting the relative importance of the attributes to an extent as decided by the respondents. Quite simply, respondents are asked to provide some pairwise attribute comparisons that are then incorporated as additional constraints in a linear programming model that estimates the partial preference values. This data collection method is typical in the analytic hierarchy process. Results of a simulation study show the new model can improve the predictive accuracy in partial value estimation by ordinal east squares (OLS) regression.

• 대한교통학회지
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• 제13권1호
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• pp.35-62
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• 1995

Traffic has a very important function but has caused such social problems as traffic congestion parking and traffic accidents in metropolitan areas. It is difficult to examine the causes of traffic accidents related to human life, which occur by human, vehicle and environmental factors. But human factor is the only measure requlating these factors together an analyzing factors influencing establishment of counterplan of traffic accidents. Consequently , this study employs the principal component analysis and stepwise multiple regression analysis to estimate the characteristics and influential factors of traffic accidents and defines the typical patterns of happening lots of traffic accidents. Accordingly, this study establishes an acknowledgement model of the causes and preference model of the counterplan of traffic accidents using Multi-Dimension Preference(MDPREF) method.

• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.146-150
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• 2021

Plasma information based virtual metrology (PI-VM) that predicts wafer-to-wafer etch rate variation after wet cleaning of plasma facing parts was developed. As input parameters, plasma information (PI) variables such as electron temperature, fluorine density and hydrogen density were extracted from optical emission spectroscopy (OES) data for etch plasma. The PI-VM model was trained by stepwise variable selection method and multi-linear regression method. The expected etch rate by PI-VM showed high correlation coefficient with measured etch rate from SEM image analysis. The PI-VM model revealed that the root cause of etch rate variation after the wet cleaning was desorption of hydrogen from the cleaned parts as hydrogen combined with fluorine and decreased etchant density and etch rate.

• Ocean Systems Engineering
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• 제12권1호
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• pp.1-22
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• 2022

The majority of tubular joints commonly found in offshore jacket structures are multi-planar. Investigating the effect of loaded out-of-plane braces on the values of the stress concentration factor (SCF) in offshore tubular joints has been the objective of numerous research works. However, due to the diversity of joint types and loading conditions, a number of quite important cases still exist that have not been studied thoroughly. Among them are internally ring-stiffened two-planar TT-joints subjected to axial loading. In the present research, data extracted from the stress analysis of 243 finite element (FE) models, verified against available numerical and experimental data, was used to study the effects of geometrical parameters on the chord-side SCFs in two-planar tubular TT-joints reinforced with internal ring stiffeners subjected to two types of axial loading. Parametric FE study was followed by a set of nonlinear regression analyses to develop six new SCF parametric equations for the fatigue analysis and design of axially-loaded two-planar TT-joints reinforced with internal ring stiffeners.

• 한국철도학회논문집
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• 제13권2호
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• pp.222-228
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• 2010

전기 기관차 중수선 시설과 같이 복잡한 시스템의 설계 변수와 중요 변수 최적화는 수리적인 형태로 분석하는 것이 매우 어려운 작업이 된다. 본 논문에서는 메타 모델의 개념을 시뮬레이션 근사 모델에 적용하여 설계 변수와 중요 변수의 최적화를 수행하였다. 시뮬레이션 설계를 위하여 Critical Path 분석과 민감도 분석 수행하여 설계 변수와 실험 횟수를 줄이기 위하여 노력을 하였다. 시뮬레이션 분석은 다 목적 비선형 계획법을 구성한 후 파레토 최적해 집합을 산출하여 설계자에게 다중 대안의 해 집합을 제시하여 실제 시스템의 적용에 대한 유동성을 제공하려고 노력하였다. 본 논문에서 제시 된 기법은 열차 중수선 시설의 설계 및 분석에 있어서 시뮬레이션과 메타 모델을 이용한 하나의 방법으로 이용이 가능 할 것이다.

• 한국콘텐츠학회논문지
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• 제17권2호
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• pp.55-70
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• 2017

작업자의 직무소진은 팀 또는 조직의 공유구조와 집단심리 상태의 형성과 상호영향을 미치며, 따라서 직무소진을 이해하기 위해서는 시장환경에 따른 작업환경뿐만 아니라 팀 또는 조직의 사회적 상황에 대한 고려가 필수적이다. 본 연구는 직무요구-자원이론에 기반하여 구성원들의 직무소진에 미치는 직무요구와 직무자원의 효과를 다층분석하였다. 즉, 팀수준의 변수인 서번트리더십과 인사관리 통제방식이 개인수준의 작업부하와 감정노동과 직무소진의 관계에 조절효과를 검정하였다. 실증분석 결과, 첫째 작업자의 개인특성 중 자기효능감이 높을수록 직무소진은 줄어드는데 반하여, 작업부하와 감정노동이 높아질수록 직무소진은 증가하였다. 둘째, 팀수준의 투입 및 결과중심 인사관리가 활발히 이루어지는 팀일수록 작업자의 작업부하와 직무소진의 정(+)의 회귀관계 강도가 줄어드는 것으로 나타났다. 또한, 서번트리더십이 발휘되는 팀일수록 자기효능감과 직무소진의 부(-)의 회귀관계 강도가 증폭되는 것으로 나타났다.

• 융합정보논문지
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• 제10권10호
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• pp.279-289
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• 2020

본 연구의 목적은 뷰티종사자의 재미요인이 직무열의 및 자기효능감에 미치는 영향을 규명하는 것이다. 본 연구의 목적을 달성하기 위하여 서울, 경기 지역 뷰티종사자 324명을 연구대상으로 선정하였다. 연구목적을 규명하기 위한 자료처리는 연구대상의 인구사회학적 변인에 대한 빈도분석, 각 요인별 신뢰도 검증, 요인분석을 실시하였으며, 재미요인, 직무열의 및 자기효능감의 상관관계분석을 사용하였다. 변인들 간의 미치는 영향을 알아보기 위해 다중회귀분석(multi-regression)을 실시하였으며, 이와 같은 연구절차를 거쳐 다음과 같은 연구결과를 도출하였다. 첫째, 뷰티종사자의 재미요인이 직무열의에 미쳤다. 둘째, 뷰티종사자의 재미요인이 자기효능감에 영향을 미쳤다, 셋째, 직무열의가 자기효능감에 영향을 미쳤다.

• Wind and Structures
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• 제2권1호
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• pp.25-40
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• 1999

In this paper, artificial neural networks, a new kind of intelligent method, are employed to model and predict amplitude dependent damping in buildings based on our full-scale measurements of buildings. The modelling method and procedure using neural networks to model the damping are studied. Comparative analysis of different neural network models of damping, which includes multi-layer perception network (MLP), recurrent neural network, and general regression neural network (GRNN), is performed and discussed in detail. The performances of the models are evaluated and discussed by tests and predictions including self-test, "one-lag" prediction and "multi-lag" prediction of the damping values at high amplitude levels. The established models of damping are used to predict the damping in the following three ways : (1) the model is established by part of the data measured from one building and is used to predict the another part of damping values which are always difficult to obtain from field measurements : the values at the high amplitude level. (2) The model is established by the damping data measured from one building and is used to predict the variation curve of damping for another building. And (3) the model is established by the data measured from more than one buildings and is used to predict the variation curve of damping for another building. The prediction results are discussed.

• 한국식품영양학회지
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• 제34권6호
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• pp.576-583
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• 2021

The purpose of this study was to estimate the influence of the determinants for home meal replacement (HMR) purchase frequency before and after COVID-19. Multinomial logistic regression was applied to the 2018~2020 Consumer Behavior Survey for Food data from the Korea Rural Economic Institute (KREI). Gender, age, number of households, monthly income, use of eating out, delivery and takeout order service, HMR food safety concern, the frequency of cooking at home, grocery shopping, and eating alone were applied as the explanatory variables to explain HMR purchase frequency. The results are as below. Compared to the previous year, the growth rate of HMR purchase frequency in 2020 was relatively high, indicating that the COVID-19 outbreak acted as a catalyst. Unlike in 2018 and 2019, there was no statistical difference in the HMR purchase frequency between single- and multi-person households in 2020, with indicating multi-person households began to emerge as one of the major HMR consumption groups. Unlike 2018, the 2020 HMR purchase frequency showed a statistically positive relationship with those of grocery shopping and eating alone. There was a positive relationship between the frequency of eating out/food delivery orders and HMR purchases. The more often cooking at home occurred, the less HMR food was purchased.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.461-463
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• 2002

Image quality and selection of optimized window for good quality reconstruction in coronary angiography using multi-detector row CT (MDCT) have not been studied by heart rate and its variation. Therefore, the effect of heart rate and its variation was systemically analyzed. Eighty-three patients were undergone contrast-enhanced coronary angiography using MDCT. In this study, sixty cases were enrolled. Two radiologists graded image quality as follows: 4, excellent; 3, good; 2, fair; l, bad. The starting points of the reconstruction window were chosen at seventy and forty percent of R wave interval. Optimized window was scored as 1 when 40% reconstruction was better quality than 70%, as 2 when 40% reconstruction is same as 70%, and as 3 when 70% reconstruction was better than 40%. Regression analysis was performed. The range of variation of beats per minute (BPM) was well correlated with image quality (r=-0.55, p=0.000), however correlation with optimized window percentage was not statistically significant (p=0.969). By contraries, median value of BPM was comparatively well correlated with optimized window grade (r=-0.24, p=0.086). Median value of BPM was not well correlated with image quality (r=0.l70, p=0.l97). Image quality is more affected by variation of heart rate (VHR) than by higher heart rate. Selection of optimized reconstruction window for good image quality is mainly affected by heart rate and there is a tendency that systolic phase reconstruction is better in image quality than diastolic reconstruction in higher heart rate.