• The Korean Journal of Applied Statistics
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• v.11 no.2
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• pp.435-449
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• 1998

In this article we have introduced a Bayes criterion for the variable selection in multiple discriminant analysis (MDA). The criterion is a default Bayes factor for the comparision of homo/heteroscadasticity of the multivariate normal means. The default Bayes factor is obtained from a development of the imaginary training sample method introduced by Spiegelhalter and Smith (1982). Based an the criterion, we also provided a test for additional discrimination in MDA. The advantage of the criterion is that it is not only applicable for the optimal subset selection method but for the stepwise method. More over, the criterion can be reduced to that for two-group discriminant analysis. Thus the criterion can be regarded as an unified alternative to variable selection criteria suggested by various sampling theory approaches. To illustrate the performance of the criterion, a numerical study has bean done via Monte Carlo experiment.

• Proceedings of the ESK Conference
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• 1997.04a
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• pp.50-55
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• 1997

본 연구에서는 일반적으로 생산 현장에서의 로봇 작업이 "getting"과 "putting"의 동작으로 구서 되는 것에 기초하여 이들 동작을 분류. 표준화하여 2단계의 단위동작 (GET, PUT) 별로 여러 가지의 모듈을 설정하고, 동작거리별로 표준시간을 산출하는 기법을 다룬다. 즉 기존의 로봇 작업측정법이 작업을 기존동작으로 분석하는 것과는 다르게 시간의 변동요인인 모듈의 Type과 동작거리의 Case를 선택함으로써 표준시간을 설정한다.를 선택함으로써 표준시간을 설정한다.

• Journal of KIISE:Software and Applications
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• v.41 no.8
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• pp.598-604
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• 2014

In this paper, we develop stepwise regression data envelopment model to select important variables. We formulate null hypothesis to understand the importance of each variable and use Kruskal-Wallis test for this purpose. If the Kruskal-Wallis test does reject the null hypothesis this will imply there is significant fluctuation in the efficiency score relative to base model. And therefore we have to further check the pair of variables that causes the fluctuation in order to determine its importance using Conover-Inman test. The proposed models helps understand the extent of misclassification decision making units as efficient/inefficient when variables are retained or discarded alongside provides useful managerial prescription to make improvement strategies.

• The Journal of the Korea Contents Association
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• v.10 no.12
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• pp.236-242
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• 2010

The porcelain fused metal was made through the progressive fused process of porcelain on substructure of metal material. The substructure was made using novel SLM method. The objective of this study was to observe the color change of porcelain using spectrophotometer equipment according to porcelain fused step and production methods after conducting the process of casting and SLM method of the substructure. The color change by step was indicated that fused opaque porcelain groups(CN1, CC1, CT1, SC1, ST1) had color difference(${\Delta}E$=30) by comparison with fused body porcelain groups(CN2, CC2, CT2, SC2, ST2) and fused glazing porcelain groups(CN3, CC3, CT3, SC3, ST3) (p<0.05). and there was no color difference between the substrates(CN, CC, CT) made by the casting method and the substrates(SC, ST) made by the SLM method. so, the color change was expressed by fused change of porcelain, and this study showed that the color of porcelain fused metal made by the SLM method can be applied clinical trials.

• The Korean Journal of Applied Statistics
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• v.34 no.6
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• pp.937-944
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• 2021

The problem of selecting variables is addressed in partial linear regression. Model selection for partial linear models is not easy since it involves nonparametric estimation such as smoothing parameter selection and estimation for linear explanatory variables. In this work, several approaches for variable selection are proposed using a fast forward selection algorithm, least angle regression (LARS). The proposed procedures use t-test, all possible regressions comparisons or stepwise selection process with variables selected by LARS. An example based on real data and a simulation study on the performance of the suggested procedures are presented.

• Journal of Korea Water Resources Association
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• v.55 no.4
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• pp.257-266
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• 2022

Inundation damage is increasing every year due to localized heavy rain and an increase of rainfall exceeding the design frequency. Accordingly, the importance of hydraulic structures for flood control and defense is also increasing. The hydraulic structures are designed according to its purpose and performance, and the amount of flood is an important calculation factor. However, in Korea, design rainfall is used as input data for hydrological analysis for the design of hydraulic structures due to the lack of sufficient data and the lack of reliability of observation data. Accurate probability rainfall and its temporal distribution are important factors to estimate the design rainfall. In practice, the regression equation of temporal distribution for the design rainfall is calculated using the cumulative rainfall percentage of Huff's quartile method. In addition, the 6^th order polynomial regression equation which shows high overall accuracy, is uniformly used. In this study, the optimized regression equation of temporal distribution is derived using the variable selection method according to the principle of parsimony in statistical modeling. The derived regression equation of temporal distribution is verified through the significance test. As a result of this study, it is most appropriate to derive the regression equation of temporal distribution using the stepwise selection method, which has the advantages of both forward selection and backward elimination.

• Journal of Information Management
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• v.5 no.3
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• pp.57-66
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• 1972

시스팀 설계(設計)는 지극히 복잡한 일련의 선택(選擇)으로 이루어져 있거니와, 어느 한가지 결정사항(決定事項)도 이미 내려졌거나 장차 내려질 여타의 결정(決定)들과 완전히 절연된 것은 없다. 문헌정보(文獻情報) 시스팀의 설계(設計)를 위한 시스팀 접근법(接近法)에 있어서는, 시스팀의 작업능력(作業能力), 성능(性能), 비용(費用) 및 기타 특징요인(特徵要因)을 감안하여 설계과정(設計過程)에 이루어질 제선택(諸選擇)과 이들 선택(選擇)에 내포된 세부사항(細部事項)에 대하여 세밀한 검토가 가해져야 한다. 이 보문(報文)의 저자(著者)들은 다음과 같이 6단계(段階)로 된 하나의 체계적 설계절차(設計節次)를 창도하고 있다. 1) 고정설계인자(固定設計因子)의 확인, 2) 가변설계인자(可變設計因子)의 확인, 3) 각(各) 가변설계인자(可變設計因子)에 내포된 제임의요소(諸任意要素)의 확인, 4) 제임의요소(諸任意要素) 가운데서 하나를 선택할 때 그 선택에 영향을 주는 요소(要素)의 확인, 5) 제임의요소(諸任意要素) 가운데서 하나를 선택할 때 그 선택으로 인하여 영향을 받는 요소(要素)의 확인, 및 6) 설계과정(設計過程)에서 내려야 할 제결정(諸決定)의 최적순서(最適順序) 및 결정과정(決定過程) 그 자체의 본질(本質)을 파악하기 위하여, 상술한 바 제단계(諸段階)를 통해서 밝혀진 전체 상황(狀況)에 대하여 논리적(論理的) 분석(分析)을 가(加)함.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.3
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• pp.107-114
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• 2022

In this paper, we have enhanced the risk prediction of hypertension using the feature selection method in the Korean National Health and Nutrition Examination Survey (KNHANES) database of the Korea Centers for Disease Control and Prevention. The study identified various risk factors correlated with chronic hypertension. The paper is divided into three parts. Initially, the data preprocessing step of removes missing values, and performed z-transformation. The following is the feature selection (FS) step that used a factor analysis (FA) based on the feature selection method in the dataset, and feature importance (FI) and multicollinearity analysis (MC) were compared based on FS. Finally, in the predictive analysis stage, it was applied to detect and predict the risk of hypertension. In this study, we compare the accuracy, f-score, area under the ROC curve (AUC), and mean standard error (MSE) for each model of classification. As a result of the test, the proposed MC-FA-RF model achieved the highest accuracy of 80.12%, MSE of 0.106, f-score of 83.49%, and AUC of 85.96%, respectively. These results demonstrate that the proposed MC-FA-RF method for hypertension risk predictions is outperformed other methods.

• Proceedings of the Membrane Society of Korea Conference
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• 1992.10a
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• pp.37-38
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• 1992

혼합물 중의 특정 분자와 선택적, 가역적으로 반응하는 운반체를 이용한 촉진 수송법은 분리막의 투과도와 선택도를 동서에 증가시킬 수 있는 한 방법으로 많은 연구가 진행되어 왔다. 촉진수송의 개념은 처음 액막에서 발견되었으나 근래에는 고체막에서도 가능하다는 보고들이 있다. 액막의 경우는 이 현상을 설명하는 모델들이 다수 보고되었으나 운반체가 고정되어 있는 고체막에 대한 보고는 아직 초보적인 단계이다.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1640-1644
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• 2007

본 연구에서는 안양천 유역에 대해 왜곡된 물순환을 건전화시키기 위한 유역통합관리 계획을 수립하였다. 대안의 효과분석은 HSPF 모형을 사용하였으며 평가지수는 건천화 방지와 수질개선 효과 요소로 구성되며 각각은 유역통합관리 6단계 결과를 모두 사용할 수 있도록 복합계획법과 지속가능성 개념(압력-상태-반응)을 활용하여 개발되었다. 특히 수량과 수질에 대한 가중치는 유역주민의 의견을 반영하기 위해 실험선택법으로 정량화하여 유역의 속성별로 달리 적용하였다. 대안은 평가지수에 따라 세 등급(Good, Acceptable, Poor)으로 나누어 제시하였다.