• Journal of applied mathematics & informatics
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• 제14권1_2호
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• pp.377-386
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• 2004

A technique that provides prediction intervals based on a model called an empirical linear model is discussed. The technique, high-dimensional empirical linear prediction (HELP), involves principal component analysis, factor analysis and model selection. HELP can be viewed as a technique that provides prediction (and confidence) intervals based on a factor analysis models do not typically have justifiable theory due to nonidentifiability, we show that the intervals are justifiable asymptotically.

• Steel and Composite Structures
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• 제22권3호
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• pp.677-690
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• 2016

In this paper, the effect of damping ratio on nonlinear dynamic analysis response and dynamic increase factor (DIF) in nonlinear static analysis of structures against column removal are investigated and a modified empirical DIF is presented. To this end, series of low and mid-rise moment frame structures with different span lengths and number of storeys are designed and the effect of damping ratio in DIF is investigated, performing several nonlinear static and dynamic analyses. For each damping ratio, a nonlinear dynamic analysis and a step by step nonlinear static analysis are carried out and the modified empirical DIF formulas are derived. The results of the analysis reveal that DIF is decreased with increasing damping ratio. Finally, an empirical formula is recommended that relates to damping ratio. Therefore, the new modified DIF can be used with nonlinear static analysis instead of nonlinear dynamic analysis to assess the progressive collapse potential of moment frame buildings with different damping ratios.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 봄 학술발표회 논문집
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• pp.215-222
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• 2001

Uncertainty study of shear strength characteristics of the marine clays was carried out based ell In-situ tests and laboratory tests on tile south-east coastal region of the Korean peninsula. Theoretical analyses were studied using both tile spherical cavity expansion theory in finite soil mass and the strain path method to determine tile cone factor using the undrained shear strengths obtained by in-situ tests, and the empirical methods in accordance with the ultimate resistance theory were also discussed. Analysis show that the empirical methods suggest more reasonable value than that of theoretical methods in terms of comparing the cone factor estimated using linear regression and frequency distribution analyses. The cone factors obtained by the empirical methods are 18, 15, and 6 respectively, from the results of total cone resistance, effective cone resistance, and excess porewater cone resistance method, and the estimated were similar to those of previous researcher's.

• 한국항해항만학회지
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• 제27권2호
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• pp.163-170
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• 2003

본 연구는 한중정기항로에서 국적선사 활성화 방안에 관한 실증연구이다. 본 연구를 위하여 한중항로의 국적정기선사, 중국적 정기선사, 3국적 정기선사 등의 종사자에 실문지 500매를 배포하여 290매 회수하였으며, 한중정기항로 국적선사 활성화 요인과 물동량 증대효과의 관련성을 검증하기 위하여 먼저, 설문문항의 신뢰성(Reliability)은 크론바하 알파(Cronbach's Alpha)에 의한 내적 일관성 검사법을 통하여 검정하였고, 독립변수의 구성타당성(Construct Validity)을 검정하기 위해서 변수들이 선형결합이라는 가정 하에 요인을 추출하는 주성분 법(Principal Components)을 이용한 요인분석(Factor Analysis)을 실시하였다. 그리고 연구가설을 검증하기 위하여 다변량 회귀분석(Multiple Regression Analysis)을 실시하였다.

• 물과 미래
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• 제28권2호
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• pp.155-168
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• 1995

본고는 개수로 마찰계수를 산정하거나 단면평균유속을 구하는 전통적인 방법의 경험식을 논의하였으며, 새로운 형태의 산정식을 제시하였다. 기존 경험식중 형태가 가능한 것은 차원의 일치를 기하기 위하여 수정하였으며, 등가조고를 도입하여 새로운 형태의 경험식을 제안하였다. 개수로에서의 마찰계수 분포도 원형판에서의 완난류 마찰계수 분포와 유사함을 고려하여 대부분의 관측자료는 완난류 구간에 드는 것으로 판단하였으며, 원형관 완난류 마찰계수 산정식을 수정하여 사각형 개수로 완난류 마찰계수 산정식을 개발하였다. 또한 차원의 일치를 이룬 새로운 형태의 경험식들을 포함하여 이들 산정식을 Bazin의 실험자료에 적용하여 비교 검토하였다.

• Communications for Statistical Applications and Methods
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• 제6권1호
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• pp.33-42
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• 1999

A method of detecting influential observations in principal factor analysis is suggested. it is based on a perturbation of the empirical distribution function and an adoption of the local influence method. An illustrative example is given.

• Journal of the Korean Data and Information Science Society
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• 제17권2호
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• pp.279-289
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• 2006

This paper concerns with the effects of the specialized projected for the local W university on education which was planned and conducted in October 2004. From the empirical study using the correlation analysis, regression analysis, and structured equation model, we found some results that educational service satisfaction was highly correlated with general instruction factor and hard ware factor less correlated. Also we investigated that university educational service satisfaction was deeply correlated with word of mouth.

• 산업경영시스템학회지
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• 제23권54호
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• pp.119-128
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• 2000

This study develops the pay satisfaction questionnaire for Korean employees. Based upon the review of previous studies, 16 questionnaire items are developed. Exploratory factor analysis results in a modified measurement through item deletion, item-to-dimension reassignment, and dimension combination. The measurement model was good fit assessed by overall fit measures(GFI; goodness of fit index, AGFI; adjusted goodness of fit index, RMR; root mean square residual) criteria, lambda score, and squared multiple correlation with confirmatory factor analysis. Implication of this work for future theoretical and empirical development are suggested.

• Journal of Mechanical Science and Technology
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• 제15권9호
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• pp.1292-1301
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• 2001

The mean-line method using empirical models is the most practical method of predicting off-design performance. To gain insight into the empirical models, the influence of empirical models on the performance prediction results is investigated. We found that, in the two-zone model, the secondary flow mass fraction has a considerable effect at high mass flow-rates on the performance prediction curves. In the TEIS model, the first element changes the slope of the performance curves as well as the stable operating range. The second element makes the performance curves move up and down as it increases or decreases. It is also discovered that the slip factor affects pressure ratio, but it has little effect on efficiency. Finally, this study reveals that the skin friction coefficient has significant effect on both the pressure ratio curve and the efficiency curve. These results show the limitations of the present empirical models, and more resonable empirical models are reeded.

• 유통과학연구
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• 제12권7호
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• pp.5-12
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• 2014

Purpose - This study identified internationalization factors forKorean SMEs and explored factor differences between AEO and non-AEO authorized companies. Research design, data, and methodology - The study was designed to assess internationalization factors for AEO authorization in Korea through a questionnaire survey and an empirical analysis. The questionnaires were conducted for AEO and Non-AEO authorized companies that were undergoing AEO authorization. The study was conducted through e-mail and AEO manager education classes. Ninety-five questionnaires were collected. We employed the exploratory factor analysis methodology to derive internationalization factors for KoreanSMEs, and explored the factor differences between AEO and Non-AEO authorized companies. Results - AEO authorized companies outperformed Non-AEO authorized companies in R&D and technology. This indicated that AEO authorized companies were recognized as reliable and safe companies by the Korea Customs Service and other Customs services in trade facilitation and customs clearance processes. Conclusions - This study has some implications for AEO authorization and internationalization processes, and involved the empirical analysis of SMEs and the exploratory factor analysis in the internationalization process.