• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.193-194
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• 2017

Effect of variable factors on carbon emissions in construction industry is hard to analysis. Therefore this study analyzies effect of variable factors on carbon emissions. This study shows importance of variable factors and emphasizes need of estimation of carbon emissions considering variable factors.

• Journal of the Korean Data and Information Science Society
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• v.15 no.3
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• pp.555-563
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• 2004

In classification and discrimination, we often face with incomplete group variable arising typically from many missing values and/or incredible cases. This paper suggests the use of K-means clustering for pre-adjusting incompleteness and in turn classification based on generalized statistical distance is performed. For illustrating the proposed procedure, simulation study is conducted comparatively with CART in data mining and traditional techniques which are ignoring incompleteness of group variable. Simulation study manifests that our methodology out-performs.

• Korean Journal of Social Welfare
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• v.66 no.2
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• pp.179-202
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• 2014

This study was designed to explore the structural relationship of social support, acculturative stress and parenting stress which influenced child abuse among married immigrant women in Korea. For study 195 married immigrant women participated and structured questionnaire was used. This study identified that the variable of parenting stress directly affected child abuse and the variable of acculturation stress indirectly affected child abuse with a variable of parenting stress as a mediator variable. In addition, the variable of social support indirectly affected parenting stress with a variable of acculturation stress as a mediator variable. Also, the variable of social support did not directly affect child abuse, but it was verified as a protective factor to reduce the risk of child abuse. This study suggested the social interventions to prevent child abuse among multi-cultural families based on the study results.

• Journal of Distribution Science
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• v.14 no.12
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• pp.99-105
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• 2016

Purpose - In the present study, it has become the most important necessity in our daily lives that consumers' psychological factors affect the use of smartphones, and it has been analyzed through behavioral economic approaches. In this respect, the present study is intended to apply the heuristic theory and the prospect theory among behavioral economics theories to examine how psychological factors affect consumers' product selection. Research design, data, and methodology - In the present study, using smartphone repurchase as a dependent variable, whether regulatory focus effects have interaction effects on behavioral economic theories and behavioral economic effects such as possession (ownership) effects, framing effects, and brand recollection. As an analysis method, questionnaire surveys conducted with university students in Incheon were examined through Two-Way ANOVAs using the SPSS23 package. Results - The analysis from the results are as follows. Using smartphone repurchase as a dependent variable, the main effects and interaction effects on two variables; satisfaction difference with product functions and positive framing variable were statistically significant. Using repurchase as a dependent variable was statistically significant, there was no interaction effect between the two variables; satisfaction difference with product functions and the difference of brands in possession. Using smartphone repurchase as a dependent variable, interaction effects on two variables; satisfaction difference with product functions and the lengths of product possession periods were not statistically significant. The results from the analyses of interaction effects of brand recollection and brands type were statistically significant in possession using repurchase as a dependent variable. The results from the analyses of the main effect of the brands type were statistically significant in possession using repurchase as a dependent variable. Conclusions - The implication of the present study is that it suggests the factors that became important for customers' smartphone purchase following the change in the meaning of smartphones from practical products in the past to hedonic products. Limitations of the present study are first, the study subjects are limited to students and the number of copies in questionnaires is only approximately 130, which is insufficient, so that the present study is not sufficient as a study for entire smartphone users.

• The Korean Journal of Applied Statistics
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• v.17 no.2
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• pp.347-357
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• 2004

It is very important to select a split variable in constructing the classification tree. The efficiency of a classification tree algorithm can be evaluated by the variable selection bias and the variable selection power. The C4.5 has largely biased variable selection due to the influence of many distinct values in variable selection and the QUEST has low variable selection power when a continuous predictor variable doesn't deviate from normal distribution. In this thesis, we propose the SRT algorithm which overcomes the drawback of the C4.5 and the QUEST. Simulations were performed to compare the SRT with the C4.5 and the QUEST. As a result, the SRT is characterized with low biased variable selection and robust variable selection power.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.6
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• pp.39-48
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• 2014

Variable valve actuation system is one of the widely used techniques to improve the fuel efficiency and power of automotive engines. 2-step variable valve actuation systems are also paid attention for the application to direct acting type valve train systems. Besides its advantages in size, weight, relatively simple structure, ets, however, 2-step variable valve actuation system has inherent disadvantages in dynamic instability of switching system to alter discontinuous lift modes. In this study, both experimental and analytical studies are performed to understand the dynamic behavior of a switching mechanism of a 2-step variable valve actuation system, and present a design method to improve its dynamic instability.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.4
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• pp.392-399
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• 1992

This paper will describe the application of variable structure control theory to the first order dynamic system and verify its robustness. The study on the first order dynamic system control which has been essential part for the control of servo motor (AC,DC) systems has been excluded in the study of variable structure control system(VSCS) because this first order system was not applicable to the previous variable structure control theory. So, for the robustness control of first order dynamic system with variable structure control theory, we propose modified switching function synthesis which guarantees the advantages of conventional VSCS and removes reaching phase which is regarded as shortcomings in VSCS. And we demonstrate the practical potential of implementation about this theory by simulation results of AC motor variable speed control.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.179-184
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• 1991

This paper will describe the application for variable structure control theory to the first order dynamic system and verify it's robustness. The study on the first order dynamic system control which has been essential part for the control of servo motor (AC, DC) systems has been excluded in the study of variable structure control system(VSCS) because this first order system was not applicable to the previous variable structure control theory. So, for the robustness control of first order dynamic system with variable structure control theory, we propose modified switching function synthesis which guarantees the advantages of conventional VSCS and removes reaching phase which regards as shortcomings in VSCS. And we demonstrate the practical potential of implementation about this theory by simulation results of AC motor variable speed control.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.167-173
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• 2003

For the measurement of mass flow rate at a wide range of operation conditions, it is required that the critical nozzle gas different diameters, since the mass flow rate through the critical nozzle depends on the nozzle supply conditions and the nozzle throat diameter. In the present study, both computational and experimental investigations are performed to explore the variable critical nozzle. Computational work using the 2-dimensional, axisymmetric, compressible Navier-Stokes equations are carried out to simulate the gas flow through variable critical nozzle. In experimnet, a cylinder with several different diameters is inserted into the critical nozzle to vary the nozzle throat diameter. Computational results are compared with the experimented ones. The computed results are in close agreement with experiment. It is found that the displacement and momentum thickness of variable critical nozzle are given as a function of Reynolds numbers. The discharge coefficient of the variable critical nozzle is predicted using an empirical equation.

• Journal of Distribution Science
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• v.15 no.9
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• pp.53-62
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• 2017

Purpose - This study aims to analyze the effects of preference for Korean Wave and heuristic on shopping satisfaction and switching barriers of Chinese people visiting Korea, and also their positive effects on consumers' behavioral intention with these variables as mediating variables by using the structural equation model. Research design, data, and Methodology - For this study, we collected 264 questionnaires of Chinese consumers' who have experienced tourism and shopping in Korea after excluding questionnaires that were not proper to be analyzed. The residence of Chinese visiter was Shandong Province, Beijing, Shanghai, Shenyang. The data of this study was analyzed using SPSS 23 statistics to verify the reliability and discriminant validity. Structural equation method was used to test the hypotheses in this study. Results - The effects of heuristic variable on shopping satisfaction and the switching barriers variable were statistically significant. The effects variables of Korean Wave effect variable were statistically significant only on the switching barriers variable. However, the Korean Wave effect variable did not have a statistically significant effect on the shopping satisfaction. Conclusions - The shopping satisfaction and Korean Wave effect variables had statistically significant effects on the behavioral intention variable. In the result of indirect analysis, only the heuristic effect had indirect effects on consumers' behavior intention.