• The Korean Journal of Applied Statistics
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• v.16 no.1
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• pp.117-128
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• 2003

The goal of non-inferiority experiments is to show that the new treatment is not inferior to the standard experiment. In this paper we compare the three methods of variance estimation used in the unconditional exact tests of two proportions. The size and power of the tests with each variance estimation method are compared using complete enumeration.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.15-22
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• 2000

Long ranged groundwater-level data often have the missing intervals because of the trouble of monitoring systems at the national groundwater monitoring wells. Geostatistical methods are very useful for the supplement of the missing data. Ordinary kriging was applied for the interpolation of the missing groundwater-level data with a smooth sinusoidal variation. Conditional simulation was used for the reproduction of the missing data with high fluctuations. Two geostatistical methods produced the very accurate estimates at the missing intervals and reproduced their original variations. This fact is proved by the cross validation test and graphical method, respectively.

• Journal of the Korea institute for structural maintenance and inspection
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• v.2 no.2
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• pp.151-161
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• 1998

In this study, an attempt is made to apply the concept of fuzzy-bayesian theory to the integrity assessment of RC highway bridge, and uncertainty states are represented in terms of fuzzy sets which define several linguistic variables such as "very good", "good", "average", "poor", "very poor", etc. Especially, the concept of fuzzy conditional probability aids to derive a new reliability analysis which includes the subjective assessment of engineers without introducing any additional correction factors. The fuzzy concept are also used as reliability indexes for the condition assessment based on the proposed models, the proposed fuzzy theory-based approach with the results of visual inspection and extensive field load tests are applied to the integrity assessment of a new RC highway bridge, namely, Jichok bridge.

• Journal of Industrial Convergence
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• v.2 no.2
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• pp.127-147
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• 2004

This paper examines the time-series relations among expected return, risk, and book-to-market(B/M) at the portfolio level. The time-series analysis is a natural alternative to cross-sectional regressions. An alternative feature of the time-series regressions is that they focus on changes in expected returns, not on average returns. Using the time-series analysis, we can directly test whether the three-factor model explains time-varying expected returns better than the characteristic-based model. These results should help distinguish between the risk and mispricing stories. We find that B/M is strongly associated with changes in risk, as measured by the Fama and French(1993) three-factor model. After controlling for changes in risk, B/M contains little additional information about expected returns. The evidence suggests that the three-factor model explains time-varying expected returns better than the characteristic-based model.

• Geosystem Engineering
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• v.21 no.6
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• pp.297-308
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• 2018

In this paper, we investigate the differences between LNG price of South Korea and Japan. Although S. Korean and Japanese LNG markets have similar structures, there are some differences in the price formation. From DCC-MGARCH, we confirm that Japan LNG price have less persistence of disturbance on time than S. Korean LNG price. The conditional correlation also shows linkage effects between LNG prices and impacts of S-curve and DS-curve. Moreover, ARDL estimation result shows that there is co-integration in all models and that impacts of Fukushima accident and LNG volumes are responsible for the increase in Japanese LNG price. Also, adjustment speed of error correction term shows that Japan's deviation from long-run equilibrium disappears faster than S. Korea does, indicating relatively strong Japanese linkage between LNG price and oil price.

• Educational Technology International
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• v.24 no.2
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• pp.237-262
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• 2023

This study focuses on the instructor's role in student-centered learning and aims to test the effects and moderating role of instructor feedback on perceived loafing in team project-based learning. A conditional effect model including team efficacy, perceived loafing, instructor feedback, and team performance was proposed. Data were collected from students who registered for team project-based learning courses at a university in South Korea. A total of 420 cases were subjected to moderated mediation analysis. The results demonstrated that instructor feedback was negatively related to perceived loafing and moderated the relationship between team efficacy and perceived loafing. Furthermore, instructor feedback moderated the relationship between perceived loafing and team performance. In particular, even when perceived loafing was high, students who received frequent instructor feedback were found to significantly reduce the damage to team performance. Based on these findings, the importance of instructors' facilitation in team project-based learning is discussed.

• Asia pacific journal of information systems
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• v.31 no.3
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• pp.257-276
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• 2021

This study investigates the factors that facilitate or hinder people to use mobile payment, especially drawing upon the theoretical perspectives on individual's privacy protection motivation and perceived market condition. Survey data (n = 200) were collected through a web-based platform and used to test a theoretical model. The results show that one's privacy protection power is formed by various individual and technological factors (i.e., perceived data exposure, self-efficacy, and response efficacy), and in turn it determines his/her intention to use mobile payment. Moreover, the relationship between privacy protection power and mobile payment use is conditional on the perceived market control by the service provider - with a perception of the high level of provider's market control, one uses mobile payment regardless of his/her privacy protection power, while under the low level of provider's market control, the decision depends on the degree of privacy protection power. The findings would help our understanding of why some people are more susceptible to mobile payment and others are not.

• Journal of Korean Academy of Nursing Administration
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• v.21 no.4
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• pp.447-456
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• 2015

Purpose: The purpose of the study was to identify factors affecting the innovative behavior of general hospital professional staff. Methods: In the final analysis, the study focuses on the 442 structured questionnaires received from the professional staff (doctors, nurses, medical technicians, and administrative staff) of H Hospital, a public medical foundation. Data were collected from August 1 to 31, 2014. The SPSS/WIN 19.0 program was used for data analysis which included t-test, ANOVA, $Scheff\acute{e}$ test, Pearson correlation coefficients, and multiple regression analysis. Results: Multiple regression showed that factors affecting innovative behavior of hospital professional staff were conditional reward, innovation-oriented culture, education, and job (Adj $R^2=.317$). Conclusion: The results of this study suggest that it is necessary for the leader to demonstrate leadership with innovation and transaction in harmony to cultivate innovative behavior in hospital staff. Also, positive support and role in the hospital organization are fundamental to developing the strengths that each type of culture possess on the basis of the organizational culture of hospital, enabling hospital staff to exhibit their best voluntary innovative behavior.

• Korean Journal of Health Education and Promotion
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• v.27 no.3
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• pp.13-22
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• 2010

Objectives: The aims of this study were to provide basic information on health behaviors of diabetics by age groups, compared to non-diabetics group. Methods: 2007 National Health Nutrition and Examination Survey Data were used to compare health behaviors between the diabetics group (191 diabetics who had been diagnosed by a doctor) and the non-diabetics group (382 general population) according to age groups. For the purpose of analysis, $x^2$-test (Fischer's exact test) and conditional logistic regression were used. Results: There were significant differences in health behaviors between the diabetics group and the non-diabetics group according to the history of health screening, BMI and alcohol consumption, and there were different pattern of health behaviors by age group. Conclusion: When developing and implementing health education and specific intervention programs for the correction of health behaviors among diabetics, one should consider age, age-adjusted health behavior patterns and priority.

• Journal of the Ergonomics Society of Korea
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• v.29 no.1
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• pp.121-128
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• 2010

The purpose of this study is to confirm the impact of noise on subject accomplishment as well as physical/mental load, and evaluates the effects of noise-masking and earplug. 15 college students participate in the test, and the comparison is performed by executing four projects according to conditional categories of noise environments; control condition, noise condition, earplug condition, and noise-masking condition. Noise in the field site of the H manufacturer was used as the noise source, the general job aptitude test which consist of linguistic ability, math ability, perception ability, reasoning ability was used as the task of this project. To estimate physical/mental load evaluation, we used the heart rate R-R interval, Criteria flicker fusion frequency(CFF) and measured NASA-TLX workload for subjective evaluation. As the research outcome, it is shown that there is a meaningful difference for the project task score, dropping rate of CFF, the heart rate, and NASA-TLX subjective evaluation score according to conditions of noise environment. Therefore, the impact of noise on capability of subject accomplishment as well as physical/mental load was confirmed along with the effects of using earplug and noise-masking.