• Publications of The Korean Astronomical Society
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• v.32 no.3
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• pp.421-438
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• 2017

Through the short-period variability survey program, we obtained time-series BV CCD images for $1.5^{\circ}{\times}1.0^{\circ}$ region around the young open cluster NGC 457. As a result, we have detected 61 variable stars including 31 new ones after checking light curves of all stars by eyes. The 61 variable stars were included 14 ${\delta}$ Scuti variable stars, a ${\beta}$ Cephei variable star, 10 variable Be and slowly pulsating B stars, 13 eclipsing binary stars, 21 semi-long periodic or slow irregular variables and an RR Lyrae variable star, respectively. Many variable B-type stars were known through a well-defined zero-age main sequence to the ${\beta}$ Cepheid region of NGC 457. Most of the variable B-type stars found this paper were known variable stars. But, 11 out of 14 ${\delta}$ Scuti variable stars were newly discovered. The new variable stars except for ${\delta}$ Scuti stars were 4 variable B-type stars, 5 eclipsing binaries and 11 semi-long periodic or slow irregular variables. We have performed frequency analysis for all ${\delta}$ Scuti stars, a ${\beta}$ Cepheid star and an RR Lyrae star.

• Asia-Pacific Journal of Business
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• v.13 no.1
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• pp.213-230
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• 2022

Purpose - The purpose of this study is to find out any potential factors for explanatory variables when calculating the virtual successful bid rate in case of no collusion. Design/methodology/approach - An empirical analysis was conducted in this study with a regression analysis that included 725 bid samples under the public construction technical type bidding. Findings - The result of the basic analysis showed that there are several factors affecting the successful bid rate. First, collusion variable; second, government variable; third, successful bidder design score variable and the number of bidder variable among bidding features; fourth, turnkey variable based on the alternative method; fifth, civil works variable and plant works variable based on building work; sixth, asset variable and the fourth-quarter performance difference variable. However, the technical proposal method variable among bidding features was found to be statistically insignificant in column(4). Research implications or Originality - The significance of this research is that new variable such as the government variable and the fourth-quarter performance difference variable were added in the regression model, which showed statistically significant research results.

• Journal of the Korean Data and Information Science Society
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• v.19 no.2
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• pp.635-644
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• 2008

We consider estimation of reliability P(Y

• East Asian mathematical journal
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• v.39 no.3
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• pp.331-347
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• 2023

We present an identity on moments of a compound random variable by using an auxiliary counting random variable. Based on this identity, we develop a new recurrence formula for obtaining the raw and central moments of any order for a given compound random variable.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.11a
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• pp.195-198
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• 2006

In this paper, we propose a 2dimension Control Chart. Suggested which Control chart augments Schwart Control chart which is 1-dimensional and Independent variable and dependent variable interrelationship by using control chart. Schwart control chart cannot use input variable and output variable together. In this paper, we try to analysis input variable and output variable dependent and effect. So called 2-dimensional control char.

• The Journal of Fisheries Business Administration
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• v.26 no.2
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• pp.75-92
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• 1995

This paper tried to estimate the pass - through of exchange rate changes to export price of fishery products using export price function. The results are as follows : 1) The variable of fluctuation of exchange rate of Won(equation omitted) to Yen(equation omitted)(variable E2) is more powerful explanatory variable than that of Won to U.S. dollar to explain the fluctiation of export price of fishery products(varible $P_{t}$)- 2) The variable of fish catches(variable K $P_{t}$) is also found to be a statistically significant varible but that of producer price index is not found. 3) The variable E2 have statistically a more influence on variable $P_{t}$ than variable K $P_{t.}$ 4) The estimation shows us that 1% of fluctuation of variable E2 could result in 0.9978% of fluctuation of variable $P_{t.}$

• 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.

• Journal of Korean Society for Quality Management
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• v.45 no.4
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• pp.943-956
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• 2017

Purpose: This paper proposes a VSS(Variable Sample Size) ${\bar{X}}$ control chart using surrogate variable and shows its effectiveness compared with FSS(Fixed Sample Size) ${\bar{X}}$ control chart using either performance variable or surrogate variable. Methods: The expected cost function of VSS ${\bar{X}}$ control chart is derived. The optimal designs are then found for numerical examples using a GA(genetic algorithm) and compared to those of the FSS ${\bar{X}}$ control charts. Results: Computational results show that VSS ${\bar{X}}$ control chart using surrogate variables is superior to FSS ${\bar{X}}$ control chart using either performance variable or surrogate variable from the economic view points. Conclusion: The proposed VSS ${\bar{X}}$ control chart will be useful in industry fields where a performance variable is not avaliable or too costly.

• Journal of the Korean Home Economics Association
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• v.51 no.2
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• pp.195-206
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• 2013

This study was conducted in order to investigate the variables that relate and affect the internalizing and externalizing problems of multicultural children. 159 multicultural children in the $3^{rd}{\sim}6^{th}$grade were selected from elementary schools in Gwangju and the Jeollanamdo area. The data was analyzed by using the frequency, Cronbach's ${\alpha}$, t-test, ANOVA, Pearson's correlation and hierarchical regression by SPSS 12.0 program. The results were as follows: first, the internalizing problems were different according to the socio-demographic variable: (gender, subjective economic level), multicultural characteristic variable: (mother's communication ability, likability of mother's nationality, etc.), parent-child relationship variable: (relationship with mother, relationship with father) and social support variable: (peer support, teacher support). Further, the externalizing problems were different according to the socio-demographic variable: (gender), multicultural characteristic variable: (mother's nationality, mother's communication ability, etc.), parent-child relationship variable: (relationship with mother, relationship with father) and social support variable: (peer support, teacher support). Second, the influential variables regarding the internalizing problems were children's stress from cultural adaptability and the likability of the mother's nationality of the multicultural characteristic variable group, peer support of the social support variable group and the subjective economic-level of the socio-demographic variable group. Moreover, the influential variable on the externalizing problems was children's stress from the cultural adaptability of the multicultural characteristic variable group. The most influential variable of such variables was children's stress from cultural adaptability of the multicultural characteristic variable group. The results of this study will provide information for the development of educational and therapeutic intervention program for multicultural children.

• Journal of Korean Society for Quality Management
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• v.29 no.3
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• pp.124-137
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• 2001

In general, it is very efficient and effective to use screening variables that are correlated with the performance variable in case that measuring the performance variable is impossible (destructive) or expensive. The general methodology for searching surrogate variables is regression analysis. This paper considers the inspection problem in CRT (Cathode Ray Tube) production line, in which the performance variable (dependent variable) is binary type and screening variables are continuous. The general regression with dummy variable, discriminant analysis and binary logistic regression are considered. The cost model is also formulated to determine economically inspection procedure with screening variables.