• Journal of the Korean Graphic Arts Communication Society
• /
• v.19 no.1
• /
• pp.4-16
• /
• 2001

Most important step for the color matching in scanner is the color coordinate transformation from the scanner RGB space to device independent uniform color space. A variety of color calibration technologies have been developed for input device. Linear or nonlinear matrices have been conveniently applied to correct the color filter's mismatch with color matching function in scanners. The color matching accuracy is expected to be further improved when the nonlinear matrices are optimized into subdivided smaller color spaces than in single matrix of the entire color space. This article proposed the scanner calibration method using subspace division regression analysis and it were compared with conventional method.

• The Korean Journal of Applied Statistics
• /
• v.24 no.1
• /
• pp.193-206
• /
• 2011

Due to the great impact of private education expenses on many areas including economics and politics, reducing private education expenses is one of the key issues in Korea. In this paper, we analyze the data from a survey on private education expenses, conducted by Statistics, Korea, in 2008. We study the effect of some demographic variables on two dependent variables, the expenses for out-of-school private education (Private) and the expenses for after-school programs (Afterschool), by using a multiple linear regression model. The analysis results show that 'residential area' and 'school level' variables have a significant effect on the two dependent variables. 'Private' increases in the order of small town, middle town, or metropolitan city, and Seoul, by about 7%. On the other hand, 'Afterschool' are about the same for all areas except for the small town. In terms of the effect of 'school level', 'Private' for high school students is about 17% larger than all other students including professional high school students. This shows a strong correlation between university admission and private education, in Korea. 'Afterschool' is larger for high school and elementary school students and decreases in the order of professional school students and middle school students. It seems that after-school programs are alternatives to expensive private education programs for elementary school students, and that high school students are attracted to after-school programs to get a good GPA, which is important for university admissions.

• The Korean Journal of Financial Management
• /
• v.24 no.4
• /
• pp.45-73
• /
• 2007

The empirical results are summarized as follows : First, In relation to effects of ownership structure on firm value, there is the non-linear relationship between major(and foreign) shareholder's holdings and firm value. So the results(the compromise hypothesis) by prior researches(Morck et al. 1988 and so forth) is supported. However Institutional shareholder's holdings do not show the significant results. Second, In relation to effects of outside directors on firm value, equally the results of prior researches(Vafeas 2000, Choi et al. 2004), the higher the ratio of outside directors in the board, the higher firm value. Also there is the non-linear relationship between outside directors ratio and firm value. Furthermore, the higher the possibility of outside directors election in the board, the higher the relationship between ownership structure and firm value. As the economic importance of KOSDAQ is more increase, the researches of KOSDAQ should be more realized.

• Journal of the Korean Data and Information Science Society
• /
• v.26 no.2
• /
• pp.387-397
• /
• 2015

In this paper, the determinants of the number of job changes in the SMEs (small and medium enterprises) youth-intern project is analysed, utilizing SMEs youth-intern DB and employment insurance DB. Since the number of job changes are count data which take integer values other than negative values, general linear regression analysis becomes inappropriate. Therefore, four models such as Poisson regression model, zero inflated Poisson regression model, negative binomial regression model and zero inflated negative binomial regression model are tried to fit count data. A zero inflated negative binomial regression model is selected to be the best model. Major results are the followings. First, the number of job changes is shown to be significantly smaller in the treatment group than in the control group. Second, the number of job changes turns out to be significantly smaller in the young-age group than in the old-age group. Third, it is also shown that the number of job changes of man is significantly greater than that of woman. Lastly, the number of job changes in the bigger firm is shown to be significantly less than that of the smaller firm.

• Journal of the Korean Data and Information Science Society
• /
• v.27 no.4
• /
• pp.935-946
• /
• 2016

In this paper, we analyzed wage determinants of the vocational high school graduates utilizing both individual-level and work region-level variables. We formulate the models in the way wage determination has multi-level structure in the sense that individual wage is influenced by individual-level variables (level-1) and work region-level (level-2) variables. To incorporate dependency between individual wages into the model, we utilize hierarchical linear model (HLM). The major results are as follows. First, it is shown that the HLM model is better than the OLS regression models which do not take level-1 and level-2 variables simultaneously into account. Second, random effects on sex, maester dummy and engineering dummy variables are statistically significant. Third, the fixed effects on business hours and mean wage of regular job for level-2 variables are statistically significant effect individual-level wages. Finally, parental education level, parental income, number of licenses and high school grade are statistically significant for higher individual-level wages.

• Journal of the Korean Society for Railway
• /
• v.13 no.2
• /
• pp.222-228
• /
• 2010

In this paper, we propose a optimization approach for the Electric Locomotive Overhaul Maintenance Facility (ELOMF), which aims at the simulation optimization so as to meet the design specification. In simulation design, we consider the critical path and sensitivity analysis of the critical (dependent) factors and the design (independent) parameters for the parameter selection and reduction of the metamodel. Therefore, we construct the multi-objective non-linear programming. The objective function is normalized for the generalization of design parameter while the constraints are composed of the simulation-based regression metamodel for the critical factors and design factor's domain. Then the effective solution procedure based on the pareto optimal solution set is proposed. This approach provides a comprehensive approach for the optimization of Train Overhaul Maintenance Facility(TOMF)'s design parameters using the simulation and metamoels.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2011.06a
• /
• pp.321-322
• /
• 2011

DGNSS 서비스는 보정정보를 제공하는 기준국과 측량지점 간의 기선거리가 멀어질수록 정확도가 저하되는 문제가 있다. 이를 해결하기 위해서는 다수의 기준국을 설치하는 방법이 있지만, 기준국 설치 시 많은 비용이 소요되기 때문에 비효율적이다. 이러한 문제는 기존의 기준국들로 기준망을 구성하고 보간을 통해 측량지점의 보정정보를 생성하는 가상기준국 기반의 방법을 적용함으로써 해결할 수 있다. 이 연구에서는 국토해양부 위성항법중앙사무소에서 운영하는 DGNSS 서비스를 이용하여 가상기준국의 보정정보 생성 알고리즘을 구현하였으며 단일기준국 기반의 DGNSS 측위의 정확도를 평가하여 가상기준국 기반의 DGNSS 측위의 효용성을 검증하였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.15 no.2
• /
• pp.1-12
• /
• 2016

This paper is to analyze characteristics of transfer trips and to identify impacts of land use on them. Using the smart transport card data of Seoul on a weekday in April 2013, we explored general characteristics of the transfer trips such as spatial and temporal distributions, transfer types, and geographical patterns of transfer trips. Then, the multiple regression model for the transfer trips was developed, considering land use as well as socio-economic variables as explanatory ones. For the characteristics of the transfer trips, their ratio to the total trips accounts for 26.7%. Nearly 87% of the trips are one-time transferred, and 64.7% are bus-subway transfer trips. In addition, the transfer trips are more likely to appear nearby subway stations and business facilities. The regression model indicates that land use variables such as the floor areas of business facilities and department stores and mixed land use index significantly positively affect the transfer trips. Our results can be used as basic data for choosing feasible locations of multi-modal transfer centers in urban areas.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.10 no.1
• /
• pp.124-132
• /
• 2022

The corrosion potential in concrete varies greatly with exposure and concrete mix conditions. In this study, RC (Reinforcement Concrete) samples were prepared considering cover depth, chloride concentration, and W/C(water to cement) ratio as variables, and HCP(Half Cell Potential) was measured, which evaluated comparative potential between embedded steel and concrete surface. In addition, OCP(Open Circuit Potential) was measured using buried steel and CE(Counter Electrode). Agar and NaOH solution were used as ion exchange materials and Hg/HgO was used for RE(Reference Electrode), which was more sensitive to temperature than HCP. Among the influencing factors, the exposure period and chloride concentration had a relatively greater effect than cover depth and w/c ratio. Additionally, the entire measured HCP and OCP showed a clearly linear relationship with increasing cover depth and w/c ratio. Through multiple regression analysis, the relationship between HCP and OCP was quantified, and an improved correlation was obtained with temperature effect.

• Korean Journal of Clinical Laboratory Science
• /
• v.52 no.1
• /
• pp.45-52
• /
• 2020

Hypertension often leads to cardiovascular disease and kidney disease, and hypertention is an important worldwide problem. Body mass index (BMI) has an important role for raising blood pressure. Further, hypertension can be affected by both environmental factors and genetic factors. Many single nucleotide polymorphisms have been associated with hypertension. Genome wide association study (GWAS) is a method of confirming a new locus of increasing the risk of disease, and GWAS has confirmed several single nucleotide polymorphisms (SNPs) that are associated with high blood pressure. This study analyzed the relationship between systolic blood pressure, diastolic blood pressure and SNP of the ATP2B1 gene in 994 Koreans. SNPs that showed the highest statistical significance with systolic and diastolic blood pressures were selected on the multiple linear regression analysis. One-way analysis of variance for systolic and diastolic blood pressures was performed, and multiple logistic regression analysis was performed on the risk of hypertension. The P values were two-tailed, and P<0.05 was considered significant. Four SNPs were associated with systolic blood pressure and six SNPs were associated with diastolic blood pressure. In addition, a genotype-based analysis showed significant odds ratios for the risk of hypertension in older men (adjusted OR, 5.743; 95% CI, 1.173~28.121; P=0.031). This study suggests that the ATP2B1 variants affect both the systolic and diastolic blood pressure.