• Journal of Labour Economics
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• v.30 no.2
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• pp.87-118
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• 2007

Using KRIVET's Graduates Economic Activities Survey for 2005, this article examines the relationship between university ranking and labor market outcome, with a focus on wage differentials existing between provincial and Seoul metropolitan area university graduates. According to the analysis results, the average monthly wage for provincial university graduates was 1,747.7 thousand Korean won, which is 11.5% lower than that for graduates of universities in the Seoul metropolitan area. School effects on individual wage were estimated to about 12.2% after applying Hierarchical Linear Model technique, which means that university explains only an insignificant part of the total variance in wage among graduates. After controlling for the selection bias, the ability difference between the two areas, by applying the Heckman type 2SLS wage function and Neumark wage differential decomposition technique, the wage gap resulting from the segregation was not identified. This implies that, to a significant extent, the wage gap between provincial and Seoul metropolitan university graduates is attributed to the difference in productivity among individual graduates, rather than to the wage segregation. Also, the estimated wage function by applying Quantile Regression technique indicates that there does not exist any significant wage segregation difference by wage quantile.

• Journal of Korea Water Resources Association
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• v.46 no.6
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• pp.585-596
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• 2013

The objective of this study is to evaluate the hybrid downscaling method combined Step-Wise Scaling (SWS) method with Regional Climate Model (RCM) simulation data for climate change impact study on hydrology area. The SWS method is divided by 3 categories (extreme event, dry event and the others). The extreme events, wet-dry days and the others are corrected by using regression method, quantile mapping method, mean & variance scaling method. The application and evaluation of SWS method with 3 existing and popular statistical techniques (linear scaling method, quantile mapping method and weather generator method) were performed at the 61 weather stations. At the results, the accuracy of corrected simulation data by using SWS are higher than existing 3 statistical techniques. It is expected that the usability of SWS method will grow up on climate change study when the use of RCM simulation data are increasing.

• Journal of Information Technology Applications and Management
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• v.27 no.3
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• pp.37-54
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• 2020

In response to the recent decline in the school-age population, universities have made attracting foreign students a major policy task for universities. As a result, the number of foreign students increased rapidly in terms of quantity, but in terms of quality, the risk is inevitable. Accordingly, the government presented education and internationalization competency certification system indicators on the basis of which quality control of students was systematized. Based on the above certification system, this study focused on analyzing the multiple factors that are actually given to the academic adaptation (performance) of the 2200 students who entered a certain university. In addition, factors other than the certification system index were discovered to comprehensively track how they affect the academic performance of students studying abroad. The researcher found the multi-reciprocal model analysis showed that the difference between the learner and the moderator was significant, and whether or not they had the Korean proficiency test (TOPIK) was significant. It also said that it could have a direct impact on Chinese University Entrance Exams (高考) are significant. If a model that is very effective in selecting students is established by each university and used as an indicator through this study, it will serve as a basis for efficient selection of students.

• The Korean Journal of Applied Statistics
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• v.29 no.1
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• pp.75-83
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• 2016

We propose methodology to analyze the dynamic mechanisms of financial market contagion under market integration using a biological contagion analytical approach. We employ U-statistic to measure market integration, and a dynamic model based on an error correction mechanism (single equation error correction model) and latent factor model to examine market contagion. We also use quantile regression and Wald-Wolfowitz runs test to test market contagion. This methodology is designed to effectively handle heteroscedasticity and correlated errors. Our simulation results show that the single equation error correction model fits well with the linear regression model with a stationary predictor and correlated errors.

• Journal of Korea Water Resources Association
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• v.33 no.4
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• pp.419-426
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• 2000

It is very important to establish sufficiently long and reliable annual maximum rainfall data in estimating areal rainfall quantiles of Han River Basin. The data from 9 gauging stations measured by Korea Meteorological Administration may meet such a requirement, however the number of these data sets is too small to estimate overall areal rainfall quantiles in large basin such as Han River Basin. In order to solve such a problem, the space correlations of many sites' data measured by Korea Ministry of Construction and Transportation and Korea Water Resources Corporation (the number of sites is 59) were used for modification of rainfall measure density. And areal rainfall quantiles according to each sub-basin were estimated based on regression analysis.

• Journal of Korean Society for Quality Management
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• v.51 no.4
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• pp.497-514
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• 2023

Purpose: This study aims to estimate the demand for various public parking lots in Seoul by clustering similar demand types of parking lots and predicting the demand for new public parking lots. Methods: We examined real-time parking information data and used time series clustering analysis to cluster public parking lots with similar demand patterns. We also performed various regression analyses of parking demand based on diverse heterogeneous data that affect parking demand and proposed a parking demand prediction model. Results: As a result of cluster analysis, 68 public parking lots in Seoul were clustered into four types with similar demand patterns. We also identified key variables impacting parking demand and obtained a precise model for predicting parking demands. Conclusion: The proposed prediction model can be used to improve the efficiency and publicity of public parking lots in Seoul, and can be used as a basis for constructing new public parking lots that meet the actual demand. Future research could include studies on demand estimation models for each type of parking lot, and studies on the impact of parking lot usage patterns on demand.

• Korean Journal of Social Welfare Studies
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• v.47 no.3
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• pp.35-60
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• 2016

This study analyzes the unequal distributional effect of threesome of family policy(child benefit, childcare services and parental leave) focusing on family income, mother's status in labor market in Korea. To measure the unequal distributional effect of family policies, this study used the quantile analysis. The results of this study are as follows. First, in terms of childcare service and parental leave, there is some difference of the rate of use by family income and mother's status in labor market. Second, total public fund for childcare services, child benefits and parental leave are high in fourth income quintile, and mothers work regularly. Third, public fund is high in fourth income quintile, dual earners, mothers work regularly, the family has many number of child, and is high educational level of parents. Finally, the results of quantile regression show the biggest factors of unequal distribution of family policy are mother's stable work and it deepens the inequalities and differences. Based on these results, this article suggests that more equal right to access and use family policy regardless of the type of employment, adequate minimum income through income transfer, and universal application of the policy.

• KDI Journal of Economic Policy
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• v.39 no.3
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• pp.1-18
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• 2017

The anchoring effect can be found when a decision shows cognitive prejudice towards the initial information given. Several studies have argued that such an effect is present even for judges in the courtroom. This paper seeks to find a relationship between judges' decisions on penalty sentences and the sentences recommended by prosecutors. In this study, 2,773 actual court cases are considered in the analysis, and quantile regression is used to show that the sentencing decisions judges make are anchored by the recommendations of prosecutors. However, this reliance on recommendations differs according to the seriousness of the crime committed. Specifically, at the lowest penalty levels, a one-month increase in the prosecutors' sentencing recommendation results in a 0.25-month increase in the judges' sentence, while at the highest sentence level, the judges' sentences increase by 0.78 months under an identical condition. The results of this research indicate the need to create more objective and clear sentencing guidelines in the future in an effort to mitigate the psychological pressure experienced by judges with regard to serious offences or heinous crimes.

• Communications for Statistical Applications and Methods
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• v.22 no.6
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• pp.543-556
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• 2015

We present a survey of contributions that defined the nature and extent of robust statistics for the last 50 years. From the pioneering work of Tukey, Huber, and Hampel that focused on robust location parameter estimation, we presented various generalizations of these estimation procedures that cover a wide variety of models and data analysis methods. Among these extensions, we present linear models, clustered and dependent observations, times series data, binary and discrete data, models for spatial data, nonparametric methods, and forward search methods for outliers. We also present the current interest in robust statistics and conclude with suggestions on the possible future direction of this area for statistical science.

• Journal of Labour Economics
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• v.33 no.1
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• pp.1-30
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• 2010

Using the College Scholastic Ability Test of year 1995, the paper investigates effects of classroom peers on a student's test scores. It exploits exogenous assignment of students across different classrooms within a school under the leveling policy in 1990s. The empirical results reveal strong impacts of peers on individual students. Negative effects of low-performing peers exceed positive effects of high-performing peers. Such a structure of peer interactions has important implications for ability grouping vs. mixing debates in Korea.