• Journal of the Korean Society for Railway
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• v.16 no.1
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• pp.59-64
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• 2013

This study analyzed passenger access and egress travel patterns related to a Korean regional railway station (Seoul station), then developed a binomial logit model. This model referred to bus and metro mode of access and egress during a national holiday (Chuseok 2009); obtained from transit smart card data. The results showed that 99% of passengers getting access to, or egress from, the regional railway station did so using less than two transfers, and that most passengers were more likely to choose a metro. However, the passengers that made access or egress trips near Seoul Station were more likely to take a bus. From the results of the mode choice model, it was found that the impact of travel time was greater than that of travel cost, in the choices made for both access and egress. Interestingly, the impact of travel time is much greater in choosing the mode of egress.

• Journal of the Korean Data and Information Science Society
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• v.27 no.3
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• pp.663-676
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• 2016

In Korean professional baseball the championship team of the year is determined by the four series of games: semi-semi-playoff, semi-playoff, playoff and korean series. To the top 5 teams in a regular season privileges are given to play the games at post season. At semi-semi playoff the winner of two teams which are ranked at 4th and 5th place in the regular season can advance to the game of semi playoff. The winner at semi playoff advances to the playoff to play with the second place team in the regular season. Finally, the championship team is to be determined in the Korean series between the winner of the playoff and the first ranked team in the regular season. We propose methods of how to calculate the winning probabilities of each of high ranked 5 teams advancing to Korean series. From our proposed methods we can estimate the championship probabilities of each of high ranked 5 teams advancing to the Korean series only if we know the winning probabilities between two teams in the regular season or the post season.

• Journal of the Korean Data and Information Science Society
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• v.21 no.3
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• pp.407-417
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• 2010

In Basel II compliance, internal rating systems are allowed for banks to enhance the self control and the validation of the system are getting more important. The validation methods are composed of qualitative test and quantitative test, three basic standards of which are discriminatory power, stability and calibration. The aim of this article is to review the quantitative tests for calibration and find a new method for it. These methods for discrimination between forecasted PD and observed PD include binomial test, chi square test, Brier score, traffic lights approach, normal test and extended traffic lights approach. We introduce a modified extended traffic lights approach considering asset correlations.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.1421-1426
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• 2016

Background: There is a considerable lack of understanding of oral cancer incidence, especially its time trend in Iran. In this study, the authors aimed to analyze time trend of oral cancer incidence with a focus on differences by gender in a period of six years - from 2005 to 2010. Materials and Methods: Both population-based cancer registry and national cancer registry (NCR) data based on pathologic reports from 2005 to 2010 were obtained from the Ministry of Health and Medical Education (MOHME). Population data were also received from Statistical Centre of Iran. Age-standardized incidence rates (ASRs) based on the World Standard Population were then calculated. Finally, Negative Binomial regression was run for time trend analysis. Results: The maximum ASR for males was calculated as 2.5 per 100,000 person-years in 2008 and the minimum was observed as 1.9 per 100,000 person-years in 2005 and 2006. Meanwhile, the maximum ASR for females was estimated as 1.8 per 100,000 person-years in 2009 and the minimum was calculated as 1.6 per 100,000 person-years in 2005 and 2006. Additionally, in females, incidence risk ratio (IRR) did not show a clear decreasing or increasing trend during the six years. Nevertheless, in males an increasing trend was observed. The maximum IRR adjusted for age group and province, for females was reported in 2009 (IRR=1.05 95% CI: 0.90-1.23), and for males was estimated in 2010 (IRR=1/2 95% CI: 1.04 - 1.38). Conclusions: Our findings highlight disparities between oral cancer incidence trends in males and females over the six years from 2005 to 2010.

• Journal of Korean Society of Transportation
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• v.25 no.1 s.94
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• pp.23-35
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• 2007

Freeway diverging areas are very vulnerable to traffic accidents due to abrupt vehicle speed changes and geometric changes. Therefore, in designing diverging areas, much attention should be Paid to safety The Present design criteria about freeway diverging areas regulate transition sections for lane changes, deceleration lanes, transition corves for direction changes. and other similar items. However, the design criteria were often violated in implementation because of ambiguities in the criteria. This study aims at clarifying and improving the present design criteria for freeway diverging areas. For this, field survey data and traffic accident data for diverging areas were analyzed.

• Journal of Technology Innovation
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• v.25 no.3
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• pp.83-113
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• 2017

This paper constructs panel data of inventors listed on patents applied for the KIPO during 1991-2005 and analyzes the effects of network characteristics on inventor productivity. The findings are as follows: ⅰ) Strong ties within a network have positive effects on inventor productivity. ⅱ) An inventor with high centrality shows high producitivity. ⅲ) Technological diversity of a network enhances inventor productivity. ⅳ) An inventor belonging to a network of good quality shows higher productivity. ⅴ) Network size is positively related with inventor producitvity. ⅵ) A lone inventor shows the highest productivity among types of inventors, and a co-inventor with the experience of standalone invention is more productive compared to an inventor with only the experience of co-invention. ⅶ) The productivity effects of network variables differ across regions. ⅷ) Differences among regions do not decrease though geographical boundaries become less important.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.20 no.1
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• pp.26-33
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• 2012

Competition between air transportation and railways has grown fiercer in major countries around the world with the rise of high-speed railways. In South Korea, air passenger travel has been rapidly decreasing since the initial launch of the Seoul-Pusan KTX line in 2004 and second opening that followed in 2010. Further expansion of the high-speed railway is expected. At present, research efforts to verify the validity of constructing an underwater express railway tunnel between Ho-nam and Jeju Island are taking place. Considering the possible high speed railway connection between Seoul and Jeju Island, this thesis has analyzed the choice behavior of existing passengers of the major and low-cost carriers. For this, Stated Preference (SP) research has been performed for three variables, including fare, travel time and the number of runs, to estimate the substitution rate of each of the three variables. Binomial Logit Model has been estimated with the obtained data. The estimation of the model has found that airline passengers of major and low-cost carriers are willing to pay approximately 7,200 KRW and 5,000 KRW, respectively, to reduce travel time by one hour. If the number of runs in one day increases, it has been estimated that the passengers are willing to pay additional fares of about 390 KRW and 30 KRW, respectively. On the other hand, the substitution rate between the number of runs and the travel time was found to be somewhat insignificant. If the construction of the Seoul-Jeju line progresses in the future, this study could be used as preliminary data for determining fares, travel time and the number of runs.

• Journal of Global Scholars of Marketing Science
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• v.11
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• pp.129-146
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• 2003

This study explores whether a NBD type of model can be applied to characterize the underlying frequency distribution of online consumer's visit behavior. In this study, the following two research questions are addressed: (1) How can we characterize the underlying distribution pattern(s) of the number of repeat i i visits to a site? (2) How can consumer's Internet usages and his/her demographics affect the average number of visits to the site? Through the empirical investigation, this study found that NBD models are directly applicable to characterize the underlying distribution of visit frequency on the Internet. Furthermore, this study addresses some managerial implications for understanding how site visits are determined. Especially this study highlights the relationship between repeated visits and the visitors' Internet Usages and demographics. The proposed models are estimated and validated by online panel data that covers more than 1000 different sites and has 800,000 observations.

• Journal of Korean Society of Transportation
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• v.26 no.4
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• pp.29-40
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• 2008

Although a good understanding of the relationship between highway traffic accidents and highway geometric features is fundamental in highway design and safety, the relationship is not well understood quantitatively. The overall goal of this paper is to formulate a reliable statistical model fitting to historical highway accident data. The model can be used to estimate the effect of road design elements on safety for the practical purposes of highway design applications. En route to achieving this goal, a number of specific research objectives were accomplished: investigate the major design elements affecting highway safety; review the existing modeling approaches in order to assess the relationship between safety and highway design features; and formulate a statistical model fitting to the accident data in order to estimate the interchange ramp junction accident frequency of rural highways.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.526-534
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• 2018

The purpose of this study is to classify the degree of change of job discrimination of the disabled according to time and to identify factors affecting life satisfaction according to each type. For this study, data from the 3rd to 8th year of the employment panel for the disabled were used and 1,227 data were used. The longitudinal profile of the disabled person's discrimination was classified through latent profile growth analysis(LPGA), and then influential factors were verified through binomial logistic regression analysis. First, the types of change of the job discrimination of the disabled were represented as the decrease group and the increase group. The factors influencing the job discrimination were the degree of disability, chronic diseases, gross income, and life satisfaction. Second, the factors of predicting the life satisfaction according to the types of job discrimination of the disabled are as follows: job discrimination, decrease and increase group have higher life satisfaction as the self - esteem and socioeconomic status are higher. Based on these results, this study suggested the implications of this study to cope with the discrimination of the workplace with the disabled.