• Journal of Technology Innovation
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• v.26 no.4
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• pp.29-56
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• 2018

The purpose of this research is to examine whether investment portfolio composition affects the technological performance of corporate venture capital (CVC). The stages of investment are categorized from "start-up/seed", "early", and "expansion", to "later" stage. We posit and test that the investment stage composition in a portfolio is highly correlated with the growth potential and downside risk of the portfolio, which in turn influences an investor's innovation performance. To test this hypothesis, we used negative binomial panel regression with 21 years of deal data from 70 cases of CVC. The results show that there is an inverted U shaped relationship between investment portfolio composition and technological performance. This means that the more seed or early stage investment within the investment portfolio, the higher the innovation performance; however, if the amount of seed or early stage investment is over a certain level, the performance decreases. Further, this study finds that the external partners of a venture negatively moderate the inverted U shaped relationship between portfolio composition and innovation performance. We believe that corporate planners, venture capitalists, and policy makers will be helped by these results showing that companies can maximize their investment performance by considering the investment stage and progress of investments.

• The Korean Journal of Applied Statistics
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• v.21 no.6
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• pp.923-932
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• 2008

We are likely to face complex multivariate data which can be characterized by having a non-trivial correlation structure. For instance, omitted covariates may simultaneously affect more than one count in clustered data; hence, the modeling of the correlation structure is important for the efficiency of the estimator and the computation of correct standard errors, i.e., valid inference. A standard way to insert dependence among counts is to assume that they share some common unobservable variables. For this assumption, we fitted correlated random effect models considering multilevel model. Estimation was carried out by adopting the semiparametric approach through a finite mixture EM algorithm without parametric assumptions upon the random coefficients distribution.

• The Journal of the Korea Contents Association
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• v.13 no.7
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• pp.361-368
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• 2013

This research aims to offer the information required for demand increase on marketing strategy level by investigating Mudeungsan visitors' demographic characteristics and social economical variables. To accomplish this study, the proper analyzing model needs to be applied because a grave error of parameters will be led if regression model appropriate for analyzing the data of a continuous probability variable is applied, in case that dependent variable is a discrete random variable which have a discrete probability distribution. Therefore data analysis was performed with Poisson model. However, as the data was showing an overdispersion, parameter was estimated with the Binomial Poisson model able to cover the problem. As a result, some explanatory variables turned out to be significant such as visitor's age, occupation, preferred season to visit, type of company, five days working, and preferring type of tourism. Author could offer to the national park the information about characteristics of core market revealed and marketing strategy for it, based on those influential variables.

• Journal of Oriental Neuropsychiatry
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• v.34 no.4
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• pp.349-358
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• 2023

Objectives: We used the 2019 Korea Health Panel Annual Data to analyze factors related to visits to Korean medicine (KM) outpatient clinics among patients with mood disorders in Korea. Methods: Individuals aged 19 years or older, with depressive or bipolar disorders, and with a record of using Western medicine (WM) and/or the KM medical service were included. The 266 subjects were classified into the WM group or the integrative medicine (IM) group. The Andersen healthcare utilization model was used to analyze factors that potentially influenced the subjects' healthcare utilization. Binomial logistic regression analysis was used to analyze factors influencing the use of IM medical services. Results: Among the subjects, 75.56% (n=201) were in the WM group, and 24.44% (n=65) were in the IM group. Statistically significant differences were observed in residential areas, total annual income, the presence of disability, and the level of pain/discomfort between the two groups. Regression analysis found that residential areas and pain/discomfort were factors related to the use of IM services. Specifically, reporting "a lot" of pain/discomfort compared to "no" pain/discomfort showed a significant positive relationship with the use of IM (odds ratio=4.57, 95% confidence interval=1.79 to 11.70). Conclusions: This study was the first to analyze the status of KM medical service use and related factors among patients with mood disorders in Korea. The finding that the presence of pain/discomfort was positively correlated with the use of KM services is potentially related to medically unexplained physical symptoms or somatization phenomena.

• Journal of Preventive Medicine and Public Health
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• v.50 no.4
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• pp.228-239
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• 2017

Objectives: This study aimed to examine the association between preschool education experiences and adulthood self-rated health using representative data from a national population-based survey. Methods: Data from the Korean Labor and Income Panel Study in 2006 and 2012 were used. A total of 2391 men and women 21-41 years of age were analyzed. Log-binomial regression analyses were conducted to examine the associations between preschool education experience and self-rated health in adulthood. Parental socioeconomic position (SEP) indicators were considered as confounders of the association between preschool education experience and adulthood subjective health, while current SEP indicators were analyzed as mediators. Age-adjusted prevalence ratios (PRs) and the associated 95% confidence intervals (CIs) were estimated. Results: Compared with men without any experience of preschool education, those with both kindergarten and other preschool education experiences showed a lower prevalence of self-rated poor health (PR, 0.65; 95% CI, 0.47 to 0.89). In women, however, such an association was not evident. The relationship of preschool education experiences with self-rated poor health in adulthood among men was confounded by parental SEP indicators and was also mediated by current SEP indicators. After adjustment for parental and current SEP indicators, the magnitude of the associations between preschool education experiences and adulthood subjective health was attenuated in men. Conclusions: Preschool education experience was associated with adulthood self-rated health in men. However, this association was explained by parental and current SEP indicators. Further investigations employing a larger sample size and objective health outcomes are warranted in the future.

• 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.