• Journal of the Korean Data and Information Science Society
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• v.25 no.2
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• pp.411-422
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• 2014

This study analyzed how average GPA (grade point average) changes as the number of completed semesters increases based on the estimates of intercept, slope, and quadratic term. The students included in this study are those who was admitted in 2011 and took 6 consecutive semesters. More precisely, it was analyzed if intercept, slope and quadratic term of average GPA were different between gender and selection method. The results showed that the intercept was different between selection method, the slope was different between gender, but the quadratic term was different between neither selection method nor gender.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.115-115
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• 2021

식생은 증발산, 강우, 토양 수분 등 다양한 수문기상 요인과 밀접한 관계가 있기 때문에 식생의 상태는 가뭄 발생 시 물 부족에 매우 큰 영향을 받는다. 가뭄에 따른 식생의 변화와 영향을 파악하기 위해서는 식생-기후의 피드백을 이해해야 한다. 식생과 기후변수의 상호관계를 묘사하고 결합 확률을 구성하는 것은 식생-기후의 피드백을 이해하는데 적절하다. Copula 함수는 모든 변수를 연결하는 이점을 가지기 때문에 다양한 확률 변수를 결합하는 강력한 접근방법으로, copula를 통한 확률론적 접근방법은 수문 기상 스트레스에 대한 식생의 반응을 효과적으로 조사할 수 있다. 이에 따라 본 연구에서는 copula 기반의 식생-기후의 상호관계를 통해 가뭄 발생 시 식생이 받을 수 있는 영향을 정량화하고자 한다. 이를 위해 위성 자료를 활용한 식생건강성지수(Vegetation Health Index, VHI)와 위성관측된 강수 및 잠재증발산 자료를 적용하여 높은 공간 해상도에서 한국 전역의 식생 가뭄 가능성을 추정하고자 하였다. 강수 및 잠재증발산 자료를 통해 다양한 가뭄지수를 산정하고, copula 결합 이론을 기반으로 VHI와 가뭄지수 간의 이변량 결합 확률모델이 제안된다. 이에 조건부 확률을 적용하여 다양한 가뭄 시나리오에서 식생의 가뭄 가능성을 추정하고, 가뭄에 취약한 지역을 공간적으로 분석하고자 한다. 이를 통해 가뭄 스트레스에 따른 식생 변화와 생태학적 가뭄의 공간적 특성을 효과적으로 파악할 수 있을 것으로 기대된다.

• Journal of Korea Port Economic Association
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• v.38 no.2
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• pp.31-47
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• 2022

The purpose of this study is to develop a reliable tool that can classify and measure detailed indicators related to the performance of ESG implementation in the country and verify their applicability. Based on World Bank's data as input data, 67 types of ESG-related detailed indicators measured in a total of 239 countries were tested to derive an optimal model that could group detailed indicators into three categories: environment, society, and governance. As a result of the analysis, it was confirmed that a total of 10 detailed indicators had a statistically significant relationship with the country's ESG performance. In addition, the detailed indicators showed a positive correlation with the primary latent variables E, S, and G, and showed a high overall index in the suitability of the model to secure the validity and reliability of variable input. As a result, this study confirmed that several detailed performance indicators constituting ESG can be classified as latent variables, and it can be said that clear criteria for the selection method and input validity of variables were presented.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.6
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• pp.49-65
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• 2023

In response to the growing global concern for the environment, the international community has recently committed to achieving 'carbon neutrality.' As a result, numerous studies have been conducted on mode choice models that include carbon emissions as a variable. However, few studies have established a correlation between individual preferences and carbon emissions. In this study, a new mode of transportation named sustainable public transit (SPT), incorporating carbon-reducing transport options like electric scooters, is proposed. Analyzing the individual preferences of commuters on carbon emissions through factor analysis, a stated preference (SP) survey was conducted. A mode choice model for SPT was constructed using multinomial logit models. The results of the analysis showed that gender, income, and specific preferences, such as a passion for exploring new routes, a preference for intermodal transfers, knowledge of carbon reduction, and carbon reduction practices, significantly influence latent preferences for SPT. Therefore, this study is significant as it considers carbon emissions as an attribute variable during the construction of mode choice models and reflects the individual preference variables associated with carbon reduction.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.1
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• pp.37-53
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• 2021

The purpose of this study is to analyze the types of latent profiles depending on the job satisfaction of youth entrepreneurs in South Korea and examine the influence of related variables. Latent profile analysis (LPA) was conducted using data from the 12th year of the Youth Panel Study. Results of the study revealed that there were five latent profiles based on job satisfaction among young entrepreneurs: lowest job satisfaction, mid-low job satisfaction, middle job satisfaction, mid-high job satisfaction, and highest job satisfaction. By applying multinomial logistic analysis, the influencing factors for each latent profiles have been derived. Gender, marital status, subjective health, self-esteem, entrepreneurial motivation, difficulty in start-up, person-job fit, intrinsic or extrinsic job values, business scale, income, work hour, education or training, and labor insurance were significant predictors of youth entrepreneurs' job satisfaction. Based on these results, the article discusses practical implications that can enhance the job satisfaction of young entrepreneurs.

• The Korean Journal of Applied Statistics
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• v.21 no.3
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• pp.399-411
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• 2008

Today, the statistical survey has been carried out variously for the decision-making and administration of the organization. We use the different items in the statistical survey according to the purpose of study. Currently, Gyeongnam province is executing the social index survey to the provincials every year. But, this survey has the limit of the analysis as execution of the different survey per 3 year cycles. The solution for this problem is data fusion technique. Data fusion is generally defined as the use of techniques that collect to combine data including multiple sources in order to raise the quality of information. But, data fusion doesn't mean the ultimate result. Therefor, efficient analysis for the fused data is also important. In this study, we suggest the application methodology of neural network by latent variable through the fused data in statistical survey.

• The KIPS Transactions:PartD
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• v.11D no.6
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• pp.1269-1276
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• 2004

The Parameter Estimation for software existing reliability models, Goel-Okumoto, Yamada-Ohba-Osaki model was reviewed and Rayleigh model based on Rayleigh distribution was studied. In this paper, we discusses comparison of parameter estimation using maximum likelihood estimator and Bayesian estimation based on Gibbs sampling to analysis of the estimator' pattern. Model selection based on sum of the squared errors and Braun statistic, for the sake of efficient model, was employed. A numerical example was illustrated using real data. The current areas and models of Superposition, mixture for future development are also employed.

• The Korean Journal of Applied Statistics
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• v.35 no.3
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• pp.357-370
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• 2022

In this paper, Tobit and Heckit models are introduced. These models have been used for analyzing censored data. Censoring occurs at a specific point and a large number of observations are distributed with a positive probability at a certain point. Censoring can occur due to observing limitation or exogenous variables. Tobit and Heckit models are used to correct sample selection bias, which can occur when an ordinary linear regression model is fitted to censored data. However, the difference between the two models is not clearly accounted for; hence, they have often been used interchangeably. Therefore, the suitability of the models was validated through simulated data, and demonstrated through real data. As the result, it was confirmed that both Tobit and Heckit models are well-fitted to the data censored due to observing limitation, although Tobit model was fitted parsimoniously. In contrast, only Heckit model is well-fitted to the data censored due to exogenous variables.

• The Journal of the Acoustical Society of Korea
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• v.41 no.6
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• pp.662-667
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• 2022

Computing music similarity is an indispensable component in developing music search service. This paper focuses on learning a music similarity function in order to boost cover song identification performance. By using the probabilistic linear discriminant analysis, we construct a latent music space where the distances between cover song pairs reduces while the distances between the non-cover song pairs increases. We derive a music similarity function by testing hypothesis, whether two songs share the same latent variable or not, using the probabilistic models with the assumption that observed music features are generated from the learned latent music space. Experimental results performed on two cover music datasets show that the proposed music similarity improves the cover song identification performance.

• Journal of Cadastre & Land InformatiX
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• v.47 no.1
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• pp.37-51
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• 2017

Despite the improvement in accuracy of heavy rain forecasting, socioeconomic costs due to heavy rain hazards continue to increase. This is due to a lack of understanding of the effects of weather. In this study, the risk of heavy rain hazard was analyzed using the concepts of hazard, vulnerability, and exposure, which are key concepts of impact forecast presented by WMO. The potential impacts were constructed by the exposure and vulnerability variables, and the hazard index was calculated by selecting three variables according to the criteria of heavy rain warning. Weights of the potential impact index were calculated by using PCA and hazard index was calculated by applying the same weight. Correlation analysis between the potential impact index and damages showed a high correlation and it was confirmed that the potential impact index appropriately reflects the actual damage pattern. The heavy rain hazard risk was estimated by using the risk matrix consisting of the heavy rain potential impact index and the hazard index. This study provides a basis for the impacts analysis study for weather warning with spatial/temporal variation and it can be used as a useful data to establish the local heavy rain hazard prevention measures.