• Journal of Korea Port Economic Association
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• v.37 no.3
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• pp.1-17
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• 2021

Forecasting the daily volume of container is important in many aspects of port operation. In this article, we utilized a machine-learning algorithm based on decision tree to predict future container throughput of Busan port. Accurate volume forecasting improves operational efficiency and service levels by reducing costs and shipowner latency. We showed that our method is capable of accurately and reliably predicting container throughput in short-term(days). Forecasting accuracy was improved by more than 22% over time series methods(ARIMA). We also demonstrated that the current method is assumption-free and not prone to human bias. We expect that such method could be useful in a broad range of fields.

• Journal of the Korean Data and Information Science Society
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• v.27 no.5
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• pp.1293-1305
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• 2016

In this paper, we develop debt collection predictive models for the person in arrears by utilizing the direct loan data of the Korea Student Aid Foundation. We suggest credit risk scorecards for overdue student direct loan using the developed 3 models. Model 1 is designed for 1 month overdue, Model 2 is designed for 2 months overdue, and Model 3 is designed for overdue over 2 months. Model 1 shows that the major influencing factors for the delinquency are overdue account, due data for payment, balance, household income. Model 2 shows that the major influencing factors for delinquency loan are days in arrears, balance, due date for payment, arrears. Model 3 shows that the major influencing factors for delinquency are the number of overdue in recent 3 months, due data for payment, overdue account, arrears. The debt collection predictive models and credit risk scorecards in this study will be the basis for segmented management service and the call & collection strategies for preventing delinquency.

• Journal of Korean Society of Transportation
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• v.35 no.4
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• pp.321-331
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• 2017

The objective of this study is to analyze the factors affecting the pedestrian accidents of roundabout near schools. To this end, this study has focus on the comparative analysis of pedestrian accidents across different school areas. The traffic accident data from 2007 to 2014 are collected from TAAS data set of Road Traffic Authority. To develop the pedestrian accident rate model, the linear regression model has been utilized in this study. 28 explanatory variables such as geometry and traffic volume factors are used. The main results are summarized as follows. First, the null hypotheses that the number of pedestrian accidents are the same are rejected. Second, 5 multiple linear regression accident models with higher statistical significance (adjusted $R^2$ of 0.651~0.788) have been developed. Third, while the common variables of 3 models (model I~III) related to school location are evaluated to be the pedestrian island, crosswalk, types of roundabout, elementary school and bus stop. Fourth, while the common variable of 3 models (model III~V) related to near school area or not is evaluated to be pedestrian island, type of roundabout, sidewalk, elementary school, speed hump, speed limit sign and number of entry lane. As a result, the installation of pedestrian islands and crosswalk might be expected to decrease the number of pedestrian accidents near schools.

• 재활복지
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• v.21 no.2
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• pp.169-190
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• 2017

The purpose of this study was to investigate item goodness-of-fit of Scale, Rasch rating scale model was applied to 5 dimensions 24 items of the Test of Performance Strategies (TOPS) in a sample of athletes with physical disabilities (n=215). An assumption to test Rasch Model, which is satisfaction of unidimensionality, is regarded through PCAR test, and WINSTEPS 3.65 program is used to test the goodness-of-fit of items. The results of this study were: First, 3-point rating category was appropriate for the TOPS instead of the existing 5-point rating category. Second, as a result of analyzing the goodness-of-fit of the items, 21 items of the TOPS were suitable, but 3 items were not. Third, the item reliability of person separation of the TOPS was acceptable, but the person reliability of item separation was not suitable and it was necessary to adjust the item order considering the difficulty level of the items. Fourth, as a result of comparing the individual attribute score and the difficulty level through the Item-Person Map, the distribution of the item difficulty distribution was shown to be biased in some factors compared to the personal attribute score distribution.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.3
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• pp.281-293
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• 2020

Recently, large and small fires have been happening more often in Korea. Fire is one of the most frequent disasters along with traffic accidents in korean cities, and this frequency is closely related to the land use and the type of facilities. Therefore, in this study, the significance of fires was analyzed by considering land use, facility types, human and social factors and using 10 years of fire data in Jinju city. Based on this, OLS (Ordinary Least Square) regression analysis, SLM (Spatial Lag Model) and SEM (Spatial Error Model) using space weights, were compared and analyzed considering the location of the fire and each factor, then a statistical model with high suitability was presented. As a result, LISA analysis of spatial distribution patterns of fires in Jinju city was conducted, and it was proved that the frequency of fires was high in the order as follow, central commercial area, industrial area and residential area. Multiple regression analysis was performed by integrating demographic, social, and physical variables. Therefore, the three models were compared and analyzed by applying spatial weighting to the derived factors. As a result of the significance test, the spatial error model was analyzed to be the most significant. The facilities that have the highest correlation with fire occurrence were second type neighborhood facilities, followed by detached house, first type neighborhood facilities, number of households, and sales facilities. The results of this study are expected to be used as significant data to identify factors and manage fire safety in urban areas. Also, through the analysis of the standard deviation ellipsoid, the distribution characteristics of each facility in the residential area, industrial area, and central commercial area among the use areas were analyzed. In, the second type neighborhood facility with the highest fire risk was concentrated in the center. The results of these studies are expected to be used as useful data for identifying factors and managing fire safety in urban areas.

• The Korean Journal of Applied Statistics
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• v.34 no.2
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• pp.255-266
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• 2021

The purpose of this study is to compare the effects of treatment on stage III stomach cancer data obtained from the SEER program of the National Cancer Institute and to identify the significant risk factors for the survival rates of stage III stomach cancer. Since the proportional hazards assumption was violated for treatment, we used the restricted mean survival time as an alternative to the proportional hazards model. The restricted mean survival time was estimated using pseudo-observations, and the effects of treatment were compared using a test statistic based on the estimated restricted mean survival times. We conducted the regression analysis using a generalized linear model to investigate the significant predictors for the restricted mean survival time of patients with stage III stomach cancer. We found that there was a significant difference between the restricted mean survival times of treatment groups. Age at diagnosis, race, substage, grade, tumor size, surgery, and treatment were significant predictors for the restricted mean survival time of patients with stage III stomach cancer. Surgery was the most significant predictor for increasing the restricted mean survival time of patients with stage III stomach cancer.

• The Journal of the Korea Contents Association
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• v.19 no.1
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• pp.256-265
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• 2019

This study, the Grindler Body Attitude Sale developed by Grindler(1991) was adopted and validation to the Korean culture. 3-factors and 25 Items were constructed through item content analysis and exploratory factor analysis. and 3 factors named through the characteristic context are 'Awareness of the Body attitude', 'evaluation of the Body attitude', and 'management of the body attitude'. The result of confirmatory factor analysis showed that the fit of the 3 factor model was good. Korean version body attitude scale was positively relate to Body esteem, Concise Measure of Subjective Well-Being and Body Cathexis Scale. and negatively related Stress response scale. At the end, limitation and suggestions for the future research were discussed.

• Journal of Korea Technology Innovation Society
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• v.9 no.3
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• pp.451-470
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• 2006

This study aims to test factors on the success of Employee Suggestion Systems (ESS). Considering the difference between manufacturing and non-manufacturing firms in the use of ESS, this study analyzes the impact of the industrial sector. Partial Least Square (PLS) is employed to analyze data front employees in an automobile company and a bank. The result shows that there is no distinctive difference between two industries but there are some differences in the strength of the relationships such as e impact of pro-activity on idea generation, the work improvement on idea generation and idea generation on idea submission. Some suggestions for managing ESS in non-manufacturing firms are presented.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.5
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• pp.209-225
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• 2009

This research has been studied to analyze affecting factors for the consumer's acceptance to mobile advertisement by worldwide survey into mobile users of Korea, U.S. and Japan. Based on TAM & Flow theory, our research adopts some factors for a theoretical model such as entertainment, information, irritation, credibility, flow experience, attitudes and acceptance intention. And our research collects data from common consumers & students of each countries to try comparative study with mobile users who has different scope & environment of markets. This data was analyzed based on using AMOS, the structural equation modeling and a second-generation multi variant technique, and has gained distinct advantages over other technique.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.102-102
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• 2017

갈수시 하천의 수질문제는 다양한 요인에 의해 발생하고 제어된다. 수질 그 자체는 상류나 지류의 점오염원과 비점오염원의 증가 또는 예상치 못한 추가적인 오염원의 유출에 직접 영향을 받으며, 조류 등의 발생도 영향인자인 수온 및 일사량 또는 바람에 의존적이다. 최근 수년간은 특히 빈번한 가뭄조건의 발생으로 인하여 갈수기의 강우 및 유출량이 저조하여 상대적으로 하천의 조류발생이 다수 발견되고 보고된 바 있다. 이와 같은 수질의 이상상태를 일시적으로라도 제어하기 위한 방편으로 유량의 증가, 인위적인 하천 수위의 변동 및 유속 변동 등이 고려될 수 있으며, 이를 위해서는 상류의 댐과 하천의 다기능보 등의 조절을 탄력적으로 수행하여야 한다. 이와 같은 시설물 운영효과는 수질문제의 원인을 근본적으로 해결하는 것은 아니지만, 이의 일시적인 효과를 극대화하기 위해서는 기존의 수리 수질 모델링이 이상 수질 발생시의 방제 및 사후분석 등을 중심으로 이루어진 부분을 넘어서, 사전 설정된 조건에 의한 예측모의와 가이드라인의 연계방식이 효과적일 것이다. 본 연구는 수질 이상이 빈번히 발생되었던 낙동강의 칠곡 하류 하천을 중심으로 2차원 CE-QUAL-W2 모형과 EFDC모형을 병행 모의하여 다기능보 인근의 표층과 저층의 수온(밀도) 성층화 및 이의 해소와 관련된 수리모의 및 수질인자에 대한 영향을 분석하였다. 수리모형 구축의 적정성은 현장의 실측 수온과 모의결과 비교를 통해 확인하였으며, 구축된 수리 수질 모델을 이용하여 추가방류량 3~23백만$m^3$ 규모에서 발생하는 수리적인 수층혼합 현상과 일시적으로 저감가능한 수질개선 효과가 의미있는 수준으로 나타날 수 있음을 예측하였다. 또한, 다기능보의 수문방류 모의시에 개방조건을 0.3~3.5m로 달리하여 방류기간 중 총방류량이 유사하더라도 최대방류량 또는 유속이 충분치 않은 경우에는 혼합효과가 급격히 감소함을 알 수 있었다. 연구에서 밝혀진 조건들을 향후 보다 효과적으로 수치모의하기 위한 방안으로서 EFDC모형의 내부경계조건을 다기능보의 문비조건(RSG, Lift 등)에 맞게 조정하는 방법을 제안하고 그 적용성을 검토한 뒤 모형을 부분 수정하여 제시하였다.