• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.33-42
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• 2007

The current left-turn split model adopted in COSMOS has an inherent limitation when a loop detector in the left-turn lanes was disconnected for a period of time. In this instance, the current model always allocated minimum green time to the left-turn phase, thus optimal split and efficient signal operation for the intersection was not guaranteed. In this paper, four mathmatical models using detector information of the intersection and four empirical models using historical profiles were developed and investigated for different traffic conditions to improve the operational efficiency of the intersection. From the model evaluation test, the empirical model using a four-week historical profile produced the least error among the eight models investigated. NETSIM simulation test results also showed that the proposed model could give significantly reduced delay time as compared to the current model. From these results, the operational efficency of the signalized intersections under the real-time control can be greatly improved by using the model proposed in case of the left-turn detector failure.

• Journal of Korea Water Resources Association
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• v.33 no.3
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• pp.375-382
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• 2000

The surface hydrology of large watershed is susceptible to several preferred stable states with transitions between stable states induced by stochastic fluctuations. This comes about due to the close coupling of land surface and atmospheric interaction. An interesting and important issue is the duration of residence in each mode. In this study, mean transition tunes between the stable modes are analyzed for the Han River Basin. On the basis of historical data, the nonlinear water balance model is calibrated for the Han River Basin. The transition times between the stable modes in the model are studied based on the stochastic representation of the physical processes and on the calibrated model parameters. This study has implications for prediction of the transition time between stable modes or residence times, that is, the time the system spends in a given stable modes, since this would be equivalent to predicting the duration of drought or wet conditions.

• Journal of Digital Convergence
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• v.14 no.2
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• pp.519-527
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• 2016

This research aims at investigating the measures of agreement between BMI classification standard and that of 9-point contour drawing rating scale(CDRS), verifying their usefulness for the application to the filed, examining university students' substantial understanding of their bodies, and offering correct information regarding the distorted recognition of their bodies. In order to examine the measures of agreement between the classification standard of BMI and that of CDRS, and the women university students' recognition of their body images depending on BMI, Cross tabulation was carried out, and ${\chi}^2$, Spearman rank correlation coefficient and kappa statistics were calculated. As the analysis results, the classification standards of CDRS and BMI judged by general female college students showed statistically the correlation was high with ${\rho}=.719$(p<.001) and an average level of confirmity with ${\kappa}=.506$(p<.001). Based on these results, regarding body shape, sizes and shapes according to racial characteristics need to be controlled later.

• Korean Business Review
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• v.18 no.1
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• pp.43-57
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• 2005

This paper investigate to test the validity of the basic assumptions of strategic trading models with the broker and informed trader using daily closing data of KOSPI 200 stock index futures for the year 2001-2003. Major results are summarized as follows: (i) For these years, while foreign investors and brokerage companies traded for the directions consistent with the model, brokerage companies and individual investors traded for inconsistent directions. (ii) Cross correlation function (CCF) analysis shows no systematic dependency in the trading between all three participants(foreign investor, brokerage companies and individual investors) for these years. (iii) Chi-square validity test for the 30 days of the largest unexpected trading volume shows some systematic dependency in the trading between three participants for these years. Finally, some limitations of this paper and direction for further research were suggested.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.2
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• pp.65-74
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• 2009

In optimizing the neural network structure, there are two methods of the pruning scheme and the constructive scheme. In this paper we use the pruning scheme to optimize neural network structure, and the genetic algorithm to find out its optimum node pruning. In the conventional researches, the input and hidden layers were optimized separately. On the contrary we attempted to optimize the two layers simultaneously by encoding two layers in a chromosome. The offspring networks inherit the weights from the parent. For teaming, we used the existing error back-propagation algorithm. In our experiment with various databases from UCI Machine Learning Repository, we could get the optimal performance when the network size was reduced by about $8{\sim}25%$. As a result of t-test the proposed method was shown better performance, compared with other pruning and construction methods through the cross-validation.

• Journal of the Korean Data and Information Science Society
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• v.28 no.2
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• pp.349-359
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• 2017

In this paper, we conducted survival analyses by fitting the Cox proportional hazards model to stage III proximal colon cancer data obtained from the Surveillance, Epidemiology, and End Results program of the National Cancer Institute. We investigated the effect of covariates on the hazard function for death from proximal colon cancer in stage III with surgery performed and estimated the survival probability for a patient with specific covariates. We showed that the proportional hazards assumption is satisfied for covariates that were used to analyses, using a test based on the Schoenfeld residuals and plots of the Schoenfeld residuals and $log[-log\{{\hat{S}}(t)\}]$. We evaluated the model calibration and discriminatory accuracy by calibration plot and time-dependent area under the ROC curve, which were calculated using 10-fold cross validation.

• Journal of Digital Convergence
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• v.16 no.7
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• pp.493-509
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• 2018

This study was performed to compare the effects of health behaviors, dietary habits, and psychological health on metabolic syndrome (MS) between young adults living in one-person households (OPHs) and multiple-person households (MPHs). The data from the Korean National Health and Nutrition Examination Survey (KNHANES), which was conducted in 2014 and 2016 were used. The subjects were 2,682, who were 20 to 39 years old. The data were analyzed using complex sample Rao-Scott ${\chi}^2-tests$, t-tests, and multiple logistic regression using SPSS 23.0 software. Sex, age, obesity, and subjective health status were associated with MS in young adults living in either OPHs or MPHs. Breakfast consumption frequency, eating alone, food label use, stress, and depression were associated with MS only in young adults living in OPHs. Thus, these differentiated risk factors of MS should be considered, when health promotion strategies and interventions are planned for young adults living in OPHs. Also, further studies are needed to evaluate the effectiveness of the strategies or interventions.

• The Journal of the Convergence on Culture Technology
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• v.6 no.1
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• pp.419-424
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• 2020

This study was to examine the educational satisfaction of students majoring in music education and provided suggestions to the college of education, Korea. First of all, 152 students majoring in music education in university, Korea, were surveyed. Second, the SPSS 22 for Windows program was used to conduct technical statistical analysis: independent sample t-test, one-way variance analysis, and cross-analysis. The result was that there were significant differences in the educational satisfaction, depending on the gender, school year, career-hopping professions, and individual efforts of students. College of Education has a huge impact on society as an institution that trains pre-service teachers who will teach future students. Therefore, based on the results of the study, I hope that the college of education will serve as fundamental institutes for the training of pre-service teachers.

• International Journal of Highway Engineering
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• v.11 no.4
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• pp.33-40
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• 2009

This study deals with the traffic accidents of elderly drivers. The objectives are to comparatively analyze the characteristics of accident between the elderly and other drivers, and to develop the models of traffic accidents. In pursuing the above, this paper gives particular attentions to testing the differences between the above two groups, and developing the models(Poisson and negative binomial regression) using the data of Cheongju 4-legged signalized intersections. The main results analyzed are as follows. First, the differences between the elderly and other drivers' accidents were clearly defined by the time of day, accident type, etc. Second, 3 accident models which were all statistically significant were developed. Finally, the differences between elderly and other drivers' models were comparatively analyzed using the common and specific variables.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.1036-1045
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• 2017

This study aimed to investigate the relationship between mental health and health risk behaviors of college students and to verify that depression has mediating effects in the relation between perceived stress and health risk behaviors. Data were obtained from the 2015 Community Health Survey conducted nationally, and the subjects of this study were 8,422 college students ranging in age from 19 to 29. Rao-Scott Chi-square test, logistic regression analysis, and Sobel test were used for data analysis. The results of the study showed that perceived stress, depression, present smoking, binge drinking, and high risk drinking of college students were associated with sex, age, and monthly household income. Smoking, binge drinking and high-risk drinking were affected by perceived stress, and depression was an influence factor of current smoking and binge drinking. Depression showed partial mediating effect between perceived stress and current smoking and between perceived stress and binge drinking. Such results suggest that a comprehensive behavioral health intervention strategy that covers mental health care of college students is necessary.