• Journal of the Korean Society for Railway
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• v.13 no.2
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• pp.222-228
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• 2010

In this paper, we propose a optimization approach for the Electric Locomotive Overhaul Maintenance Facility (ELOMF), which aims at the simulation optimization so as to meet the design specification. In simulation design, we consider the critical path and sensitivity analysis of the critical (dependent) factors and the design (independent) parameters for the parameter selection and reduction of the metamodel. Therefore, we construct the multi-objective non-linear programming. The objective function is normalized for the generalization of design parameter while the constraints are composed of the simulation-based regression metamodel for the critical factors and design factor's domain. Then the effective solution procedure based on the pareto optimal solution set is proposed. This approach provides a comprehensive approach for the optimization of Train Overhaul Maintenance Facility(TOMF)'s design parameters using the simulation and metamoels.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.3
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• pp.65-77
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• 2015

The urban park has important functions as a habitat for wildlife as well as open space of rest and community for people. This study was carried out to find what factors of structure and vegetation of urban parks could affect forest bird species diversity in Cheonan city. The study surveyed bird and vegetation species in 26 urban parks, Cheonan city. A correlation analysis and multiple linear regressions were performed to test whether habitat structure and vegetation were the major correlate with species diversity. The results showed the Dujeong park was the most high bird species diversity (H' = 2.13), and the Dujeong-8 park (H' = 2.02) and the Cheongsa park (H' = 1.73) were considerably higher than the other urban parks. The variables that were strongly correlated with bird species diversity were park area, number of subtree species, canopy of shrub, number of shrub species, shape index, canopy of subtree, canopy of tree, and impervious surface ratio. The regression of bird species diversity against the environmental variables showed that 3 variables of park area, canopy of subtree, and canopy of tree were included in the best model. Model variable selection was broadly similar for the 5 optimal models. It means park area and multi-layer vegetation were the most consistent and significant predictor of bird species diversity, because urban parks were isolated by built-up areas. Especially the subtree coverage that provides shelter and food for forest birds was an important variable. Therefore, to make parks circular-shaped and abundant multi-layer vegetation, which could be a buffer to external disturbances and improve the quality of habitats, may be used to enhance species diversity in creation and management of urban parks.

• Journal of Biomedical Engineering Research
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• v.31 no.5
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• pp.375-384
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• 2010

The purpose of this study is to determine whether there is a correlation between the segmental bio-impedance measurement with the frequency modulations and the life-style disease of obesity. An obesity is not simply the factor for estimating the life-style disease of obesity, but also the risk factor occurring. There are many methods (BMI, WHR, Waist, CT, DEXA, BIA, etc.) for measuring a degree of obesity; the bio-impedance measurement is more economic and more effective than others. The physical examination, the blood test, the medical imaging diagnosis and the bio-impedancemeasurementswithmultiple frequencies for each body parts have been conducted for 77 people. The estimated value has been calculated through a segmental bio-impedance model based on multi-frequency that was created to reflect the highest correlation by analyzing correlation with linear regression analysis method for the measured bio-impedance and the risk factors. Then we compared with the clinical diagnosis. In case of high level cholesterol, low HDL-C and high LDL-C for life-style disease, the sensitivity is 80~100%and the specificity is 83~100%. This study has shown conclusively that bio-impedance can be a possible predictor to analyze the disease risk rate of population and individual health maintenance. And also the multi-frequency segmental bio-impedance can be used as early predictor to estimate the life-style disease of obesity.

• Journal of the Korean earth science society
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• v.38 no.4
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• pp.283-292
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• 2017

In this study, the empirical models were established to estimate the concentrations of surface-level $PM_{2.5}$ over Seoul, Korea from 1 January 2012 to 31 December 2013. We used six different multiple linear regression models with aerosol optical thickness (AOT), ${\AA}ngstr{\ddot{o}}m$ exponents (AE) data from Moderate Resolution Imaging Spectroradiometer (MODIS) aboard Terra and Aqua satellites, meteorological data, and planetary boundary layer depth (PBLD) data. The results showed that $M_6$ was the best empirical model and AOT, AE, relative humidity (RH), wind speed, wind direction, PBLD, and air temperature data were used as input data. Statistical analysis showed that the result between the observed $PM_{2.5}$ and the estimated $PM_{2.5}$ concentrations using $M_6$ model were correlations (R=0.62) and root square mean error ($RMSE=10.70{\mu}gm^{-3}$). In addition, our study show that the relation strongly depends on the seasons due to seasonal observation characteristics of AOT, with a relatively better correlation in spring (R=0.66) and autumntime (R=0.75) than summer and wintertime (R was about 0.38 and 0.56). These results were due to cloud contamination of summertime and the influence of snow/ice surface of wintertime, compared with those of other seasons. Therefore, the empirical multiple linear regression model used in this study showed that the AOT data retrieved from the satellite was important a dominant variable and we will need to use additional weather variables to improve the results of $PM_{2.5}$. Also, the result calculated for $PM_{2.5}$ using empirical multi linear regression model will be useful as a method to enable monitoring of atmospheric environment from satellite and ground meteorological data.

• Journal of Korean Neurosurgical Society
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• v.57 no.6
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• pp.455-459
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• 2015

Objective : A cost comparison of the surgical clipping and endovascular coiling of unruptured intracranial aneurysms (UIAs), and the identification of the principal cost determinants of these treatments. Methods : This study conducted a retrospective review of data from a series of patients who underwent surgical clipping or endovascular coiling of UIAs between January 2011 and May 2014. The medical records, radiological data, and hospital cost data were all examined. Results : When comparing the total hospital costs for surgical clipping of a single UIA (n=188) and endovascular coiling of a single UIA (n=188), surgical treatment [$mean{\pm}$standard deviation (SD) : \$8,280,000{\pm}1,490,000$] resulted in significantly lower total hospital costs than endovascular treatment ($mean{\pm}SD$ : \$11,700,000{\pm}3,050,000$, p<0.001). In a multi regression analysis, the factors significantly associated with the total hospital costs for endovascular treatment were the aneurysm diameter (p<0.001) and patient age (p=0.014). For the endovascular group, a Pearson correlation analysis revealed a strong positive correlation (r=0.77) between the aneurysm diameter and the total hospital costs, while a simple linear regression provided the equation, y (\)=6,658,630+855,250x (mm), where y represents the total hospital costs and x is the aneurysm diameter. Conclusion : In South Korea, the total hospital costs for the surgical clipping of UIAs were found to be lower than those for endovascular coiling when the surgical results were favorable without significant complications. Plus, a strong positive correlation was noted between an increase in the aneurysm diameter and a dramatic increase in the costs of endovascular coiling.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.5
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• pp.81-89
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• 2021

This study aimed to investigate the factors affecting Logistics capabilities for Logistics Service Providers in Vietnam. Researchers inherited and developed based on previous research to focus on analyzing and evaluating dynamics, measuring Logistics capabilities, and the factors affecting Logistics capabilities for Logistics Service Providers. The logistics capabilities Model is used based on three factors: customer demand management capability, innovation capability, and information management capability. The empirical analysis used data from the survey data of l90 managers of Logistics Service Providers in Hai Phong, Ho Chi Minh City, Da Nang, Hue, Hanoi with reliable tools (SPSS 26.0 software). The data were analyzed by frequencies, percentages, means, Pearson's Linear Correlation Coefficient, exploratory factor analysis, and multi-linear regression model based on the survey data. The research results identified the following factors affecting Logistics capabilities for Logistics Service Providers: innovation capability has the strongest impact on Logistics capabilities; customer demand management capability has the following strong effects on Logistics capabilities; and finally, information management capability that affects Logistics capabilities. There is also a positive relationship between all factors and Logistics capabilities. Several recommendations are further suggested to enhance to improve Logistics capabilities for Logistics Service Providers in Vietnam.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.2
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• pp.164-173
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• 2013

In this paper, we propose multi-frame based super resolution algorithm by using motion vector normalization and edge pattern analysis. Existing algorithms have constraints of sub-pixel motion and global translation between frames. Thus, applying of algorithms is limited. And single-frame based super resolution algorithm by using discrete wavelet transform which robust to these problems is proposed but it has another problem that quantity of information for interpolation is limited. To solve these problems, we propose motion vector normalization and edge pattern analysis for 2*2 block motion estimation. The experimental results show that the proposed algorithm has better performance than other conventional algorithms.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.2
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• pp.55-65
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• 2012

In the winter season, when the ventilation system is operating, the fresh cold air from the slot-type openings of broiler house which directly reached the animal zone can cause various problems such as thermal stress, decreasing of feed and water consumption, occurrence of respiratory disease, and etc. Therefore it is very important to control the trajectory of aero-flow from the slot openings to induce an efficient thermal heat change. Jet-drop distance model was proposed to predict and control the jet-trajectory. However their study was restricted due to the small scaled model and difficulties of measuring the Jet-drop distance. In this study, CFD was applied to analyze qualitatively and quantitatively the jet-drop distance in a real broiler house. The various variables were considered such as installed slot-angle, designed ventilation rate, and the outdoor ambient temperature. From the present study, two linear-regression models using the Jet-drop factor and corrected Archimedes number, and their R-squared values 0.744 and 0.736, respectively, were used. From this study, the applicability of CFD on the analysis of Jet-drop distance model was confirmed.

• Journal of Korean Academy of Rural Health Nursing
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• v.18 no.1
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• pp.11-18
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• 2023

Purpose: This study is to compare adolescents' health behaviors by city size and to propose regionally tailored health promotion. Methods: We analyzed the data from the 17th Youth Health Risk Behavior Online Survey, national widly performed in 2021. Multi-sample descriptive and linear regression analysis was performed by city size. Results: The frequency of fruit consumption in the last week was 2.88 in the rural area, which is lower than 2.98 and 3.05 in other cities (F=10.98, p<.001). The number of high-intensity physical activity days in the last week (7 days) was 2.90 days in the rural area, higher than 2.74 and 2.73 days in other cities (F=3.36, p=.038). The number of days smoking cigarettes in the last 30 days was 3.23 days in the rural area, higher than 3.08 and 3.02 days in other cities (F=3.41, p=.035). BMI was 22.01 in the rural area, which was higher than 21.57 and 21.61 in other cities (F=4.19, p=.015). Conclusion: School health offices in the rural area districts need to operate to manage lack of fruit intake, smoking, and weight management programs in association with local healthcare institutions.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.2
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• pp.128-135
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• 2007

In response to anthropogenic global warming due to a buildup greenhouse gas, the effect of the air temperature on water temperature has been noticed. Therefore, effects have been made to build an air/water temperature relationship at three study regions using the data collected by the Ministry of the Maritime Affairs and Fisheries (MOMAF). The air/water relationship varies with time-scale and weekly time-scale was chosen for the study. The data were fitted to the S-shaped non-linear relationship, and the parameters for the S-curve were derived using a single-criteria multi-parameter optimization scheme. Separate regression curves were fitted to consider seasonal hysteresis at the Masan site. The study results support the S-shaped non-linear relationship is the best fit for the air/water relationship at the Korean coastal zone. This study will contribute to determine the future policy regarding water quality and ecosystem for the decision-driving organization.