• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.3
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• pp.119-131
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• 2010

Drought is one of disaster causing factors to produce severe damage in the World because drought is destroyed to the ecosystem as well as to make difficult the economy of the drought area. This study, using Palmer Drought Severity Index carries out correlation analysis with sea surface temperatures. Comparative analysis carries out by calculated Palmer Drought Severity Index and past drought occurrence year. Result of comparative analysis, PDSI indexes were in accord with the past drought. Cluster analysis for correlation analysis carries out using precipitation and temperature that is input datas palmer drought severity index, and the result of cluster analysis was classified as 6. Also, principal component carries out using result of cluster analysis. 14 principal component analyze out through principal component analysis. Using analyzed 14 principal component carries out correlation analysis with sea surface temperature that is delay time from 0month until 11month. Correlation analysis carries out sea surface temperatures and calculated cycle component of the low frequency through Wavelet Transform analysis form principal component. Result of correlation analysis, yang(+) correlation is bigger than yin(-) correlation. It is possible to check similar correlation statistically the area of sea surface temperature with sea surface temperature in the Pacific. Forecasting possibility of the future drought make propose using sea surface temperature.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.6
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• pp.789-803
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• 2003

The purpose of this study is to compare the usefulness between Gaussian dispersion model and receptor model with the experimental result of the dispersion tracing of the particulate pollutants from Taean coal-fired power plants. For this purpose, the component analysis of the collected PM 10 samples was performed. In order to trace the pollution sources, factor analysis was done with the result of the component analysis. As a result of the correlativity analysis of the fifteen power plants' profiles offered by US EPA, the correlativity of No.11202 source profile showed highest rate up to 84.5%. Thus it was adopted as proper one and the contribution rate by each pollution source was calculated by Chemical Mass Balance (CMB)-8 model. The contribution rate, which was the effect rate of the power plants on each measuring point, were calculated with a range of 24∼52％ and the standard error was below 0.9 $\mu\textrm{g}$/㎥. This indicates the selection of the source profile was appropriate. Also, the concentrations of each point were calculated by the ISCST3 which is suggested by US EPA as one of the regulatory Gaussian dispersion model. The calculation result showed that the predicted concentration was 50∼58 $\mu\textrm{g}$/㎥, comparing with the measured result of 9∼65 $\mu\textrm{g}$/㎥. It was found that the concentration calculated by ISCST3 was underpredicted. It was thought that the receptor model was more favorable than the Gaussian dispersion model in estimating the effect of the particulate matter on a certain receptive point.

• Journal of Global Scholars of Marketing Science
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• v.8
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• pp.183-206
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• 2001

The purpose of this thesis is to find out mediational role of risk about the repurchasing intention of hotel services. The result of this study can provide some directives for the strategic marketing implementation in the hotel industry. The results of the analysis are as follows: 1. To study the effect of perceived service quality on the repurchasing intention of customers, multi regression analysis was executed and, in the personnel service as well as in the physical service, it showed a plus (+) effect on the result. 2. To study the effect of perceived service quality on the perceived risk, multi regression analysis was executed and, in the part of performance risk and socio-psychological risk of the personnel service, it showed a negative(-) effect on the result; however, in the physical service, it doesn't give any statistical meaningful influence on the result. And, on the physical risk, those two service quality showed a negative(-) effect in the meaningful level. 3. To study the effect of perceived Risk on the repurchasing intention of customers, a multi regression analysis was also executed and, in the parts of all risks of performance, socio-psychological and physical, it showed a negative(-) effect on the result in the meaningful level.

• The Korean Journal of Applied Statistics
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• v.27 no.7
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• pp.1077-1095
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• 2014

Unlike randomized trial, statistical strategies for inferring the unbiased causal relationship are required in the observational studies. Recently, new methods for the causal inference in the observational studies have been proposed such as the matching with the propensity score or the inverse probability treatment weighting. They have focused on how to control the confounders and how to evaluate the effect of the treatment on the result variable. However, these conventional methods are valid only when the treatment variable is categorical and both of the treatment and the result variables are directly observable. Research on the causal inference can be challenging in part because it may not be possible to directly observe the treatment and/or the result variable. To address this difficulty, we propose a method for estimating the average causal effect when both of the treatment and the result variables are latent. The latent class analysis has been applied to calculate the propensity score for the latent treatment variable in order to estimate the causal effect on the latent result variable. In this work, we investigate the causal effect of adolescents delinquency on their substance use using data from the 'National Longitudinal Study of Adolescent Health'.

• Journal of Fisheries and Marine Sciences Education
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• v.23 no.1
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• pp.67-74
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• 2011

The study was constructed an analysis of postures of a expert diver's wearing and taking off with skinscuba equipment using ergonomics tools(REBA, RULA, OWAS) for prevention of Musculoskeletal injuries. This survey is consisted of 4 postures in terms of wearing and taking off : Crouching(alone), Standing(alone), Helping of assistance, Using of stanchion. Their rate of injuries is getting higher due to instability postures, exposed dangers and excessive physical actions. So this study provides basic and educational information for prevention of that. The result is as follows : The result of crouching postures of wearing alone was REBA 9(Ac Level 3), RULA 7(Ac Level 4), OWAS AC 2, and crouching postures of taking off alone was REBA 12(Ac Level 4), RULA 7(Ac Level 4), OWAS AC 4. The result of standing postures of wearing alone was REBA 8(Ac Level 3), RULA 7(Ac Level 4), OWAS AC 3, and standing postures of taking off alone was REBA 8(Ac Level 3), RULA 7(Ac Level 4), OWAS AC 3. The result of helping of assistance postures of wearing was REBA 4(Ac Level 2), RULA 3(Ac Level 2), OWAS AC 2, and standing postures of taking off alone was REBA 4(Ac Level 2), RULA 4(Ac Level 2), OWAS AC 1. The result of using of stanchion postures of wearing was REBA 3(Ac Level 1), RULA 3(Ac Level 2), OWAS AC 1, and standing postures of taking off alone was REBA 3(Ac Level 1), RULA 3(Ac Level 2), OWAS AC 1. Especially both postures of wearing and taking off alone showed high results in the analysis of postures using ergonomics tools(REBA, RULA, OWAS).

• Journal of Korean Academy of Dental Administration
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• v.11 no.1
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• pp.28-37
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• 2023

In this study, in order to analyze the effects of dental technology students' degree of satisfaction with their major and sense of self-esteem on college life stress, we conducted a self-administered questionnaire for 270 dental technology students. conducted a frequency analysis, t-test, one-way ANOVA, correlation analysis, and multiple regression analysis, and the results are as follows. As a result of analyzing the degree of major satisfaction, there was a significant difference in the department satisfaction (p<.05). The average score in major satisfaction was relatively high at 3.68. As a result of analyzing the level of self-esteem, there was a significant difference in grade and department satisfaction (p<.05). The average score in self-esteem question was relatively high at 3.75. As a result of analyzing the level of college life stress, there was a significant difference in the department satisfaction (p<.05). The average score for each college life stress area was relatively low at 1.97. As a result of analyzing the correlation between college life stress, major satisfaction, and self-esteem, college life stress was found to have a significant negative (-) correlation with major satisfaction and self-esteem. As a result of a regression analysis conducted on the effect of self-esteem and major satisfaction on college life stress, the variable that most influenced college life stress was found to be the self-esteem factor.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.52-63
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• 2008

The side collision reconstruction algorithm is developed using three dimensional car crash analysis. Medium size passenger car is modeled for finite element analysis. Total 24 side collision configurations, four different speed and six different angle, are set up for making side collision database. Deformation index and degree index are built up for each collision case. Deformation index is a kind of deformation estimate averaging displacement of side door of crashed car from finite element analysis result. Angle index is constructed measuring deformed angle of crashing car. There are two kinds of angle index, one is measured at driver's side and the other is measured at passenger's side. Also a collision analysis information in side of cars is used for giving a basis for scientific and practical reason in a reconstruction of the car accident. The analysis program, LS-DYNA3D is utilized for finite element analysis program for a collision analysis. Those database are used for side collision reconstruction. Side collision reconstruction algorithm is developed, and applied to find the collision conditions before the accident occurs. Three example collision cases are tried to check the effectiveness of the algorithm. Deformation index and angle index is extracted for the case from the analysis result. Deformation index is compared to the established database, and estimated collision speed and angle are introduced by interpolation function. Angle index is used to select a specific collision condition from the several available conditions. The collision condition found by reconstruction algorithm shows good match with original condition within 10% error for speed and angle. As a result, the calculation from the reconstruction of the situation is reproducing the situation well. The performance in this study can be used in many ways for practical field using deformation index and degree index. Other different collision situations may be set up for extending the scope of this study in the future.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.3
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• pp.395-406
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• 2015

This research carried out an analysis on input cost and leakage reduction effect by leakage reduction method, focusing on the project for establishing an optimal water pipe network management system in the Taebaek region, which has been executed annually since 2009. Based on the result, optimal cost-benefit analysis models for water distribution network rehabilitation project were developed using DEA(data envelopment analysis) and multiple regression analysis, which have been widely utilized for efficiency analysis in public and other projects. DEA and multiple regression analysis were carried out by applying 4 analytical methods involving different ratios and costs. The result showed that the models involving the analytical methods 2 and 4 were of low significance (which therefore were excluded), and only the models involving the analytical methods 1 and 3 were suitable. From the result it was judged that the leakage management method to be executed with the highest priority for the improvement of revenue water ratio was installation of pressure reduction valve, followed by replacement of water distribution pipe, replacement of water supply pipe, and then leakage detection and repair; and that the execution of leakage management methods in this order would be most economical. In addition, replacement of water meter was also shown to be necessary in case there were a large number of defective water meters.

• Journal of the Korean Applied Science and Technology
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• v.22 no.1
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• pp.71-76
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• 2005

We extracted pine-needles using ethanol as solvent, and we obtained the refined oil component from pine-needles extract. Also we tested the tyrosinase activated inhibition effect with melanin experiment and analysed with ICP/OES and UV/VIS. Accordingly we obtained the next conclusion from the result of this experiment. From the first result of this experiment, we could know that the degree of recovery of refined oil component from pine-needles extract appeared in about 8.0%. From the second result of this experiment, we could know that the tyrosinase activated inhibition rate increased more and more in case of increasing concentration of pine-needles, green-tea, vitamine-C. Also we could know that vitarnine-C influences to tyrosinase activated inhibition contained in pine-needles. From the third result of this experiment, we could know that inorganic materials of Ca, Mg, V, Mn, etc contained in pine-needles detected with ICP/OES analysis, and the absorbance of pine-needles extract appeared very high in UV/VIS analysis.

• Journal of the Korean Applied Science and Technology
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• v.28 no.4
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• pp.393-401
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• 2011

Natural Curcumin belongs to Zingiber Officinale Roscoe was known to possess natural odor, natural taste, natural color, and other pharmaceutical & chemical characteristics. Natural Curcumin extract was made to use ethanol as a solvent was to show a yellow color having state of solid powder and an active component. Natural Curcumin extract tested pharmaceutical & chemical experiment to dilute in curcumin 1%-water solution. Curcumin extract tested antimicrobial experiment using microbe, and tested dye experiment using fiber. Some conclusions in the result of characteristics experiment was obtained as follow. The result of antimicrobial experiment showed that the growth of staphylococcus aureus (ATCC-001) and aspergillus niger (ATCC-002) as microbes decreased according to passage of time. This phenomenon could know that Curcumin compoment showed influence to antimicrobial effect. Also, the result of dye experiment showed that cotton and sick with fiber dyeing dyed in direction of dark yellow color. This phenomenon could know that Curcumin extract showed influence to dyeing effect in observation of optical electron microscope(OEM.) The result of instrument analysis ascertained inorganic components of K(53.300ppm), Na(1.150ppm), Ca(0.711ppm), Ti(0.351ppm), Li(0.256ppm), Cu(0.233ppm) etcs from Curcumin component with ICP/OES, and ascertained organic components of propanoic acid(1.859), benzene(10.814), phenol(14.194) etcs from Curcumin component with GC/MSD.