• Journal of Korean society of Dental Hygiene
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• v.19 no.2
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• pp.287-295
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• 2019

Objectives: The purpose of this study was to investigate the factors affecting subjective oral symptoms according to the gender of youth from multi-cultural families in Korea using data from the 14th (2018) Korean Youth Health Behavior Survey. Methods: The independent variables used in this study consisted of gender and sweet drink intake. The dependent variable was experience of subjective oral symptoms. Compensation variables consisted of general characteristics of school type, academic performance, economic status, drinking status, smoking status, and number of tooth brushings day before. The subjects of the study were 835 children of multi-cultural families whose parents were foreigners. All statistical analyses were performed by complex samples cross-tabulation analysis and complex samples logistic regression analysis. Statistical analysis was performed using the PASW statistical package 21.0 (Statistical Packages for Social Science Inc., Chicago, IL, USA). A significance level of 0.05 was used for statistical significance. Results: The composite sample logistic regression analysis showed that there was a statistically significant difference between gender and intake of sweet drinks in experience of subjective oral symptoms. Conclusions: These results suggest that factors influence subjective oral symptoms in Korean multi-cultural adolescents. Therefore, I hope that they will be used as basic data for the introduction and development of a customized oral health education program for improving oral health of multi-cultural adolescents.

• Journal of Environmental Health Sciences
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• v.35 no.3
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• pp.191-200
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• 2009

We investigated a trait of odor and the relationship between odor unit and odorous compounds using multiple regression analysis based on data compiled from Sihwa (SIC), Banwol (BIC), Banwol plating (BPIC) and Poseung industrial complex (PIC). These areas are odor control areas in Gyeonggi province. It was revealed that $NH_3$ and styrene concentrations in SIC and BPIC were relatively higher and $H_2S$ concentration especially in mc was more than five times higher than other areas. As a result of regression analysis using SAS, intensity of odor unit was highly related to concentrations of $H_2S$, TMA, styrene and n-valeraldehyde in SIC, $H_2S$, acetaldehyde, and butyraldehyde in BPIC and $NH_3$ in BIC.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.6
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• pp.90-96
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• 2009

Ultrasonic method using SH(shear horizontal) wave has been developed to determine the surface damage in fatigued material. Fatigue damages based on propagation energy were analyzed by multi-regression analysis in interrupted fatigue test specimen including CrMoV and 12Cr alloy steel. From the test results, as the fatigue damage increased the propagation time of the launched waves increased and amplitude of wavelet decreased. Also, analysis for the waveform modulation showed a reliable estimation, with confidence limit of 97% for 12Cr steel and 95% for CrMoV steel, respectively. Therefore, It is thought that SH ultrasonic wave technique can be applied to determine fatigue damage of in-service component nondestructively.

• Health Policy and Management
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• v.30 no.3
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• pp.399-408
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• 2020

Background: The purpose of this study was to examine the impact of the regional characteristics on the accessibility of emergency care and the impact of emergency medical accessibility on the patients' prognosis and the emergency medical expenditure. Methods: This study used the 13th beta version 1.6 annual data of Korea Health Panel and the statistics from the Korean Statistical Information Service. The sample included 8,119 patients who visited the emergency centers between year 2013 and 2017. The arrival time, which indicated medical access, was used as dependent variable for multi-level analysis. For ordinal logistic regression and multiple regression, the arrival time was used as independent variable while patients' prognosis and emergency medical expenditure were used as dependent variables. Results: The results for the multi-level analysis in both the individual and regional variables showed that as the number of emergency medical institutions per 100 km² area increased, the time required to reach emergency centers significantly decreased. Ordinal logistic regression and multiple regression results showed that as the arrival time increased, the patients' prognosis significantly worsened and the emergency medical expenses significantly increased. Conclusion: In conclusion, the access to emergency care was affected by regional characteristics and affected patient outcomes and emergency medical expenditure.

• Transactions of Materials Processing
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• v.26 no.6
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• pp.341-347
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• 2017

Flexibly-reconfigurable roll forming (FRRF) is a novel sheet metal forming technology conducive to produce multi-curvature surfaces by controlling strain distribution along longitudinal direction. Reconfigurable rollers could be arranged to implement a kind of punch die set. By utilizing these reconfigurable rollers, desired curved surface can be formed. In FRRF process, three-dimensional surface is formed from two-dimensional curve. Thus, it is difficult to predict the forming result. In this study, a regression analysis was suggested to construct a predictive model for a longitudinal curvature of FRRF process. To facilitate investigation, input parameters affecting the longitudinal curvature of FRRF were determined as maximum compression value, curvature radius in the transverse direction, and initial blank width. Three-factor three-level full factorial experimental design was utilized and 27 experiments using FRRF apparatus were performed to obtain sample data of the regression model. Regression analysis was carried out using experimental results as sample data. The model used for regression analysis was a quadratic nonlinear regression model. Determination factor and root mean square root error were calculated to confirm the conformity of this model. Through goodness of fit test, this regression predictive model was verified.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.7
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• pp.601-608
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• 2015

The static aeroelastic analysis and optimization of flexible wings are conducted for steady state conditions while both aerodynamic and structural parameters can be used as optimization variables. The system of multidisciplinary design optimization as a robust methodology to couple commercial codes for a static aeroelastic optimization purpose to yield a convenient adaptation to engineering applications is developed. Aspect ratio, taper ratio, sweepback angle are chosen as optimization variables and the skin thickness of the wing. The real-coded adaptive range multi-objective genetic algorithm code, which represents the global multi-objective optimization algorithm, was used to control the optimization process. The support vector regression(SVR) is applied for optimization, in order to reduce the time of computation. For this multi-objective design optimization problem, numerical results show that several useful Pareto optimal designs exist for the flexible wing.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.6
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• pp.531-555
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• 2011

This study aims to derive the statistical models for the estimation of the required specifications of a rock TBM as well as for its cutterhead design suitable for a given rock mass condition. From a series of multi-variate regression analysis of 871 TBM driving data and 51 linear rock cutting test results, the optimum models were newly proposed to consider a variety of rock properties and mechanical cutting conditions. When the derived models were applied to two domestic shield tunnels, their predictions of cutter penetration depth, cutter acting forces and cutter spacing were very close to real TBM driving data, showing their high applicability.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.4
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• pp.38-44
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• 2007

This paper describes the structural safety of solid fuel in the Hybrid Rocket Motor (HRM). Hybrid rocket combustion has the distinct regression characteristics which include the process of thermal pyrolysis and fuel vaporization. Most of all, this regression characteristics would structurally affect the strength of the fuel having a multi-port configuration, and even may cause the breaking from the fuel grain. This problem would probably influence the performance and operating safety of HRM. Therefore, for the safe operation of HRM, the critical port radius which determines the structurally safe region was discussed from the heat analysis of the solid fuel.

• 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.

• Journal of the Korean Data and Information Science Society
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• v.23 no.1
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• pp.151-159
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• 2012

This paper proposes to develop multi-currencies portfolio strategy using principal component analysis (PCA) and logistic regression (LR) in foreign exchange market. While there is a great deal of literature about the analysis of exchange market, there is relatively little work on developing trading strategies in foreign exchange markets. There are two objectives in this paper. The first objective is to suggest portfolio allocation method by applying PCA. The other objective is to determine market timing which is the strategy of making buy or sell decision using LR. The results of this study show that proposed model is useful trading strategy in foreign exchange market and can be desirable solution which gives lots of investors an important investment information.