• Proceedings of the Korean Geotechical Society Conference
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• 1991.10a
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• pp.289-311
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• 1991

Analysis of supported excavation system by Elasto-Plastic Isoparametric Finite Element Method and Elasto-Plastic Beam Method have been conducted for the simulation of stepwise underground excavation. Conventional methods, fixed Supported Beam and Spring Supported Beam method, also have been examined and compared with the results of elasto-plastic beam method and field data. Except unavoidable result of upward ground settlement near the top of retaining wall and relatively high bending moment of wall at each excavation level, satisfactory results have been derived using elasto-plastic isopara metric finite element method. The results from elasto-plastic beam analysis program, developed by the author, are proved to be fit field data in acceptable variance as shown in the paper. Displacement and bending moment, of the wall by conventional methods, both fixed supported beam and spring supported beam, are always underestimated than field data, and attention must be given that the diffence increases with deeper excavation depth and lower horizontal subgrade reaction of the ground.

• Korean Journal of Occupational Health Nursing
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• v.21 no.2
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• pp.87-97
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• 2012

Purpose: This study was to examine the relationship between recovery experience and the burnout among hospital nurses. Methods: A cross-sectional survey design was used. The participants were 281 nurses working at three general hospitals located in Seoul and Gyeonggi Province. The data were collected by convenience sampling using self-reported questionnaires that consisted of general characteristics, burnout, recovery experiences, self-efficacy, social support, job demand and organizational system. The data were analyzed with descriptive statistics, t-test, ANOVA, correlation, and stepwise multiple regression. Results: Stepwise multiple regression showed that organizational system had the greatest impact on hospital nurses' burnout, followed by job demand, self efficacy, position and recovery experience. Conclusion: Recovery experience is found to be a new factor that influences the burnout among hospital nurses. Therefore, further research is needed for confirming that recovery experience influences the burnout of hospital nurses. Also there is a need to develop a program to increase recovery experience from job stress at the organizational level to reduce hospital nurses' burnout.

• Journal of Korean Institute of Industrial Engineers
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• v.42 no.5
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• pp.314-326
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• 2016

The purpose of variable selection techniques is to select a subset of relevant variables for a particular learning algorithm in order to improve the accuracy of prediction model and improve the efficiency of the model. We conduct an empirical analysis to evaluate and compare seven well-known variable selection techniques for multiple linear regression model, which is one of the most commonly used regression model in practice. The variable selection techniques we apply are forward selection, backward elimination, stepwise selection, genetic algorithm (GA), ridge regression, lasso (Least Absolute Shrinkage and Selection Operator) and elastic net. Based on the experiment with 49 regression data sets, it is found that GA resulted in the lowest error rates while lasso most significantly reduces the number of variables. In terms of computational efficiency, forward/backward elimination and lasso requires less time than the other techniques.

• Journal of Radiation Protection and Research
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• v.9 no.1
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• pp.11-18
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• 1984

A Standard gamma-ray ionization chamber system was developed with a well type ionization chamber and micro current measuring circuit. Micro current was measured by the automatic Townsend balance with stepwise compensation method. For gamma emitting nuclides such as $^{241}Am,\;^{133}Ba,\;^{60}Co,\;^{134}Cs,\;^{137}Cs,\;and\;^{22}Na$ relative calibration factors to $^{226}Ra$ reference source were calculated and detection .efficiency curve was determined as a fudnction of gamma energy.

• Journal of Environmental Science International
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• v.14 no.11
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• pp.1049-1056
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• 2005

[ $NO_2$ ] concentration characteristics of Busan metropolitan city was analysed by statistical method using hourly $NO_2$ concentration data$(1998\~2000)$ collected from air quality monitoring sites of the metropolitan city. 4 representative regions were selected among air quality monitoring sites of Ministry of environment. Concentration data of $NO_2$, 5 air pollutants, and data collected at AWS was used. Both Stepwise Multiple Regression model and ARIMA model for prediction of $NO_2$ concentrations were adopted, and then their results were compared with observed concentration. While ARIMA model was useful for the prediction of daily variation of the concentration, it was not satisfactory for the prediction of both rapid variation and seasonal variation of the concentration. Multiple Regression model was better estimated than ARIMA model for prediction of $NO_2$ concentration.

• Journal of Korean Academy of Nursing
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• v.33 no.6
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• pp.762-771
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• 2003

Purpose: This study was undertaken in order to determine factors affecting health promoting lifestyle of elderly women. Method: The subjects were 299 elderly community residing women over the age 65 living in 2 large cities. The instruments used for this study were a survey of general characteristics, health promoting lifestyle(47items), perceived health status(6 items), self-efficacy(l7 items), and social support(18 items). The data was analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation coefficients, and Stepwise Multiple Regression. Result: The result of the study are as follows: The average item score for the health promoting lifestyle was 2.46, the highest score on the subscale was interpersonal support(M=2.83). A significant difference between age, education level, income, experience of smoking, alcohol, exercise, and health promoting lifestyle were found. Stepwise multiple regression analysis revealed that the most powerful predictor of health promoting lifestyle was social support(55%). Conclusion: Social support accounted for 54% of the variance in health promoting lifestyle in the elderly women. Therefore, health promoting programs that increase social support should be developed to promote a healthy lifestyle of the elderly women.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.481-488
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• 1999

Recently a removable soil nail is demanded due to problems beyond of economical and engineering purpose. In this study controlled displacement and controlled force field pull-out tests are carried out 7 times in order to evaluate short-term and long-term pull-out characteristics of the removable soil nail. For evaluating application of removable soil nailing system, bending tests of removable soil nails and tensile tests of fixed sockets are carried out. In the removable soil nailing system, the predicted horizontal displacements from FLAC-2D are also compared with the field measurements occurred in stepwise excavation. And approach for the stability analysis of removable soil nailing system after removed is proposed.

• Journal of Families and Better Life
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• v.10 no.1 s.19
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• pp.43-51
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• 1992

The purpose of this study was to investigate the impacts of managerial behaviors on the satisfaction with management. The data were collected by means of questionnaire distributed to a stratified sample of 560 housewives in Seoul. The questionnaire consisted of 107 items was developed by the researchers. Frequency, percentile, mean, and stepwise multiple regression were used to analyze the data. The results of stepwise multiple regression analyses indicate that the wives who had more reality in planning and higher standards tended to more satisfy with managerial behaviors. The elements of inplementing such as facilitating conditions and checking behaviors were positively related with managerial satisfaction. The recommendations for the ways to increase satisfaction with management and future research were suggested.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.1 no.1
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• pp.133-140
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• 2002

The object of this paper is to predict the surface roughness using the experiment equation of surface roughness, which is developed with a full factorial design in turning. $3^3$ full factorial design has been used to study main and interaction effects of main cutting parameters such as cutting speed, feed rate, and depth of cut, on surface roughness. For prediction of surface roughness, the arithmetic average (Ra) is used, and stepwise regression has been used to check the significance of all effects of cutting parameters. Using the result of these, the experimental equation of surface roughness, which consists of significant effects of cutting parameters, has been developed. The coefficient of determination of this equation is 0.9908. And the prediction ability of this equation was verified by additional experiments. The result of that, the coefficient of determination is 0.9718.

• Journal of Nutrition and Health
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• v.26 no.3
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• pp.357-366
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• 1993

The purposes of this study were to investigate the operational affecting productivity in hospital foodservice, and to examine the relationships between operational factors affecting productivity. The 28 hospitals over 400 beds in Seoul were mailed questionnaires assessing the factors that affect productivity in hospital foodservice(23 hospitals responded). Data analyses included descriptive statistics. Pearson product moment correlation analysis, and stepwise multiple regression analysis. The result of Pearson product moment correlation analysis indicated that the percentage of patient meals was significantly correlated to the productivity (r=.5560, p<.01). Stepwise multiple regression analysis indicated that the percentage of patient meals and the average work hours of employees were significant predictors of the operational factors at productivity.