• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.321-327
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• 1996

The result of an experimental study on the mechanical properties of different types of polypropylene fiber reinforced concrete are presented in this paper. This study has been performed to obtain the properties of PFRC such as slump, Vee-Bee time, compressive strength, tensile strength, flexural strength, toughness and resistance to impact. The test variables are fiber content, fiber types, fiber length and W/C ratio. Polypropylene fibers were effective in reinforcing the matrix. A remarkable increase in toughness was observed by the addition of polypropylene fibers.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.857-860
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• 2000

An experimental study on the behavior of Steel Fiber Reinforced Concrete Columns under eccentric compression are presented. Forth-one columns were tested; the variables were column type, eccentricity of load, fiber contents, and longitudinal reinforcement ratio. The column size was $250\times160$ mm in cross section with an effective length of 1150 mm. Eccentricity of load was varied in the range from 1/6 to 1/2 times the column depth. This paper is to provides a framework for basic understanding of the steel fiber concrete columns.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.447-452
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• 1996

An experimental study was conducted to evaluate the bond performance of reinforcing bars embedded in high-strength concrete. Ten beam spice Specimens using concrete with compressive strength of 240kg/$\textrm{cm}^2$ and 640kg/$\textrm{cm}^2$ were tested. The effect of several variables on basic development length is discussed. The test results showed that the current trend in concrete specification of making the splice length longer to compensate for having smaller cover and spacing may not be an effective approach.

• The Korean Journal of Financial Studies
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• v.10 no.1
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• pp.249-269
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• 2004

Free cash flow is known as a typical type of agency conflict between managers and shareholders in a firm. The insurance industry, which is not growing, is particularly susceptible to such excessive cash flow. We herein investigate the effects of stock ownership plans on reducing agency conflicts. We adopt undistributed cash flow to proxy free cash flow, and size, default risk, group membership, leverage, investment opportunity, and stock options are selected as explanatory variables. We find that stock option plans are effective(at a 10% level) in reducing free cash flow.

• Transactions of Materials Processing
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• v.10 no.1
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• pp.23-29
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• 2001

In this study, the optimized initial hole shape for T-branch forming was proposed to obtain effective welding region. Design variables were determined by approximation analysis using volume constant condition. We performed 3D elastic-plastic FEM(Finite Element Method) analysis to simulate T-branch forming process. The variation of height and thickness of T-branch with various hole shapes was investigated. The optimized initial hole shape equation was obtained by using results for the numerical analysis.

• Journal of Korean Academy of Nursing Administration
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• v.2 no.1
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• pp.125-139
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• 1996

Organizational commitment is characterized by a strong belief in and acceptance of the organization's goal and values ; a willingness to exert considerable effort on behalf of the organization ; a strong desire to maintain membership in the organization. The purpose of this study was to identify the variables which influence the organizational commitment and to test the relationship between the clinical nurses' organizational commitment and turnover intention. The subjects were 412 nurses who were working on general wards at three General Hospitals in Chounbuk. The data were collected by self-reporting questionnaire from Sept. 20 to Sept. 31, 1995. The instruments used in this study were Likert-type scale which were Organizational Commitment Scale by Mowday et al, and Turnover Intention Scale by Mobley et al. The questionnaire of organizational characteristics was made through reviewing literature. The data were analyzed by frequency, percentage, t-test, one-way ANOVA, Scheffe test, Pearson's correlation coefficient, and stepwise multiple regression with $SPSS-PC^+$ program. Major findings are as follows : 1. Mean scores for organizational commitment were 3.008 and turnover intention 3.167 on a 5 point scale. 2. Age and clinical experience were positively related to organizational commitment(r=.4806, p=.000; r=.4792, p=.000). 3. In the personal variables, hospital type(F=21.374, p=.000), education level(F=5.481, p=.001), position(F=30.867, P=.000), and marital status(t=-5.63, p=.000) of the nurses showed significant differences in organizational commitment. 4. The variables to the organizational characteristic were statistically significant in organizational commitment : formalization(r=.3458, p=.000), human-centered organizational characteristic(r=.4302, p=.000), performance- centered organizational characteristic(r=-.1502, p=.000), payment(r=.2234, p=.000), promotion(r=.2710, p=.000), benefit & service(r=.2325, p=.000), and resource inadequacy(r=-.2172, p=.000). 5. For the purpose of identifying the predicting variables in organizational commitment, stepwise multiple regression is conducted. The results show that age, human-centered organizational characteristic, formalization, hospital type, resource inadequacy, promotion, and benefit & service were significant variables and explained 46% of the variance. 6. Organizational commitment was significantly negatively correlated with turnover intention(r=-.6442, p=.000). As a result of stepwise multiple regression analysis, organizational commitment is the most powerful variable predicting turnover intention and explained 41.5% of the variance. In conclusion, this study shows that the higher the organizational commitment level, the lower the turnover intention. Therefore, for effective turnover management, it is important to improve the organizational commitment among clinical nurses. In order to enhance the organizational commitment by the clinical nurses, it will be useful to consider significant organizational characteristics variables identified in this study.

• Journal of Korean society of Dental Hygiene
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• v.13 no.1
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• pp.69-81
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• 2013

Objectives : The purpose of this study was to examine whether the subjective oral health awareness and oral health behavior of Korean adults would affect their oral health indexes. It's meant to utilize existing data of epidemiological and alternative indexes in an effort to have a comprehensive and understanding of the relationship between the subjective oral health awareness and oral health behavior of Korean adults. And the following findings were obtained Methods : The subjects in this study were 7,285 adults who were selected from the third-year(2009) raw data of the fourth national health & nutrition survey. Results : As for the relationship between oral health awareness and oral health indexes, there were statistically significant differences in DMFT index, FS-T index, T-health index and CPI index according to self-rated health status, self-rated oral health state, necessity of dental treatment and oral health concern. Concerning the relationship between oral health behavior and the oral health indexes, whether they got a dental checkup over the past year, daily toothbrushing frequency, use or nonuse of oral health supplies and mastication problems made statistically significant differences to DMFT index, FS-T index, T-health index and CPI index. The variables that had a significant impact on oral health were selected from among the variables of oral health awareness and oral health behavior that affected oral health, and the variables were selected as independent variables. And then the oral health indexes were selected as dependent variables, and a multiple regression analysis was carried out by using the selected independent and dependent variables. As a results, it's found that the variables made a 22.4% prediction of DMFT index; 51.3% for FS-T index; 52.0% for T-health index; 47.4% for CPI index. Conclusions : The above-mentioned findings illustrated that the relationship between the subjective oral health awareness and oral health behavior of the Korean adults exercised an influence on their oral health indexes. Accurate and effective oral health plans should be mapped out by grasping the oral health status of adults from diverse angles to facilitate the maintenance and promotion of their oral health status.

• The Korean Journal of Applied Statistics
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• v.37 no.1
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• pp.1-12
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• 2024

In many real-world data, multiple response variables are often dependent on the same set of explanatory variables. In particular, if several response variables are correlated with each other, simultaneous estimation considering the correlation between response variables might be more effective way than individual analysis by each response variable. In this multivariate regression analysis, least distance estimator (LDE) can estimate the regression coefficients simultaneously to minimize the distance between each training data and the estimates in a multidimensional Euclidean space. It provides a robustness for the outliers as well. In this paper, we examine the least distance estimation method in multivariate linear regression analysis, and furthermore, we present the penalized least distance estimator (PLDE) for efficient variable selection. The LDE technique applied with the adaptive group LASSO penalty term (AGLDE) is proposed in this study which can reflect the correlation between response variables in the model and can efficiently select variables according to the importance of explanatory variables. The validity of the proposed method was confirmed through simulations and real data analysis.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.519-524
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• 1998

The current study is a part of series of research about the evaluation method of the unbonded tendon stress in prestressed concrete member at flexural failure. As the experimental study, a test program with 14 beams and slabs was planed to identify the contribution of each important variable. The variables are (1) the effective prestress, (2) the concrete strength, (3) the amount of tendons (4) the amount of bonded reinforcements, (5) the loading type, (6) the span/depth ratio. It was found that the tendon stress increment decreases as the effective prestress increases. Also, the contributions of concrete strength, amount of tendons, bonded reinforcements, and loading type were observed to affect on tendon stresses. However, the tendon stress increments were minimal at high values of span/depth in contrast with the ACI Code.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.5
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• pp.325-331
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• 2004

The multiobjective optimization (MO) problem usually includes the conflicting objectives and the use of conventional optimization algorithms for MO problem does not so good approach to obtain an effective optimal solution. In this paper, genetic algorithm (GA) as an effective method is used to solve such MO problem of brushless DC motor (BLDCM). 3D equivalent magnetic circuit network (EMCN) method which enables us to reduce the computational burden is also used to consider the 3D structure of BLDCM. In order to effectively obtain a set of Pareto optimal solutions in MO problem, ranking method proposed by Fonseca is applied. The objective functions are decrease of cogging torque and increase of torque respectively. The airgap length, teeth width and magnetization angle of PM are selected for the design variables. The experimental results are also shown to confirm the validity of the optimization results.