• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.585-586
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• 2010

An induction motor operated with a conventional direct self controller(DSC) shows a sluggish response during startup and under changes of torque command. Fuzzy logic controller(FLC) is used in conjunction with DSC to minimize these problems. A FLC chooses the switching states based on a set of fuzzy variables. Flux position, error in flux magnitude and error in torque are used as fuzzy state variables. Fuzzy rules are determinated by observing the vector diagram of flux and currents. This paper proposes hybrid FLC for direct torque control(DTC) of induction motor drives. This controller is controlled speed using hybrid FLC. The performance of the proposed induction motor drive with hybrid FLC is verified by analysis results at various operation conditions.

• Journal of Digital Convergence
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• v.8 no.1
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• pp.55-69
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• 2010

This thesis looks closely at the moderating effect of individual variables while we analyzed how corporate's ethics policies have influence on his ethical decision-making behaviors. The subjects of the research were full-time employees (n=211) in the Seoul metropolitan region. The research model was substantiated through statistical analysis of credibility and validity, correlation, variance, and moderated regression analysis (MRA). This study found that within an organization with a code of ethics, the level of enforcement of the code and the level of employee awareness of core values sought by the company determined the level of influence of the code on ethical decision making. In other words, internal factors exerted a greater influence than external evaluation of a corporation's ethical decision making practices and therefore, it is necessary for decision-making practices to be transparent and recognized by the members within an organization. The study also found that the employee's awareness about the long-term visions of the company at a higher level and the employees who have a locus of control to their members internally acted as independent variables as well as control variables on the ethical decision-making. In addition, there were great differences in the level of ethical decision-making among the variables used as controls, which means these differences were related to the individual variables. Accordingly, in order to get ethical decision-making practices at a higher level, a education & training program will be designed and implemented variously as considering on the particular characteristics of the control variables we used in this study.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.754-758
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• 2005

Optimization of process variables such as arc current, welding voltage and welding speed in terms of the weld characteristics desired is the key step in achieving high quality and improving performance characteristics without increasing the cost. Consequently, incorrect settings of those process variables give rise to deviations in the welding characteristics from the desired bead geometry. Therefore, trainee welders are referred to the tabulated information relating different metal types and thickness as to recommend the desired values of process variables. Basically, the bead geometry plays an important role in determining the mechanical properties of the weld. So that it is very important to select the process variables for obtaining optimal bead geometry. However, it is difficult for the traditional identification methods to provide an accurate model because the optimized welding process is non-linear and time-dependent. In this paper, the possibilities of the Infra-red sensor in sensing and control of the bead geometry in the automated welding process are presented. Infra-red sensor is a well-known method to deal with the problems with a high degree of fuzziness so that the sensor is employed to build the relationship between process variables and the quality characteristic the proposed above respectively. Based on several neural networks, the mathematical models are derived from extensive experiments with different welding parameters and complex geometrical features. The developed system enables to select the optimal welding parameters and control the desired weld dimensions during arc welding process.

• The Korean Journal of Community Living Science
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• v.11 no.2
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• pp.1-14
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• 2000

The purpose of this study was to empirically verify influence of objective variables and subjective variables of time management strategy of unmarried men and women and provide a basis for the development of time management. The subject of this study were 370 unmarried men and women and interviewed with a questionnaire. The data were analyzed by SPSS/PC+ program for the frequency, mean, standard deviation, and regression analysis. The major results of this study were as follows: 1. The score of implementing time management strategy of unmarried men and women was the highest. The score of getting support time management strategy of unmarried men and women was the lowest. 2. Variables that affect overall time management strategy were age, academic career, sex, degree of information using fate control orientation and communication. 3. The relative contribution of subjective variables on time management strategy were higher than objective variables.

• The Korean Journal of Community Living Science
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• v.14 no.1
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• pp.37-53
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• 2003

The purpose of this study was to empirically verify influence of objective variables and subjective variables of life management strategy of unmarried man and women and provide a basis for the development of time management. The subject of this study were 355 unmarried men and women and interviewed with a questionnaire. The data were analyzed by SPSS program for the frequency, mean, standard deviation, t-test and regression analysis. The major results of this study were as follows: 1. The score of time management strategy of unmarried man and women was the highest. The score of leisure management strategy of unmarried man and women was the lowest. 2. Variables that affect overall life management strategy were academic career, degree of information using, fate control orientation and perception level of living relative to others. 3. The relative contribution of subjective variables on life management strategy were higher than objective variables.

• Communications for Statistical Applications and Methods
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• v.21 no.2
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• pp.161-168
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• 2014

In mixture experiments with process variables, we consider the case that some of process variables are either uncontrollable or hard to control, which are called noise variables. Given the such mixture experimental data with process variables, first we study how to search for candidate models. Good candidate models are screened by the sequential variables selection method and checking the residual plots for the validity of the model assumption. Two methods, which use numerical optimization methods proposed by Derringer and Suich (1980) and minimization of the weighted expected loss, are proposed to find a cost-effective robust optimal condition in which the performance of the mean as well as the variance of the response for each of the candidate models is well-behaved under the cost restriction of the mixture. The proposed methods are illustrated with the well known fish patties texture example described by Cornell (2002).

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.32-44
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• 2015

In general, a series of ship steering motion is represented by the combination of translational motion and rotational motion of the ship. Especially, special-functioned ships such as large-scale cruises, ships for installing underwater optical cable, and diver ships must be able to reveal only a translational motion without the change of orientation. In this paper, a method to comprise an integrated control system based on the joystick as a command instrument for translational motion control is suggested. In order to realize the translational motion control system, several algorithms are suggested including the velocity command generation, the selection of motional variables, and the generation and tracking of reference inputs for the selected motional variables. A simulation bench is composed to execute simulations for several translational motion commands. At last, the effectiveness of the proposed method is verified by analyzing the simulation results.

• Journal of Digital Convergence
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• v.17 no.11
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• pp.395-407
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• 2019

This study attempted to verify the structural model of the effects of stress, self-efficacy, and self-control on smartphone addiction in University students. The subjects of this study were 440 University students in G and P city. Results, First the most influential variables on smartphone addiction were self-control, followed by stress, and two variables explained explanation about smartphone addiction in 34%. Second, self-efficacy had a positive effect on self-control and stress had a negative effect. Both variables had an indirect effect on smartphone addiction through self-control. In groups less than 4 hours and above, there was a partial regulation effect because of differences between groups in the smartphone addiction pathway coefficients of stress and self-efficacy. Therefore, in order to reduce smartphone addiction, it is important to find ways to reduce stress and increase self-control and self-efficacy, and necessary to develop various programs and tailor educational interventions for each individual situation.

• Korean Journal of Culture and Social Issue
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• v.9 no.spc
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• pp.75-88
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• 2003

This study reviewed behavioral studies that have been conducted to prevent accidents. The studies were analyzed according to settings, subjects, experimental design, dependent and independent variables. Based on this analysis, issues important for conducting future research are proposed. The analysis indicated that behavioral studies have several limitations although they have been successful in preventing accidents. Especially, variables in individual levels that have been related to the accidents have not been appropriately dealt with in the behavioral studies. Similarly, several important variables in organizational levels have not been implemented in the behavioral studies. Therefore, these variables should be more appropriately dealt with in future behavioral research to increase the effectiveness of accident prevention programs. In addition, theoretical relationship between dimensions of independent and dependent variables and maintenance of programs need to be studied further.

• Proceedings of the Korea Association of Information Systems Conference
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• 1996.11a
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• pp.29-48
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• 1996

Previous studies on user training have largely focused on assessing models which describe the determinants of information technology usage or examined the effects of training on user satisfaction, productivity, performance, and so on. Scant research efforts have been made, however, to examine those effects of training by using theoretical models. This study presented a conceptual model to predict intention to use information technology and conducted an experiment to understand how training for computer skill acquisition affects primary variables of the model. The data were obtained from 32 student subjects of an experimental group and 31 students of a control group, and the information technology employed for this study was a university's electronic mail system. The study results revealed that attitude toward usage and perceived behavioral control helped to predict user intentions; outcome expectations were positively related to attitude toward usage; and self - efficacy and perceived behavioral control. The changes in those variables suggest more causal effects of user training than other survey studies.