• Journal of Korean Home Economics Education Association
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• v.21 no.3
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• pp.29-43
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• 2009

The purposes of this study were to examine effective variables influencing on adolescents' mobile phone addiction. The subjects were the 666 middle or high school students who had their own mobile phone in Gwangju. Data were analyzed with frequency, percentage, cronbach's ${\alpha}$, mean, SD, pearson's correlation and multiple regression using SPSS/PC WIN 14.0 program. The major findings were as follows: 1. The most frequently used function of student mobile phones was text message and they used text message more than 41 times a day. Mostly they were talking to the same sex friends on the phone and the monthly charges ranged from 20,000 to 30,000 won. In general, they called to their friends after school. Their parents' attitudes toward their mobile phone using showed that the most of their parents did not care about their children's mobile phone use. The restriction of using their mobile phone at school was normal. 2. The average scores of mobile phone addiction were lower than median(3.0) and self esteem, self control, family strengths, peer conformity and school life adaptation were higher than median. 3. The adolescence's mobile phone additions were influenced by peer conformity, school life adaptation, school levels, sex and self control. And these variables explained to the adolescence's mobile phone additions about 28%.

• Journal of Korean Home Economics Education Association
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• v.18 no.4 s.42
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• pp.85-102
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• 2006

The objectives of this study were to classify of life style of secondary school girl students, to investigate the relationships between life styles, attitude toward appearance and clothing attitude. The method of this study was survey research by using questionnaires. Subjects were 658(middle school students 327, high school students 331) girl students located in Jeollabukdo province. In this statistical analysis, SPSS 11.5 for Windows program was utilized to calculate frequency, mean, cronbach's ${\alpha}$, factor analysis, t-test, Pearson's correlation, multiple regression analysis. The results of this research were as follows: The results of analysing the factors to the response lifestyles, attitude toward appearance and clothing attitude emerged five dimensions(digital orientation, material orientation, positive activity, achievement orientation, frugality), three dimensions(needs conformity value toward appearance), five dimensions(fashion pursuit, gender attractiveness, self-expression, aesthetic, and modesty). High school girls' students showed higher digital orientation and positive activity life styles, attitude toward appearance, clothing attitude except of modesty. Clothing attitude variables except of modesty had positive correlations with lifestyles and attitude toward appearance. However, modesty of clothing had negative correlations with life styles and attitude toward appearance. As a conclusion, secondary school girl students' life styles and attitude toward appearance constituted important characteristics which could affect clothing attitude directly.

• CRM연구
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• v.3 no.2
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• pp.1-20
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• 2010

Due to the nature of teenage students' common tendency of being drawn to consumption conformity engendered by popular trends, and further expanding their unique collectivist culture, this study presumes that middle and high school female students as well have an influential factor that creates their distinctive trait. This study is intended to investigate the students' personal characteristics and effects of social reference groups, and further scrutinize how these influences transcends to deviant make-up behaviors. A total of 297 subjects, middle and high school female students, participated in a survey, using questionnaires focused primarily on the degrees of color makeup and the influences imposed by classmates. The findings of the study are as follows. First, regarding makeup behavior displayed by middle and high school female students, social self-esteem had positive influence on innovation and peer pressure. Second, perceived visibility conversely had negative impacts on innovation and peer pressure. This indicates that if perceived visibility is at a salient level, this already signifies lack of innovation. Third, makeup innovation and peer pressure demonstrated by middle and high school students all showed positive influence on their makeup behaviors. Additionally, peer pressure, in comparison to innovation, had greater influence on makeup behaviors, which indicates that peer pressure play a great role in makeup behavior of middle and high school students. Fourth, makeup behaviors showed strong impacts on makeup satisfaction and rendering deviant behaviors, which indicates that a new direction and perspective regarding middle and high school students' makeup behavior is critical.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.173-175
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• 2004

This paper presents a novel design of a self tuning PI controller of induction motor using fuzzy control. In this approach, the fuzzy tuning of a PI controller gains is achieved through fuzzy rules deduced from many robustness simulation tests applied to several induction motors, for a variety of operating conditions such as response to speed command from standstill, step load torque application and speed variations, with nominal parameters and an changed rotor resistance, self inductance and inertia. Simulation results on a speed controller of induction motor are presented to show the effectiveness of the proposed gain tuner. And this controller is better than the fixed gains one in terms of robustness, even under great variations of operating conditions and load disturbance.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.1
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• pp.61-72
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• 2005

In this paper, we develop anti-sway control in proposed techniques for an ATC system. The developed algorithm is to build the optimal path of container motion and to calculate an anti-collision path for collision avoidance in its movement to the finial coordinate. Moreover, in order to show the effectiveness in this research, we compared NNP PID controller to be tuning parameters of controller using NN with 2 DOF PID controller. The experimental results for an ATC simulator show that the proposed control scheme guarantees performances, trolley position, sway angle, and settling time in NNP PID controller than other controller. As a result, the application of NNP PID controller is analyzed to have robustness about disturbance which is wind of fixed pattern in the yard. Accordingly, the proposed algorithm in this study can be readily used for industrial applications

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.7
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• pp.667-672
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• 2009

This paper is concerned with the development of linear magnetic actuator for active vibration control. The newly developed linear magnetic actuator consists of permanent magnets and copper coils. On the contrary to the voice-coil type actuator, the linear magnetic actuator utilizes magnetic flux to generate the shaft movement. In this study, experiments on the prototype linear magnetic actuator were carried out to investigate its dynamic characteristics. Block and inertia forces generated by the actuator were measured. The experimental results show that the actuator can be used as both actuator and active tuned-mass damper. The linear magnetic actuator was attached to a cantilever as the active-tuned mass damper and active vibration control experiment was carried out. The experimental results show that the newly developed linear magnetic actuator can be effectively used for the active vibration control of structures.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.3
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• pp.173-183
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• 1998

In this paper, an auto-tuning method for fuzzy controller's membership functions based on the neural network is presented. The neural network emulator offers the path which reforms the fuzzy controller's membership functions and fuzzy rule, and the reformed fuzzy controller uses for speed control of induction motor. Thus, in the case of motor parameter variation, the proposed method is superior to a conventional method in the respect of operation time and system performance. 32bit micro-processor DSP(TMS320C31) is used to achieve the high speed calculation of the space voltage vector PWM and to build the self-learning fuzzy control algorithm. Through computer simulation and experimental results, it is confirmed that the proposed method can provide more improved control performance than that PI controller and conventional fuzzy controller.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.398-403
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• 1993

A rule based fuzzy expert system to self-tune PID controllers is proposed in this paper. The proposed expert system contains two rule bases, where one is responsible for "Long term tuning" and the other for "Incremental tuning". The rule for "Long term tuning" are extracted from the Wills'map and the knowledge about the implicit relations between PID gains and important long term features of the output response such as overshoot, damping and rise time, etc., while 'Incremental tuning" rules are obtained from the relations between PID gains and short term features, error and change in error. In the PID control environment, the proposed expert system operates in two phases sequentially. In the first phase, the long term tuning is performed until long term features meet their desired values approximately. Then the incremental tuning tarts with PID gains provided by the long term tuning procedure. It is noticeable that the final PID gains obtained in the incremental tuning phase are only the temporal ones. Simulation results show that the proposed rule base for "Long term tuning" provides superior control performance to that of Litt and that further improvement of control performance is obtained by the "Incremental tuning'.ance is obtained by the "Incremental tuning'.ing'.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.61-64
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• 1996

This paper presents a new approach to the design of self-tuning adaptive control system that is robust to the changing dynamic configuration as well as to the load variation factors using Digital signal processors for robot manipulators. TMS32OC50 is used in implementing real-time adaptive control algorithms to provide advanced performance for robot manipulator. In this paper, an adaptive control scheme is proposed in order to design the pole-placement self-tuning controller which can reject the offset due to any load disturbance without a detailed description of robot dynamics. Parameters of discrete-time difference model are estimated by the recursive least-square identification algorithm, and controller parameters are determined by the pole-placement method. Performance of self-tuning adaptive controller is illustrated by the simulation and experiment for a SCARA robot.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.10
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• pp.1251-1258
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• 1999

The water level control of a steam generator in the unclear power plant is an important process. Most of the water level controllers of the actual plant are PID controllers. But they have limitations in appling for tracking the set point and getting rid of disturbances, so there are some defects to apply in the actual ground even though many research works represented the resolutions to solve it. In this paper, it is suggested that the established simple PID controller in low power has the ability to remove disturbances and trace the set-point, and then possesses the real-time self-tuning function according to the variety of moving peculiarity of a plant. This function realized by making use of fuzzy logic. PID parameters are formulated by a variable ${\alpha}$ and made it fluctuate by a fuzzy inference according to level error and level error change. This mechanism makes application of actual plant effective as well as taking advantage of improving the efficiency of water level controller by way of adding the function of self-tuning instead of replacing PID controller. The computer simulation of this scheme shows the improved performance compare to conventional PID controller.