• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.291-293
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• 1996

Logic simulation is playing a very important role for design verification as circuits are larger and more complicated. However unknown values in 3 value simulators may generate the X-propagation problem which makes inaccurate output values. In this paper, a new partitioning method and a new simulation algorithm are developed to deal with the X-propagation problem efficiently. The new algorithm can optimize simulation time and accuracy by controlling partition depth. Benchmark results prove the effectiveness of the new simulation algorithm.

• Journal of Power System Engineering
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• v.6 no.1
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• pp.96-101
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• 2002

In this paper, we address the problem of controlling an end-effector to track and grab a moving target using the visual servoing technique. A visual servo mechanism based on the image-based servoing principle, is proposed by using visual feedback to control an end-effector without calibrated robot and camera models. Firstly, we consider the control problem as a nonlinear least squares optimization and update the joint angles through the Taylor Series Expansion. And to track a moving target in real time, the Jacobian estimation scheme(Dynamic Broyden's Method) is used to estimate the combined robot and image Jacobian. Using this algorithm, we can drive the objective function value to a neighborhood of zero. To show the effectiveness of the proposed algorithm, simulation results for a six degree of freedom robot are presented.

• Corrosion Science and Technology
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• v.5 no.1
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• pp.5-14
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• 2006

A lot of parts in FGD (Flue Gas Desulphurization) systems of fossil-fuel power plants show the environments in which are highly changeable and extremely acidic corrosive medium according to time and locations, e.g. in duct works, coolers and re-heaters etc.. These conditions are formed when system materials are immersed in fluid that flows on them or when exhausted gas is condensed into thin layered medium to contact materials of the system walls and roofs. The environments make troublesome corrosion and air pollution problems that are occurred from the leakage of the condensed solution. The frequent shut-down and repairing works of FGD systems also demand costs and low efficiencies of those facilities. In general, high corrosion resistant materials have been used to solve this problem. However, even the super alloys and Teflon linings sometimes have not been good enough to preventing corrosion. Further more, they are expensive and not easily repairable in short periods of operation stops. In this work, new technology that is effective, economical and easily repairable has proposed to solve the corrosion problems in FGD facilities. This technology contains cathodic protection, coatings and remote monitoring-controlling systems.

• Journal of the Semiconductor & Display Technology
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• v.13 no.4
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• pp.65-70
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• 2014

This paper is to improve the problem of the LED dimming control system using the conventional PWM and DAC method. The conventional PWM method controls the average current to switch dimming signal. This method generates the flicker when controlling at a low current. In order to solve the problem, this system prevents the flicker with the DAC method. The LED is lit at micro-current flowing in the LED. And offset voltage is generated in the output of the DAC when the DAC output is very low voltage as 0V. This was resolved by the voltage drop of the output voltage to construct a negative offset circuit. In addition, the LED current can't flow as set values because of overheating of FET. In order to solve the problem, the 16 bits ADC in the microprocessor is a more accurate current control receives the LED current in comparison with the set value. Therefore, the LED dimming control system proposed in this paper showed the accurate and reliable more than conventional systems.

• Journal of Korean Academy of Nursing
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• v.34 no.7
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• pp.1234-1242
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• 2004

Purpose: This cross-sectional study was designed to identify anger-expression types of adolescent women and investigate the relation between the identified anger-expression types and their problem behaviors and health status. Method: One hundred ninety nine high school freshmen were recruited from September to November, 2003. Data was analyzed using descriptive statistics, cluster analysis, 2-test, ANOVA, and Duncan's multiple comparison test. Result: Three anger-expression types in adolescent women were found; Anger-out/in, Anger-control/in, and Anger-control type. Adolescent women with frequently using the anger-out/in type and with higher state anger reported more delinquent behaviors, more health risk behaviors, and higher psychosomatic symptoms. However, adolescent women with lower state anger and frequently using the anger-control type reported more depression scores. Conclusion: There is a need to further clarify the relationship between anger-expression type sand depression in adolescent women. The findings suggest the necessity of a development of the program for lowering the anger level and controlling the unfavorable anger expression types such as the anger-out in.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.3
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• pp.85-92
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• 2005

Due to the friction characteristic of pump, cylinder, and between passenger car and the rail, there exist dead zone in the hydraulic system actuated with inverter, which can not be controlled by a PID controller. In this paper, the friction characteristic of a cylinder is considered first, which may cause the uncontrolled speed in the zero-crossing speed region. And then, the zooming fuzzy logic controller is designed to overcome the drawback by the existing PID speed controller. Finally, The proposed hybrid fuzzy controller is applied to the PID controller in the normal speed region and to the fuzzy controller in the zero-crossing speed region. The reason is that the problem of the uncontrolled speed in the zero-crossing speed region caused by the friction characteristic of the cylinder in hydraulic elevator can be solved, and the effectiveness of the controlling system not only in the zero-crossing speed region but also the overall controlling region including steady-state can be simulated and performed.

• Journal of IKEEE
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• v.16 no.3
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• pp.235-243
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• 2012

In this study, we developed two legged multi-joint robot by using wireless servo motor that was applied by wireless sensor network technology, which is widely used recently, and performed an experiment of walking method of two legged multi-joint robot. We constructed the star network with servo motors which were used at each joint of two-legged robot. And we designed the robot for operation by transmission of joint control signal from main control system or by transmission of the status of each joint to the main control system, so it operates with continuously checking the status of joints at same time. We developed the humanoid robot by using wireless digital servo motor which is different from existing servo motor control system, and controlled it by transmitting the information of angles and speeds of robot joints to the motor(node) as a feedback through main control system after connecting power and setting up the IDs to each joint. We solved noisy problem generated from wire and wire length to connection point of the control device by construction of the wireless network instead of using existing control method of wiring, and also solved problem of poor real time response to gait motion by controlling the position with continuous transmission of control signals to each joint. And we found that the effective control of robot is able by performing the simulation on walking motion in advance with the developed control algorithm which was downloaded into installed memory. Also we performed the stable walking with two-legged robot by attaching pressure sensor to robot sole. And we examined the robot gait operated by application of calculated algorithm on robot movement to each joint. In this study, we studied the method of controlling robot gait motion by using wireless servo motors and measured the torque applied to each joint, and found that the developed wireless servo motor by ZigBee sensor network offers easier control of two legged robot gait and better circuit configuration of it than the existing wired control system could do.

• Journal of Educational Research in Mathematics
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• v.17 no.1
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• pp.51-66
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• 2007

The purpose of this study is to analyse the cases of the posed problems while the mathematically gifted students are playing the NIM game. The findings of a qualitative case study have led to the conclusions as follows. Most of all mathematically gifted students in the elementary school are not intend to suggest the solutions of the posed problem unless the teacher or the 'problem is requested. But a higher level of promising children were changing each data components of a problem in a consistent way and restructuring the problems while controlling their cognitive process. This is compared to that a relatively lower level of promising children tends to modify one or two data components instantly without trying to look at the whole structure. And we gave 2 suggestions to teach the mathematically gifted students in the problem posing.

• The Journal of the Korea Contents Association
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• v.20 no.1
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• pp.701-710
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• 2020

The purpose of this study is to investigate the moderating effect of anger expression styles on the relationship between school stress and interpersonal problem in adolescent. A total 300 students of middle and high school located in Chungcheongbuk-do completed the questionnaires to assess school stress, anger expression styles, and interpersonal problem during September to October, 2015 and 261 data were used in this report. Using multiple and hierarchical regression analysis, the results indicated that school stress, anger-in and anger-out significantly contributed to interpersonal problem. The interaction effect of school stress and anger expression styles were not significant. But anger-out significantly moderated the impact of school stress on domineering/controlling of interpersonal problem. These findings suggest that the intervention for preventing and relieving interpersonal problem in adolescent should focus on reducing school stress and maladaptive anger expression. Limitations and futre directions were discussed.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.1165-1171
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• 2012

Latest, it is dealt with seriously problems that an intruder kidnapping students in elementary school. Especially young students is more vulnerable in these risks. Elementary School has many limitations in controlling the intrusion of trespassers. A problem occurs that requires a lot of manpower through the deployment and management of security systems such as CCTV and control systems. In this paper, we is designed and implemented the outsider access management system using a sensor network and PZT camera called the USN's core technology to monitoring the access control for controlling the mobility of the trespassers.