• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.153-156
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• 2003

Many researchers have tried to develop the piezoelectric shell element and verified them with the benchmarking problem of the piezoelectric bimorph beam since there is no experimental result for the control of shell structure with piezoelectric sensor/actuator. In this paper, the experiments are designed and performed to verify the control Performance of piezoelectric sensor/actuator on the shell structure. PVDF is easy to be attached on the surface of a shell structure but makes weak control forces. On the contrary, PZT makes control forces large enough to control the structure, but it is not easy to make a PZT element with curvature. To use PVDF as an actuator, the structure should be designed as flexible as possible and the voltage amplifier could make high control voltage. PVDF actuator powered by a voltage amplifier that generates output voltage from -200 to +200 volts, shows little control performance to control the vibration of an arch type shell structure. The performance of sensor looks good and the negative velocity feedback control works perfectly. The actuator voltage seems to be too small to verify the control effect Quantitatively. An experiment with high voltage amplifier is scheduled to verify the control effect Quantitatively.

• International Journal of Contents
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• v.15 no.2
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• pp.20-28
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• 2019

This study was conducted with a non-equivalent control group experimental design to investigate the effects of a video-based infection control program through the application of the social cognitive theory on caregivers. Forty-six caregivers were recruited, with 23 pairs being randomly assigned to the control and experimental groups each. While the experimental group took part in the video-based education, the control group was involved in typical lectures. For two weeks, both groups were educated on the principles of infection control, medical and external handwashing, standard precautions, and quarantine. Their knowledge, performance, and self-efficacy were evaluated before and after the program. There was a significant increase in knowledge (p<.001 and p=.005) and infection control performance (p<.001) in the experimental and control groups. Similarly, self-efficacy, self-regulatory efficacy, task-difficulty preference and confidence significantly increased in the experimental group (p<.001). In the control group, only task-difficulty preference significantly increased (p=.005). Consequently, the online video-based infection control education program applying the social cognitive theory proved effective in improving the caregivers' knowledge and performance in infection control, and their self-efficacy. We suggest the use of this program in effective infection control education for caregivers in the future.

• Journal of IKEEE
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• v.23 no.2
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• pp.543-551
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• 2019

Permanent Magnet Synchronous Motors(PMSMs) have a wider range of applications due to their high output density and high efficiency. PMSMs are used not only in high-power density, high-performance motor-driven systems such as vehicle and robots, but also in systems where cost-cutting is very important, such as washing machines, air conditioners and refrigerators. To reduce costs, position sensorless control is required, which is generally difficult to be used under conditions of starting the motor. Thus, the I-F speed control that rotates the current vector at any speed in the starting procedure should be used at first, and then the sensorless speed control could be applied after PMSM rotates above a certain speed. Speed control performance in I-F speed control and sensorless speed control is very important. And more speed control performance should be maintained even in the transient in which the two control techniques are changed. In this paper, the speed controller transition method from I-F speed control to sensorless speed control of permanent magnet synchronous motor is proposed. Experiments were carried out on the washing machine drive system to verify the performance of the proposed technique.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.779-782
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• 1997

In this paper, accurate position control of a stenciling robot manipulator is designed. The stenciling robot is requried to draw lines and characters on the pavement. Since the robot is huge and heavy, the inertia is expected to play a major role in the tracking performance as desired. Here we are proposing neural network control scheme for a computed-torque like controller for the stenciling robot. On-line compensation is achieved by neural network. Simulation studies with stenciling robot are carried out to test the performance of the proposed control scheme.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.28-31
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• 1997

This paper describes the quick and precise controlling method for home-applied refrigerator. The proposed controller is based on the fuzzy logic control method and is designed for better performance in maintaining the constant temperature of the refrigerator. The temperature of the refrigerator is controlled by the cooling air blowing fan motor which is put on, off according to fuzzy logic controller. Finally, I study the performance of the proposed controller through the computer simulation about the approximated model of the refrigerator.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.3
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• pp.145-151
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• 2004

In this paper, a pressure control type ratio control valve(RCV) is designed for a metal belt CVT. Steady state and transient characteristics of the pressure control CVT are investigated by simulations and experiments. In addition, P-line is proposed to predict the shift performance. It is found that the bigger the pressure margin, the faster the shift response. It is expected that the P-line can be used in design of the RCV to meet the desired shift performance.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.40.2-40
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• 2002

This paper presents the reconfigurable flight controller in the presence of jammed actuator fault using the adaptive sliding mode control scheme. It is developed under the assumption that the control surface fault cannot be detected and the positions of stuck control surfaces are unknown. It is well known that sliding mode controller shows good performance for the systems with various uncertainties. None-operating stuck actuator makes the system behave like bias which degrades the system performance and sometimes destabilizes the system. Therefore, the bias term generated by actuator faults has to be compensated by the control system. To the objective, we adopt the adaptive sliding mode cont...

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.6-11
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• 1988

Alight-weight robot arm carrying a payload is modelled as a cantilever beam with a tip mass subjected to a high speed rotation. Equations of Motion, for modal control, are represented as discrete state variable form. Digital optimal control law with observer is developed to suppress the arm vibration and control the position of the joint angle. The effects of the number of controlled modes, weighting factors of the performance index, reference rotation time, and sampling time on the control performance are analyzed by computer simulation and experiments.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.481-484
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• 1990

Normal operation when deeply submerged is a relatively easy task, and human operator control can often provide adequate performance. Near surface depthkeeping, on the other hand, is difficult to both man and machine. Because of the inherent limitation of the human operator, manual control may prove inadequate for near surface depthkeeping in some sea state. This paper describe the control algorithm of an automatic depth control system for submerged body that can be used for both near surface and deeply submerged depthkeeping operations. The computer simulations demonstrate the excellent depthkeeping performance of the controller under seaway effects.

• Journal of Korean society of Dental Hygiene
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• v.12 no.5
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• pp.953-961
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• 2012

Objectives : The purpose of this study is to examine the infection control practice and performance study on knowledge of dental hygienist between their knowledge and general characteristics. Methods : The subjects in this study are 305 dental hygienists who received local in-service education on December 10, 2011 and February 28, 2012. Results : The infection prevention knowledge and performance are higher as work experience is more (p<.05), as the education level is higher and when they have undergone in-service education (p<.001). Also these are higher when they are working in the dentist at the present (p<.001). The infection prevention practice are different with respect to ages (p<.01), work experience (p<.001), and the highest level of education (p<.01). There are correlations between the infection control practices and knowledge, performance and knowledge. As the practice level is higher, it is shown that the performance is higher (r=.049, p=.01). Conclusions : It would be necessary to develop the systematic and continuous program in infection control education and to build system which makes in-service training for dental hygienists mandatory. These could improve the level of infection prevention knowledge, practice and performance of dental hygienists to prevent the exposure to infection of the people.