• Proceedings of the KSME Conference
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• 2007.05a
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• pp.921-926
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• 2007

A dynamic system under random disturbance is considered in the study. In order to control the system efficiently, proper reduction of system dimension is indispensible in design stage. The reduction method using component cost analysis in conjunction with stochastic analysis is proposed for the control of a system. System response is obtained in terms of dynamic moment equation via Fokker-Plank-Kolmogorov(F-P-K) equation. The dynamic moment response of the system under random disturbance are reduced by using of deterministic version of component cost analysis. The reduced system via proposed "stochastic component cost analysis" is successfully implemented for dynamic response and shows remarkable control performance effectively utilizing "stochastic controller" in physical time domain.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.2
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• pp.206-211
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• 2010

Since high-speed train is a dynamic load in which electric power is externally supplied, contact loss between the catenary and pantograph occurs. This phenomena including vibrations generates frequently irregular arcs, which, in turn causes EMI. Thus it is very important to develop the approach to reduce arc phenomenon by contact loss, as speed of electric railway vehicle increases. In case of an electric railway vehicle using electrical power, compared with diesel rolling stock, Power Line Disturbance(PLD) such as harmonics, transient voltage and current, Electromagnetic Interference(EMI), and dummy signal injection etc usually occur. In this study, the dynamic characteristics of a contact wire and a pantograph suppling electrical power to high-speed train are investigated with an electrical response point. To implement power line disturbance induced by contact loss phenomenon for high speed train operation, a hardware simulator which considers contact loss between contact wire and pantograph as well as contact wire deviation is developed. It is confirmed by the experiments that contact loss effect is largely dependent on voltage conditions when the contact loss occurs. Also, a passive filter is designed to reduce power disturbance and the designed system is verified by experiment.

• The Korean Journal of Pain
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• v.31 no.3
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• pp.199-205
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• 2018

Background: Sleep disturbance and depression are becoming more recognized as important symptoms among individuals with chronic low back pain. This study evaluated the effect of stabilization exercise on pain-related disability, sleep disturbance and the psychological status of patients with non-specific chronic low back pain (NSCLBP). Methods: A total of 26 patients (M/F = 17/9) with NSCLBP with a mean age of $50.0{\pm}15.5$ took part in this study. Participants were recruited from selected hospitals in Lagos state. Ethical approval was sought and obtained from the health research and ethics committee of Lagos University Teaching Hospital Idi-araba, Lagos, Nigeria. Participants performed stabilization exercise for eight weeks consecutively and were assessed for pain-related disability, anxiety, depression, and sleep disturbance using the pain-disability index, hospital anxiety and depression scale, and the insomnia severity index at baseline, the 4th week, and the 8th week, postintervention. Results: The participants studied recorded significant reduction in pain-related disability (P = 0.001). There was also improvement in the sleep quality (P = 0.001), depression level (P = 0.001), and anxiety level (P = 0.001), post intervention. Conclusions: This study revealed that stabilization exercise is very useful in the management of sleep disturbance, pain-related disability, depression, and anxiety in NSCLBP patients.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1341-1342
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• 2015

In this paper, we propose a PID control scheme with noise reduction for attitude control of quad-rotor. To reduce the measurement noise, the disturbance observer with noise reduction is employed and then the PID controller is designed to control the attitude of quad-rotor. Finally, simulation results are provided to verify the effectiveness of the designed control scheme.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.4
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• pp.286-289
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• 2002

In the treatment of mandibular condylar fractures, arthrocentesis, lavage and selective intermaxillary fixation were performed after closed reduction. In this lavage group, the physiotherapy performed for 3-6 months after injury. in control group, continuous intermaxillary fixation was done for 1-3 weeks, and physiotherapy followed in the same method of the lavage group. In the comparative study of the both groups, the following results are shown. 1. Compared to control group, the lavage group had a slightly superior result at range of motion, joint pain and occlusal deviation, from I day after arthrocentesis to 6 months after injury. 2. The significant differences between both groups were seen at range of motion and joint pain in 1 month after injury. 3. At 6 months after injury, the differences between both groups were not significant at range of motion, joint pain and occlusal deviation. From this study, in the mandibular condylar fracture, the arthrosentesis, lavage and selective intermaxillary fixation after closed reduction can improve symptoms such as joint pain and occlusal deviation, also increase range of motion. in this therapeutic way, intracapsular hemarthrosis which can cause TMJ ankylosis or dysfunction can be removed effectively. in addition, patient's discomfort such as swallowing disturbance, speech disturbance and emotional stress can be reduced signuficantly.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.780-783
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• 2004

Recently Intake noise has been extensively studied to reduce the engine noise. In order to diminish intake noise several resonators were added to the intake system. However this can cause a reduction of engine output power and an increase of fuel consumption. In this study, active noise control simulation of the Filtered-x LMS algorithm is applied real instrumentation intake noise data under rapid acceleration because intake noise is more excessively increased under the such a harsh condition. But the FXLMS algorithm has poor control performance when the system is disturbed. Thus modified FXLMS algorithm using L-point running average filter is developed to improve the control performance under the rapid acceleration and disturbance. The noise reduction quantity of modified Filtered-x LMS algorithm is more than original one in two cases. In the case of control for real instrumentation intake noise data, maximum residual noise of modified FXLMS algorithm is 2.5 times less than applied the FXLMS and also in the case of disturbed, the modified FXLMS algorithm shows excellent control performance but FXLMS algorithm cat not control.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.111.1-111
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• 2001

In this paper, a robust speed control is proposed for Permanent Magnet Synchronous Motor system. PMSM without reduction gear has been widely used in high performance application such as robots and machine tools. It is well known that the control performance of the PMSM is very sensitive to load disturbance and system parameter variation. The idea of the proposed speed controller based on combination of sliding mode control with fuzzy gain scheduling. The sliding mode controller leads to fast system dynamics of slight sensitivity to the load disturbance and system parameter variations, the fuzzy gain scheduling mechanism reduces the chattering phenomenon. The simulation results have proved that the proposed control scheme provides a robust control performance under load disturbance and system parameter variation.

• The Korean Journal of Rehabilitation Nursing
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• v.18 no.2
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• pp.128-134
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• 2015

Purpose: The purpose of this study was to compare the effects of hand massage provided with different intervals and periods on pain and sleep disturbance after orthopedic surgery. Methods: A non-equivalent control group pretest- posttest design was used. The subjects were admitted in an orthopedic hospital to get a surgery. They were divided into three groups. Group I (n=30) had hand massage every day. Group II (n=30) had hand massage every other day. Control group (n=31) had usual care. Data of all three groups were collected on the day before operation, POD (postoperative day) 6 and POD12. Hand massage was given for 2 and half minutes per hand. Results: Pain on POD6 of experimental group II was reduced more than those of control group. Pains on POD12 of both experimental groups were reduced more than those of control group. On POD6, only perceived sleep disturbance (PSD) was significantly different among groups. On POD12, PSD, total sleeping time, and sleep efficiency were more improved in the experimental groups. Conclusion: Hand massage was effective on the reduction of pain and sleep disturbance after orthopedic surgery. Applying hand massage on alternate day was effective enough. Also the effects were more obvious after 12 days.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.4
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• pp.192-197
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• 2013

Road traffic noise barriers being used to reduce the noise, but the city surroundings inhibition, ecosystem disturbance, and it is difficult to maintain. Can enhance or complement the existing noise barrier performance, so that it is necessary to develop an electronic noise-reduction system In this paper, we proposed an electronic road noise reduction devices to reduce road noise for a DSP-based signal processing and analog signal input-output controller. In order to verify the control performance, we performed noise reduction experimentation of ANC by filtered-X LMS algorithm and traffic noise signal injection. The controller is equipped with noise reduction algorithms were tested on the characteristics of directional and omnidirectional speaker.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.72-72
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• 2000

This paper presents a methodology combining sliding mode control and fuzzy control to tune the boundary layer and input gain according to the system state. The equivalent control is designed such that the nominal system exhibits desirable dynamics, The robust control with fuzzy self-tuning is then developed to guarantee the reaching condition and reduce chattering phenomenon in the presence of parameter and disturbance uncertainties.