• 대한물리의학회지
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• 제7권4호
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• pp.493-500
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• 2012

PURPOSE: The purpose of this study was to investigate effect of self-controlled feedback on proprioception in elbow flexion. METHODS: Thirty young adult volunteered to participate and were randomly assigned to one of three groups (self-controlled, yoked, control). Power and velocity in elbow flexion was measured by PRIMUS RS (BTE Tech., Hanover, U.S.A). Statistical analysis was used multivariate ANOVA to know effect of self-controlled feedback on proprioception in elbow flexion. Post hoc was used Scheffe. RESULTS: In acquisition phase to practice effect, variable errors in self-controlled group was significantly low scored more than yoked and control group. In retention phase to learning effect, variable errors in self-controlled group was significantly low scored more than yoked and control group. CONCLUSION: Self-controlled feedback was more effective on movement control when the learner could make a decision about receiving feedback after the trial. This seems to support the view that self-controlled feedback benefits learning, because learners can make a decision about feedback based on their performance on a given trial.

• 한국전문물리치료학회지
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• 제12권1호
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• pp.36-44
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• 2005

The purpose of this study was to examine the effects of self-controlled learning using the (KR) feedback schedule versus the yoked KR on the acquisition and retention of balance training for individuals with hemiplegics. Sixteen hemiplegics were randomly assigned to either a self-controlled or yoked KR group. All subjects were ambulatory with or without an assistive device. The self-controlled group was provided with feedback whenever they requested it, whereas the yoked group had no influence on the feedback schedule. All subjects performed 10 acquisition trials and 10 retention trials the day after acquisition. The data were analyzed using an independent t-test and a Mann-Whitney U test. Participants in the self-controlled group achieved significantly more effective learning than the yoked group during the acquisition and retention test except anterior/posterior (AP) body sway. These results suggest that a feedback schedule which is controlled by the individuals with hemiplegics may be more effective in balancing training than a yoked KR which is not controlled by the subject.

• 국제물리치료학회지
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• 제9권4호
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• pp.1602-1607
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• 2018

This study examined the correlation between power error (PE) and velocity error (VE) according to the condition and frequency of self-controlled feedback (SCF) during knee extension. One hundred participants were randomly assigned to 30% SCF, 70% SCF, 30% yoked feedback (YF), 70% YF and control group, respectively. The SCF group was provided with feedback when they requested it, whereas the YF group did not influence the feedback schedule. Participants in the control group were not given any visual feedback during the experiment. The isotonic, isometric, and isokinetic dynamometer (PRIMUS RS, BTE, USA) was used to measure the power and velocity error during knee extension. The collected data was analyzed using a Pearson test and SPSS 21.0. The correlation between PE and VE according to the condition and frequency of feedback on each phase during knee extension was significant. Both PE and VE were significantly higher when the feedback was provided with high frequency, passive, and no feedback. Our study suggests that application of SCF can help to improve the proprioception of the healthy person while reducing errors through low frequency and active feedback.

• 대한물리의학회지
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• 제4권2호
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• pp.93-100
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• 2009

Purpose：The purpose of this study was to examine the effects of self-controlled knowledge of result (KR) versus the yoked KR on learning of knee joint proprioception. Methods：Forty volunteer subjects (20 men and 20 women) were randomly assigned to each four groups: 1) self-controlled KR in open kinematic chain, 2) yoked KR in open kinematic chain, 3) self controlled KR in close kinematic chain, and 4) yoked KR in close kinematic chain. The difference between the angle of position and reproduction angle was determined as a proprioception error and measured using an angle reproduction test. The subjects in self-controlled groups were provided with feedback whenever they requested it, whereas the subjects in yoked groups were not provided with feedback. The data were analyzed using a one-way ANOVA. Results：The proprioception errors in close kinematic chain groups decreased significantly compared with those in close kinematic chain groups(p<.05). The proprioception errors in the self-controlled group decreased significantly compared with those in yoked groups during acquisition and retention test(p<.05). Conclusion：Self-controlled knowledge of result during open kinematic chain movement is considered to be a good method on motor learning.

• 한국산업정보학회논문지
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• 제18권1호
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• pp.37-45
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• 2013

뇌졸중 환자들은 운동장애, 감각장애, 인지장애 등 다양한 후유증을 경험하게 되며 이를 극복하기 위하여 많은 재활훈련을 받게 된다. 이러한 재활훈련은 병원에서만 이루어 질 때 보다 일상 속에서 지속적으로 수행될 때 그 효과가 극대화 된다. 이를 위해서 다양한 가정용 훈련프로그램이 보급되었지만 이를 수행함에 있어서 적절한 피드백에 제공되어 지는 프로그램 부족한 실정이다. 따라서 본 연구에서 3차원 깊이 측정이 가능한 키넥트 센서를 이용하여 사용자에게 필요한 피드백을 제공 받을 수 있는 가정용 운동프로그램을 개발하고자 한다. 본 연구에서 제안된 프로그램은 사용자가 원할 때만 수행지식(knowledge of performance; KP) 피드백과 결과지식(knowledge of result; KR) 피드백을 선택적으로 제공하며 이러한 사용자 주도적인 선택적 피드백은 사용자의 운동효과를 극대화 시킬 것이다.

• ETRI Journal
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• 제25권3호
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• pp.149-155
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• 2003

A self-pulsating multisection distributed-feedback laser diode (DFB LD) can potentially realize all-optical clock extraction. This device generally consists of three sections, two DFB sections and one waveguide section. The most important variable in this device is detuning, which is the relative spectral position between the stop bands of two DFB sections. We fabricated a novel structure in which two gratings were located one over and one under the active layers. Each grating structure was independently defined in processing so that detuning, which is the prerequisite for self-pulsation, could be easily controlled. Observing various self-pulsating phenomena in these devices under several detuning conditions, we characterized the phenomena as dispersive Q-switching, mode beating, and self-mode-locking.

• Journal of Power Electronics
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• 제3권3호
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• pp.185-196
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• 2003

In this paper, the single-phase static VAR compensator (SVC) is applied to regulate and stabilize the generated terminal voltage of the single-phase self-excited induction generator (single-phase SEIG) driven by a variable-speed prime mover (VSPM) under the conditions of the independent inductive load variations and the prime mover speed changes The conventional fixed gain PI controller-based feedback control scheme is employed to adjust the equivalent capacitance of the single-phase SVC composed of the fixed excitation capacitor FC in parallel with the thyristor switched capacitor TSC and the thyristor controlled reactor TCR The feedback closed-loop terminal voltage responses in the single-phase SEIG coupled by a VSPM with different inductive passive load disturbances using the single-phase SVC with the PI controller are considered and discussed herem. A VSPM coupled the single-phase SEIG prototype setup is established. Its experimental results are illustrated as compared with its simulation ones and give good agreements with the digital simulation results for the single-phase SEIG driven by a VSPM, which is based on the SVC voltage regulation feedback control scheme.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1993년도 춘계학술대회 논문집
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• pp.213-217
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• 1993

This paper presents an end-point of 1-link flexible robot arm with a tip-mass by using self-turning fuzzy algorithm. The arm is mounted on a translational mechanism driven by a ballscrew, whose rotation is controlled by CD servomotor. Tip position is controlled so that it follows a desired position. A feedback signal is composed of both the tip-displacement error and change in error. This paper gives the experimental tip responses according to the variations of tip-mass and beam-length, and also showes the effects of reducing the residual vibrations occuring at the end-point.

• 한국정밀공학회지
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• 제18권2호
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• pp.119-125
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• 2001

This paper presents an experimental study on active control of self-excited vibration for a high speed turbomachinery. In order to suppress the self-excited vibration, it is necessary to actively control the air film pressure or the air film thickness. In this study, active pads are used to control the air film thickness. Active pads are supported by pivots containing piezoelectric actuators and their radial position can be actively controlled by applying voltage to the actuators. The transfer characteristics from actuator inputs to shaft vibration outputs are experimentally investigated. In a tilting-pad gas bearing (TPGB), a shaft is supported by the pressurized air film. Four gap sensors were used to measure the vibration of the shaft and PID was used in the feedback control of the shaft vibration. The experimental results show that the self-excited vibration of the rotor can be effectively suppressed if the PID controller gains are properly chosen. As a result we find that the feedback control is effective for suppressing the self-excited vibration of a rotor system using stack-type PZT actuators.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제3B권1호
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• pp.10-15
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• 2003

This paper presents the digital computer performance evaluations of the three-phase self-excited induction generator (SEIG) driven by the variable speed prime mover such as the wind turbine using the nodal admittance approach steady-state frequency domain analysis with the experimental results. The three-phase SEIG setup is implemented for small-scale rural renewable energy utilizations. The experimental performance results give a good agreement with those ones obtained from the digital computer simulation. Furthermore, a feedback closed-loop voltage regulation of the three-phase SEIG as a power conditioner which is driven by a variable speed prime mover employing the static VAR compensator (SVC) circuit composed of the thyristor phase controlled reactor (TCR) and the thyristor switched capacitor(TSC) is designed and considered herein for the wind-turbine driven the power conditioner. To validate the effectiveness of the SVC-based voltage regulator of the terminal voltage of the three-phase SEIG, an inductive load parameter disturbances in stand-alone are applied and characterized in this paper. In the stand-alone power utilization system, the terminal voltage response and thyristor triggering angle response of the TCR are plotted graphically. The simulation and the experimental results prove the effectiveness and validity of the proposed SVC which is controlled by the Pl controller in terms of fast response and high performances of the three-phase SEIG driven directly by the rural renewable energy utilization like a variable-speed prime mover.