• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.5
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• pp.683-689
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• 2014

The paper introduces dynamic generation technique of foot trajectories for humanoid robots using CPG(Central Pattern Generator) and proposes adaptive walking method for slope terrains combining a feedback network. The proposed CPG based technique generates the trajectory of foot in the Cartesian coordinates system and it can change the step length adaptively according to the feedback information. To cope with variable slope terrains, the sensory feedback network in the CPG are designed using the geometry relationship between foot position and body center position such that humanoid robot can maintain its stability. To demonstrate the effectiveness of the proposed approach, the experiments on humanoid robot Nao are executed in the Webot simulation. The performance and motion features of the CPG based approach are compared and analyzed focusing on the adaptability in slope terrains.

• Proceedings of the KOSOMBE Conference
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• v.1994 no.05
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• pp.88-91
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• 1994

We develope a assistant system of foot pressure distribution for improvement gait Pattern, adapted working speed, and minimitation of muscle fatigue of the sensory feedback type FES system(SEFES). This measurement system consist of mat type pressure sensor with piezo electric films. The pressure data signal multiflexed input scanning method processed A/D conversion after two step amplify and integrate. Matrix sensor interface to PC for pseudo color display by level of Pressure distribution data. This measurement system clinically evaluated in hemiplegic patients. It has produced acceptable results with optimal location of the food sensor's pressure point and avoid the muscle fatigue.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1020-1024
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• 2005

In this paper, an approach to dynamic systems control is addressed based on exploiting the potential features of the new nonlinear neural oscillator. Neural oscillators have recently enabled robots to exhibit natural dynamics using their robustness and entrainment properties. To technically accomplish this objective, the neural oscillator should be connected to the robot joints under the sensory feedback. This also requires the neural oscillator to adapt to the non-periodic nature of arbitrary input patterns. However, even in the most widely-used Matsuoka oscillator, when an unknown quasi-periodic or non-periodic signal is applied, its output signal is not always closely entrained. Therefore, current neural oscillators may not be applied to the precise control of the dynamic systems response. We illustrate the enhanced entrainment properties of the new neural oscillator by numerical simulation and show the possibility for implementation to control a variety of dynamic systems. It is verified that the oscillator can produce rhythmic signals for generating actuator signals which can be naturally modified by incorporating sensory feedback to adapt to outer circumstances.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.4
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• pp.105-112
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• 2017

PURPOSE: The purpose of this research was to know the effect of visual feedback self exercise (VFSE) on postural control in stroke patients. METHODS: 26 CVA patients were participated. The experimental group (EG) 12 (46.2%) and the control group (CG) 14 (53.8%), 17 males and 9 females. The subjects preformed VFSE on training instrument 10 minutes for 20 times in 2-3 weeks. The test was done 3 times. RESULTS: There were no statistically significant differences of the general characteristics of subjects between EG and CG by sex, affected site, muscle tone, sensory deficit, unilateral neglects, and vestibular dysfunction. The postural control effects of VFSE, in the EG showed that there were statistically significant differences among the tests during VFSE. However in the CG there were no statistically significant differences among the tests during VFSE. Also there was statistically significant difference between EG and CG after VFSE (p<.05). On the right hemiplegic EG showed that there was statistically significant difference between premid test and pre-post test after VFSE. But, the left hemiplegic EG showed that there was no statistically significant difference between before and after VFSE with all of tests. CONCLUSION: CVA patients had significant different of body weight ratio between hemiplegic side and the other side. This research suggested that CVA patients need self exercise with visual feedback for the improvement postural control ability. Therefore Physical therapist should not only prescribe hand-on exercise but also need to teach them self sensory feedback exercise to help them improve their postural control.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2464-2467
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• 2005

The purpose of this study was to explore the effectives of a virtual bicycle system in improving the ability of equilibrium sense of normal healthy adults. Experiments were performed to find the factors related to the training of equilibrium sense. The subjects consisted of young and elderly people and the group of young people was compared against the group of elderly people. We investigated three different running modes of virtual bicycle system with two successive sets in total. W measured the parameters related to the running time, the velocity, the weight movement, the degree of the deviation from the road, and the location of the center of pressure (COP). The results showed that the running capability of the elderly became much better after repeated training. In addition, it was found out that the ability to control postural balance and the capability of equilibrium sensory were improved with the presentation of the visual feedback information of the distribution of weight. We also found that the running time and the running velocity reduced when there was no visual feedback information. From the results, our newly developed bicycle system seems to be effective in the diagnosis of equilibrium sense as well as in the improvement of the sense of sight, and vestibular function of the elderly in the field of rehabilitation training.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.935-938
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• 2004

This paper describes the quantitative analysis on the improvement of equilibrium sensory using virtual bicycle system. We have used a virtual bicycle system that combines virtual reality technology with a bicycle. In this experiment, 10 subjects were tested to investigate the influencing factors on equilibrium sensory. Straight road and curved road driving at several factors including cycling time, number of times of path deviation, and center of pressure(COP) were extracted and evaluated to quantify the extent of control. Also, To improve the effect of balance training, we investigated the usefulness of virtual feedback information by weight shift. The result showed that the system could be effective for equilibrium sensory rehabilitation training device. The analysis method might also have wider applicability to the rehabilitation field.

• Journal of Korean Academy of Medicine & Therapy Science
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• v.10 no.2
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• pp.21-30
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• 2018

Objective: The purpose of this study was to investigate questions and instructions for internal feedback effects on functional recovery and task performance while chronic stroke patients practised task-specific training. Method: Twenty-four chronic stroke patients were randomly divided into two groups; when patients performed same tasks, one was treated using questions and the other using instructions for internal feedback Both lasted 30 minutes, 5 times a week for 8 weeks. Outcome measures included Erasmus MC Modifications to the Nottingham Sensory Assessment (EmNSA), Measurement Properties of the Motor Evaluation Scale for Upper Extremity in Stroke patients (MESUPES), Chedoke Arm and Hand Activity Inventory (CAHAI), Korean version of Modified Barthel Index (K-MBI). Results: There were no significant differences between the two groups in EmNSA and K-MBI(p>.05). But, in MESUPES and CAHAI, there was significant difference between the two groups(p<.05). Conclusion: In this study, questions for internal feedback during task-specific training are more effective in improving upper extremity motor function and task performance than instructions for internal feedback.

• Journal of the HCI Society of Korea
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• v.2 no.1
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• pp.41-47
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• 2007

This study aims to empirically examine the effect of feedback on attention recovery. The role of feedback has been proven to be positive in particular to extend the limitation of attention resource. We studied the impact of feedback on attention by varying its type and modality. An experimental system was developed to observe how accurately the participants performed the pattern-matching task with differential feedback provided on a real-time basis based on the ADHD diagnostic model. Six university students participated in this study with 6 different feedback conditions and controlled conditions. The participants experienced the feedbacks before experiment. They was asked two hundred tasks in four feedback conditions. The difference of feedback effect according to different modality is to find within a subject. The results indicated that the combined feedback of cognitive with perceptual stimulus led better performance than the combined of perceptual feedbacks.

• Proceedings of the ESK Conference
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• 1995.10a
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• pp.3-12
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• 1995

In this research, we investigated the effect of three visual feedback conditions (direct viewing, one-monitor viewing, and tow-monitors viewing) on the task performance of human operator in teloperation task. The three different level of task difficulties under each concitions were performed by thirty-six subjects. The result of the experiments was analysed by the task difficulties, and the measurements of performance are the task completion time and the frequency of task errors. In a teleoperator, the participation of a human operator is always required, and the man-machine interface and the operator's abilities is an important issue. Recently, the different types of sensory feedback conditions(force, vision, sound, tactile, etc) for teleoperation is a very active research area in ergonomics. Among them, visual feedback conditon is an important sense that can provide the information of task environment. Therefore, the sufficient understandings and investigation for human ability under various visual feedback conditions is required to establish the efficient man-machine interface of teleoperation. The result showed that the visual feecback conditions and the level of task difficulties have a significant effect on the task performance. For three level of task difficulties, the task completion time was the shortest under the condition of direct viewing. The number of task errors under the conditions of direct viewing and two-monitors viewing were reduced by more than half compare to that of one-monitor viewing.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.5
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• pp.1573-1581
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• 1996

This paper present as experimental demonstratio of DSP and a sensory actuator that is used to actively control sound transmission/radiation through a vibrating plate. A plane acoustic wave incident on a clamped, thin circular plate was used as a noise source, and a sensory actuator bounded to the plate was used to control and sense vibration of the plate. The sound transmission reduction problem was tranformed as a structural vibration control problem that actively control the structural vibration modes coupled to acoustic modes. The results show that the first structural vibration mode is controlled with a reduction of 78 percent in the displacement and velocity of the plate. This corresponds to a 13dB reduction in the acoustic response. These experimental results indicate that a sensory actuator bounded to the plate can be employed to attenuate the sound transmitted to radiated from the plate.