• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.7
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• pp.594-599
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• 2017

In this thesis, the development and the verification of the test-aid are described, providing various attitude errors through the electric stimulus to the Sun sensor. This test-aid for 2-axis analogue Sun sensor is used for polarity test in the assembly stage for GK2 satellite. The test-aid used for GK2 satellite is for COMS satellite and, due to the failure risk, manufactured by domestic company. The characteristics of the COMS test-aid used for GK2 satellite and the manufactured test-aid are showed with similar through the several tests. In this thesis, there are conformed the capability for replacing of test-aid because the characteristics of the manufactured test-aid is acquired same as that of the COMS test-aid using the controller tuning functions.

• Physical Therapy Korea
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• v.2 no.1
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• pp.62-70
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• 1995

The use of electricity to evoke s skeletal muscle response is FES, which is a form of functional electrical stimulation. In the case of the damaged spinal cord, the technique can supply stimulation to the lower moter neurons and their muscle fiber, which have been disconnected from control of the higher nervous system. Recent advances in electronics, particularly miniaturization, have made possible the design of much improved systems of electrodes and stimulaters for FES. Clinical research has followed two main lines: the use of FES in the upper extremities for producing functional hand rehabilitation in quadriplegics and in the lower extremities for producing standing and gait in paraplegics.

• Physical Therapy Korea
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• v.2 no.2
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• pp.85-97
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• 1995

When applying FES to patients, proper evaluation must be performed prior to treating patient. Patients with thoracic lesions between $T_4{\sim}T_{12}$ are suitable for FES. However, these patients must have excitability of the leg muscles. Thus, excitability testing is an essential part of the screening program(stimulation at 80V gives a response). Before standing or walking is attempted the patients must perform restrengthening exercise, so that the Quadriceps muscle group minimum strength is 40 Nm (corresponding to a manual grade of F+ to G). After that walking and standing can be attempted. The effects of FES are as follows: prevents pressure sores; development and maintenance of muscle properties; prevents disuse atrophy and contractures.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.1967-1974
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• 1991

When the functional electrical stimulation is employed to recover mobility to the plegic, it is very important to understand functions of the selected muscles. I have investigated how a muscle acts to accelerate the body segments, since the body segements are connected by joints so that contraction of a muscle not only rotates the segments to which it is attached but also causes other segments to rotate by creation a reaction force at every joint, which is called the inertial coupling. I found that a single-joint muscle always acts to accelerate the spanned joint in the same direction as the joint torque produced by the muscle. However, a double-joint muscle can act to accelerate the spanned joint in the opposite direction to the joint torque produced by the muscle depending on (1) the body position, (2) the body-segmental parameters, and (3) the type of the movement. Investigating the condition number of the inertia matrix of the body-segmental model gave us some insights into how controllable the body-segmental system is for different values of the factors mentioned above. The results suggested that the upright position is the most undesirable position to independently control the three segments(trunk, thigh and shank) and that the controllability is the most sensitive to variation of the shank length and the trunk mass, which implies that accuracy is required particularly when we estimate these two body-segmental parameters before the paralyzed muscles are innervated by using electrical stimulation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1232-1235
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• 2004

The purpose of this study is to design electrical stimulation system for pharyngeal dysfunction(dysphagia) in stroke patients. Pharyngeal muscle group activity is important, because contracting muscles provide the driving force at the initiation of the swallow and generate the pressure gradients necessary for bolus movement into the esophagus. Although we have many treatment methods for dysphagia, electrical stimulation system will be useful for stroke patients having dysphagia. Electrical stimulation can be divided into the body stimulation and electrodes. The body stimulation is divided again into frequency counter, time control and current measurement part. These parts are to control the current intensity, frequency and stimulating time. And they can be variable according to the patient's clinical assessment. The electrode plays a role to deliver the current from the system to the muscle. Also the position of the electrode can be variable according to the treatment method. We performed the clinical experiment with the stroke patient who has swallowing disorder. The videofluoroscopy was used for the observation. From the result of clinical experiment based on electrical stimulation, we expected that the dysfunction(in pharynx) level of the patient can be improved. However we could not have enough effectiveness of the treatment because of the number of patients, patient's adaptation and treatment period. We will design the optimized electrical stimulation system based on enough clinical experiment in the future.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.185-190
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• 2005

The purpose of this study is to design electrical stimulation system fur stroke patients with pharyngeal dysfunction(dysphagia). Dysphagia is that the food has trouble in passing to the mouth from the stomach. Although we have many treatment methods for dysphagia, electrical stimulation system will be useful for stroke patients having dysphagia. Electrical stimulation system can be divided into body and electrodes. The body stimulation is composed to frequency counter, time control and current measurement part. These parts are to control the frequency, stimulating time and current intensity And they can be variable according to the patient's clinical assessment. The electrode plays a role to deliver the current from the system to the muscle. Also the position of the electrode can be variable according to the treatment method. We performed the clinical experiment with stroke patients who had swallowing disorder. The videofluoroscopy was used fur the observation. From the result of clinical experiment based on electrical stimulation, we expected that the dysfunction(in pharynx) level of the patient could be improved. However we could not have enough effectiveness of the treatment because of the number of patients, patient's adaptation and treatment period. We will design the optimized electrical stimulation system based on enough clinical experiment in the future.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.4 no.1
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• pp.39-47
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• 2006

Functional Electrical Stimulation(FES) cause paralysed muscles to contract in some clinical circumstances. Generally, FES has been thought of as a valuable tool in activating any skeletal muscle paralysed as a result of upper motor neuron damage. But, the function of cardiac and smooth muscle is also affected by upper motor neuron damage. Today, various applications of FES are investigated, including conditioning cardiovascular exercise, caugh and breathing assistant, improving bowel and bladder control, hand grasp, standing and walking etc. This review will focus on the literature reporting application of FES to control respiratory capabilities and internal organ function as well as increase muscular strength, hand grasp, standing and walking in patients with upper motor diseases.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.55-62
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• 2013

The exoskeleton robot to assist walking of hemiplegia patients or disabled persons has been studied in this paper. The exoskeleton robot with degrees of freedom of 2 axis has been developed and tested for joint motion. The obtained EMG signal from normal person was analyzed and the control signal was extracted from it for convenient and automotive performance of assistance robot to help hemiplegia patient walks as normal person does. the purpose of using FES(Functional Electrical Stimulation) for hemiplegia patient's walk is to restore damaged body function by this, but this could give fatal electrical shock to patients by wrong use or cause quick fatigue in muscle by continuous stimulation. The convenient movement of hemiplegia patients with minimum muscle fatigue was looked possibly by operation of assistance robot exoskeleton using control signal. and the walking assistance exoskeleton robot seemed works more efficiently than using FES stimulator. The experiment in this study was performed based on usual motion in our life like walking, standing-up, sitting-down, and particularly feedback control system using Piezo sensor along with button switch was applied for smooth swing motion in walking. The experiment also shows that hemiplegia patients can move conveniently by using electromyogram signal of healthy leg for the operation signal of assistance robot system attached at damaged symmetrical leg.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.6
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• pp.49-58
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• 2002

Based on electrophysiological retina mechanism, a retina model is proposed, which has similar response characteristics compared with the real primate retina. Photoreceptors, horizontal cells, and bipolar cells are modeled based on the previously studied retina models. And amacrine cells known to have relation to movements detection, and bipolar cell terminals are newly modeled using 3 NDP mechanism. The proposed model verified by analyzing the spatial response characteristics to stationary and moving stimuli, and characteristics for different speeds. Through this retina model, human vision system could be applied to computer vision systems for movement detection, and it could be the basic research for the implantable artificial retina.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.15 no.1
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• pp.79-85
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• 2009

목적 : 브라운시쿼드는 대부분 척추손상과 수질외 척추 종양에서 주로 나타난다. 드물게 경추 디스크가 브라운시쿼드의 원인이 된다. 경추디스크에 의한 브라운시쿼드 증세의 수술후 물리치료 및 도수치료 결과를 보고하기 위함이다. 방법 : 50세 남자로써 브라운시쿼드 증세로 진단을 받고 수술후 좌측 팔과 다리에 운동신경에 의한 마비증세가 있었으며(팔>다리), 우측으로 감각과 온도감각이 저하된 경우이다(팔>다리). 측정방법은 통증지수(VAS), 근력(Distal PowerTracII$^{TM}$ test), 지구력(Ergometer) 측정과 심리상태(설문)를 치료전과 후를 비교하였다. 물리치료에서는 기능적 전기자극 치료와 도수치료 및 운동치료 방법을 실시하였다. 도수치료는 통증완화와 근력강화를 위한 MET, MFR, Mobilization 등을 실시하였으며, 운동은 슬링시스템 등을 이용한 운동과 견관절의 불안정을 위해 안정화운동을 실시하였다. 결과 : 이 케이스는 수술후 이상 징후가 척수압박으로 인하여 보다 넓게 통증이 나타났으며, 운동 및 감각신경이 둔해지고 온도에 대한 감각이 반대편 결손으로 나타났으며, 좌측 어깨, 팔 견갑부의 근육 마비와 우측의 감각이 떨어진 현상이 나타났다. 물리치료 후 단기목표와 장기목표에 있어서 통증과 운동 및 감각 기능이 회복되어 각각 팔 통증에서는 VAS 8 ${\rightarrow}$ 1, 상지 하지의 운동기능은 Trace ${\rightarrow}$ Good 로 평가 회복되었으며, 근력측정에서 모두 유의한 차이를 보였다. 모든 치료과정 결과에서 심리적 상태의 설문에서도 높은 점수를 얻어 긍정적 신뢰가 높아 진 것으로 나타났다. 검사결과 다리의 근력이 증가는 걷기 운동 및 에르고메터의 지구력 및 균형이 레벨1의 10분 수행능력이 레벨 20에서 30분 수행능력으로 향상되어 일상적인 활동이 가능해졌다. 결론 : 예상하지 못했던 수술 후유증(side effects)에 대한 치료과정이 환자의 심리에 심각한 부정적인 생각이 신체의 기능과 감정의 손상에 영향을 미치기 때문에 체계적이고 장기적인 치료 과정에서 기능적 향상과 더불어 정신적인 심리의 정서 안정이 매우 필요하다고 사료된다.