• Journal of Biomedical Engineering Research
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• v.10 no.2
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• pp.109-111
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• 1989

An electrical stimulator was designed to induce locomotion for paraplegic patients caused by central nervous system injury. Optimal stimulus parameters, which can minimize muscle fatigue and can achieve effective muscle contraction were determined in slow and fast muscles in Sprague-Dawley rats. Stimulus patterns of our stimulator were designed to simulate electromyographic activity monitored during locomotion of normal subjects. Muscle types of the lower extremity were classified according to their mechanical property of contraction, which are slow muscle (msoleus m.) and fast muscle (medial gastrocneminus m., rectus femoris m., vastus lateralis m.). Optimal parameters of electrical stimulation for slow muscles were 20 Hz, 0.2 ms square pulse. For fast muscle, 40 Hz, 0.3 ms square pulse was optimal to produce repeated contraction. Higher stimulus intensity was required when synergistic muscles were stimulated simultaneously than when they were stimulated individually. Electrical stimulation for each muscle was designed to generate bipedal locomotion, so that individual muscles alternate contraction and relaxation to simulate stance and swing phases. Portable electrical stimulator with 16 channels built in microprocessor was constructed and applied to paraplegic patients due to lumbar cord injury. The electrical stimulator restored partially gait function in paraplegic patients.

• Proceedings of the KOSOMBE Conference
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• v.1992 no.05
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• pp.203-208
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• 1992

In order to restore the gait function by functional electrical stimulation(FES) in hemiplegic patients, an electrical stimulator and foot sensor were developed on the basis of optimal parameters which resulted from animal experiments. Physical properties of the soleus muscle were quite different from those of themedial gastrocnemius muscle, that is, the former had a characteristic or slow muscle and the letter had a characteristic of fast muscle in rats. Optimal parameters for electrical stimulation were 0.2ms of pulse width and 20Hz of frequency in the soleus muscle and 0.3ms, 40Hz in the medial gastrocnemius muscle. Amplitude modulated electrical stimulator with -15V of maximal output was made and automatic on-off time if the stimulator was 5 seconds. The foot sensor composed of 3 sensors in 3 pressure points of the foot was made in order to control the gai t function by closed loop feedback system. The gait function was improved by using the stimulator and foot sensor in peroneal palsy. These results suggest that the electrical stimulator with closed loop feedback system may restore the gait function in hemiplegic patients.

• Journal of Biomedical Engineering Research
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• v.15 no.4
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• pp.429-438
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• 1994

An electrical stimulator was designed to induce locomotion for paraplegic patients caused by central nervous system injury. Optimal stimulus parameters, which can minimize muscle fatigue and can achieve effective muscle contraction were determined in slow and fast muscles in Sprague-Dawley rats. Stimulus patterns of our stimulator were designed to simulate eleclromyographic activity monitored during locomotion of normal subjects. Muscle types of the lower extremity were classified according to their mechanical property of contraction, which are slow muscle (msoleus m.) and fast muscle (medial gastrocnemius m., rectus femoris m., vastus lateralis m.). Optimal parameters of electrical stimulation for slow muscles were 20 Hz, 0.2 ms square pulse. For fast muscle, 40 Hz, 0.3 ms square pulse was optimal to produce repeated contraction. Higher'stimulus intensity was required when synergistic muscles were stimulated simultaneously than when they were stimulated individually. Electrical stimulation for each muscle was designed to generate bipedal locomotion, so that individual muscles alternate contraction and relaxation to simulate stance and swing phases. Portable electrical stimulator with 16 channels built in microprocessor was constructed and applied to paraplegic patients due to lumbar cord injury. The electrical slimulator restored partially gait function in paraplegic patients.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.462-466
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• 2002

This paper describes a low frequency electrical nerve stimulator for muscle care. The developed system consist of 8bit low power consumed MPU, voltage boosting circuit converting 9V input to 120V output, repairing circuit for distorted output pulse, LED and buttons for I/O, and electro-chemical pad. The pulse generation algorithm for the muscle care effect is developed with basic pulses such as a single phase rectangle pulse, symmetric rectangle pulse, and depolarized interrupt pulse.

• The Journal of Korea Robotics Society
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• v.12 no.3
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• pp.270-278
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• 2017

The electrical muscle stimulator (EMS) based human machine interface (HMI) free to mechanical constraint and muscle fatigue problems are proposed for force feedback in a virtual reality. The device was designed to provide force feedback up to 4.8 N and 2.6 N each to the thumb and forefingers. The main objective of the HMI is to make unnecessary mechanical structures to attach on the hand or fingers. It employs custom EMSs and an interface arranged in the forearm. In this work, major muscle groups such as extensor pollicis brevis (EPB), extensor indicis proprius (EIP), flexor pollicis longus (FPL) and flexor digitorum profundus (FDP) are selected for efficient force feedback and controlled individually. For this, a human muscular-skeletal analysis was performed and verified. The validity of the proposed multi-channel EMS based HMI was evaluated thorough various experiments with ten human subjects, interacting with a virtual environment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.645-646
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• 2010

• The Journal of Korean Physical Therapy
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• v.13 no.2
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• pp.273-280
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• 2001

The purpose of this study was to analyze the effect of quadriceps setting exercise(N= 10) and electrical stimulation(N= 10) on improvement of quadriceps muscle strength. The experiment were performed for 6weeks. The subject of this study was 20 college students(male) who had not any medical problems. The quadriceps muscle strength was evaluated by make use of the KIN COM(Isokinetic dynamometer). The electrical stimulator was used to stimulate the quadriceps muscle. The results were as follows: 1. The mean increment ratio was 29.6% for concentric muscle strength and 36.4% for eccentric muscle strength after quadriceps setting exercise(p<0.05). 2. The mean increment ratio was 21.2% for concentric muscle strength and 24.3% for eccentric muscle strength after electrical stimulation, but did not significantly higher than pre-electrical stimulation In this study, we have found that quadriceps setting exercise on left side affect the improvement of the muscle strength in college students(male). However, electrical stimulation did not affect on the muscle strength.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.12
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• pp.708-716
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• 2003

The surface EMG signal detected from voluntarily activated muscles can be used as a control signal for functional electrical stimulation. To use the voluntary EMG signal, it is necessary to eliminate the muscle response evoked by the electrical stimulation and enable to process the algorithm in real time. In this paper, we propose the Gram-Schmidt(GS) algorithm and implement it in FPGA(field programmable gate array). GS algorithm is efficient to eliminate periodic signals like muscle response, and is more stable and suitable to FPGA implementations than the conventional least-square approach, due to the systolic array structure.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.99-102
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• 1996

The ultimate object of FES is on the recovering function of body and shape demaged from desease or injury to original state. On this study, object is recovering of gait function of the disabled who, especially, have gait disturbance. Paralyzed muscle from the central nerve disable, if peripheral nerves which be in the lower part of the harmed are activated, muscle contraction is possible. The traumatic trouble, peripheral nerves aren't connected to a central nerve but origin of peripheral nerve cells which are in the lower part of the harmed are alive, react on stimulation. We design 4-channel stimulator, being based on standard stimuli pattern. stimulator is manufactured with compact size and light weight to portable.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.1 no.1
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• pp.57-72
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• 2003

This study conducts electrical stimulation to male white rat of Spargue-Dawley which is 7 weeks, has the weight of 240 g and is seemingly healthy for one or two weeks by means of neuromuscular electrical stimulator in order to examine the effects of neuromuscular electrical stimulation on its gastrocnemius, measures change of weight of gastrocnemius, serum and enzyme activity and then obtains the following conclusions. There is little difference in AST and CPK of weight and serum of gastrocnemius after one or two weeks of conducting neuromuscular electrical stimulation in all experimental groups. On the one hand, as a result of histochemical observation, NMES I group showed hypertrophy of perimysium and increase of sectional diameter of muscle fiber compared to comparison group, but NMES II group showed a similar result to comparison group. When ultrasubstructure was observed under electron microscope, I-type muscle fiber of NMES I group showed well-arranged mitochondria and it was similar to comparison group. II-type muscle fiber showed a large quantity of glycogen granules within sarcoplasmatic and the extension of luminal of T-tubule. I-type muscle fiber of NMES II group had small mitochondria and showed the vacuolar degeneration of mitochondria and extended T-tubule. II-type muscle fiber showed the extension of agranule cytoplasma reticulum with T-tubule and the reduction of amount of glycogen granule within partial sarcoplasmatic.