• Journal of Biomedical Engineering Research
• /
• v.25 no.6
• /
• pp.479-487
• /
• 2004

Biopotential signals have been used as command in systems using electrical stimulation of motor nerves to restore movement after an injury to the central nervous system (CNS). In order to use the voluntary EMG (electromyography) among the biopotentials as a control signal for the electrical stimulation of the same muscle for CNS injury patients, it is necessary to remove M-wave of having high magnitude from raw data. We designed an optimal filter for removing the M-wave and preserving the voluntary EMG and showed that the optimal filter is eigen filter. We also proved that the previous method using the prediction error filter(PEF) is a suboptimal filtering in the sense of preserving the voluntary EMG. On basis of the data obtained from a model for M-wave and voluntary EMG and from actual CNS injury patients, with false-positive rate analysis, the proposed adaptive filter showed a very promising performance in comparison with previous method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2011.10a
• /
• pp.675-676
• /
• 2011

• Journal of the Korean Applied Science and Technology
• /
• v.38 no.2
• /
• pp.453-464
• /
• 2021

Abdominal obesity is increasing due to a decrease in physical activity and westernization of diet in busy daily life. Therefore, in order to satisfy the desire for body shape management, a management program with high efficiency versus time is needed. In this study, the diet-gel (i.e., slimming cosmetics) with the electrical muscle stimulation therapy was used to promote the effect of reducing waist circumference and body fat mass (or abdominal fat). For men and women in their twenties, the subjects simply applied diet-gel to their waist, wore EMS, and massaged for 20 minutes twice a day after waking up and before going to sleep. The experiment period was carried out for 2 weeks. The reduction of subcutaneous fat was observed using non-contrast CT, and it was confirmed by measuring waist circumference and body fat mass. In conclusion, the developed EMS and diet-gel combination program showed excellent waist management effects by reducing waist circumference by about 3 cm (p<0.001) and body fat mass by about 1 kg (p<0.01). This result suggests that the use of EMS shows a massage effect by muscle stimulation, and plays a role in promoting fat decomposition by helping the absorption of diet gel.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.48 no.8
• /
• pp.1046-1053
• /
• 1999

The musculotendon model is presented to show the declines in muscle force and shortening velocity during muscle fatigue due to the repeated functional electrical stimulation (FES). It consists of the nonlinear activation and contraction dynamics including physiological concepts of muscle fatigue. The activation dynamics represents $Ca^{2+}$ binding and unbinding mechanism with troponins of cross-bridges in sarcoplasm. It has the constant binding rate or activation time constant and two step nonlinear unbinding rate or inactivation time constant. The contraction dynamics is the modified Hill type model to represent muscle force - length and muscle force - velocity relations. A muscle fatigue profile as a function of the intracellular acidification, pH is applied into the contraction dynamics to represent the force decline. The computer simulation shows that muscle force and shortening velocity decline in stimulation time. And we validate the model. The model can predicts the proper muscle force without changing its parameters even when existing the estimation errors of the optimal fiber length. The change in the estimate of the optimal fiber length has an effect only on muscle time constant in transient period not on the tetanic force in the steady-state and relaxation periods.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.31 no.4
• /
• pp.545-552
• /
• 1998

This study was undertaken to clarify the effects of electrical stimulation on the biochemical properties of plaice sarcoplasmic reticulum and myofibrils at early period of death. The plaices were electrically stimulated (110V/60 Hz) In sea water bath for 15, 35, and 60 seconds, and killed instantly by spiking at the head. Killed samples were investigated for the changes in $Ca^{2+}$-ATPase activity of FSR (fragmented sarcoplasmic reticulum), LSR (light SR), HSR (heavy SR), and SDS-PAGE pattern of FSR. $Ca^{2+}$-ATPase activity of FSR increased until $45^{\circ}C$ and inactivated over $50^{\circ}C$. $Ca^{2+}$-ATPase activity of FSR remarkably decreased according to the duration of electrical stimulation. Myofibrillar $Mg^{2+}$-ATPase activity of electrically stimulated plaices in the presence of $Ca^{2+}$ was higher than that of sample instantly killed by spiking. $Mg^{2+}$-ATPase activity of myofibrils increased by electrical stimulation and the activity decreased during storage at $5^{\circ}C$. Myofibrillar $Mg^{2+}$-ATPase activity in sample killed by spiking was not affected by $Ca^{2+}$ ion. Myofibrillar $Mg^{2+}$-ATPase activity of electrically stimulated sample in the absen-re of $Ca^{2+}$ decreased during storage at $5^{\circ}C$, whit $Mg^{2+}$-ATPase activity in unstimulated sample did not show any change. $Ca^{2+}$-sensitivity of myofibrils showed no differences between electrically stimulated sample and sample killed by spiking, and the was no change during at $5^{\circ}C$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2000.05a
• /
• pp.455-459
• /
• 2000

신경의 기본단위인 뉴런을 계층 구조형태로 연결하여 자극에 대한 각 뉴런의 신경전달 메카니즘을 분석하고 Na 이온의 값을 변형시켜 활성전위에 미치는 영향을 LINUX를 기초로 한 GENESIS를 이용하여 시뮬레이션을 해 보았다. 뉴런은 미세한 자극뿐만 아니라 이온농도의 변화로 인한 매우 민감하게 반응함으로 신경의 활성전위와 인체를 구성하는 모든 세포에서의 이온농도의 중요성을 간과해서는 안 된다. 본 연구에서는 신경세포를 전기회로 적인 모텔을 기준으로 설계하였으며, 농도의 변화에 의해 활성전위 전달에 큰 변화를 일으켰다. 과대한 농도 변화는 신경에서의 과도한 활성전위와 매우 낮은 전위가 발생함을 알 수 있었다. 이로 인해 인체에 미치는 영향은 신체의 어느 부분이냐에 따라 다르겠지만 뇌에서의 열, 뇌 세포 손상, 근육마비, 심장마비 등의 이상 현상을 추정할 수 있을 것이다.

• Prospectives of Industrial Chemistry
• /
• v.24 no.6
• /
• pp.19-31
• /
• 2021

자극응답성 액정 엘라스토머(liquid crystal elastomer)는 하이드로겔(hydrogel), 형상 기억 고분자(shape memory polymer)와 더불어 생체 특성을 모방한 인공 근육, 소프트 액추에이터 및 소프트 로봇을 위한 스마트 소재로 최근 높은 관심을 받고 있다. 특히, 액정 엘라스토머는 고무 탄성과 액정 이방성이 결합된 비등방성 탄성 고분자로, 열, 빛, 전기 및 수분과 같은 외부자극에 반응하여 가역적이며, 액정 분자들의 배향조절을 통한 프로그램된 변형이 가능하다. 액정 엘라스토머가 개념 증명을 하는 수준을 넘어 실제로 유용한 소프트 액추에이터 및 로봇 시스템에 적용되기 위해서는 우수한 구동력 및 작업 용량, 높은 구동 변형률, 빠른 응답 시간, 낮은 구동 온도, 다양한 외부 자극반응성 및 높은 에너지 전환 효율 등을 확보하는 것이 중요하다. 본 기고문에서는 액정 엘라스토머의 개념에 대해 소개하고, 이러한 소재가 소프트 액추에이터로써 광범위하게 활용될 수 있도록 다양한 성능들을 향상시킬 수 있는 방법에 대해 소개하고자 한다.

• Prospectives of Industrial Chemistry
• /
• v.23 no.2
• /
• pp.40-50
• /
• 2020

소프트 로봇의 수요와 관심이 증가함에 따라 생체 모방형 액추에이터 연구가 큰 관심을 받고 있다. 액추에이터란 외부 에너지를 기계적인 동작으로 변환하는 장치이며, 재료 자체가 유연하여 부드러운 움직임을 재현할 수 있는 소프트 액추에이터의 연구가 활발히 진행되고 있다. 고분자 연성 재료 중에 하나인 하이드로겔은 90% 이상이 물로 구성되어 있기 때문에 생체 친화적이면서 동시에 환경 친화적인 재료이며 이를 기반으로 한 액추에이터 연구가 새로이 각광받고 있다. 최근에는 하이드로겔 액추에이터의 성능 향상을 위해 나노재료를 하이드로겔에 첨가하는 연구가 진행되고 있으며, 나노재료가 갖는 고유의 특성을 활용함으로써 하이드로겔 액추에이터의 자극 감응성 향상, 변형 방향의 제어, 높은 변형 효율 그리고 기계적 물성 증가가 보고되고 있다. 이는 헬스케어를 위한 웨어러블 장치, 재활을 목적으로 한 인공 근육 등에 적용이 가능하다. 본 기고문에서는 자극 감응성 고분자와 나노재료를 이용한 하이드로겔 액추에이터 연구에 대해 자극(전기장, 빛, 열, 자기장)의 종류에 따라 분류하여 소개하고, 합성 전략 및 구동 원리에 대해 간략하게 설명하고자 한다.

• Journal of Korean Academy of Nursing
• /
• v.36 no.6
• /
• pp.917-924
• /
• 2006

Purpose: This study was to examine the effects of electrical muscle stimulation therapy on chronic knee pain in the elderly. Method: The research design was a one-group pretest-posttest design. The subjects were 45 (TE: 17, SE: 15, SY: 13) elderly, 65 years old and above with chronic knee pain. Pain was measured by the S-F McGill Pain Questuionnaire (S-F MPQ) and Arthritis Impact Measurement Scale (AIMS). Electrical muscle stimulation therapy experimental treatment was applied for 12 weeks, 3 times/week, 15 min/time. Data was collected from March 2005 to February 2006. Data was analyzed using the SPSS PC+ 12 version. Results: After receiving electrical muscle stimulation therapy, chronic knee pain in TE (S-F MPQ: t=-62.143, p=.000, AIMS: t=-29.155, p=.000), SE (S-F MPQ: t=-76.345, p=.000, AIMS: t=-39.323, p=.000), and SY (S-F MPQ: t=-43.691, p=.000, AIMS: t=-30.306, p=.000) groups were significantly decreased. Conclusion: Electrical muscle stimulation therapy can be a better effective primary nursing intervention for chronic knee pain for community dwelling elderly people with TE, SE, and SY.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.52 no.9
• /
• pp.560-567
• /
• 2003

EMG recordings of the electrical activity of muscle have proved to be a valuable tool in studying muscle function and reflex activity. SP(silent period) is elicited by a electrical stimulation on the chin during isometric contraction of jaw muscle. This paper proposes a model of the inhibitory reflex mechanism of jaw muscle after electrical stimulation. The SPs of jaw muscle after a electrical stimulation to the chin were divided into SP1 and SP2. SP1 is produced by the activation of periodontal receptors. The activation of nociceptors contributes to the SP2. As a result, the EMG signal generated by a proposed a model of inhibitory reflex mechanism is similar to real both EMG signal including SP1 and SP2. The present study have shown differences of SP1 and SP2 induced by inhibitory reflex mechanism.