• Korean Chemical Engineering Research
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• 제60권2호
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• pp.249-254
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• 2022

최근 반도체와 같은 정보통신 기술의 발전과 함께 사물인터넷(IoT) 기술 발전이 급격히 이루어지면서 센서와 무선 통신 기능을 내장하여 주변 사물 및 환경 조건을 감지 및 분석하여 대응하는 원격 환경 모니터링 기술이 주목받고 있다. 하지만, 기 개발된 원격 환경 모니터링 시스템은 모두 별도의 전원 공급 장치를 필요로 하기 때문에 시·공간적 기기 사용의 제한을 야기하여, 사용자의 불편함을 유발할 수 있다. 따라서, 본 연구에서는 생체 역학적 에너지의 역학적 특성이 고려된 기구학적 설계 기반 전자기 발전 소자(Electromagnetic generator, EMG)를 개발함으로써 이의 에너지 자립형 원격 환경 모니터링 구동을 위한 전원 공급 장치로써 활용한다. 낮은 진동 주기 및 큰 진폭 변화의 역학적 특성을 지닌 생체 역학적 에너지를 효과적으로 이용하기 위해 자석의 기구학적 배치를 통한 깨지기 쉬운 힘의 평형을 유도하는 Levitation-EMG (L-EMG)를 설계했다. 이를 통해, L-EMG는 외부 진동에 민감하게 반응하여 자석과 코일 간의 효과적인 상대 움직임을 야기하여 고품질 전기 에너지 공급을 가능하게 했다. 뿐만 아니라, 실제 환경 감지 센서와 무선 통신 모듈의 필요 전력을 최소화하기 위한 마이크로 컨트롤러(Micro control unit, MCU)를 구성하였으며, 내장기능 중 저전력모드(Sleep mode)를 접목하여 소비전력의 최소화 및 이의 구동시간 증가를 달성했다. 최종적으로 사용자의 편의성을 극대화하기 위해 휴대폰 어플리케이션을 구축하여 손쉽게 주변 환경 모니터링을 가능하게 했다. 따라서, 이번 연구는 생체역학적 에너지를 이용한 에너지 자립형 원격 환경 모니터링 구축 가능성을 검증할 뿐만 아니라, 더 나아가 별도의 외부 전원 없이 주변 환경 모니터링이 가능한 설계 방안을 제시할 수 있다.

• 국제물리치료학회지
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• 제10권3호
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• pp.1818-1822
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• 2019

Background: Ipsilateral pelvic elevation has been reported as a common compensatory movement during side-lying hip abduction. It has been reported that pelvic elevation inhibits sufficient contraction of gluteus medius. However, few studies have identified the effects of controlled pelvic elevation on the trunk and hip muscles. Objective: To examine the effects of controlled pelvic elevation using visual biofeedback on the muscle activity of the trunk and hip muscles. Design: Crossover study. Methods: Twelve healthy males performed side-lying hip abduction exercises with and without visual biofeedback for pelvic elevation. Electromyography (EMG) activities of the gluteus medius, quadratus lumborum, and multifidus were analyzed using a wireless EMG system while the ipsilateral pelvic elevation angle was measured using a motion sensor during side-lying hip abduction exercises. Results: EMG activities of the gluteus medius (p = .002), quadratus lumborum (p = .022), and multifidus (p = .020) were significantly increased and ipsilateral pelvic elevation was significantly decreased (p = .001) during side-lying hip abduction with visual biofeedback compared to without visual biofeedback. Conclusions: The results of this study suggest that the application of biofeedback for pelvic motion could improve the trunk and hip muscle activation pattern and decrease compensatory pelvic motion during side-lying hip abduction exercise.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.821-825
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• 2008

Requirements of wireless sensor are increasing in machine condition monitoring. But, the limitation of battery power, self-power wireless sensor is necessary for the purpose of stand-alone operation. To overcome this problem, energy harvester is developed by the vibration energy. The purpose of this study is to develop a high efficiency energy harvester with high precision tuning.

• 한국컴퓨터정보학회논문지
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• 제29권5호
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• pp.111-121
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• 2024

근력 트레이닝은 운동의 효과와 함께 부상의 위험도 함께 공존한다. 운동에 대한 지식과 경험이 부족하거나 과도한 운동 강도에서의 반복은 부상으로 이어질 수 있다. 운동 진행 중 과정에 대한 적절한 피드백은 과학적 데이터 제공을 통한 운동 효과증대 및 부상의 감소는 물론 심리적 동기부여의 효과도 기대할 수 있다. 무선 근전도를 적용한 8주 동안의 바이오피드백 트레이닝의 적용에 따른 EMG(Electromyography) 장비 검증 및 운동 효과를 살펴보는 데 목적이 있다. 최근 3개월 이내 근골격계 진단을 받은 사람들을 제외하고 20대의 48명을 대상으로 4개의 그룹에 대해 8주간의 근전도 바이오피드백 트레이닝이 진행되었으며, 측정은 사전, 4주차, 8주차에 각각 실시되었다. 트레이닝 프로그램은 상지 근육을 강화하기 위한 것으로, 그룹별로 다른 운동이 시행되었다. 근전도 프로토타입인 Fitsig를 트레이닝 중에 사용하였고 근육의 변화를 확인하였다. 연구 분야에서 잘 알려진 Noraxon사의 제품과 Fitsig^®(EMG, FS-100)의 상관성 분석 결과, 중등도 상관성이 나타났다. 상완골 둘레, 상완골 근육량, 상완 이두근과 상완 삼두근 근력은 좌우 모두 시기간 통계적으로 유의한 차이가 발생했으며, 운동 종류에 따른 차이는 발생하지 않았다. 실시간 근전도를 활용한 피드백 트레이닝은 근비대 성장 및 근력 향상에 긍정적인 것으로 나타났다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권2호
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• pp.787-806
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• 2016

Traditional radio-based gesture recognition approaches usually require the target to carry a device (e.g., an EMG sensor or an accelerometer sensor). However, such requirement cannot be satisfied in many applications. For example, in smart home, users want to control the light on/off by some specific hand gesture, without finding and pressing the button especially in dark area. They will not carry any device in this scenario. To overcome this drawback, in this paper, we propose three algorithms able to recognize the target gesture (mainly the human hand gesture) without carrying any device, based on just Radio Signal Strength Indicator (RSSI). Our platform utilizes only 6 telosB sensor nodes with a very easy deployment. Experiment results show that the successful recognition radio can reach around 80% in our system.

• 대한인간공학회지
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• 제30권2호
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• pp.357-363
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• 2011

Objective: The aim of this study is to set the design direction of the lift chair's tilting seat for development. Background: Great attention has been shown to the development of senior friendly product, because of increasing elderly population rapidly in Korea. Therefore, we need to study on sit-to-stand(STS) motion of elderly systematically for developing lift chair that is one of senior friendly products. Method: In this study, we analyzed joint moment(knee, hip) and muscle activity (Erector spinae, Rectus femoris, Vastus lateralis) on STS motion of elderly(female, 60~70: 7) and young people(female, 20~30: 7) using 3 dimension motion capture camera, force plate, wireless EMG. Results: The results of muscle activity showed a similar trend but the results of joint moment were a lot of differences between the young and the elderly. Conclusion: The results of knee joint moment suggest the angle(10~30deg)-adjustable seat that can be better than to find the optimal seat's angle. Application: The method and results of this study are expected to develop senior friendly product and verification as well as be available to various application.

• 국제물리치료학회지
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• 제4권1호
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• pp.516-522
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• 2013

The purpose of this study is to analysis of muscle fatigue in the upper trapezius and splenius capitis muscles according to therapy table height variation. The subjects were consisted of 15 healthy adults(10 males, 5 females) who had no medical history of neurological and musculoskeletal problems. In experiment, wireless electrode EMG system was measured for each the upper trapezius and splenius capitis muscles during the treatment performed on table. the differences in the muscle fatigue was compared for 4 types of table height(-6cm, -3cm, 0, +3cm from elbow in $90^{\circ}$ flexion position). Muscle fatigue according to therapy table height were significant difference except for left upper trapezius. And muscle fatigue of right upper trapezius and splenius capitis showed significant decrease in +3cm table height compared to -6cm table height(p<.05). Muscle fatigue of right upper trapezius and splenius capitis were the highest in -6cm table height, but those were the lowest in +3cm table height. This study propose to change therapy table height higher than +3cm from elbow in $90^{\circ}$ flexion position, if you hope to reduce muscle fatigue.

• The Journal of Korean Physical Therapy
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• 제34권4호
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• pp.187-191
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• 2022

Purpose: The purpose of our study aimed to identify the effect of static and dynamic bridge exercise with gym ball using gym ball on muscle activation of trunk and lower-limb in healthy individuals. Methods: A total of 20 healthy adults participated in this study. The individuals performed general bridge exercise, static and dynamic bridge exercise using gym ball. During the three methods of bridge exercises, electromyography (EMG) data (% maximum voluntary isometric contraction) of the rectus abdominis, erector spinae, biceps femoris, and gastrocnemius were recorded using a wireless surface EMG system. Results: Rectus abdominis activation showed significantly greater during dynamic bridge exercise compared with general bridge exercise and dynamic bridge exercise. Erector spinae, biceps femoris, and gastrocnemius were greater during static and dynamic bridge exercise compared with general bridge exercise. Conclusion: Based on our results, bridge exercise using gym ball, particularly integrating lower-limb movement, could be a useful method to enhance muscle activation of trunk and lower-limb (rectus abdominis, erector spinae, biceps femoris, and gastrocnemius).

• The Journal of Korean Physical Therapy
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• 제35권2호
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• pp.53-57
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• 2023

Purpose: The purpose of this study was to compare the changes in the muscle activation of the quadriceps muscle (rectus femoris, vastus lateralis, vastus medialis) during the stand-to-sit (StandTS) movement according to the plantar flexion angle of the ankle joint. Methods: A total of 22 healthy young females participated in this study. During the StandTS under the three conditions (plantarflexion angle 0°, 20°, and 45° of the ankle), electromyography (EMG) data (% maximum voluntary iso¬metric contraction) of the rectus femoris, vastus lateralis, and vastus medialis were recorded using a wireless surface EMG system. Results: There was a significant difference in the muscle activation of rectus femoris, vastus lateralis, and vastus medialis according to the plantar flexion angle (0°, 20°, and 45°) of the ankle. The muscle activation of the quadriceps was the highest at a 45° angle of plantarflexion and the lowest at 0°. One-way repeated ANOVA was used to analyze the muscle activation data of the lower extremity muscles according to the angle of the ankle joint. Conclusion: Based on the results of our study, it was confirmed that the muscle activity of the quadriceps can be increased even in the StandTS movement, which involves the eccentric contraction of the quadriceps muscle. This suggests that maintaining a plantar flexion posture for a long time, say by wearing high-heeled shoes, can quickly cause muscle fatigue in the lower-limb muscles, which can cause a decrease in balance ability leading to falls.

• The Journal of Korean Physical Therapy
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• 제35권5호
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• pp.151-155
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• 2023

Purpose: This study examined the effect of the degree of neck flexion on the muscle activity of the upper trapezius and sternocleidomastoid muscles in the sitting position. Methods: Twenty-five healthy young adults participated in this study. The study was designed to compare the muscle activity of the upper trapezius and sternocleidomastoid muscles according to the neck flexion angle under the three conditions (neutral position, 15° neck flexion, and 45° neck flexion) in the sitting position. During the neck position of three conditions in sitting, the electromyography (EMG) data (% maximum voluntary isometric contraction) of the muscles were recorded using a wireless surface EMG system. Results: The muscle activity of the upper trapezius muscle and the sternocleidomastoid muscles showed a significant difference according to the three-neck position conditions (p<0.05), and in the post-hoc test results, both muscles showed significant differences between the neutral position and 15° flexion, the neutral position and 45° flexion, and the 15° flexion and 45° flexion, respectively. Conclusion: The load on the muscles around the neck and shoulders increased as the neck flexion angle increased. This suggests that performing various daily activities and tasks with the neck as neutral as possible can prevent muscle fatigue or musculoskeletal disorders.