• 전자공학회논문지SC
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• 제46권6호
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• pp.38-43
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• 2009

표면 근전도 신호를 이용하여 손가락의 굽힘 동작을 추론하는 방법을 제안한다. 표면 근전도 신호는 인체 근육의 표면에서 무해하고 손쉽게 취득되나, 전극이 근육 내부에 침투하는 침습식 근전도와는 달리 특정 근육의 활동만을 반영하지 않는다. 따라서 소수의 전극을 사용하는 표면 근전도 신호로 다양한 신체 동작을 구분하기는 쉽지 않다. 본 연구에서는 전완 둘레에 부착된 4채널 근전도 센서를 사용하여 신호를 취득하였고, 구분을 위하여 사용한 동작은 엄지, 검지, 중지, 약지, 소지의 개별 손가락의 굽힘 동작이다. 피검자 한 명은 숙련자였으며, 다른 한 명은 비숙련자였다. 근전도 신호의 특성으로 정보 엔트로피를 추출하였으며 최대우도추정법을 사용하여 실제 동작을 추정하였다. 실험 결과 평균 95% 이상의 성능을 보였으며, 제안하는 방법이 손가락 동작의 구분에 유용함을 확인하였다.

• 대한전자공학회논문지
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• 제25권3호
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• pp.335-342
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• 1988

In this paper, we proposed a new algorithm for EMG low frequency analysis. Through the power spectrum analysis of Gaussian's, Gamma's and Erlang's PDF(probability density function) based on the proposed algorithm, the proper PDF of IPI (inter pulse interval) representing the firing rate of muscle was suggested. In order to verify the proposed algorithm EMG signals of masseter and biceps muscle were detected by surface electrode and its power spectrum analysis was performed. The experimental results are compared with the computer simulaiton. As a result, the masseter muscle's IPI was fitted by Gamma PDF, having a 10Hz fundamental frequency including n(1+\ulcornerfp high harmnic frequency on 10% MVC(maximum voluntary contaraction). And the biceps muscle's IPI was fitted by Gaussian PDF, also it have a 14Hz fundamental frequency.

• 대한의용생체공학회:의공학회지
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• 제22권2호
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• pp.171-178
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• 2001

본 연구에서는 강건 시지연추정 알고리즘을 바탕으로 하여 표면근전도 신호로부터 새로운 근섬유 전도속도 측정방법을 제안하였다. 제시한 방법은 가우시안 가정 하에서 유도된 기존의 방법들로는 불가능한 비가우시안 충격성잡음을 포함하는 표면근전도 신호를 대상으로도 정확하게 근섬유 전도속도를 측정할 수 있다. 제시한 방법의 평가를 위하여 먼저, 마미총 증후군에 걸린 근질환자의 근전도 신호가 비가우시안 $\alpha$-stable 확률분포로 모델링할 수 있음을 보였으며, 정상인과 근질환자 6명의 피검자로부터 족저단신근과 내측광근에서 각각 근전도 신호를 수집하여 실험한 근섬유 전도속도 측정결과를 타 연구자들과 비교, 평가하였다. 실험결과, 족저단신근의 경우 근섬유 전도속도가 평균 4.60$\pm$0.50m/s로 내측광근의 경우 5.66$\pm$0.59m/s로 각각 구할 수 있었다.

• 전기학회논문지
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• 제59권8호
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• pp.1497-1505
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• 2010

The present study was performed to investigate the effect of aging on muscular activity of older subjects under the condition of fixed load muscle contraction. SEMG signals were recorded from old (46 women) and young (45 women) groups performing sustained isometric elbow flexion contraction with a fixed load during 30 seconds. Linear regression and mean square error (MSE) analysis with four characteristic variables (ARV, RMS, MDF, MNF) were used to compare the age-related difference (of local muscle fatigue and fluctuation of the amplitude and frequency) in the SEMG signal. The main results can be summarized as follows: During sustained muscle contraction with a fixed load: i) the MSE values of amplitude (ARV, RMS) and frequency (MDF, MNF) variables were more than 30% higher for the young than for the old adults; ii) the measures of local muscle fatigue (slope of the MDF and MNF) indicated greater fatigue in the old; and iii) the rate of increase of the SEMG amplitude was higher for the young than the old.

• 전기학회논문지
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• 제57권9호
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• pp.1674-1680
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• 2008

The objective of this study is to compare age-related differences of 15 characteristic variables estimated from SEMG signals, which were obtained from the old group(62 subjects) and young group(72 subjects). The SEMG signals were recorded from biceps brachii muscle under sustained isometric elbow flexion contraction with constant load(4kg dumbbell) during 30 seconds. Ten time domain (ARV, RMS, MSA, MTA, ZC, MSF, MTF, MSD, MTD, MSS) and five frequency domain(MNF, MDF, $f_{max}$, $P_{max}$, $P_{to}$) variables were extracted from the SEMG signals and then statistically analyzed, respectively. The findings of the analysis indicate significant age-related differences in the SEMG signal during constant load contraction.

• 한국전문물리치료학회지
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• 제29권2호
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• pp.106-116
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• 2022

Background: Shoulder external rotation exercises are commonly used to improve the stabilizing ability of the infraspinatus. However, during exercise, excessive activation of the posterior deltoid compared to the infraspinatus causes the humeral head to move anteriorly in an abnormal position. Many researchers have emphasized selective activation of the infraspinatus during shoulder external rotation exercise. Objects: This study aims to delineate the optimal exercise method for selective activation of infraspinatus by investigating the muscle activities of the infraspinatus and posterior deltoid according to the four shoulder exercise methods and two forearm positions. Methods: Thirty healthy individuals participated in this study. The participants were instructed to perform shoulder external rotation exercises following four exercise methods: sitting external rotation (SIER); standing external rotation at 90° abduction (STER); prone external rotation at 90° abduction (PRER); side-lying external rotation (SLER), and two forearm positions (neutral, supinated). The electromyography (EMG) signal amplitude was measured during each exercise. Surface EMG signals were recorded from the posterior deltoid, infraspinatus, and biceps brachii. Results: EMG results of the infraspinatus and posterior deltoid in PRER, were significantly higher than that of the other exercises (p < 0.01). The EMG ratio (infraspinatus/posterior deltoid) in SIER was significantly higher than that of the other exercises. EMG activation of the posterior deltoid in SIER, PRER, and SLER was significantly higher in neutral than in supinated (p < 0.01). Furthermore, the EMG of the infraspinatus in SIER was significantly higher in neutral than in supinated (p < 0.01). The EMG ratio (infraspinatus/ posterior deltoid) in SIER was significantly higher in neutral than in supinated (p < 0.05.) Contrarily EMG ratios in PRER and SLER were significantly higher in supinated than in neutral (p < 0.05). Conclusion: The results show that clinicians should consider these exercise methods and forearm positions when planning shoulder external rotation exercises for optimal shoulder rehabilitation.

• 로봇학회논문지
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• 제15권1호
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• pp.62-69
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• 2020

This paper proposes a pattern recognition and classification algorithm based on a circular structure that can reflect the characteristics of the sEMG (surface electromyogram) signal measured in the arm without putting the placement limitation of electrodes. In order to recognize the same pattern at all times despite the electrode locations, the data acquisition of the circular structure is proposed so that all sEMG channels can be connected to one another. For the performance verification of the sEMG pattern recognition and classification using the developed algorithm, several experiments are conducted. First, although there are no differences in the sEMG signals themselves, the similar patterns are much better identified in the case of the circular structure algorithm than that of conventional linear ones. Second, a comparative analysis is shown with the supervised learning schemes such as MLP, CNN, and LSTM. In the results, the classification recognition accuracy of the circular structure is above 98% in all postures. It is much higher than the results obtained when the linear structure is used. The recognition difference between the circular and linear structures was the biggest with about 4% when the MLP network was used.

• 한국운동역학회지
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• 제23권3호
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• pp.235-243
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• 2013

The purpose of this study was to analyse scientific according to period of rehabilitation training of ACL patients. ACL patients seven subjects participated in this study. Gait (1.58 m/sec) analysis was performed by using a 3-D Cinematography, a Zebris system and a electromyograph system. The data were analyzed by paired t-test. The joint angles were recorded from the ankle, knee, hip joints. Peak max dorsi-flexion and peak max plantar-flexion identified significant differences (p<0.05). Another angles were no significant difference. Vertical force (Fz) and max pressure variables improved 6 month RTP better than 3 month RTP. EMG were collected from 4 muscles (rectus femoris, biceps femoris, gastrocnemius, tibialis anterior) with surface electrides in gait system. EMG signals were rectified and smoothed data. EMG signas were no significant difference but they also improved 6 month RTP better than 3 month RTP. More research is necessary to determine exactly what constitutes optimal rehabilitation training period for ACL patients.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1641-1648
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• 2017

Many researchers had examined the validity of using the high-to-low ratio between two fixed frequency band amplitudes (H/L-FFB) from the surface electromyography of a face and body as the first spectral index to assess muscle fatigue. Despite these studies, the disadvantage of this index is the lack of a criterion for choosing the optimal border frequency. We tested the potential of using the high-to-low ratio between two signal spectral moments (H/L-SSM), without fixed border frequencies, to evaluate muscle fatigue and predict endurance time ($T_{end}$), which was determined when the subject was exhausted and could no longer follow the fixed contraction cycle. Ten healthy participants performed five sets of voluntary isotonic contractions until they could only produce 10% and 20% of their maximum voluntary contraction (MVC). The $T_{end}$ values for all participants were $138{\pm}35s$ at 10% MVC and $69{\pm}20s$ at 20% MVC. Changes in conventional spectral indices, such as the mean power frequency (MPF), Dimitrov spectral index (DSI), H/L-FFB, and H/L-SSM, were extracted from surface EMG signals and were monitored using the initial slope computed every 10% of $T_{end}$ as a statistical indicator and compared as a predictor of $T_{end}$. Significant correlations were found between $T_{end}$ and the initial H/L-SSM slope as computed over 30% of $T_{end}$. In conclusion, initial H/L-SSM slope can be used to describe changes in the spectral content of surface EMG signals and can be employed as a good predictor of $T_{end}$ compared to that of conventional spectral indices.

• 대한물리의학회지
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• 제6권3호
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• pp.323-330
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• 2011

Purpose : The purpose of this study was to examine the effects of using a pressure bio-feedback unit (PBFU) and a pelvic belt (PB) on the electromyographic (EMG) signal amplitude of the gluteus medius (Gmed) and the quadratus lumborum (QL) during hip abduction exercise when lying on the side. Methods : Twenty able-bodied volunteers (10 male, 10 female) were recruited for this study. The EMG signal amplitude was randomly measured during hip abduction with preferred hip abduction (PHA), with PBFU, and with PB. The surface EMG signal was recorded from the Gmed and the QL. Data were analyzed using a one-way repeated ANOVA. Results : Muscle activity of Gmed was significantly higher in PBFU and in PB than in PHA (p<.05). There were no significant difference between PBFU and PB(p>.05). Muscle activity of the QL was significantly lower in PB than in PHA(p<.05). The Gmed/QL muscle activity ratio was also significantly higher in PBFU and in PB than in PHA(p<.05), with no significant difference between PBFU and PB (p>.05). Conclusion : Based on these findings, using a PBFU and a PB is an effective method to disassociate QL use from Gmed use during hip abduction exercises when lying on the side.