• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.8
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• pp.1271-1276
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• 2013

This study selected 22 male subjects to examine the maintenance period of static and ballistic stretching applied to rectus femoris, divided them into 11 static stretching group and 11 ballistic stretching group and analyzed changes in median frequency and in maximal voluntary isometric contraction before stretching and at 30 sec, 1 min, 3 min, 5 min, and 10 min after stretching. Median frequency showed significant differences in changes according to time and groups after the test of main effects. It was reduced after 3 min. in both static stretching and ballistic stretching groups and then increased again. Maximal voluntary isometric contraction showed significant differences in changes according to time and groups from the results of the main effect test. Static stretching group was reduced at 3 min after the experiment and then increased after that and ballistic stretching group was reduced at 5 min after the experiment and then increased again. In conclusion, changes were shown according to time after stretching and the effects of ballistic stretching were maintained a little longer than those of static stretching.

• Journal of the korean veterinary medical association
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• v.42 no.10
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• pp.943-948
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• 2006

• Proceedings of the ESK Conference
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• 1993.04a
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• pp.79-87
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• 1993

등척성 수축에서 국소근육피로의 연구에는 표면전극을 사용한 근전도신호의 스펙트럼분석 이 효과적이다. 많은 연구결과에서 자발적 수축동안 근전도신호의 주파수 성분이 근육의 피로에 의해 낮은 쪽으로 천이 된다는 사실이 밝혀졌으며, 이를 근육피로의 지수로 사용하려는 노력이 계속되어 왔다. 본 연구에서는 실제와 유사한 형태의 주기적 작업수행시에 얻어진 근전도신호의 중간주파수 천이양상을 지속적 수축에서 얻어진 중간주파수의 천이양상과 비교하여, 주기적 작업의 피로축적은 지속적 수축에서의 피로축적과 같은 경향성을 지님을 찾아냈으며, 이 결과를 근거로 주기적 수축의 수축지속시간으로 정규화된 개념의 피로지수를 개발하였다. 이러한 피로지수는 정량적으로 제시될 수 있음은 물론, 작업설계와 허용한계의 설정등에 응용될 수 있을 것이다.

• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.471-478
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• 2004

Electromyogram (EMC) signal generated by voluntary contraction of muscles is often used in a rehabilitation devices such as an upper limb prosthesis because of its distinct output characteristics compared to other bio-signals. This paper proposes an EMG-based human-computer interface (HCI) for the control of the above-elbow prosthesis or the wheelchair. To control such rehabilitation devices, user generates four commands by combining voluntary contraction of two different muscles such as levator scapulae muscles and flexor-extensor carpi ulnaris muscles. The muscle contraction is detected by comparing the mean absolute value of the EMG signal with a preset threshold value. However. since the time difference in muscle firing can occur when the patient tries simultaneous co-contraction of two muscles, it is difficult to determine whether the patient's intention is co-contraction. Hence, the use of the comparison method using a single threshold value is not feasible for recognizing such co-contraction motion. Here, we propose a novel method using double threshold values composed of a primary threshold and an auxiliary threshold. Using the double threshold method, the co-contraction state is easily detected, and diverse interface commands can be used for the EMG-based HCI. The experimental results with real-time EMG processing showed that the double threshold method is feasible for the EMG-based HCI to control the myoelectric prosthetic hand and the powered wheelchair.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.567-569
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• 1999

본 논문에서는 골격근의 지속적인 수의 수축시에 발생하는 근육의 수축상태변화를 규명하기 위하여 심리 변화와 생리변화를 계측하여 이들의 해석방법을 제안하였다. 지금까지는 근육의 수축상태를 근전도의 변화로부터 정상상태와 피곤상태로 구분하고 있다. 그러나 본 연구에서 제안한 심리적 변화를 기초로한 생리 신호 해석 방법에서는 근육수축 상태가 정상상태, 피곤상태, 아픈상태의 3단계 변화를 한다는 사실을 얻었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.1129-1137
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• 2012

The aim of this study was to find useful parameters of the between myotonometer and surface electromyography(sEMG) on the medialis gastrocnemius of stroke patients and investigate between these parameters and modified Ashworth scale(MAS) relationship. 5 years clinical experience physical therapist using the Modified Ashworth Scale(MAS) was selected 15 patients with ankle spasticity and divided randomly MAS2, MAS3, MAS4 groups. Myotonometer and sEMG was measured during relaxed and maximum voluntary contractions of the gastrocnemius muscle. The results of this study, the higher MAS score was the lowered the relaxation and contraction state tissue compliance and muscle activity and in the correlation analysis the higher MAS score during voluntary contraction in the cylinder receiving low-intensity correlation could see that increased than relaxation. Therefore, the myotonometer is a useful clinical and research tool with spasticity muscle and can provide objective quantitative data about the efficacy of physical therapy interventions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3991-3998
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• 2012

The aim of this study was to effect of muscle activity on muscle architectural of medial gastrocnemius in chronic stroke patient based on ankle joint degree. The subjects of this study were 10 chronic stroke patients modified Ashworth scale(MAS) 2. Ultrasonographic and dynamometer was measured during resting and maximum voluntary isometric contraction(MVIC) on muscle thickness, pennation angle, fascicle length, MVIC. Result from analysis showed that muscle thickness was thinner in the paretic side than in the non-paretic side(p<.001) and the more plantarflexion increased, the thinner muscle thickness became. And at the time of resting rather than of MVIC significant(p<.001). Result from analysis showed that penneation angle was smaller in the paretic side than in the non-paretic side(p<.001) and the more plantarflexion increased, the larger pennation became. And at the time of resting rather than of MVIC significant(p<.001). Result from analysis showed that fascicle was shorter in the paretic side than in the non-paretic side(p<.001) and the more plantarflexion increased, the shorter fascicle length became. And at the time of resting rather than of MVIC significant(p<.001). The results of this study showed that effect of muscle activity on muscle architectural of medial gastrocnemius in chronic stroke patient based on ankle joint degree. Therefore, Ultrasonographic evaluation of chronic stroke patients according ankle joint degree and muscle activity in the clinical diagnosis and therapy is considered a very useful data.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.1
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• pp.147-151
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• 2013

연구목적: 본 연구는 허리 골반의 수의적 조절을 동반한 다리 들기 운동이 배 근육에 미치는 영향을 알아보기 위하여 엉덩 관절의 벌림 각도에 따라 다리 들기 시 배근육의 활성도를 확인하였다. 연구방법: 20대 정상성인을 대상으로 엉덩 관절 벌림각도($0^{\circ}$, $30^{\circ}$)에서 압력 센서 사용 그룹과 사용하지 않는 그룹으로 나우어 다리 들기를 실시하는 동안 복부 근육의 근활성도를 측정하였다. 연구결과: 엉덩 관절 벌림 $0^{\circ}$와 $30^{\circ}$ 모두에서 오른쪽 다리를 들어 올리는 동안 반대측 내복사근과 동측 외복사근에서 수의적 조절을 한 그룹과 하지 않은 그룹 사이에 통계적인 유의한 차이를 보였다(p<.05). 결론: 허리 골반의 수의적 조절을 통한 다리 들기 시 몸통 안정성의 증가를 통하여 안정적인 배 근육 강화 훈련을 수행 할 수 있을 것으로 생각되며 요통 환자에게도 안정적인 임상적용이 기대된다.

• Restorative Dentistry and Endodontics
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• v.28 no.5
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• pp.419-424
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• 2003

이 연구의 목적은 원래의 치수조직과 유사한 조직을 재생하기 위한 pulp tissue engineering의 한 방법으로 건전한 조직으로부터 배양된 치수세포와 쥐의 조섬유세포(NIH 3T3 cell)를 Rat tail type I collagen solution에서 3차원적으로 관찰하기 위한 것으로, 콜라젠 젤의 수축량과 세포의 증식 량을 비교하였으며, 또한 마모된 사람치아의 표면과 배양용기에서 두 세포의 증식 량을 비교하여 다음과 같은 결과를 얻었다. 1. 콜라젠 젤에 NIH 3T3 세포를 배양한 경우 그 수축량은 최소였으나, 치수세포를 배양한 경우 그 수축량은 현저하였다. 2. 서로 다른 수의 치수세포를 콜라젠 젤에서 배양시킨 경우 세포 수가 많을수록 수축량이 증가하였으며, 세포가 없는 콜라젠 젤은 수축하지 않았다. 3. 치수세포를 콜라젠 젤에서 18일간 배양시킨 후 세포의 증식은 거의 없는 반면, NIH 3T3 세포는 계속 증식하였다. 4. 마모된 사람 치아 표면과 배양 용기에서 치수세포와 NIH 3T3세포를 배양한 경우 NIH 3T3세포가 치수세포에 비해 빠르게 증식 하였으며 , 특히 사람 치아의 표면에서 NIH 3T3세포가 현저히 빠른 증식을 보였다. 이상의 결과는 치수세포를 type I collagen gel에서 3차원 적으로 배양 후 치수조직의 재생을 유도하는 pulp tissue engineering에 관한 연구에 발판이 될 것으로 사료된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.7
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• pp.959-969
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• 1993

In this paper, the performance of DS/SS DPSK communications is analysed over fading dispersive channels considering the spreads of the channel in time and in frequency. The two spreads mentioned above are represented with multipath spread and Doppler spread, respectively. The bit error probabilities of DS/SS DPSK systems are derived in terms of channel and system parameters, and an approximation method is presented for computational efficiency. And the numerical results are given for various chip numbers in Rayleigh and Rician fading channels using the approximation method.