• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.461-464
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• 2001

본 연구에서는 생체 임피던스를 이용하여 3채널 상지(upper arm) 운동 분석 시스템을 제작하였다. 각 채널은 상지의 외전(supination)과 내전(pronation), 팔꿈치(elbow)의 폄과 굽힘, 손목(wrist)의 평과 굽힘에 따른 각 관절의 임피던스 변화를 얻을 수 있도록 설계되었다. 상체 임피던스는 전극의 부착위치에 의존하므로 정밀한 감지를 위해 상지 운동에 대한 임피던스의 변화와 각도계(goniometer)의 각도 변화와의 상관관계를 통하여 상관 관계가 높고, 변화량이 가장 크고 다른 관절의 움직임에 따른 영향이 최소인 곳을 찾아 이를 최적의 전극 위치로 정하였다. 그리고, 선정된 최적의 전극 위치에서 임피던스 변화를 얻어 상지 운동을 분석해 보았다. 최적의 전극 위치에서 손목과 팔꿈치의 각도 변화와 임피던스 변화의 상관 계수는 각각 0.94, -0.97로 아주 높은 상관 관계를 보였다. 또한 이전의 다른 연구에서 임피던스 방법으로 구현해 본적이 없는 팔의 회전(rotation)도 분석이 가능하였다. 이 시스템은 피검자의 동작에 거의 제한을 주지 않고, 가벼우며, 장시간 측정이 용이할 뿐만 아니라 시스템 구성이 영상 분석기에 비해서 단순하다는 장점을 가지고 있다. 본 연구에서 제안하는 방법은 재활과 생체역학, 로봇의 원격 제어, 그리고 가상 현실에서의 동작 구현 등에 활용 할 수 있을 것으로 사료된다.

• Journal of the Korea Convergence Society
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• v.7 no.2
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• pp.43-52
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• 2016

The purpose of this study was to suggest the effective squat exercise position to strengthening vastus medialis oblique, and vastus lateralis in quadriceps. Subjects were twenty patients with patellofemoral pain syndrome (PFPS) volunteered to participate in this study. All subjects were applied to static squat convergence exercise with knee flexed $45^{\circ}$, $60^{\circ}$, and $90^{\circ}$ for 30 seconds total 5 times. Measurement variables were maximal voluntary isometric contraction (MVIC) of the quadriceps, Q angle and length of thigh. Those were measured before and after the squat exercise on knee joint angle, change rate of which were used for statistical analysis. As a result, squat exercise with knee flexed $90^{\circ}$ increase significantly among knee joint angle in the MVIC change rates of quadriceps (p<.05), however the rates of Q-angle and length change of thigh showed no significant difference. Therefore, this findings suggest that squat exercise with knee flexed $90^{\circ}$ strengthen quadriceps effectively in patients with PFPS.

• Composites Research
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• v.31 no.6
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• pp.293-298
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• 2018

In this paper, we have studied the physical properties of braided composites for use as aircraft stringers. Process variables such as drum winder speed, braid velocity, and mandrel diameter for $30^{\circ}$, $45^{\circ}$ and $60^{\circ}$ braid preforms were quantified and different epoxy resin types were applied to the braided preform using TGDDM, YD-128. Physical properties such as tensile strength and flexural strength of braided composites were investigated. Thermal properties and decomposition temperature of epoxy resin were investigated by TGA analysis. As a result, the lower the angle of the braid composites, the higher the tensile strength and the Flexural strength. The physical properties of braided composites fabricated using TGDDM epoxy resin were superior to the physical properties of braided composites fabricated using YD-128 epoxy resin. This is because the molecular weight of TGDDM epoxy resin was higher than that of YD-128 epoxy resin.

• Physical Therapy Korea
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• v.10 no.4
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• pp.77-83
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• 2003

본 연구는 발가락 벌림 보조기(toe spreader)가 긴장성 발가락 굽힘 반사(Tonic Toe Flexion Reflex: TTFR)가 있는 양하지 뇌성마비 아동의 보행에 미치는 영향을 알아보고자 하였다. 12명의 TTFR이 있는 양하지 뇌성마비 아동을 대상으로 같은 날에 맨발과 발가락 벌림 보조기를 착용한 상태에서 보행분석을 실시하였다. 시간 거리 보행변수로 활보장(step length), 보장(step length), 보폭(step width), 발가락 외전각도(toe out angle), 활보시간(stride), 입각기(stance phase), 유각기(swing phase), 분속수(cadence), 보행속도(speed)를 측정하였다. 발가락 벌림 보조기 착용 시 시간 거리 보행변수는 통계적으로는 유의한 차이가 없었다(p>.05). 양하지 뇌성마비 아동에서 TTFR을 억제하기 위한 발가락 벌림 보조기의 즉시적인 효과는 유의하지 않다고 볼 수 있으며, 추후연구로 장기간 일상생활에서의 지속적인 착용을 통한 연구가 필요하다고 본다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.7-14
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• 2011

Soft copper tube is one of the popular materials which are used for shipbuilding, automobiles, and freezing and HVAC equipment. However, these materials have problems that they cause occasionally outside wrinkle, spring back, wall thinning phenomena. In this study, to avoid these phenomena, was manufactured a mild materials devoted bending machine, which selected a bending method where the mandrel presses the pipe along with the sliding guide rail during bending process. During the course of confirming this performance, it was found that as the diameter of copper tube used for materials became smaller, the spring back phenomenon increased. And as the bending angle became larger, it became larger. In addition, we could manufacture mold products which scarcely generated wrinkle when bending copper tubes.

• Science of Emotion and Sensibility
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• v.25 no.4
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• pp.119-128
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• 2022

This study analyzes the effects of the number of angles and bends on resistance in a conductor-embroidered stitch circuit for efficient power transfer through a conductor of wearable energy harvesting to study changes in power lost through connection with actual solar panels. In this study, the angle of the conductive stitch circuit was designed in units of 30˚, from 30˚ to 180˚, and the resistance was measured using an analog Discovery 2 device. The measured resistance value was analyzed, and in the section of the angle where the resistance value rapidly changes, it was measured again and analyzed in units of 5˚. Following this, from the results of the analysis, the angle at which the tension was applied to the stitch converges was analyzed, and the resistance was measured again by varying the number of bends of the stitch at the given angle. The resistance decreases as the angle of the stitch decreases and the number of bends increases, and the conductor embroidery stitch can reduce the loss of power by 1.61 times relative to general embroidery. These results suggest that the stitching of embroidery has a significant effect on the power transfer in the transmission through the conductors of wearable energy harvesting. These results indicate the need for a follow-up study to develop a conductor circuit design technology that compares and analyzes various types of stitches, such as curved stitches, and the number of conductors, so that wearable energy harvesting can be more efficiently produced and stored.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.9
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• pp.961-970
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• 2012

The behavior of the load bearing capacity of a pipeline with unequal wall thickness was evaluated using finite element analyses. Pipelines with a wall thickness ratio of 1.22-1.89 were adopted to investigate plastic collapse under tensile, internal pressure, or bending stress. A parametric study showed that the tensile strength and moment of a pipeline with a wall thickness ratio less than 1.5 were not influenced by the wall thickness ratio and taper angle; however, those of a pipeline with a wall thickness ratio more than 1.5 decreased considerably at a low taper angle. The failure pressure of a pipeline with unequal wall thickness was not influenced by the wall thickness ratio and taper angle.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.56-60
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• 2004

2단 또는 3단형으로 설계되고 있는 KSLV-I 발사체의 단연결부는 직경의 변화에 따라 원뿔대(Truncated cone) 구조물이 필요하다. 원뿔대형 구조물이 발사체의 외피일 경우에는 일반적인 실린더형 동체와는 다르게 공력에 의한 버페팅(buffeting)과 공력가열 등이 추가적인 설계인자로 고려되어야 한다. 복합재료 샌드위치 구조물은 외피의 굽힘 강성이 크고, 일체성형으로 실린더형 혹은 원뿔대형 구좁물을 쉽게 제작할 수 있어 단연결부에 적용되고 있다. 또한 위성어댑터(Payload Adapter)등에도 사용되어 우주발사체에는 매우 일반적인 구조물이다. 복합재료 샌드위치 구조물의 제작과 정적시험을 통하여 구조 특성을 알아보았다. 일체형 샌드위치 구조물의 효율을 높이기 위해서는 프레임과의 체결부를 효율적으로 설계하여야 하며 하중의 종류에 따라서 면재의 적층각도가 중요함을 알 수 있었다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.51
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• pp.109-116
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• 1999

Most of carrying works have been performed in almost all production process, conveyer objects, machine equipment and work method. Then, they are made by unfitted design which doesn't consider physical condition of workers. So, it causes them to bring about forceful motion. This study investigated the back power for what difference between lumbar bending angle and back power by selecting 21 male aged 22∼30 years old. Lumbar angle were shared each 30, 60, 90 degrees and measured. The results of this study was that as lumbar angle was increasing, back power was decreased and were very significant differences for angles respectively. Besides. sample correlation coefficients were calculated in order to analyze the relationship between back power, anthropometric dimensions and grip strength. Back power was correlated with weight, arm length, hand length, breadth of palm, breadth of lower arm, breadth of wrist and left-right grip strength.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.253-258
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• 1996

원자로의 가동 중지 중이나 재장전시 원자로가 설치되어 있는 수조의 냉각수가 증기발생기 안으로 유입되는 것을 막는 장비로써 노즐댐을 사용한다. 현재의 노즐댐은 알루미늄 재질로 그 무게가 무거워 노즐댐 작업자가 취급하기 어렵다. 이 노즐댐의 경량화와 동시에 구조적 강도를 증가시키기 위해서 비강성이 높은 탄소섬유 강화 복합재료와 굽힘 강성 및 전단강성을 증가시키기 위하여 벌집구조(honeycomb)의 알루미늄을 사용하여 KAERI 노즐댐-II를 설계하였다. 노즐댐에 발생하는 응력 해석을 통하여 중앙판과 측면판의 변위가 충분히 작은 값을 가지면서 파괴지수도 충분히 작은 값이 되는 탄소섬유의 적층각도를 구하였으며, 중앙판은 ［$\pm$15］로 적층하고 측면판은 ［$\pm$45 ］로 적층 하였다. 그리고 각 판의 최대 파괴지수는 중앙판의 경우 0.32, 측면판의 경우 0.27 이었고 최대변위는 각각 3.1mm, 2.7mm로 노즐댐을 사용할 때 예상되는 하중에 대하여 노즐댐의 구조적 건전성을 입증하였다.