• 재활복지공학회논문지
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• 제7권2호
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• pp.55-62
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• 2013

본 논문은 편마비 환자나 장애인의 보행을 지원하는 외골격 로봇에 대해 연구하였다. 2축 자유도를 가진 외골격 로봇 개발 및 관절 운동에 대해 테스트 하였다. 정상적인 사람으로부터 얻어진 EMG 신호를 분석하고, 편마비 환자를 정상적인 사람처럼 보행 할 수 있도록 보조 로봇을 편리하고 자동화된 보행이 되도록 제어신호를 추출 하였다. 편마비 환자의 보행을 위한 기능적 전기 자극(FES)를 사용하는 목적이 손상된 기능을 복원하는 것이다. 그러나 이것은 사용을 잘못하면 환자에게 치명적인 전기 충격을 줄 수 있거나 지속적인 자극으로 근육피로의 원인이 될 수 있다. 최소한의 근육 피로도로 편마비 환자의 편리한 걸음은 제어 신호로 외골격 보조 로봇의 조작을 통해 가능성을 제시하였다. 보행 보조 외골격로봇은 FES 자극기를 사용하는 것보다 보다 효율적으로 동작할 수 있음을 보였다. 본 연구 실험은 앉아, 서, 걷기같이 우리의 생활에 보통의 움직임을 수행하고, 버튼스위치, 피에조 센서와 특별히 피드백 제어 시스템은 부드러운 보행 모션이 되도록 하였다. 그리고 실험결과도 건강한 다리의 근전도 신호를 편마비 환자의 손상된 다리의 보조로봇 시스템의 동작신호로 이용하여 편리하게 이동할 수 있음을 보여준다.

• 한국운동역학회지
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• 제21권5호
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• pp.521-528
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• 2011

The purpose of this study was to analyze the kinematic characteristics of the finalists in the women's 100 m event to provide important information to coaches and athletes. Three different biomechanics techniques were applied for analyzing sprinter motion: LAVEG, a panning technique, and 12 video cameras for 3 dimensional analysis of the 40 m - 70 m portion of the race. Carmelita Jeter(USA) performed the maximum speed of 10.54 m/s at the distance of 58.2 m. There was a tendency to show a better performance time with a high number of steps (p=.13) and shorter stride length (p=.14) among the 8 sprints. Furthermore, the stride frequency and the performance time were negatively correlated as a higher stride frequency had a positive impact on the performance time (p=.02). Based on 3 dimensional analysis, the 4 top ranked sprinters used the different strategies to maintain a high COM (Center of Mass) velocity during the mid portion of the race (40 m - 70 m). Carmelita Jeter(USA) showed more flexed knee and hip motion at heel contact (HC) to maintain a high COM velocity while S.A. Fraser-Pryce (JAM) showed more extended knee and hip motion at HC. On the other hands, Veronica Campbell-Brown (JAM) and Kelly-Ann Baptiste (TRI) showed a tendency to have high knee lifts during the swing phase to maintain the high COM velocity during the race. These biomechanical analyses of the women's 100 m final event in the 2011 WC, Daegu, will provide important scientific information to coaches and athletes for understanding the sprinting mechanism of today's top-class sprinters.

• 한국전문물리치료학회지
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• 제20권1호
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• pp.18-27
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• 2013

The purpose of this study was to compare the ring lock type knee-ankle-foot orthosis (KAFO) with newly developed 4-bar linkage KAFO on the gait characteristics of persons with poliomyelitis clinically. This 4-bar linkage is the stance control type KAFO which provide the stability during stance phase and knee flexion during swing phase. Two subjects participated in this study voluntarily. We provided the customized 4-bar linkage KAFO then asked the subjects to walk in level surface and stairs under the two different KAFO conditions. The characteristics of gait in the persons with poliomyelitis were evaluated using a 3D motion analysis system and force plate. Additionally 6 minute walk test for physiological cost index were conducted using pulse oximeter to measure the energy consumption. In the results of this study, the differences of 4-bar linkage KAFO compared with ring lock type KAFO are as follows: (1) Walking speed, stride length, and step length on level increased in subjects, (2) The gait symmetry was improved by generated knee flexion and decreased pelvic external rotation on level and stairs walking, (3) Decreased vertical excursion of center of mass and pelvic elevation during swing phase was decreased on level, (4) Knee extension moment, hip flexion moment, hip and knee internal rotation moment of non-braced limb were decreased on level walking, (5) Walking speed in 6-minute walk test was increased and physiological cost index was decreased. These findings indicate that 4-bar linkage KAFO compared with ring lock type KAFO is effective in enhancing pattern, endurance, and energy consumption in level surface and stairs walking.

• The Journal of Korean Physical Therapy
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• 제17권4호
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• pp.633-650
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• 2005

The aim of this study was to investigate the kinematics of young adults during ascent ramp climbing at different inclinations. Twenty-three subjects ascended a four step at four different inclinations(level, $8^{\circ},\;16^{\circ},\;24^{\circ}$). The 3-D kinematics was analysed by a camera-based falcon system. Groups difference was tested with one -way ANOVA and SNK test. The different kinematic patterns of ramp ascent were analysed and compared to level walking patterns. The kinematics of ramp walking could be clearly distinguished from the kinematics of level walking. In sagittal plane, Ankle joint was more dorsiflexed at initial contact and Max. dorsiflex. during stance phase with $16^{\circ},\;24^{\circ}$ inclination and more plantarflexed at toe off and Max. plantarflex. during swing phase with $24^{\circ}$(p<.001). Knee joint was more flexed at initial contact with $16^{\circ},\;24^{\circ}$ inclination(p<.001). Hip joint was more flexed at initial contact and Max. flex. during swing phase with $16^{\circ},\;24^{\circ}$ inclination and at toe off with $24^{\circ}$(p<.001) and was more extended at Max. ext. during stance phase with $24^{\circ}$(p<.05). In frontal plane, ankle joint was more everted at Max. eversion. during stance phase with $16^{\circ},\;24^{\circ}$ inclination(p<.001). Knee joint was more increased at Max. varus. during stance phase with $16^{\circ},\;24^{\circ}$ inclination(p<.001). Hip joint was not differentiated with different inclinations. In horizontal plane, all joints were not differentiated with different inclinations. Conclusionally, In ascent ramp walking, the different gait pattern generally occurred at over $16^{\circ}$ on the ascending ramp in sagittal and frontal plane. These results suggest that there is a certain inclination angle or angular range where subjects do switch between a level walking and a ascent ramp walking gait pattern. This shows their motor control strategy between level and ascent ramp walking. Further studies are necessary to confirm and detect the ascent ramp gait patterns.

• 대한기계학회논문집B
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• 제36권12호
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• pp.1193-1199
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• 2012

액체연료를 사용하는 풀화재에서 화염불안정성에 대하여 산화제 유속변화와 농도변화의 효과를 알아보기 위해 컵버너 실험을 수행하였다. 연료는 헵탄을 사용하였고, 산화제는 공기에 질소와 이산화탄소를 희석하였다. 소화근처에서 축방향 및 화염 밑면에서 두 가지 형태의 대표적인 불안정성이 관찰되었다. 화염 밑면에서 발생되는 불안정성은 셀, 스윙, 회전 모드로 특성화 할 수 있고, 산화제의 유속이 증가할수록 모든 불활성 기체에서 셀, 스윙 모드에서 회전모드로 천이하였다. 이러한 화염밑면 불안정성에 영향을 미치는 변수들을 파악하기 위하여 초기혼합률, Le 수, 단열화염온도에 대해서도 함께 조사되었다. 이 중 Le 수가 불안정성 모드와 가장 큰 상관관계를 보이고 있지만 보다 정확한 관계를 규명하기 위해서는 더 많은 실험조건에서의 결과가 요구된다. 또한, 소화농도근처의 화염에서는 유속이 작거나 큰 경우에는 축방향 주기적인 진동불안정성이 나타나지 않고, 적절한 산화제 속도 영역에서만 관찰된다. 이는 작은 유속에서는 증발하는 연료속도가 임계유속이하이며, 큰 유속에서는 반응중인 연료유속과 산화제 유속이 유사하기 때문으로 판단된다.

• 한국운동역학회지
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• 제23권1호
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• pp.25-35
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• 2013

This study examined 24 right-handed amateur baseball players. Twelve who had played baseball for more than 6 years were grouped as skilled players, while 12 who had played for 1-3 years were the unskilled player group. The swing motion was divided into four event phases: stance, backswing, impact, and follow-through. The mean and maximum plantar pressure, center of pressure, and ground reaction force were measured during each event phase. The mean and standard deviations for each variables were calculated and differences were validated with the independent sample t-test. A p-value <0.05 was considered statistically significant. The results were as follows. 1)The ideal stance is a stable, balanced position with more than 65% of weight on the right foot. There was significant difference in mean left plantar pressure, while the maximal plantar pressure and mean right plantar pressure did not differ significant. 2)The effective backswing of a skilled player is comprised a rightward shift in weight to build maximum energy. More than 90% of the weight was on the right foot. There was a significant difference in the mean left plantar pressure, while the maximal plantar pressure and mean right plantar pressure did not differ significantly. 3) For an effective impact, a rapid shift in weight to the left foot is essential, so that a power hit is obtained. Significant difference in the mean and maximum plantar pressures of both feet were observed. 4)Follow-through requires wight balance, more on the right than the left, without leaning leftward. There was no significant difference in the mean or maximum plantar pressure. 5)The center of plantar pressure should move from the center of the foot to the toe. 6)The analyses of the ground reaction force suggest that a good swing involves a gradual shift in weight to the right side and a rapid leftward shift at impact. Good balance, with the center of gravity on the right side at follow-through, is also required.

• 재활복지공학회논문지
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• 제10권3호
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• pp.207-214
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• 2016

본 연구의 목적은 무릎 신전 제한형 보조기 착용 후 보행시 하지 내 협응에 미치는 영향을 평가하는 하는 것이다. 본 연구에는 7명의 건강한 성인 남성($32.3{\pm}2.7$ 세, $175.2{\pm}3.8cm$, $76.2{\pm}8.7kg$)이 참여하였다. 이들은 무릎보조기를 착용하거나 착용하지 않고 10m의 평지를 보행하였다. 이때 시공간적 파라미터, 하지의 각도, 하지 내 연속상대 위상(CRP)를 측정 및 계산하였다. 그 결과 시공간적 요인은 차이가 없었다 (all p > 0.05). 무릎보조기 착용 시 엉덩관절의 가동범위 및 각도 변화는 없었으나, 무릎관절의 가동범위는 감소하였으며 ($65.5{\pm}3.75^{\circ}$ vs. $60.5{\pm}3.5^{\circ}$, p < 0.05), 최대 굴곡 역시 감소하였다 (입각기: $31.9{\pm}4.6$ vs. $25.6{\pm}5.5$, 유각기: $76.7{\pm}3.1$ vs. $68.9{\pm}3.4$, all p < 0.05). 발목관절의 가동범위는 변화가 없었으나, 최대 배측굴곡 ($22.4{\pm}2.6$ vs. $19.2{\pm}2.1$, p< 0.05)은 감소하였으며, 최대 족저굴곡이 증가하였다 ($9.5{\pm}3.0$ vs. $15.7{\pm}2.2$, p<0.05). 대부분의 CRP는 차이가 없었으며, 유각기 엉덩관절과 무릎관절 사이의 CRP만 감소하였다 ($93.0{\pm}7.8$ vs, $84.7{\pm}4.9$, p < 0.05). CRP의 표준편차는 대부분 증가하였다 (유각기 엉덩관절과 무릎관절사이: $25.1{\pm}6.7$ vs. $32.4{\pm}1.9$, 입각기 무릎관절과 발목관절사이: $46.0{\pm}12.9$ vs. $80.1{\pm}31.1$, 유각기 무릎관절과 발목관절 사이: $34.5{\pm}4.1$ vs. $37.6{\pm}3.1$, all p < 0.05). 이와 같은 결과로부터 무릎 신전 제한형 보조기 착용은 관절의 각도, 하지 내 협응에는 영향을 미치지만, 보행특성에는 큰 영향을 미치는 않는다는 것을 확인하였다.

• 한국항해항만학회지
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• 제31권3호
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• pp.247-252
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• 2007

항만의 하역 향상성을 위해 그동안 컨테이너 크레인의 작업효율을 높이는 연구가 진행되어 왔다. 특히 화물이 목표치에 도달했을 때 흔들림을 단시간에 제어하는 데 초점이 맞추어져 왔다. 일반적으로 컨테이너 크레인을 제어하기 위해서 PID 제어나 LQ제어가 주로 사용되었는데, 이는 제어기 설계가 용이하고, 주어진 제어 환경 하에서 우수한 제어성능을 발휘하기 때문이다. 본 연구에서는 LQ 제어의 관점에서 실수코딩 유전알고리즘을 이용한 상태 피드백 제어기의 설계 방법을 제안한다. 즉, 실수코딩 유전알고리즘을 이용하여 상태 피드백 이득을 탐색하는 방법이다. 실수코딩 유전알고리즘은 주어진 목적함수가 최소가 되도록 상태 피드백 이득을 최적으로 탐색한다 컴퓨터 시뮬레이션은 이렇게 탐색한 상태 피드백 이득을 컨테이너 크레인의 선형 및 비선형 모델에 적용하여 그 유효성을 확인한다.

• 한국운동역학회지
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• 제14권3호
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• pp.17-35
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• 2004

The purpose of this study is to explain developmental process of gait via angle-angle diagram to understand how coordinated relationships and control change with age. Twenty four female children, from one to five years of age were the test subjects for this study, and their results were compared to a control group consisting of twenty one adult females. The Vicon 370 CCD camera, VCR, video timer, monitor, and audio visual mixer was utilized to graph the gait cycle for all test subjects. Both coordinated Intra-limb relationships, and range of motion and timing according to quadrant were explained through the angle angle diagram. Movement in the sagittal plane showed both coordinated relationships and control earlier than movement in the coronal or transverse plane. In the sagittal plane, hip and Knee coordinated relationships developed first (from one year of age.) Coordinated relationships in the Knee and ankle and hip and ankle developed next, respectively. Both hip and ankle and knee and ankle development were inhibited by the inability of children to completely perform plantar flexion during the swing and initial double limb support phases. Children appeared to compensate for this by extending at their hip joint more than adults during the third phase, final double limb support. In many cases the angle angle diagram for children had a similar shape as adult's angle angle diagram. This shows that children can coordinate their movements at an early age. However, the magnitudes and timing of children's angle angle diagrams still varied greatly from adults, even at five years of age. This indicates that even at this age, children still do not possess full control of their movements.

• 한국운동역학회지
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• 제21권4호
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• pp.421-427
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• 2011

The purpose of this study was to analyze the difference between male and female tennis players' two-handed backhand stroke and to provide basic data which helps precise and efficient instruction for the sake of precise postures, enhanced performances and skills. 5 male and 5 female university players were recruited as subjects, and the mean difference between the kinematic variables such as the time from backswing to impact and total swing time, racket head velocity, change of the center of body gravity in two-handed backhand stroke through three-dimensional motion analysis. The test data was analyzed by t-test, and the alpha level of ${\alpha}$=.05 was set for all tests of significance. The findings of the study were as follows; First, there was no difference in the time from backswing to impact and total time of