• 제목/요약/키워드: Joint stability

검색결과 883건 처리시간 0.033초

Coastal Environments 블록의 개발을 위한 연결부 마찰 실험 (An Expremental Study on Connections Friction Test of Improvement for Coastal Environment Block)

  • 김춘호;김상훈
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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    • pp.49-52
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    • 2008
  • 최근 지구 온난화 현상에 따른 해수면 상승으로 삼면이 바다에 접한 우리나라는 향 후 많은 피해가 예측되므로 이에 따른 방호개념으로 기존의 단조로운 형상과 비 자연친화형 콘크리트 구조물의 설치 및 연안침식방지 기능부재로 인한 또 다른 피해가 발생된다. 국민소득의 증대와 Waterfront 개념의 빠른 확산으로 연안 어항의 낙후된 시설개선 등에 많은 사업이 추진되고 있으나 이러한 용도에 맞는 자연 친화형 구조물이 개발된 바 없어 기존의 Solid Block, Igloo Block, Tunnel Block 등이 일부 현장에 적용되고 있는 실정이다. 선박이 계류하는 안벽이나 물양장 등에서 항내 진입파와 항파 등으로 인한 반사파의 발생에 의한 공진현상으로 항내파고가 높아져 정온도유지가 어렵고 선박의 계류 및 하역에 지장을 주게 되며, 선박과의 충돌 발생으로 인한 소형선박의 손괴 발생율이 높은 실정이므로 새로운 형태의 블록(Block)개발이 필요하다. 이에 따라 개발한 C.E(Coastal Environments)블록을 현장에서 사용하기 위해서는 전단키 부분의 내하력 평가가 요구 된다. 따라서, 본 연구는 C.E 블록의 연결부 시험편을 제작하여 C.E블록 경계면의 마찰실험을 실시하였으며, C.E블록 연결부의 마찰계수를 측정하여 분석한 다음 C.E블록의 연결부 마찰계수를 평가하고자 한다.

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여수로 구조물 하부 암반 내 발달한 절리들을 통한 지하수 누수량 분석 (Evaluation on the leakage of ground-water through fractured rock under a spillway)

  • 김형수;이주현;정의진;이중우
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2006년도 춘계 학술발표회 논문집
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    • pp.69-74
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    • 2006
  • Recently, spillways are need to control stable water level for supporting main dams because of floods by unusual change of weather such as Typhoon Rusa. This study has been focused on the amount of leakage through the rock mass distributed fractures and joints under the opened emergency spillway. It is very important to evaluate the amount of leakage as these affect stability of spillway by interaction between effective stress and pore pressure. The commercial program MAFIC has been used for analyzing groundwater flow in fractured rock mass. The results showed that the values of range, average and deviation of leakage were $2.85\sim\;3.79\times10^{-1}$, $3.32\times10^{-1}$ and $1.70\times10^{-2}\;m^3/day/m^2$ respectively. Secondary, we have estimated the effect of grouting after the transmissivity$(T_f)$ of joint 1 as main pathway of leakage known from above results was changed from $1.78\times10^{-7}$ to $1.59\times10^{-9}\;m^2/s$. The results showed that the values of range, average and deviation of leakage were $7.80\times10^{-4}\sim1.53\times10^{-3}$, $1.18\times10^{-3}$ and $1.32\times10^{-4}\;m^3/day/m^2$ respectively. As the result, the amount of leakage after grouting has been decreased by a ratio of 1 to 277.

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기능적인 저항훈련이 운동이상형 뇌성마비 아동의 대동작과 균형능력에 미치는 영향 : 단일사례설계 (Effects of Functional Resistance Training on Gross Motor and Balance Abilities in Children with Dyskinetic Cerebral Palsy : Single Case Design)

  • 권해연
    • 대한통합의학회지
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    • 제4권3호
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    • pp.109-119
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    • 2016
  • Purpose : The purpose of this research is to find clinical effects of functional resistance training using weighted vest on gross motor and balance abilities of children with dyskinetic cerebral palsy. Methods : This study selects 3 subjects for 8~12 years old who were diagnosed with children with dyskinetic cerebral palsy. The Design is ABA design of single-subject research design. Baseline(A) and TypeII Baseline(A : 12weeks) phases were received with NDT treatment, Intervention(B : 12weeks) phase provided with 40 minute functional resistance training using weighted vest in a session twice a week. In order to analyze the measure results of gross motor function and performance, balance abilities in children dyskinetic cerebral palsy during baseline, intervention and typeII baseline phase. Result : A statistically significant differences in the total GMFM including walking/running/jumping during baseline, intervention, typeII baseline, but no significant differences in the lying/rolling, sitting, crawling/kneeling and standing. A statistically significant differences in the total GMPM including dissociated movement, coordination, weight shift, stability during baseline, intervention, typeII baseline, but no significant differences in the body alignment domains. A statistically significant differences in the length and surface area ellipse of center of pressure during baseline, intervention, typeII baseline. Conclusion : The intervention method to facilitate multi-joint and closed kinematic chain movement equipped weighted vest applied functional resistance training on children with dyskinetic cerebral palsy effectively improve on gross motor function and performance, balance abilities.

잔여 조직을 보존한 단일 다발 후방십자인대 보강재건술 (Single Bundle PCL Reconstruction with Remnant Preservation)

  • 이동철;김원호
    • 대한관절경학회지
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    • 제15권2호
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    • pp.125-131
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    • 2011
  • 후방십자인대 파열의 최선의 치료법은 논쟁의 대상이며, 후방십자인대 재건술시 고려해야할 사항들로는 경골 고정방법(transtibial vs inlay), 대퇴터널의 위치(central, eccentric or isometric), 재건다발의 수(single-bundle vs double-bundle)등이 있다. 후방십자인대는 중슬부 동맥의 분지와 가깝게 위치하고, 두꺼운 활액막에 싸여있어 손상시 전방십자인대보다 자연 치유력이 뛰어난 것으로 알려져 있다. 일반적으로 후방십자인대 재건술시, 이식물 통과를 용이하게 하고 터널 위치 선정을 위한 인대 부착부를 잘 보기 위해 남아 있는 후방십자인대 잔여 조직을 모두 제거한다. 그러나 잔여 조직을 보존하면 슬관절 후방 안정성에 기여하며, 이식물 치유를 빠르게 하고, 잔여 인대에 남아 있는 기계 수용체의 고유 수용 감각 기능을 살리게 된다. 수술 술기의 어려움과 터널 합병증이 발생될 수 있는 이중 다발 재건술에 비해, 대퇴부 인대 부착부를 보전하기 쉽고 합병증이 적은 단일 다발 재건술을 이용한 잔여 조직을 보존한 보강법이 유용한 수술 방법으로 사료된다.

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로봇 매니플레이터의 실시간 특이점 회피를 위한 작업 재구성법: 동적 작업 우선도에 기초한 해석 (Task Reconstruction Method for Real-Time Singularity Avoidance for Robotic Manipulators : Dynamic Task Priority Based Analysis)

  • 김진현;최영진
    • 제어로봇시스템학회논문지
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    • 제10권10호
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    • pp.855-868
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    • 2004
  • There are several types of singularities in controlling robotic manipulators: kinematic singularity, algorithmic singularity, semi-kinematic singularity, semi-algorithmic singularity, and representation singularity. The kinematic and algorithmic singularities have been investigated intensively because they are not predictable or difficult to avoid. The problem with these singularities is an unnecessary performance reduction in non-singular region and the difficulty in performance tuning. Tn this paper, we propose a method of avoiding kinematic and algorithmic singularities by applying a task reconstruction approach while maximizing the task performance by calculating singularity measures. The proposed method is implemented by removing the component approaching the singularity calculated by using singularity measure in real time. The outstanding feature of the proposed task reconstruction method (TR-method) is that it is based on a local task reconstruction as opposed to the local joint reconstruction of many other approaches. And, this method has dynamic task priority assignment feature which ensures the system stability under singular regions owing to the change of task priority. The TR-method enables us to increase the task controller gain to improve the task performance whereas this increase can destabilize the system for the conventional algorithms in real experiments. In addition, the physical meaning of tuning parameters is very straightforward. Hence, we can maximize task performance even near the singular region while simultaneously obtaining the singularity-free motion. The advantage of the proposed method is experimentally tested by using the 7-dof spatial manipulator, and the result shows that the new method improves the performance several times over the existing algorithms.

탄성밴드 사용유무에 따른 발레 아라베스크 동작의 운동 역학적 분석 (The Biomechanical Analysis of Ballet Arabesque by Using Elastic Band)

  • 김민정;이경옥
    • 한국운동역학회지
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    • 제25권3호
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    • pp.265-274
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    • 2015
  • Objective : The purpose of this study was to analyze the effect of the elastic band on ballet arabesque based on kinematics analysis. Methods : To observe the effect of the elastic band, the availability of the elastic band during movement was set as the independent variable, and the dependent variables were set by using factors from two different categories such as motor mechanics and kinematics variables. For motor mechanics variable, the muscle activity and the center of pressure(COP)'s trajectory and velocity were used. Furthermore, the physical angle was used for kinematic variables. Data samples from the experiment was used to understand the correlation between independent and dependent variables while using paired samples t-test as a data analysis tool. Results : After analyzing the result of experiment, the usage of the Elastic band on ballet arabesque movement seemed to increase the activity of the agonistic muscle, which is mainly used for movement, and to improve the stability of the supporting leg by decreasing the trajectory and velocity of the center of pressure(COP). Moreover, the elastic band increased the level of elevation of the stretching leg with reducing the angle of the hip joint that resulted into a more stable movement and furthermore providing more beauty while standing on it. Conclusion : The movement training program while the using elastic band are expected to lead to appropriate muscular development and reduce the muscle imbalance, which usually occurs to dancers, during training with unfamiliar specific movements or strengthening muscular strength for a specific movement. In addition, this work is expected to be used as a training reference to understand and learn the fundamentals of movements of ballet and other dance fields.

정상인에서 요천추 코르셋 착용이 엉덩관절을 펼 때 배곧은근과 엉덩관절 폄근의 수축 개시시간에 미치는 영향 (The Effect of a Lumbosacral Corset on the Onset of Rectus Abdominis and Hip Extensor Activity During Hip Extension in Healthy Subjects)

  • 박철홍;권오윤;조상현
    • 한국전문물리치료학회지
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    • 제9권3호
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    • pp.23-37
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    • 2002
  • This study examined the muscle recruitment order during extension of the hip joint in normal subjects, and evaluated whether the external support obtained from wearing a lumbosacral corset had an effect on muscle recruitment leading to increased lumbar stability. The subjects were 40 normal adults (32 male, 8 female) with no history of low back pain and no pathological findings in the nervous or musculoskeletal systems. All subjects extended their hip joints under 3 positions (prone, sidelying, standing). During extension, the onsets of contraction of the rectus abdominis, gluteus maximus, and semitendinosus muscles were measured. Electromyographic activity was measured using a surface electrode, and the muscle contraction onset time was designated as the point exceeding a threshold of 25 ms, using a mean plus twice of the standard deviation. To compare the average order of muscle contraction onset time, a Freedman two-way analysis of variance by ranks was used. The relative difference between muscle contraction onset time wearing and not wearing a lumbosacral corset was measured using a paired t-test. A difference in the average muscle contraction onset order for the rectus abdominis, gluteus maximus, and semitendinosus muscles was observed (p<.05) among three positions. However, wearing a lumbosacral corset did not. change the contraction order. In addition, wearing a lumbosacral corset produced a significant difference (p<.05) in the relative onset time between the rectus abdominis and gluteus maximus in the standing position, but no difference was observed for the other muscles or positions. In the future, patients suffering from low back pain should be compared with normal subjects to determine the effectiveness of a lumbosacral corset in changing muscle recruitment order.

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Influence of Tibial Rotation on EMG Activities of Medial and Lateral Hamstrings During Maximal Isometric Knee Flexion

  • Lim, Woo-taek
    • 한국전문물리치료학회지
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    • 제25권4호
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    • pp.46-52
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    • 2018
  • Background: The hamstring muscles in the lower extremity are highly important for knee joint stability and can be classified into medial and lateral hamstrings according to the anatomical position, which have some different functions. To measure the strength of the individual hamstring muscles, manual muscle testing is clinically performed by dividing rotation postures into internal and external postures. However, this has no sufficient scientific background. Objects: This study aimed to test the difference that the tibial rotation would cause in the muscle activity of the medial and lateral hamstrings. Methods: The muscle activities of the biceps femoris, semitendinosus, and semimembranosus were measured in a total of three different postures (neutral position and internal and external rotations) with 3 replications. During the maximal isometric contraction, resistance was constantly provided by the string attached to the strap, not by manual resistance of the examiner. Before and after electromyography measurements, the participants underwent hamstring flexibility measurement using the active knee extension test in the supine position on the treatment table. Results: The semitendinosus had a 12.56% reduction in muscle activity in external rotation as compared with that in neutral position. The biceps femoris and semimembranosus showed reduced muscle activities in both external and internal rotations as compared with those in neutral position. Only the women showed significant decreases in the comparison between pre and post-active knee extension. Conclusion: Only the semitendinosus muscle was consistent with the anatomical speculation. However, the reduction in the muscle activity of the semitendinosus as compared with that in neutral position was only 12.56%, the clinical value of which may be difficult to justify.

개착과정에서 인장균열이 발생된 동해고속도로 건설현장 암반사면의 거동 해석 (An Analysis of the Behavior of Rock Slope with Excavation-Induced Tension Cracks Located in DongHae Highway Construction Site)

  • 조태진;이창영;고기성
    • 한국지반공학회논문집
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    • 제20권8호
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    • pp.15-27
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    • 2004
  • 개착과정에서 대규모 인장균열이 발생한 암반사면의 파괴거동 양상을 분석하였다. 사면지역 암반의 구조적 특성분석을 위하여 전기비저항 탐사를 수행하였으며, DOM 시추작업을 수행하여 불연속면의 방향성과 시추공 내의 출현위치를 측정하였다. 회수된 코어를 관찰하여 개착면 및 인근 자연사면의 파괴 거동이 진행되었을 것으로 추측되는 예상 활동면의 존재성을 확인하였으며, 협재된 팽윤성 점토광물의 조성을 XRD 회절분석을 통하여 조사하였다. 사면 안정성 분석은 사면지역에 표출되는 절리들의 trace 분포 및 방향성을 고려하여 수행하였으며, 사면파괴를 유발시킬 수 있는 절리들의 시추공 내에서의 위치 및 방향성에 의거하여 심도별 지반 거동특성을 분석하였다. 시추공 별 예상 파괴 활동면의 3차원 위치 좌표에 의거하여 구역별 거동 벡터를 산정하고 예상되는 전체적 인 사면거동 양상을 고찰하였다.

폐출혈을 동반한 현미경적 다발혈관염 1예 (A Case of Microscopic Polyangiitis with Diffuse Alveolar Hemorrhage)

  • 이상진;이재웅;김혜진;신경철;정진홍;이관호;박혜정
    • Journal of Yeungnam Medical Science
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    • 제21권1호
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    • pp.101-107
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    • 2004
  • Diffuse alveolar hemorrhage is a rare but serious and frequently life-threatening complication of a variety of conditions. The first goal in the management of patients with diffuse alveolar hemorrhage is to achieve or preserve stability of the respiratory status. Subsequently, the differential diagnosis is aimed at the identification of a remediable cause of the alveolar hemorrhage. The most common causes of diffuse alveolar hemorrhage with glomerulonephritis are microscopic polyangiitis and Wegener's granulomatosis, followed by Goodpasture syndrome and systemic lupus erythematosus. Microscopic polyangiitis (MPA) is a distinct systemic small vessle vasculitis affecting small sized vessels with few or no immune deposits and with no granulomatosus inflammation. The disease may involve multiple organs such as kidney, lung, skin, joint, muscle, gastrointestinal tract, eye, and nervous system. MPA is strongly associated with antineutrophil cytoplasmic autoantibody (ANCA) that is a useful serological diagnostic marker for the most common form of necrotizing vasculitis. Our report concerns a case of microscopic polyangiitis with diffuse alveolar hemorrhage in a 54-year-old man. He was admitted to our hospital due to dyspnea upon exertion and recurrent hemoptysis. Laboratory findings showed hematuria, proteinuria and deterioration of renal function. In the chest CT scan, diffuse ground glass appearance was seen in both lower lungs. A lung biopsy revealed small vessel vasculitis with intraalveolar hemorrhage and showed a positive reaction to against perinuclear ANCA. The patient was treated with prednisolone and cyclophosphamide. Chest infiltration decreased and hemoptysis and hypoxia improved. He is still being followed up in our hospital with a low dose of prednisolone.

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