• 대한정형도수물리치료학회지
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• 제13권2호
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• pp.12-20
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• 2007

The purpose of this study was designed to find out the effectiveness of vertebral segment instability, muscle fatigue response on lumbar spine after apply lumbosacral stabilization exercise program to 4 patients with chronic low back pain and for 12 weeks. In this study, the lumbar spine motion with blind by MedX test machine and the difference of instability to lumbar vertebra segments in flexion, extension test of standing position and spinal load test(Matthiass Test) by Spinal Mouse. The stabilization exercise program was applied 2 times a week for 12 weeks in hospital and 2 times a day for 20 minutes at home. The results of the present study were as follows: 1. Instability test of lumbar vertebra segment is 2 type differential angle test between vertebrae segment and loading test of spine(matthiass) by Spinal Mouse. It appeared to improve stability of segments in sagittal plane after applying program. So lumbar spine curve increased lordosis toward anterior and was improved of the lumbar spine flexibility in flexion and extension. Specially, in matthiass test, (-) value was increased between lumbar vertebra segment when was the load on spine. And so applying stability improved after program. 2. Fatigue response test(FRT) results, in male, was raised muscle fatigue rate during increase weight, on the other hand female appeared lower than male. As a results, lumbosacral stabilization exercise was aided to improvement of lumbar spine vertebra segments stabilization. Spine instability patients will have a risk when in lifting a load or working with slight flexion posture during the daily of living life and it is probably to increase recurrence rate. Thus, not only lumbar extension muscle strength but also stability of vertebra segments in lumbar spine may be very important.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.276-276
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• 2010

Large-area micropatterned array of Co/Ni bilayer anti-dots was fabricated using photolithography and wet etching process. The surface morphology as well as the surface topography was checked by scanning electron microscopy and atomic force microscopy, whereas the magnetic properties were studied by magneto-optical Kerr effect (MOKE) and magnetic force microscopy (MFM). Systematic studies of the magnetic-reversal mechanism, the in-plane anisotropy and the switching field properties were carried out. To get a comprehensive knowledge about the domain configuration, we also employed OOMMF simulations. It was found from the MOKE measurements that a combined effect of configurational and the magneto-crystalline anisotropy simultaneously works in such micropatterned bilayer structures. In addition, the inclusion of holes in the uniform magnetic film drastically affected the switching field. The MFM images show well-defined domain structures which are periodic in nature. The micromagnetic simulations indicate that the magnetization reversal of such a structure proceeds by formation and annihilation of domain walls, which were equally manifested by the field-dependent MFM images. The observed changes in the magnetic properties are strongly related to both the patterning that hinders the domain-wall motion and to the magneto-anisotropic bilayered structure.

• 대한물리치료과학회지
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• 제13권4호
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• pp.7-16
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• 2006

The purpose of this study was designed to find out the effectiveness of vertebral segment instability, muscle fatigue response on lumbar spine after apply lumbosacral stabilization exercise program to 4 patients with chronic low back pain and for 12 weeks. In this study, the lumbar spine motion with blind by MedX test machine and the difference of instability to lumbar vertebra segments in flexion, extension test of standing position and spinal load test(Matthiass Test) by Spinal Mouse. The stabilization exercise program was applied 2 times a week for 12 weeks in hospital and 2 times a day for 20 minutes at home. The results of the present study were as follows: 1. Instability test of lumbar vertebra segment is 2 type differential angle test between vertebrae segment and loading test of spine(matthiass) by Spinal Mouse. It appeared to improve stability of segments in sagittal plane after program. So lumbar spine curve increased lordosis toward anterior and was improved of the lumbar spine flexibility in flexion and extension. Specially, in matthiass test, ( - ) value was increased between lumbar vertebra segment when was the load on spine. And so stability improved after program. 2. Fatigue response test(FRT) results, in male, was raised muscle fatigue rate during increase weight, on the other hand female appeared lower than male. As a results, lumbosacral stabilization exercise was aided to improvement of lumbar spine vertebra segments stabilization. Spine instability patients will have a risk when in lifting a load or working with slight flexion posture during the daily of living life and it is probably to increase recurrence rate. Thus, not only lumbar extension muscle strength but also stability of vertebra segments in lumbar spine may be very important.

• 디지털콘텐츠학회 논문지
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• 제16권6호
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• pp.909-916
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• 2015

본 논문에서는 위상 공간 분석을 통해 3D 벡터 필드를 표현하는 방법을 제안한다. 이 방법은 상미분 방정식과 벡터 필드 위상과의 연결에 기초를 두고 있다. 위상 공간 분석은 위상 공간 형태의 자율 방정식 시스템의 기하학적 보간법이 되어야 한다. 이 방정식 시스템의 모든 해는 공간에서의 곡선이 아니라 곡선을 따라가는 점의 움직임과 일치한다. 이러한 분석은 이 논문의 기반이다. 새로운 방법은 3차원 벡터필드에서 육면체 셀을 5 또는 6개의 사면체 셀로 분해하는 것을 요구한다. 임계점은 각 사면체의 간단한 선형 시스템을 풀어서 간단하게 구할 수 있다. 각 사면체의 일반해에 의해 그려지는 전체 곡선과 사면체의 한 면을 포함하는 평면과의 교차점을 계산함으로써 탄젠트 곡선은 구해진다.

• 한국해양공학회지
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• 제30권1호
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• pp.25-31
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• 2016

In this study, hydrodynamic coefficients were obtained from a Rotating Arm (RA) test, which is one of the captive model tests used to provide accurate coefficients in the control motion equation of an underwater vehicle. The RA test was carried out at the RA facility of ADD (Agency for Defense Development), and the forces and moments acting on the underwater vehicle were measured using a six-axis waterproof gage. A multiple regression analysis was used in the analysis of the measured data. The experimental results were also verified by comparison with the theoretical values of the previous linear coefficients. In addition, the stability indices in the horizontal plane were calculated using the linear and nonlinear coefficients, and the dynamic stability of the underwater vehicle was estimated to have a good dynamic performance with a depth ratio of 6.0.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제4권1호
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• pp.101-110
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• 2004

The robots that will be needed in the near future are human-friendly robots that are able to coexist with humans and support humans effectively. To realize this, humans and robots need to be in close proximity to each other as much as possible. Moreover, it is necessary for their interactions to occur naturally. It is desirable for a robot to carry out human following, as one of the human-affinitive movements. The human-following robot requires several techniques: the recognition of the moving objects, the feature extraction and visual tracking, and the trajectory generation for following a human stably. In this research, a predictable intelligent space is used in order to achieve these goals. An intelligent space is a 3-D environment in which many sensors and intelligent devices are distributed. Mobile robots exist in this space as physical agents providing humans with services. A mobile robot is controlled to follow a walking human using distributed intelligent sensors as stably and precisely as possible. The moving objects is assumed to be a point-object and projected onto an image plane to form a geometrical constraint equation that provides position data of the object based on the kinematics of the intelligent space. Uncertainties in the position estimation caused by the point-object assumption are compensated using the Kalman filter. To generate the shortest time trajectory to follow the walking human, the linear and angular velocities are estimated and utilized. The computer simulation and experimental results of estimating and following of the walking human with the mobile robot are presented.

• 한국항공우주학회지
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• 제44권5호
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• pp.439-446
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• 2016

이 논문에서는 무베어링 로터의 동특성을 비회전 강성 및 진동수 측정 시험과 회전 훨타워 시험을 통해 살펴보았다. 무베어링 로터의 주요 구성품인 블레이드, 유연보, 토크튜브에 대해 강성 및 고유진동수를 측정하여 해석을 위한 물성치를 확보하였고, 훨타워 시험 전에 댐퍼와 스너버를 장착한 무베어링 로터를 조립하여 지상에서 하중이 부가되는 조건하에 기능시험을 수행하여 로터 구성품간의 간섭 여부, 기구학적 거동 등을 확인하였다. 4개의 블레이드를 가지고 회전반경이 5.82m인 무베어링 로터의 회전 동특성시험을 회전면 높이가 9.65m인 훨타워에서 수행하였다. 정지비행성능을 확인하기 위해 추력과 사용동력을 측정하였으며, 회전시 블레이드의 고유진동수 및 감쇠를 측정하기 위해 유압 가진기를 통하여 사이클릭 가진을 하였다.

• 한국산학기술학회논문지
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• 제18권11호
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• pp.794-801
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• 2017

전도성 평판의 모서리에 래디얼 동전기 휠을 부분적으로 중첩시켜 회전시키면 휠에는 부상력과 모서리 방향의 추력 그리고 중첩 영역을 감소시키는 방향으로의 횡력이 발생한다. 이러한 휠을 조합하면 진행 방향을 제외한 나머지 축에서의 자기 안정성이 담보되는 시스템 구현이 가능하다. 실증차원에서 래디얼 동전기 휠을 이용한 자기 부상 방식 이송 시스템을 제안한다. 시스템은 네 개의 동전기 휠에 의해 부상, 추진되며 앞뒤 휠에 의한 추력이 서로 상쇄되도록 대항하는 구조로 배치되어있다. 휠의 동적 안정성과 동전기력에 미치는 휠 극수의 영향이 유한요소법을 이용하여 분석된다. 단동 휠에 의한 추력과 부상력은 강하게 연성되어있고 이를 가변시킬 수 있는 인자는 휠의 회전속도뿐이다. 따라서 두 힘을 독립적으로 제어하기 위해 추력과 부상력간의 비율이 속도에 비례하고 공극의 크기와 무관하다는 사실을 이용한다. 이러한 제어 방법으로 시스템의 면내, 면외 운동 제어를 수행하고 이를 시뮬레이션 결과와 비교하였다. 실험 결과는 휠의 속도만으로 연성된 자유도를 효과적으로 제어할 수 있음을 보여준다.

• 한국전산구조공학회논문집
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• 제28권5호
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• pp.441-449
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• 2015

본 논문에서는 커코프 판이론과 폰-칼만 비선형 변형율-변위 관계를 이용하여 서형화된 좌굴해석을 수행하였다. 평면응력과 좌굴문제에서 영률과 두께에 관한 설계민감도식을 유도하였고, 고유치를 최대화하면서 컴플라이언스를 최소화하는 위상최적설계 기법을 정식화하였다. 좌굴해석에서의 프리스트레스를 이용하여 판 좌굴문제에 적용할 수 있는 위상최적설계 기법을 개발하였다. 폰-칼만 비선형 변형률을 사용하여 좌굴문제의 응력행렬을 구성하는데 프리스트레스가 필요하므로 면외로의 운동을 도입하였다. 위상최적설계를 위하여 정규재료밀도를 설계변수로 하고, 목적함수는 최소 컴플라이언스와 최대 고유진동수로 하였으며 제한조건은 허용되는 재료량이다. 여러 수치예제를 통하여 개발된 설계민감도 해석법은 유한차분 민감도와 비교하여 매우 정확한 값을 가지고, 위상최적설계는 물리적으로 의미있는 결과를 제공함을 확인하였다.

• 한국전문물리치료학회지
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• 제11권1호
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• pp.53-67
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• 2004

This simulation study investigated the characteristics of normal gait, $30^{\circ}$ crouch gait, $30^{\circ}$ crouch/equinus gait, $45^{\circ}$ crouch gait, $45^{\circ}$ crouch/equinus gait. The knee flexion angles were restricted using a specially designed orthosis. This study was carried out in a motion analysis laboratory of the National Rehabilitation Center. Fifteen healthy male subjects were recruited for the study. The purposes of this study were (1) to compare spatiotemporal parameters, kinematics, and kinetic variables in the sagittal plane among the different gait, (2) to investigate the secondary compensatory strategy, and (3) to suggest biomechanical physical therapy treatment methods. The pattern and magnitude observed in each condition were similar to those of normal gait, except the peak knee extension moment of the unrestricted ankle motion-crouch gait. However, the speed of the $45^{\circ}$ crouch gait was half that of a normal gait. The ankle joint moment in the crouch/equinus gait showed the double-bump pattern commonly observed in children with spastic cerebral palsy, and there was no significant difference in gait speed as compared with normal gait. The peak ankle plantar-flexor moment and ankle power generated during the terminal stance in the crouch/equinus conditions were reduced as compared with normal and $45^{\circ}$ crouch gaits (p<.05). The crouch/equinus gait at the ankle joint was an effective compensatory mechanism. Since ankle plantarflexion contracture can be exacerbated secondary to the ankle compensatory strategy in the crouch/equinus gait, it is necessary to increase the range of ankle dorsiflexion and the strength of plantarflexion simultaneously to decrease the abnormal biomechanical advantages of the ankle joint.