• 한국산업융합학회 논문집
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• 제20권1호
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• pp.34-48
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• 2017

This study proposes a new approach to control a trajectory control of vertical type articulated robot arm with six revolution joints by computed torque method for manufacturing process automation. The proposed control scheme takes advantage of the properties of the fuzzy controllers. The proposed method is suitable to control of the trajectory and path control in cartesian space for vertical type articulated robot manipulator for forging manufacturing process automation. The results is illustrated that the proposed fuzzy computed torque controller is more stable and robust than the conventional computed torque controller. This study is included with an analytical methodology of inverse kinematic computation for 6 DOF manipulators. And an intelligent PID based on feed forward fuzzy control structure is applied to control the working path control with disturbances caused by uncertainty parameters of the manipulator dynamic model. Lastly, the validity of proposed is verified by simulations and experiments.

• 지능정보연구
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• 제15권3호
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• pp.119-136
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• 2009

컨테이너 물동량 증가와 컨테이너선의 대형화에 따라서 항만 하역장비는 지속적으로 변화하고 있다. 본 연구는 항만 하역장비 가운데 컨테이너크레인의 기계적 생산성을 상세히 평가하기 위해 개발된 시뮬레이션 모델을 소개한다. 모델은 컨테이너크레인의 메커니즘으로 싱글 및 듀얼 트롤리 방식을, 스프레더 유형으로 싱글, 트윈, 탠덤 방식을 고려하고 컨테이너크레인의 규모와 속도 등에 관련된 세부 사양을 입력받아 기구학적 특성을 구현한다. 또한 외부의 물리적 제약으로 선박의 크기, 컨테이너의 적재위치와 무게를 고려한다. 본 모델은 다양한 입력변수가 파라미터 (parameter)로 분리되어 실험 조건을 편리하게 설정할 수 있으며, 객체 지향적으로 설계 개발되어 향후 새롭게 개발되는 장비 유형이나 기존 장비의 변화를 유연하게 수용할 수 있다.

• 한국전문물리치료학회지
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• 제24권4호
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• pp.1-10
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• 2017

Background: Flexion-relaxation phenomenon (FRP) was a term which refers to a sudden onset of myoelectric silence in the erector spinae muscles of the back during standing full forward flexion. Hamstring muscle length may be related to specific pelvic and trunk movements. Many studies have been done on the FRP of the erector spinae muscles. However, no studies have yet investigated the influence of hamstring muscle flexibility on the FRP of the hamstring muscle and lumbopelvic kinematics during forward bending. Objects: The purpose of this study was to examine the flexion-relaxation ratio (FRR) of the hamstring muscles and lumbopelvic kinematics and compare them during forward bending in subjects with different hamstring muscle flexibility. Methods: The subjects of two different groups were recruited using the active knee extension test. Group 1-consisted of 13 subjects who had a popliteal angle under $30^{\circ}$; Group 2-consisted of 13 subjects who had a popliteal angel above $50^{\circ}$. The kinematic parameters during the trunk bending task were recorded using a motion analysis system and the FRRs of the hamstring muscles were calculated. Differences between the groups were identified with an independent t-test. Results: The subjects with greater hamstring length had significantly less lumbar spine flexion movement and more pelvic flexion movement. The subjects with greater pelvic flexion movement had a higher rate of flexion relaxation during full trunk bending (p<.05). Conclusion: The results of this study suggest that differences in hamstring muscle flexibility might cause changes in people's hamstring muscle activity and lumbopelvic kinematics.

• 천문학회보
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• 제37권1호
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• pp.75.1-75.1
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• 2012

We have observed the part of the second quadrant of the Galactic Plane in $^{13}CO(1-0)$ using the multibeam receiver system installed on the 14 m telescope at Taeduk Radio Astronomy Observatory. The target region (L=108 to 112.5) is the part of the $^{12}CO$ Outer Galactic Plane Survey (Heyer et al. 1998), and it is for the exact Galactic plane with the latitude range of +1 and -1 degree. Total of 48,000 spectra (about 9 square degees) were obtained on 50" grid. The selected velocity resolution is 0.63 km/sec and sensitivity per channel is 0.17 K, and the covered velocity is 320 km/sec. We developed a new reduction method, which effectively deals with a relatively noisy 3-dimensional database. The collected $^{13}CO$ database will be manipulated with pre-existing $^{12}CO$ data to get several physical parameters. As it is located in the second quadrant, the kinematic distances of the individual clouds, which will be identified, can be estimated relatively easily without any distance ambiguity. In this meeting we present the reduction method, statistics, and some channel maps, integrated intensity maps, and spatial-velocity maps. We intend to clarify any difference of their characteristics between the clouds in the Outer Galaxy and Inner Galaxy using our data base.

• 천문학회보
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• 제42권2호
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• pp.66.2-66.2
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• 2017

The Korea Astronomy and Space Science Institute plans to develop a coronagraph in collaboration with National Aeronautics and Space Administrative (NASA) and install it on the International Space Station (ISS). The coronagraph is an externally occulted one stage coronagraph with a field of view from 2.5 to 15 solar radii. The observation wavelength is approximately 400 nm where strong Fraunhofer absorption lines from the photosphere are scattered by coronal electrons. Photometric filter observation around this band enables the estimation of 2D electron temperature and electron velocity distribution in the corona. Together with the high time cadence (< 12 min) of corona images to determine the geometric and kinematic parameters of coronal mass ejections, the coronagraph will yield the spatial distribution of electron density by measuring the polarized brightness. For the purpose of technical demonstration, we intend to observe the total solar eclipse in 2017 August for the filter system and to perform a stratospheric balloon experiment in 2019 for the engineering model of the coronagraph. The coronagraph is planned to be installed on the ISS in 2021 for addressing a number of questions (e.g. coronal heating and solar wind acceleration) that are both fundamental and practically important in the physics of the solar corona and of the heliosphere.

• 대한기계학회논문집B
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• 제26권12호
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• pp.1738-1746
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• 2002

In the FSI (Fluid-Structure Interaction) problems, two different governing equations are to be solved together. One is fur the fluid and the other for the structure. Furthermore, a kinematic constraint should be imposed along the boundary between the fluid and the structure. We use the combined formulation, which incorporates both the fluid and structure equations of motion into a single coupled variational equation so that it is not necessary to calculate the fluid force on the surface of structure explicitly when solving the equations of motion of the structure. A two-dimensional channel flow divided by a Bernoulli-Euler beam is considered and the dynamic response of the beam under the influence of channel flow is studied. The Navier-Stokes equations are solved using a P2P1 Galerkin finite element method with ALE (Arbitrary Lagrangian-Eulerian) algorithm. The internal structural damping effect is not considered in this study and numerical results are compared with a previous work fer steady case. In addition to the Reynolds number, two non-dimensional parameters, which govern this fluid-structure system, are proposed. It is found that the larger the dynamic viscosity and density of the fluid are, the larger the damping of the beam is. Also, the added mass is found to be linearly proportional to the density of the fluid.

• 한국운동역학회지
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• 제24권3호
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• pp.217-227
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• 2014

The purpose of this study was to investigate the relationship between distance and factors of javelin in korean male's javelin throwing. To accomplish this purpose, the analyzed trail selected total 29 trails (subjects 9) recorded more than 65 m in the 93rd National Sports Festival. The Kwon3D 3.1 version was used to obtain the three dimensional coordinates about the top, grip, end of javelin. And the kinematic data such as projection factors and direction angle of javelin calculated using Matlab2009a program. The statical analysis on the records (n=29) were used to Pearson's product moment correlation coefficient. There was a statistically positive relationship between the records and horizontal velocity (r=.866, ${\rho}$<.01), height (r=.541, ${\rho}$ <.001), height rate (r=.373, ${\rho}$ <.05) and horizontal displacement of javelin (r=.749, ${\rho}$ <.01), but the medial/lateral velocity showed a negative relationship to r=-.663 (${\rho}$ <.01). The attack and yaw angle showed not a significant relationship between the records, but the medial-lateral tilt (E1:r =-.557 [p<.01)] E2:r=-.629 [${\rho}$<.01], E3:r=-.528 [${\rho}$ <.01]) and attitude angle (E2:r=-.629 [[${\rho}$<.01], E3:r=-.619 [${\rho}$ <.01]) of javelin showed a negative relationship between the records, as well as the projection angle of javelin (r=-.419, ${\rho}$ <.05) showed a negative relationship between the records.

• The Journal of Korean Physical Therapy
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• 제30권2호
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• pp.73-77
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• 2018

Purpose: The prefrontal lobe, supplementary motor area, cerebellum, and basal ganglia are activated during gait. In addition, gait is controlled by nerves, such as the corticospinal tract (CST) and corticoreticular pathway (CRP). In this study, the presence of an injury to the CST and CRP was identified by diffusion tensor imaging and the characteristics of the gait pattern were investigated according to inferior cerebral artery infarction. Methods: One patient and six control subjects of a similar age participated. A 69-year-old female patient had an injury to the left basal ganglia, insular gyrus, corona radiata, dorsolateral prefrontal cortex, and postcentral gyrus due to an inferior cerebral artery infarction. Diffusion tensor imaging (DTI) data was acquired 4 weeks after the stroke. The kinematic and spatio-temporal parameters of gait were collected using a three-dimensional gait analysis system. Results: On 4 weeks DTI, the CST and CRP in the affected hemisphere did not show injury to the affected and unaffected hemisphere. Gait analysis showed that the cadence of spatio-temporal parameter was decreased significantly in the patient. The angle of the knee joint was decreased significantly in the affected and unaffected sides compared to the control group. Conclusion: The results of diffusion tensor imaging showed that although the patient was evaluated to be capable of an independent gait, the quality and quantity of gait might be reduced. This study could help better understand the gait ability analysis of stroke patients and the abnormal gait pattern of patients with a brain injury.

• 한국운동역학회지
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• 제19권4호
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• pp.627-636
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• 2009

본 연구는 한국무용 시 내면의 아름다움뿐만 아니라, 외면으로 표현되고 기술적으로 한층 세분화된 한국무용의 호흡에 대한 중요성을 인식하는 연구의 필요성을 갖고, 호흡의 사용이 한국무용 걸음체 동작에 어떠한 영향을 미치는 가를 분석하여, 무용의 추상적인 아름다움을 과학적인 근거로 명확하게 제공하는 데 연구의 목적을 갖는다. 연구 결과, 호흡을 사용한 걸음체가 호흡을 사용하지 않는 걸음체 보다 신체중심과 골반이 이동변위가 낮게 나타났다. 슬관절과 족관절의 각변위에서 호흡을 사용하는 걸음체가 호흡을 사용하지 않는 걸음체보다 굴곡되어 굽힘이 많이 사용되었고, 이것은 굴신이 일어나고 있는 시전에서 나타났다. 호흡을 사용한 걸음체 동작은 수직지면반력에서 호흡을 사용하지 않은 걸음체에서 볼 수 없는 pre정점이 나타났고 이것은 한국무용 걸음체 시 호흡이 시작되는 들숨의 시점을 의미하며, 뒤꿈치 닿는 구간(1정점)에서 호흡을 사용한 걸음체의 부하 값이 날숨에 의해 호흡을 사용하지 않는 걸음체 보다 부하 값이 더 크게 나타났다. 전후지면반력 결과 호흡을 사용한 걸음체가 제동력이 더욱 크게 나타났다.

• 폴리머
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• 제39권2호
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• pp.346-352
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• 2015

폴리알파올레핀(PAO)은 유동점, 점도지수, 열/산화 안정성이 광유 기반의 윤활유보다 우수한 합성 윤활유이다. 본 연구에서는 1-펜텐, 1-헥센, 1-옥텐, 및 1-도데센을 단량체로 사용하고 세가지 종류의 알루미늄계 루이스 산촉매로 양이온 중합을 수행하여 다양한 PAO를 합성하였다. PAO 중합 성능과 제조된 PAO의 분자량, 동점도, 유동점과 점도지수를 다양한 중합 조건에서 조절할 수 있었다. 알킬 알루미늄 할라이드계 촉매가 기존의 $AlCl_3$계 촉매에 비하여 촉매 성능이 우수하였다. PAO의 미세구조를 비행-시간형 질량분석기(TOF-MS) 해석을 통하여 PAO의 미세구조와 윤활유로의 성능(점도지수, 유동점)과의 상관관계를 규명하였다. 특히, PAO의 점도지수는 알파 올레핀의 탄소수 증가에 따라 상승하여, PAO의 분지길이가 점도지수와 밀접한 상관관계가 있음을 확인하였다.