• Structural Engineering and Mechanics
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• 제71권3호
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• pp.245-255
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• 2019

In this paper, an inverted-pendulum model consisting of a point supported by spring limbs with roller feet is adopted to simulate human walking load. To establish the kinematic motion of first and second single and double support phases, the Lagrangian variation method was used. Given a set of model parameters, desired walking speed and initial states, the Newmark-${\beta}$ method was used to solve the above kinematic motion for studying the effects of roller radius, stiffness, impact angle, walking speed, and step length on the ground reaction force, energy transfer, and height of center of mass transfer. The numerical simulation results show that the inverted-pendulum model for walking is conservative as there is no change in total energy and the duration time of double support phase is 50-70% of total time. Based on the numerical analysis, a dynamic load factor ${\alpha}_{wi}$ is proposed for the traditional walking load model.

• 인터넷정보학회논문지
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• 제10권4호
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• pp.1-11
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• 2009

대규모 인간 동작 데이터베이스에서 고차원의 데이터를 처리하는 것이 큰 비용을 요구하기에, 최근 데이터베이스 및 그래픽스 학계는 인간 동작 데이터 질의 및 접근에 큰 관심을 가지게 되었다. 특히, 인간 동작 데이터를 위한 효과적인 유사도(거리) 측정 방법이나 질의 처리는 여전히 많은 연구진들이 도전하고 있는 문제이다. 이에, 본 연구진은 SMoFinder 라고 명명한 동작 질의 처리 시스템을 제안한다. SMoFinder는 새롭게 고안된 운동학적 거리 측정 그리고 적응적 프레임 세그멘테이션에 기반하는 효율적인 인덱싱을 사용하여 동작 질의를 처리한다. 이를 위해, SMoFinder에서는 인간 동작을 다연결 물리 운동으로 간주하고 새로운 가중치 Minkowski 함수를 정의했다. 또한, 효율적인 인덱싱을 위해 모든 프레임을 저장하지 않고 유사한 프레임들 중에서 대표 프레임을 뽑아서 저장하는 적응적 세그멘테이션을 고안했다. 그리고, 효율적인 검색을 위해 이들 대표 프레임들만 가지고 k-근접 이웃 질의를 수행하는 새로운 방법을 제안한다. 마지막으로, SMoFinder가 데이터베이스 용량이 크게 줄지만(1/25배), 검색 능력은 다른 시스템과 동일하거나 우월하다는 것을 실험을 통해 보여주고자 한다.

• 한국운동역학회지
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• 제20권3호
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• pp.277-284
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• 2010

The purpose of this study was to investigate the trunk rotation type by wheel and axle. In order to analysis, 3D-motion analysis and electromyography were conducted on kinematic variables, impulse, average-EMG and integrated-EMG. Twelve healthy (age: $21.8{\pm}2.2$ yrs, height: $175.4{\pm}5.0cm$, weight: $66.7{\pm}6.4kg$) participated in the experiment. The results were as follows; in hand's velocity and acceleration, wheel and axial rotating movement using kinematic chain(type 3) were much faster. In impulse, type 3 was much stronger. In average-EMG, right and left, latissimus dorsi muscles was much stronger. In integrated-EMG, left erector spinae, right/left latissimus dorsi, and left external oblique muscles was much stronger. These results considered that, in the trunk rotation utilizing the kinematic chains action, latissimus dorsi muscles highly contribute to the muscle utilization that makes the rotating movement maximally effective.

• The Journal of Korean Physical Therapy
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• 제21권2호
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• pp.79-85
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• 2009

Purpose: This study examined the characteristics of gait in patients with chronic low back pain. Methods: The subjects were out-patients suffering from chronic low back pain at the department of physical therapy, B hospital in Seoul. Gait analysis was performed by dividing the subjects into two groups. The study and control group comprised 15 chronic low back pain patients and 14 healthy people, respectively. Gait analysis was performed using a VICON 512 Motion Analysis System to obtain the spatio-temporal and kinematic parameters. Results: First, there was a significant difference in the spatio-temporal parameters between the two groups (p<0.05). Second, the study group showed significant differences in the kinematic parameters during the stance phase (p<0.05). Third, there were significant differences in kinematic parameters in the study group during the swing phase (p<0.05). Conclusion: The gait pattern of patients with chronic low back pain is characterized by more rigid patterns. Compared to the control group, there was a decrease in the spatio-temporal parameters and kinematic parameters in patients with chronic low back pain. These findings are expected to play a role as basic data and to form a rehabilitation program for low back pain patients.

• 한국철도학회논문집
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• 제8권1호
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• pp.27-33
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• 2005

This paper presents a development of 6DOF motion platform far a tilting train simulator. The tilting train simulator will be used to verify the tilting electronics and tilting control algorithm which are to be applied the Korean 180km/h tilting train. The tilting train simulator is composed of a 6-axis motion platform, a track generation system, a graphic user interface, and a visualization system with 1600mm-diameter dome screen. In this study, the 6DOF motion platform for a tilting train simulator has been designed and manufactured. The motion platform developed is a motion platform of Stewart type. The inverse kinematic analysis has been performed to determine the length of the links of the platform. Furthermore, the specification of the motors have been evaluated by the equation of motion of the platform.

• 대한인간공학회지
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• 제17권2호
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• pp.11-23
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• 1998

Dynamic motion difference between normal subjects and low-back pain (LBP) patients has been investigated in terms of kinematic variables such as range of motion, velocity and acceleration of the back and hip. Ten healthy subjects and ten LBP patients were recruited in this study. Electro-goniometer such as Lumbar Motion Monitor and Hip Monitor have been used for quantitative measurement of the trunk motion during repetitive flexion and extension for ten seconds. Results indicated that the velocity and acceleration of the back and hip were important parameters to quantitatively identify LBP patients. The consistency of cyclic trunk motion and the relationship between the back and hip were measured in terms of Variance Ratio and Phase Angle in order to accurately assess the motion characteristics of LBP patients. In particular, the hip motion has been proven to be a very important factor in describing the kinematics of damaged lower back. The functional evaluation technique suggested in this study will be a tool to assist physicians for an accurate diagnosis and timely rehabilitation along with current image diagnosis techniques.

• Journal of Mechanical Science and Technology
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• 제19권spc1호
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• pp.444-451
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• 2005

The analysis of human arm motion during steering maneuver is carried out for investigation of man-machine interface of driver and steering system Each arm is modeled as interconnection of upper arm, lower arm, and hand by rotational joints that can properly represents permissible joint motion, and both arms are connected to a steering wheel through spring and damper at the contact points. The joint motion law during steering motion is determined through the measurement of each arm movement, and subsequent inverse kinematic analysis. Combining the joint motion law and inverse dynamic analysis, joint stiffness of arm is estimated. Arm dynamic analysis model for steering maneuver is setup, and is validated through the comparison with experimentally measured data, which shows relatively good agreement. To demonstrate the usefulness of the arm model, it is applied to study the effect of steering column angle on the steering motion.

• 한국운동역학회지
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• 제26권2호
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• pp.205-211
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• 2016

Purpose: The aim of this study was to analyze biomechanical factors and PMT (premotor time) of body muscles between elite college and amateur baseball players during the baseball batting motion. Method: Kinematic and electromyographic data were obtained for 10 elite college baseball players and 10 amateur baseball players who participated in this study. All motion capture data were collected at 200 Hz using 8 VICON cameras and the PMT of muscles was recorded using a Delsys Trigno wireless system. The peak mean bat speed and the peak mean angular velocities of trunk, pelvis, and bat with PMT of 16 body muscles were computed. These kinematic and PMT data of both groups were compared by independent t-tests (p < .05). Results: The pelvis, trunk, and bat showed a sequence of angular velocity value during baseball batting. The PMTs of right tibialis anterior, left gastrocnemius, external oblique, and erector spinae were significantly different between the two groups. Conclusion: The PMT of body muscles was related to the shifting of body and rotation of the pelvis and the trunk segment, and this action can be considered the coordinated muscle activity of the lower and upper body.

• 한국운동역학회지
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• 제24권1호
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• pp.11-18
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• 2014

The purposes of this study were to analyze the kinematics and electromyographic variables of the upper extremity for the backhand clear motion according to the type of hitting in badminton. Seven elite male university players were selected as the subjects. Four digital video cameras and Noraxon Telemyo 2400 were used to collect the 3D kinematics and electromyographic data. The results were as follows: 1) in the phase of impact, the time of motion for the overhead backhand clear was the longest, 2) in the event of impact, the distance of step toward X direction was the longest and the distance of step toward Y direction was the shortest for the overhead backhand clear, 3) in the event of backswing, the rotation angles of shoulder and pelvis and the flexion angle of shoulder for the overhead backhand clear were the biggest, 4) the maximum flexion angular velocity of shoulder and the maximum extension angular velocity of elbow for the overhead backhand clear were the biggest, and 5) in the phase of impact, mean EMG of the wrist flexor, triceps, and trapezius muscle for the overhead backhand clear was bigger than that for the underhand stroke and in the phase of follow-through, mean EMG of the wrist flexor and extensor, biceps, triceps, and trapezius muscle for the overhead backhand clear was the biggest.

• 한국운동역학회지
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• 제13권3호
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• pp.67-79
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• 2003

The purpose of this study is to investigate the effective skill motion through the kinematic analysis of the Yurchenko Streched motion in new horse vaulting. The subjects in this study were 3 male gymnasts who were ranked as national athletes. After the 3D motion analysis, kinematic variables were analyzed to comparison with the difference between this study and the previous study(Yang, D. Y and Lee, C. S, 1999). As a result, the following conclusions was drawn; 1. In the board contact phase, this study showed a shorten contact time to maintain in condition highly extension of hip and hee angle than the previous study. 2. In the pre-flight phase, this study appeared more shortly flight duration time and horizontal flight displacement than the previous study. 3. In the horse contact phase, the contact duration time and horizontal displacement of COG shortened than the previous study, but appeared to the fast horizontal and vertical velocity and highly extension of shoulder an. 4. In the post-flight phase, a stable horse contact appeared to the increase of the flight duration time and the apex height during the post-flight. And it showed that these results have a stable and good landing.