• 한국운동역학회지
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• 제27권1호
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• pp.19-23
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• 2017

Objective: The aim of this study was to investigate the relationship between the ball velocity and the upper extremity kinematics for both dominant and non-dominant side in inexperienced participants about an overarm throwing task. Method: Seven women who are inexperienced in overarm throwing participated in this study (Age: $25.1{\pm}2.4years$, Height: $160.8{\pm}3.5$; Weight $56.5{\pm}7.8$). Participants visit the laboratory for three days with one day rest between test sessions. Whole body 3-dimensional (3D) motion capture was recorded during the overarm throwing trials with ten cameras Vicon motion analysis system (T-10, T40, Oxford Metrics Ltd, UK). Total 45 overarm throwing were recorded for each side for each test session. Ball speed also was measured 3 meters away behind the subjects and recorded for every trial. Results: Mean ball velocity was higher for dominant hand compared to non-dominant hand (p <.05). Trunk segment variables (maximum angles and angular velocities) showed the most consistent relationship with the ball velocity. Conclusion: The importance of the trunk segment during the throwing activities can be seen in some individuals. But inconsistent results between subjects emphasize the importance of the individuals' movement patterns especially for bilateral sports. The future studies should be conduct about the sequence of segments, kinetic variables and effect of training.

• Advances in aircraft and spacecraft science
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• 제10권2호
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• pp.127-140
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• 2023

The present article focuses on the thermoelastic deformation behavior of inhomogeneous functionally graded metal/ceramic cylindrical shell structure with multiple perforations using 2D finite element approximation. Here, cylindrical shell structure is considered with single (1×1) and multiple (2×2, 3×3 and 4×4) perforations. The temperature-dependent elastic and thermal properties of functionally graded material are evaluated using Voigt's micromechanical material scheme via power-law function. The kinematics of the proposed model is based on the equivalent single-layer first-order shear deformation mid-plane theory with five degrees-of-freedom. Here, 2D isoparametric finite element solutions are obtained using eight-node quadrilateral elements. The mesh refinement of present finite element model is performed to confirm the appropriate number of elements and nodes for the analysis purpose. Subsequently, a comparison test is conducted to demonstrate the accuracy of present results. In later section, numerous numerical illustrations are demonstrated at different set of conditions by varying structural, material and loading parameters and that confirms the significance of various parameters such as power-law index, aspect ratio, thickness ratio, curvature ratio, number of perforations and temperature on the deformation characteristics of functionally graded cylindrical shell structure.

• 한국운동역학회지
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• 제27권1호
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• pp.9-18
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• 2017

Objective: The purpose of this study was to identify kinematic variables that govern successful performance and judges' scores and to establish correlative relationships among those of Yurchenko layout with a full twist in female vaults. Method: Four video cameras with sampling rate of 60 Hz collected 32 motion data of Yurchenko vaults from twenty-two female participants (age: $18.6{\pm}3.6years$, height: $153.0{\pm}6.5cm$, mass: $44.7{\pm}7.3kg$) during national competition. Posting processing and calculations of kinematic variables were performed in Kwon 3D XP and $Matlab^{(R)}$ programs. Correlation and regression analyses were applied to find the relationships between the obtained scores and kinematic variables. Deterministic model (Hay & Reid, 1988) was used to investigate the strength of correlative relationships among kinematic variables. Results: The obtained scores from the judges' decision were mainly affected by post-flight peak height, horse contact time, knee angle at landing, and horse takeoff angle. Strong blocking during horse contact was required to get successful performance and obtain high scores. Modified deterministic model showed that round-off entrance and takeoff angles and resultant velocity of the center of mass (CM) during the roundoff phase were the starting variables affecting performance in the following kinematics. Knee angle at landing, a highly influential variable on the obtained point, was only determined by judges' decision without significant correlative relationship with previous kinematic variables. Conclusion: The obtained scores highly depended on kinematic variables of post-flight and horse contact phases that were affected by those from the previous phases including round-off postures and resultant velocity of the body center of mass.

• Earthquakes and Structures
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• 제1권3호
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• pp.253-267
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• 2010

A novel simple approach is presented for the seismic analysis of continuous buried pipelines subject to fault ruptures. The method is based on the minimization of the total dissipated energy during faulting, taking into account the basic factors that affect the problem, namely: a) the pipe yielding under axial and bending load, through the formation of plastic hinges and axial slip; b) the longitudinal friction across the pipe-soil interface; c) the lateral resistance of soil. The advantages and drawbacks of the proposed method are highlighted through a comparison with previous approaches, as well as with finite element calculations accounting for the 3D kinematics of the pipe-soil-fault systems under large deformations. Parametric analyses are also provided to assess the relative influence of the various parameters affecting the problem.

• 한국지능시스템학회논문지
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• 제23권1호
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• pp.24-28
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• 2013

이 논문에서는 아동 크기 휴머노이드 로봇의 설계 및 개발과정에 대하여 기술한다. 경량형 휴머노이드 로봇의 설계 개념을 제시하고, 3차원 설계 툴을 이용하여 1m 이상 크기 휴머노이드 로봇의 메커니즘을 설계하였다. 로봇의 구동을 위한 하드웨어는 제한된 로봇의 무게 내에서 최적의 성능을 낼 수 있도록 설계하였다. 3차원 설계 툴을 사용하여 설계한 로봇의 프레임 및 링크들은 가볍고 강도가 좋은 재료를 선정하고 정밀 가공을 통해 제작하였다. 제작된 아동 크기의 휴머노이드 로봇은 역기구학, 균형제어를 적용하여 기본 동작을 구현하고 그 성능을 실험을 통하여 확인하였다.

• 한국수정란이식학회지
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• 제27권1호
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• pp.51-55
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• 2012

The objective of this study was to investigate the motility and kinematics of boar sperm that while stored at 4C. The samples of fresh boar semen were place into an extender, Androhep, and stored at $4^{\circ}C$. In three of these samples, cryoprotectants were added. The sperm's motilities and kinematics were evaluated by using microscope (${\times}400$) and the viability status was evaluated by using with eosin staining method. The 5 sample groups are; Goup A:Androhep (extender), stored at $17^{\circ}C$. Group B:Androhep (extender), stored at $4^{\circ}C$. Group C:Androhep (extender), + 3% glycerol (cryoprotectant), stored at $4^{\circ}C$. Group D:Androhep (extender), + 3% DMSO (cryoprotectant), stored at $4^{\circ}C$. Group E:Androhep (extender), + 3% ethylene glycol (cryoprotectant), stored at $4^{\circ}C$. In group A, the sperm's motility was reduced. On day one the sperm's motility was ($85.7{\pm}2.3$) and day 5 the motility was ($43.9{\pm}3.3$). In group B, C and D the sperm's motility were reduced to 0 on day 5. In group E the sperm's percentage of motility decreased. On day one the sperm's motility was ($42.0{\pm}0.5$) and day 5 the motility was ($2.3{\pm}0.3$). When comparing cryoprotectant in samples of boar sperm there is a slight improvement in the results when the use of Androhep Lite (extender), + 3% ethylene glycol (cryoprotectant), stored at $4^{\circ}C$ are used. Based on these results, ethylene glycol can protect sperm from heat shock at $4^{\circ}C$, but not satisfactory level. However, it showed the possibilities of liquid semen preservation at $4^{\circ}C$ by using cryoprotectant.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.916-919
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• 2004

In this paper, we proposed a new method of pre-operative planning for tibial deformity correction using double hexapod external fixator in pseudoacondroplasia. The 3-D computer graphic model of deformed tibia was reconstructed from 3 mm sliced CT data, and CAD model of double hexapod external fixator was developed. The fixator was composed of 170 mm diameter of three rings and 90 mm of twelve struts. The bone deformities and the osteotomy lines for double osteotomy were measured using X-rays, and the necessary joint values to correct the given deformities were obtained by inverse kinematics analysis. The computer graphic simulation was performed to visualize the deformity correction process and evaluate the analysis result. By examining the pre-op and post-op X-rays, the simulation result was in good agreement with the clinical outcomes.

• 소성∙가공
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• 제16권3호
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• pp.163-171
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• 2007

Due to the complicated character of the hemming process for automobile panels, it is very difficult to setup a consistent and reliable die design guide rule that require subtle decision of experienced experts and multiple trials during hemming die design and making. In this paper an automatic die design system of hemming units is pursued by presenting some algorithms, in which geometric data and constraints of the hemming units were converted to formula. The geometries and kinematics of all part for two kinds of hemming units, 2-link type and 4-link type were analysed kinematically to build the design algorithm. The algorithms were verified by automatic drawing used AutoCAD VBA program in example for the hemming unit design of a bonnet.

• 반도체디스플레이기술학회지
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• 제10권4호
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• pp.79-87
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• 2011

In this paper, suggested is a hybrid-type visual alignment system to align mask and panel in 3-D space, where mask and panel are to be controlled independently by two individual positioning mechanisms in order to compensate for spatial misalignments. In the hybrid visual alignment system, the below 4-PPR parallel mechanism provides in-plain motions to pattern mask like the other conventional alignment systems while the above 4-RPS parallel mechanism is to move glass panel to achieve a complete spatial alignment. For the control of the hybrid alignment system, first, inverse kinematic solutions for the parallel mechanisms are given to determine the driving distance of each active joint, and also an efficient way to determine the spatial alignment error is developed by exploiting three in-plane cameras.

• 한국운동역학회지
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• 제13권2호
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• pp.29-47
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• 2003

This study is to analyze the kinematic variables in release motion of discuss throwing. For the matter, 5 people from the national team and collegiate discuss throwing in the year 2001 were chosen as the subjects and two S-VHS video cameras set in 60frames/sec were used for recording their motions. Coordinated raw positions data through digitizing are smoothing by butter-worth 's low-pass filtering method at a cut off frequency 6.0Hz. and the direct linear transformation(DLT) method was employed to obtain 3-D position coordinates. The conclusions were as follows; 1. The better record players showed the shorter approach time in the last support phase. 2. In the displacement CG, the better record players showed the shorter displacement in medial-lateral direction, and the longer displacement in horizontal direction. In the motion, the COG showed longer displacement vertical direction. 3. The better record players showed the faster horizontal velocity than vertical velocity in the release. 4. The better record players showed to take the posture of vertical axis in the release.