• The Journal of Korean Physical Therapy
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• v.23 no.5
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• pp.15-21
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• 2011

Purpose: The purpose of this study was to describe the influence of respiration on the segmental motion of the lumbar spine in the lying position. Methods: Twelve healthy females without a history of low back pain participated. Lumbosacral lordosis, intervertebral body angles, intervertebral body displacements, and anterior heights of the intervertebral disc of the lumbar spine were measured at inspiration, expiration and forced expiration in the supine and prone positions via fluoroscopy. Results: The results of lumbar kinematic analysis in the supine position according to respiration pattern were as follows. The L4/5 intervertebral body angle was significantly higher at forced expiration than at expiration (p<0.05). The L3/4 anterior height of the intervertebral disc was significantly higher at expiration than at forced inspiration and the L5/S1 anterior height of the intervertebral disc was significantly higher at inspiration than at forced expiration (p<0.05). There were no significant differences in the intervertebral body displacements and lumbosacral lordosis in the supine position (p>0.05). The results of lumbar kinematic analysis in the prone position according to respiration pattern were as follows. The L5/S1 anterior height of the intervertebral disc was significantly higher at inspiration than at forced expiration (p<0.05). However, there was no significant difference in the intervertebral body angle, the intervertebral body displacements, and the lumbosacral lordosis (p>0.05). Conclusion: These findings suggested that respiration can affect the intervertebral body angle and anterior height of the intervertebral disc in some segments. The results from this study serve as a step in the development of guidelines for lumbar kinematic analysis for lumbar breathing training.

• Korean Journal of Applied Biomechanics
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• v.23 no.4
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• pp.295-306
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• 2013

The purpose of this study was to provide high school male shot putters training methods of gliding and delivery motion through comparative analysis of kinematic characteristics. To accomplish this purpose, three dimensional motion analysis was performed for the subjects(PKC, KKH, YDL) who participated in high school male shot putter competition on 92nd (2011), 93rd (2013) National Sports Festival. The subjects were filmed by four Sony HXR-MC2000 video cameras with 60 fields/s. The three-dimensional kinematic data of the glide, conversion and delivery phase were obtained by Kwon3d 3.1 version. The data of the shoulder rotational angles and projection angles were calculated with Matlab R2009a. The following conclusions had been made. With the analysis of the gliding and stance length ratio, the gliding length was shorter at the TG than the SG with short-long technique but the gliding and stance length ratio was 46.8:53.2% respectively. The deviation of the shots trajectory from APSS(Athlete-plus-shot-system) revealed that the PKC showed similar to "n-a-b-c-I" of skilled S-shape type, KKH and YDL showed "n-a-d-f-I'" of unskilled type. Furthermore, they showed smaller radial distance from the central axis of the APSS and the shots were away from the linear trajectory. From this characteristics, The PKC who performed more TG than SG had shorter glide with S-shape of APSS(skilled type) showed the better record than others with technical skill. But KKH and YDL had bigger glide ratio with "n-a-d-f-I'" of unskilled type and improved their records with technical factor. The projection factor had an effect on the record directly. Because PKC maintained more lower glide and transition posture with momentum transfer through COG's rapid horizontal velocity respectively the subject possessed the characteristics of high horizontal and vertical velocity with large turning radius from shot putter to APSS.

• Korean Journal of Applied Biomechanics
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• v.22 no.4
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• pp.395-404
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• 2012

This study was to perform the kinetic analysis of tucked backward salto on the balance beam. Eight women's gymnastics players(age: $15.88{\pm}2.45yrs$, career: $6.38{\pm}0.52yrs$, height: $152.38{\pm}7.35cm$, weight: $44.25{\pm}7.54kg$) of the I-region participated in this study. The kinematic variables were analyzed response time of motion, angle, velocity, acceleration and the kinetic variables were analyzed ground reaction force(GRF) of motion. For measure and analysis of kinematic and kinetic variables of this study, used to synchronized to 6 Eagle camera and 1 force plate, used to the Cortex(Ver. 1.0) for analyzed of variables. The results were as follows; To the kinematic variables of tucked backward salto on the balance beam, a time appeared longer landing than air rotation, changes of angle regulated segment of body smaller moment of inertia when air rotation, larger moment of inertia when releasing and landing. A velocity appeared fast motion when releasing and air rotation of body, but appeared more decelerations from landing and acceleration showed to be tended to velocity. A GRF appears jump more than twice the weight at the moment that showed the power of motion to all subject.

• Korean Journal of Applied Biomechanics
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• v.23 no.2
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• pp.109-116
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• 2013

The purpose of this study was to provide fundamental information for the enhancement of performance through kinematic analysis of cornering according to the radius of curve course in short track speed skating. To perform this study, six skaters: three narrow radius players(N, body mass: $56.0{\pm}7.2$ kg, height: $163.7{\pm}5.1$ cm, age: $21.3{\pm}1.5$ yrs) and three wide radius players(W, body mass: $61.0{\pm}9.5$ kg, height: $169.0{\pm}4.4$ cm, age: $20.0{\pm}1.7$ yrs). Three-dimensional motion analysis was performed on the section from the forth block starting to show the change of radius to the sixth block using eight infrared cameras(sampling frequency of 100 Hz for N and W players). The time of push-off was greater for N than for W(p<.05) while the radius of center of mass was greater for W than for N(p<.05). The flexion and extension of knee and hip joint were greater for N than for W(p<.05). The external rotation of left knee joint was greater for N than for W(p<.05). Based on the findings, a small radius by increasing the range of the flexion and extension of knee and hip joint with greater external rotation of left knee joint would be related to more efficient run at curve. It is expected that these results will be useful in developing a training program for enhancing performance of short track speed skating athletes.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.989-995
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• 2009

Short-time Fourier transforms (STFT) are useful for analyzing signals with harmonics that vary with time. If the variation of the harmonics with time is smooth, such as in kinematic vibrations in vehicles, then it is possible to improve the STFT using order spectra and correlation analysis. In this paper, it is shown how correlation analysis can be performed when the speed signal is noisy or unknown and then it is shown how order spectra become simple to compute after this analysis. The results are illustrated by an analysis of axle and car body vibrations in the prototype high-speed train, HSR-350x.

• 한국기계연구소 소보
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• s.17
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• pp.93-97
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• 1987

This paper is concerned on kinematic analysis and simulation of an automatic feeding mechanism and a curved inverse earn. The main objective is the development 0 fan algorithm of the earn-feeding mechanism and a CAD program. The computer program CACAFS (Computer-Aided Cam and Automatic Feeding System) is developed by using the state-of-the-art for CAD. Thus, the program CACAFS is independent of computer hardwares and also interactive. As the second part of paper, this paper introduces the technique for the mechanism simulation and graphics-oriented CAD programming. The first part of r paper presents the algorithm to analyze the motion of the inverse earn and the automatic feeding mechanism.

• 한국기계연구소 소보
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• s.17
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• pp.83-91
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• 1987

This paper is concerned on kinematic Analysis and Simulation of an automatic feeding mechanism and a curved inverse cam. The main objective is the development of an algorithm of the cam-feeding mechanism and a CAD program. The computer program CACAFS (Computer-Aided Cam and Automatic Feeding System is developed by using the state-of-the-art for CAD. Thus, the program CACAFS is independent of computer hardwares and also interactive. As the first part of paper, this paper introduces the algorithm to analyze the motion of the inverse cam and the automatic feeding mechanism. The second part of paper presents the technique for the mechanism simulation and graphics-oriented CAD programming.

• Structural Engineering and Mechanics
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• v.30 no.6
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• pp.665-678
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• 2008

The beams components subjected to the loading such as axial, bending and cyclic thermal loads were studied in this research. The used constitutive equations are those of elasto-plasticity coupled to ductile and/or creep damage. The nonlinear kinematic hardening behavior was considered in elastoplasticity modeling. The unified damage law proposed for ductile failure and fatigue by the author of Sermage et al. (2000) and Kachanov's creep damage model applied to cyclic creep and low cycle fatigue of beams. Based on the results of the analysis, the shakedown limit loads were determined through the calculation of the residual strains developed in the beam analysis. The iterative technique determines the shakedown limit load in an iterative manner by performing a series of full coupled elastic-plastic and continuum damage cyclic loading modeling. The maximum load carrying capacity of the beam can withstand, were determined and imposed on the Bree's interaction diagram. Comparison between the shakedown diagrams generated by or without creep and/or ductile damage for the loading patterns was presented.

• The Journal of Korean Physical Therapy
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• v.25 no.6
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• pp.399-404
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• 2013

Purpose: To investigate the effects of initiation side on gait symmetry in the chronic stroke patients. Methods: Twenty one patients with independent gait after stroke were divided into the paretic-leg gait initiation group (PLI) and the nonparetic-leg gait initiation group (NPLI). The symmetry ratio (SR) was calculated from of the spatiotemoral and kinematic parameter which measured by 3D motion analysis. Results: In the spatiotemporal variables, SR-step length and SR-velocity was significantly different between groups (p<0.05). In the kinematic variables, SR-TOAA and SR-SwPAA of the hip joint was significantly different between groups (p<0.05). Conclusion: We suggest that the initiating leg may influence on the gait symmetry of stroke patient These results will be a helpful reference in hemiplegic gait training or intervention.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.6
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• pp.543-549
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• 2005

This paper deals with modeling and analysis fer the landing motion of a human-body model. First, the dynamic model of a floating human body is derived. The external impulse exerted on the ground as well as the internal impulse experienced at the joints of the human body model is analyzed. Second, a motion planning algorithm exploiting the kinematic redundancy is suggested to ensure stability in terms of ZMP stability condition during a series of landing phases. Four phases of landing motion are investigated. In simulation, the external and internal impulses experienced at the human joints and the ZMP history resulting from the motion planning are analyzed for two different configurations. h desired landing posture is suggested by comparison of the simulation results.