• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.133-149
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• 2003

The purposes of present study were to determine the major check-points of golf swing from the review of previous studies, and to suggest additional information on the teaching theory of golf. The golf swing motion of 6 male and female elite university golf players were filmed with 16mm Locam II high speed cameras at the speed of 200f/s, and variables such as time, displacement, angle, velocity were calculated and analyzed by 3D Cinematography using DLT method. The results were: 1. Differences were shown in the ratio of weight distribution on the feet, cocking angle, take-back velocity, club-head velocity at impact depending upon the physical characteristics and club used for swing. 2. Time for the down-swing and impact were $0.27{\sim}0.29s$ in men and $0.29{\sim}0.32s$ in women, which was 1/3 of the time for the back-swing. Women showed longer total swing time than men because of longer time in back-swing, follow-through and finish. 3. Men showed larger range of motion in shoulder and knee joints than women, on the other hand women showed larger range of motion in hip joint than men. 4. Cocking motion and right elbow flexion were occurred at the top of back-swing and cocking release was occurred at the moment of impact. Maximum rotations of shoulder and hip joints were found between the top of back-swing and down-swing phase. 5. Women showed lower back-swing velocity than men, and men showed higher club velocity(men: $38.2{\sim}38.6m/s$, women: $35.1{\sim}36.4m/s$) than women.

• Korean Journal of Applied Biomechanics
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• v.21 no.2
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• pp.173-179
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• 2011

This study aims to analyse difference in biomechanical factors between dominant legs and recessive ones according to muscular imbalance during drop landing targeting talented children in sports. The subjects of the study were ten primary students who are attending to Sports Program for Talented Children organized by C university (age: $12.28{\pm}0.70$ year, height: $1.52{\pm}0.11$ m, and weight: $45.2{\pm}4.9$ kg). Strength legs were classified into dominant side and strengthless legs were classified into non-dominant legs. For three-dimensional analyses of the data collected, 6 video cameras(MotionMaster200, Visol, Korea) were used. To analyse ground reaction force, two force platforms(AMTI ORG-6, MA) were used and to analyse electromyograghy a 8-channeled wireless Noraxon Myoresearch made in USA was used at 1000 Hz for sampling. As a result, it was discovered that the dominants legs controlled knee bending motions more stably than strengthless legs as the maximum vertical ground reaction force was significantly high in dominant legs(p<.05), and joint moment of knee joints of the dominant legs was high(p<.05). Therefore, this study suggested that injury prevention program focusing on muscular balance as well as the existing sports programs for talented children should be developed based on results of the study and it is expected that the results will be useful for improvement of sports programs for talented children.

• Structural Engineering and Mechanics
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• v.68 no.4
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• pp.475-483
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• 2018

Square tubular columns are commonly used in moment resisting frames, while through-diaphragm connection is the most typical configuration detail to connect the H-shaped beam to the column. However, brittle fracture normally occurs at the complete joint penetration weld between the beam flange and the through-diaphragm due to the stress concentration caused by the geometrical discontinuity. Accordingly, three improved types of through-diaphragm are presented in this paper to provide smooth force flow path comparing to that of conventional connections. Tensile tests were conducted on four specimens and the results were analyzed in terms of failure modes, load-displacement response, yield and ultimate capacity, and initial stiffness. Furthermore, strain distributions on the through-diaphragm, the beam flange plate, and the column face were comprehensively evaluated and discussed. It was found that all the proposed three types of improved through-diaphragm connections were able to reduce the stress concentration in the welds between the beam flange and the through-diaphragm. Furthermore, the stress distribution in connection with longer tapered through-diaphragm was more uniform.

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.21-30
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• 2008

The purpose of this study was to investigate changes in mechanical properties of human tibialis anterior following eccentric exercise. Healthy subjects (n=12) performed 120 maximum eccentric contraction of ankle dorsiflexor. Before and 1- and 24- hour after the eccentric exercise, ankle dorsiflexion moment-angle relationships were obtained. Along with significant decrease in maximum isometric muscle strength, the shift of the optimum ankle joint angle toward the longer muscle length direction was observed, independent of the ranges of motion of the eccentric exercise. The results of this study demonstrated that eccentric exercise-induced micro muscle damage(Morgan & Allen, 1999) does rut seem to be a sole mechanism of eccentric contraction-induced muscle damage, suggesting further investigation for the better understandings of this phenomenon.

• Physical Therapy Korea
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• v.8 no.4
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• pp.45-61
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• 2001

본 연구는 보행주기 동안 정상인과 당뇨병성 족부궤양 환자의 족관절 운동역학적 변수와 족관절 근육들의 근활성도에 차이가 있는지 알아보기 위하여 실시하였다. 본 연구의 대상자는 당뇨병성 족부궤양이 있는 환자 9명(남자: 6명, 여자: 3명)과 성, 연령, 체중으로 짝짓기(matching)시킨 대조군 9명이었다. 3차원 동작분석기, 힘판, 표면 근전도를 이용하여, 보행주기 동안 족관절의 관절가동범위, 모멘트(moment), 일률(power), 그리고 내측가자미근, 전경골근, 비복근의 근수축 개시시간(onset time)과 종료시간(cessation time)을 측정하였다. 정상군과 비교하여 당뇨병성 족부궤양군의 보행속도는 느렸고, 입각기 기간이 길었으며, 족관절의 가동범위가 적었고, 족관절 최대 족저굴곡 모멘트와 일률이 정상군에서보다 유의하게 낮았다. 보행주기에서 당뇨병성 족부궤양군에서 내측 가자미근과 비복근의 근수축 개시시간은 유의하게 빨랐으며, 전경골근과 비복근의 근수축 종료시간은 유의하게 지연되었다. 당뇨병성 족부궤양 환자군의 족관절 근육에서 동시수축(co-contraction)이 증가되고, 보행속도가 느리며, 입각기 기간이 증가하였다. 이러한 보행특성의 차이는 족부 감각손실에 따른 보행의 안정성을 유지하기 위한 보행전략 때문으로 판단된다. 앞으로 이러한 비정상적인 보행특성이 당뇨병성 족부궤양에서 발생하는 비정상적인 족저부 압력분포과 족부궤양 발생과 어떤 관계가 있는지 알아보는 연구가 필요할 것이다.

• Journal of the Korea Concrete Institute
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• v.22 no.6
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• pp.741-751
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• 2010

An experimental study was performed to investigate the earthquake resistance of the beam-column connections as a part of a precast concrete moment-resisting frame that uses precast concrete U-shaped shells for the beams. Five full-scale precast concrete specimens and one conventional monolithic concrete specimen were tested under cyclic loading. The parameters for this test were the reinforcement ratio, stirrup spacing, and end-strengthening details of the precast beam shell. The test results showed that regardless of the test parameters, the precast concrete beam-column connections showed good load-carrying capacity and deformation capacity, which were comparable to those of conventional monolithic concrete specimen. However, at large deformations, the beam-column connections of the precast concrete specimens were subjected to severe strength degradation due to diagonal shear cracks and the bond-slip of re-bars at the joint region. For this reason, the energy dissipation capacity and stiffness of the precast concrete specimens were significantly less than those of the cast-in-place specimen.

• Journal of the Korean Society of Marine Environment & Safety
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• v.8 no.2
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• pp.71-78
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• 2002

For the first Maritime Accident Inquiry System in Korea, Central Marine Accidents Inquiry Committee were founded in Seoul and District Marine Accidents Inquiry Committee in Busan city In 1963 to determine the circumstances of the accidents and causes. At the present day, it was settled as Maritime Safety Tribunal tough several revision of the Law and regulations regarding the Maritime Accident Inquiry System. In Korea, there occurred about m cases of marine accident, and as a result, about 200 people were lost human lives in average per year. In accordance with the change of circumstances such as traffic increasing and being bigger in size, being faster in speed, etc., the causes of the marine accidents become complicated year by year. Accordingly, in this moment, it is meaningful that the introduction of the Research Official who assists the Judges probing the cases fair and square. In this Paper, with the consideration of the several kinds of Research Official System, such as the Research Official of the Korean Supreme Court, the Supreme Public Prosecutors' Office and the Constitutional Court, Japanese Supreme Court, Law Clerk in USA, etc., the selection, numbers, duty of the Research Official were studied. The results of the study are as follows; 1. The Research Official to be appointed among the person having long enough career as a Judge, Investigator engaged in the Maritime Safety Tribunal due to he sho띨d have capability to confirm perfectly logical judgement and to collect enough material for the conclusion of the causes of the case. The one who understands the foreign language is preferred for the study of the foreign cases; 2. It will be logical to post 3 joint Research Officials in Korea Maritime Safety Tribunal in Seoul after due consideration the cases treated a year; 3. It will be logical for the Research Official to perform the collection of material and inspection of the scene for the trial and inquiry of the cases, to attend the cases filed suit to the Supreme Court, to make commentarial papers regarding the judged cases, to collect statistics of marine accidents and to devise a reform measure through in-depth analysis of the accidents frequently occurred, to study for the improvement of the Maritime Accident Inquiry System;

• Journal of the Korean Society for Precision Engineering
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• v.23 no.4 s.181
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• pp.176-182
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• 2006

Although several artificial disc designs have been developed for the treatment of discogenic low back pain, biomechanical changes with its implantation were rarely studied. To evaluate the effect of artificial disc implantation on the biomechanics of functional spinal unit, a nonlinear three-dimensional finite element model of L4-L5 was developed with 1-mm CT scan data. Biomechanical analysis was performed for two different types of artificial disc having constrained and unconstrained instant center of rotation(ICR), ProDisc and SB Charite III model. The implanted model predictions were compared with that of intact model. Angular motion of vertebral body, forces on the spinal ligaments and facet joint, and stress distribution of vertebral endplate for flexion-extension, lateral bending, and axial rotation with a compressive preload of 400N were compared. The implanted model showed increased flexion-extension range of motion compared to that of intact model. Under 6Nm moment, the range of motion were 140%, 170% and 200% of intact in SB Charite III model and 133%, 137%, and 138% in ProDisc model. The increased stress distribution on vertebral endplate for implanted cases could be able to explain the heterotopic ossification around vertebral body in clinical observation. As a result of this study, it is obvious that implanted segment with artificial disc suffers from increased motion and stress that can result in accelerated degenerated change of surrounding structure. Unconstrained ICR model showed increased in motion but less stress in the implanted segment than constrained model.

• Journal of Korean Society of Steel Construction
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• v.18 no.5
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• pp.633-642
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• 2006

Serviceability design is required to control the cracking at the joint of precast decks with longitudinal prestress in continuous composite bridges. Details of twin-girder bridges are especially complex not only due to their main reinforcements and transverse prestresses for the design of long-span concrete slabs, but also due to the shear pockets for obtaining the composite action. This paper suggests the design guidelines for the magnitude of the effective prestress and for the selection of filling materials and their requirements that would allow for the use of precast decks for twin-girder continuous composite bridges. The necessary initial prestress was also evaluated through long-term behavior analysis. From the analysis, existing design examples were revised and their effectiveness was estimated. When a filling material with a bonding strength higher than the requirement is used in the region of a high negative moment, a uniform configuration of the longitudinal prestressing steels along thewhole span length of continuous composite bridges can be achieved, which would result in the simplification of the details and the reduction of the construction costs.

• Physical Therapy Korea
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• v.11 no.1
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• pp.1-17
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• 2004

The purposes of this study were to find correlations among Fugl-Meyer Assessment scale, gait speed, and Timed Up & Go test (TUG) and to predict gait ability from subscales of Fugl-Meyer Assessment scale. The study population consisted of 30 stroke patients referred to the Department of Rehabilitation Medicine in the Bundang Jaesang General Hospital. All subjects were ambulatory with or without an assistive device. All participants were assessed on Fugl-Meyer Assessment scale and gait speed (m/s), TUG (s). The data were analyzed using independent t-test, Pearson product moment correlation analysis and stepwise multiple regression. The results revealed that all items of Fugl-Meyer Assessment scale, except passive joint range of motion were significantly correlated with gait speed and TUG. In particular, sensation score, lower extremity motor and coordination score have a significant correlation with gait speed and TUG (p<.05). The sensation score and lower extremity motor score were important factors in comfortable gait and maximal gait speed. Their power of explanation regarding comfortable gait and maximal gait speed were 63.0% and 65.0%, respectively. The sensation score and lower extremity coordination score were important factors in TUG. Their power of explanation regarding TUG was 55.0%. These results showed that Fugl-Meyer Assessment scale is significantly correlated with gait speed and TUG. Therefore Fugl-Meyer Assessment scale is an appropriate assessment tool to predict gait ability of patients with stroke. Further study about gait speed and TUG by change of Fugl-Meyer Assessment score is needed using a longitudinal study design.