• 대한의용생체공학회:의공학회지
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• 제24권6호
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• pp.495-500
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• 2003

본 연구의 목적은 컴퓨터 그래픽 모델을 사용하여 보행 시 족부 관절의 기구학적 특성을 알아보는 것이었다. 모델에서 모든 관전은 단일중심(monocentric), 1 자유도 힌지 관절로 구성되었다. 보행 시 족부의 모션데이터는 4대의 카메라를 사용한 모션측정기로 얻었으며, 이 모션데이터를 피험자의 밭의 크기에 맞게 스케일링된 모델에 입력하여 시뮬레이션을 수행하였다. 첫 번째 발목발허리관절(tarsometatarsal joint)의 운동 범위(range of motion)는 $-8^{\circ}\;\~\;-13^{\circ}$ 이었으며, 발허리발가락관절(metatarsophanlangeal joint)에서의 운동범위는 $-13^{\circ}\;\~\;-48^{\circ}$ 이었다. 발목발허리관절과 발허리발가락관절에서의 기구학적인 데이터는 이전 연구와 비교했을 때 비슷한 경향을 나타내었다. 따라서 본 연구에서 제시하는 컴퓨터 그래픽을 기반으로 한 족부 모델링은 족부 관절의 생체역학적 해석을 위한 유용한 방법이라 할 수 있을 것이다.

• Restorative Dentistry and Endodontics
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• 제43권4호
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• pp.48.1-48.13
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• 2018

Objectives: To analyze the influence of thickness and incisal extension of indirect veneers on the stress and strain generated in maxillary canine teeth. Materials and Methods: A 3-dimensional maxillary canine model was validated with an in vitro strain gauge and exported to computer-assisted engineering software. Materials were considered homogeneous, isotropic, and elastic. Each canine tooth was then subjected to a 0.3 and 0.8 mm reduction on the facial surface, in preparations with and without incisal covering, and restored with a lithium disilicate veneer. A 50 N load was applied at $45^{\circ}$ to the long axis of the tooth, on the incisal third of the palatal surface of the crown. Results: The results showed a mean of $218.16{\mu}strain$ of stress in the in vitro experiment, and $210.63{\mu}strain$ in finite element analysis (FEA). The stress concentration on prepared teeth was higher at the palatal root surface, with a mean value of 11.02 MPa and varying less than 3% between the preparation designs. The veneers concentrated higher stresses at the incisal third of the facial surface, with a mean of 3.88 MPa and a 40% increase in less-thick veneers. The incisal cover generated a new stress concentration area, with values over 48.18 MPa. Conclusions: The mathematical model for a maxillary canine tooth was validated using FEA. The thickness (0.3 or 0.8 mm) and the incisal covering showed no difference for the tooth structure. However, the incisal covering was harmful for the veneer, of which the greatest thickness was beneficial.

• 한국응용과학기술학회지
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• 제38권1호
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• pp.1-8
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• 2021

본 연구에서는 골프 드라이버 스윙 시 운동역학적 변인들이 비거리와 어떠한 관련성이 있는지를 분석하는 것이 목적이었다. 연구대상자는 신체 건강한 15명의 KPGA 골프 선수들이 참여하였다. 8대의 VICON 모션 캡쳐 카메라(250 Hz), 2대의 지면반력기(1000 Hz), 그리고 Trackman을 이용하여 운동학적 및 운동역학적 자료를 수집하였으며, 통계 분석은 Pearson 상관관계를 실시하였다. 드라이버 비거리와 볼 스피드, 클럽 헤드 스피드, 엑스 펙터, 그리고 지면반력 간 유의한 상관관계가 나타났으나, 스매쉬 팩터와 무릎 토크는 비거리와 상관관계가 나타나지 않았다. 볼 스피드, 클럽 헤드 스피드, 엑스 펙터, 지면반력은 비거리에 영향을 미치는 것으로 나타났으나, 스매쉬 팩터와 무릎 토크는 비거리에 영향을 미치지 않는 것으로 나타났다.

• 한국운동역학회지
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• 제19권2호
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• pp.273-286
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• 2009

본 연구는 고등학교 여자선수들을 대상으로 3차원 영상분석을 이용하여 스윙시 나타나는 각 신체분절 및 클럽의 직임을 운동학적 및 운동역학적 변인들을 산출하여 성공과 실패시에 대한 중요변인들을 비교 분석함으로써 정량적 자료의 추출과 더불어 정성적 평가를 하는데 목적이 있다. 운동학적 변인으로써 위치변화, 속도, 각도에 대한 3차원 분석과 지면반력에 대한 분석을 하였다. 그 결과 스윙시 클럽헤드는 어드레스와 톱스윙시 전후 이동(X축)이 매우 적게 나타남으로써 안정적 스윙이 유지 되는 것으로 나타났다. 또한 좌우방향(Y)의 신체중심이동속도는 성공적인 스윙 동작 시 실패동작시보다 임팩트시 매우 빠른 속도를 나타냄으로써 운동량 증가에 많은 기여를 하였으며 코킹각은 톱스윙에서부터 임팩트까지의 성공시가 코킹각을 더 크게 풀어 줌으로써 임팩트시 선속도 증가에 영향을 주어 비거리 증가에 유리하게 작용할 것으로 판단된다. 지면반력(GRF)은 전후방(X축)과 좌우방향(Y축)에서 안정적인 지지율로 나타남으로써 성공적 스윙으로 연결된 것으로 나타났다.

• 한국산업보건학회지
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• 제18권3호
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• pp.239-247
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• 2008

Low back disorders (LBDs) have been the most common musculoskeletal problem in Korean workplaces. It affects many workers, and is associated with high costs to many companies as well as the individual, which can negatively influence even the quality of life of workers. The _evaluation of low back disorder risk associated with manual materials handling tasks can be performed using variety of ergonomic assessment tools such as National Institute for Occupational Safety and Health (NIOSH) Revised Lifting Equation (NLE), the Washington Administrative Code 296-62-0517 (WAC), the Snook Tables etc. But most of these tools provide limited information for choosing the most appropriate assessment method for a particular job and in finding out advantage and disadvantage of the methods, and few have been assessed for their predictive ability. The focus of this study was to _evaluate spinal loads in real time with lifting and pulling heavy cow leathers in variety of postures. Data for estimating mean trunk motions were collected as employees did their work at the job site, using the Lumbar Motion Monitor. Eight employees (2 males, 6 females) were selected in this study, in which the load weight and the vertical start and destination heights of the activity remained constant throughout the task. Variance components (three dimensional spaces) of mean trunk kinematic measures were estimated in a hierarchical design. They were used to compute velocity and acceleration of multiple employees performing the same task and to repetitive movements within a task. Therefore, a results of this study could be used as a quantitative, objective measure to design the workplace so that the risk of occupationally related low back disorder should be minimized.

• 한국운동역학회지
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• 제14권3호
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• pp.135-147
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• 2004

This study was conducted to investigate the technical factors of Lu Yu Fu vault actually performed by three men gymnasts participated in artistic gymnastics competition of 2003 summer Universiade in Daegu through the DLT method of three dimensional cinematography. To analyze these vaults, the instant events of Lu Yu Fu were set in the board touchdown(BTD), the board takeoff(BTO), the horse touchdown(HTD), the horse takeoff(HTO), the peak height(PH), the mat touchdown(MTD) respectively and the phases of that vault were set in the board contact(BC), the preflight(PRF), the horse contact(HC), the postflight(POF), the grounding on mat(GM) respectively After calculating the performance times, the CG displacement velocity, the kinetic energy impulse reaction force moment arm torque at the horse, the released angle piked angle addressed angle, the angular momentum angular velocity of whole body in x axis, and the horizontal displacement between the feet and CG, the following conclusions were reached. To perform the better Lu Yu Fu vault, a gymnast must have the large horizontal velocity of whole body with fast run-up, decrease the duration time and the horizontal vertical displacement of whole body in PRF, have the enough time to judge the correct magnitude and direction of force to brake or push the horse so as to lengthen the HC duration time at any cost. Also it is desirable to increase the horizontal vertical displacement of whole body in POF if possible, maintain the adequate piked position to decrease the angular velocity of whole body in x axis, prepare the grounding on mat previously and delay the release of the hand from the body to keep the angular momentum.

• 한국CDE학회논문집
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• 제17권6호
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• pp.443-455
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• 2012

The configuration of a musculoskeletal (MS) system is closely related to the individual motions of the human body. Many researches have been focused on evaluating the associations between the MS configuration and the individual motion using patient-specific MS models, but it still remains a challenging issue to accurately predict the motion by differed configurations of the MS system. The main objective of this paper is to predict the changes of a patient-specific gait by altering the geometric parameters of the hip joint using function-based morphing method (FBM). FBM is suitable for motion analysis since this method provide a robust way to morph a MS model while preserving the biomechanical functions of the bones. Computed-muscle control technique is used to calculate the muscle excitations to reproduce the targeted motion within a digital MS model without the motion-captured data. We applied this approach to a patient who has an abnormal gait pattern. Results showed that the femoral neck length and the angle significantly affect to the motion especially for the hip abduction angle during gait, and that this approach is suitable for gait prediction.

• The Journal of Advanced Prosthodontics
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• 제10권1호
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• pp.73-78
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• 2018

PURPOSE. The purpose of this study was to analyze the effects of two different implant surface treatments on initial bone connection by comparing the Removal Torque Values (RTQs) at 7 and 10 days after chemically modified, sandblasted, large-grit and acid-etched (modSLA), and Laser-etched (LE) Ti implant placements. MATERIALS AND METHODS. Twenty modSLA and 20 LE implants were installed on the left and right tibias of 20 adult rabbits. RTQs were measured after 7 and 10 days in 10 rabbits each. Scanning electron microscope (SEM) photographs of the two implants were observed by using Quanta FEG 650 from the FEI company (Hillsboro, OR, USA). Analyses of surface elements and components were conducted using energy dispersive spectroscopy (EDS, Horiba, Kyoto, Japan). RESULTS. The mean RTQs were $12.29{\pm}0.830$ and $12.19{\pm}0.713$ Ncm after 7 days (P=.928) and $16.47{\pm}1.324$ and $16.17{\pm}1.165$ Ncm after 10 days (P=.867) for LE and modSLA, respectively, indicating no significant inter-group differences. Pore sizes in the LE were $40{\mu}m$ and consisted of numerous small pores, whereas pore sizes in the modSLA were $5{\mu}m$. In the EDS analysis, Ti, O, and C were the only three elements found in the LE surfaces. Na, Ca, Cl, and K were also observed in modSLA, in addition to Ti, O, and C. CONCLUSION. The implants showed no significant difference in biomechanical bond strength to bone in early-stage osseointegration. LE implant can be considered an excellent surface treatment method in addition to the modSLA implant and can be applied to the early loading of the prosthesis clinically.

• 한국운동역학회지
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• 제17권2호
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• pp.1-9
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• 2007

Walking is not only an essential component of the human mobility, but also is a good exercise. Inability to walk freely can reduce an individual's quality of life and independence substantially. Being a relatively low impact activity, walking is particularly good for the elderly and research has shown that regular walking in the elderly reduces the chance of fall-related injuries and mental diseases as well. In spite of the documented benefits of regular walking, it is still difficult to walk without the aid of assistive devices for the frail elderly who have lower extremity problems. Assistive walking devices(AWD), such as crutches, canes, hiking-poles, T-Poles and walkers, are often prescribed to the elderly to make their walking be safe and efficient. Many researchers have demonstrated the effects of AWDs such as reducing lower extremity loading, improved dynamic/gait stability, yet, no study has been done for gait pattern when the elderly gait with AWDs. Therefore, the purpose of this study was to examine whether T-Poles, one of the AWDs, change the elderly gait pattern. Eight community-dwelling female elderly participated in this study. Laboratory kinematics during walking with T-Poles(PW) and with out T-Poles(NPW) was assessed. PW showed significant increase in step width, stride length, gait velocity and decrease in swing time. No significances were found in lower body joint angles but meaningful trend and pattern were found. Maybe the reason was due to the participants. Our participants were healthy enough so that the effect of T-Poles was minimum. PW also showed typical gait phases which are no single support phase during a gait cycle. It indicates that walking with T-Poles may guarantee safe and confident walking to the frail elderly.

• 한국운동역학회지
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• 제18권1호
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• pp.179-190
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• 2008

본 연구에서는 양측 하지의 비대칭성이 수직점프의 수행, 즉 양측운동손실에 미치는 영향을 알아보기 위해 13명의 성인 남성을 대상으로 좌/우의 외발과 양발을 각각 이용한 수직반동점프를 비교, 분석하였다. 분석 결과 양발점프가 외발점프에 비해 2배 이상 점프하였으나 외발점프에서 하지가 발현하는 충격량과 일량이 양발점프보다 24% 정도 높게 나타나 양측운동손실을 보여주었다. 또한 우성과 열성하지의 외발점프에서 충격량과 일량은 4-7% 정도의 유의한 역학적 비대칭성이 나타났다. 하지만 양측하지의 비대칭성과 양측운동손실 사이에는 유의한 차이가 보이지 않았으며, 양발점프에서 우성하지와 열성하지의 역학적 변인들 사이에는 유의한 차이가 나타나지 않았다. 양발 점프는 외발점프에 비해 짧은 시간에 관절의 높은 각속도로 긴 거리를 추진하였으며, 낮은 근활동을 보였는데 이러한 요인이 수행의 감소에 영향을 미쳤을 것으로 보인다.