• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1993년도 춘계학술대회논문집
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• pp.145-145
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• 1993

In bicycle design, saddle is the major part which effects the subjective comfort of rider. This study examines the correlation between the subjective comfort and elastic body pressure. The elastic body pressure measuring instrument for free-form surface such as saddle is developed by force sensor register, A/D converter and computer. The subjective comfort is measured quantit- atively by 11-point scale method and the elastic body pressure distribution is obtained through 3 different saddles at 4 postures. The pressure distribution is presented by computerized equi- pressure contour. While mean pressure, standard deviation of pressure, maximum pressure are inversely proportional to subjective comfort, the modified saddle-bearing weight which is the surface integral of pressure is directly proportional. Consequently, standard deviation of pressure is most important characteristic which affects variation of subjective comfort.

• PNF and Movement
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• 제17권3호
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• pp.411-419
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• 2019

Purpose: This study determined the effects of elastic bands in coordinative locomotor training on the body alignment of elementary school baseball players. Methods: Thirty subjects were recruited for this study and separated into two groups: the coordinative locomotor training group with elastic bands (n=15) and the non-training control group (n=15) were five times a week for eight. The trunk inclination, trunk imbalance, kyphotic angle and lordotic angle were used to evaluate body alignment. Results: The experimental group showed significant improvements in trunk inclination, trunk imbalance, kyphotic angle and lordotic angle (p<0.05). Conclusion: Coordinative locomotor training impacted postural alignment in elementary school baseball players.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1317-1318
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• 2007

On this paper, unimorph type piezoelectric vibrator made by attaching ceramic plates on rectangular elastic body, to find the basic characteristic of the actuators. In experiment, elastic body's displacement and resonance frequency were measured according to changes of ceramic's length and elastic body's length. Also, temperature changes were observed according to time. The displacement and resonance frequency were increased when the ceramic's length were increased. When elastic body's length was increased, the displacement was increased. Also, the temperature was increased according to time, but at some time it was saturated and the temperature was not increased any more.

• Smart Structures and Systems
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• 제3권2호
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• pp.173-188
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• 2007

The general solution for two-dimensional magneto-electro-elastic media in terms of four harmonic displacement functions is proposed analytically. The expressions of specific solutions of magneto-electro-elastic plane problems with specific body forces are derived. Finally, based on the general solution in the case of distinct eigenvalues and the specific solution for density functionally gradient media, two kinds of beam problems with body forces depending only on the z or x coordinate are solved by the trial-and-error method.

• 한국산학기술학회논문지
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• 제18권3호
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• pp.199-208
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• 2017

신체조성과 혈관탄성의 변화로 인한 심혈관질환과 근감소로 인한 낙상의 발생은 노화로 인하여 가장 빈번하게 발생하게 된다. 그래서 탄력밴드 저항운동은 노인들이 쉽고 안전하게 수행할 수 있으며 신체조성과 혈관탄성에 긍정적인 영향을 미칠 수 있을 것이다. 따라서 본 연구는 고령여성(>65 years)을 대상으로 12주간 저항운동을 실시한 후 신체조성, 혈관탄성, 낙상위험도지수에 어떠한 효과를 미치는지에 대하여 살펴보았다. 저항운동은 주3회 한 회당 60분으로 구성되었고 운동 강도는 Borg의 운동자각도(6 - 20)에서 11-14로 설정되었다. 신체조성에 해당하는 체중, 근육량, 체지방률, BMI(Body Mass Index)와, 혈관탄성(맥파속도 (Pulse wave velocity (PWV)), 낙상위험도지수(Risk of falling)는 훈련 전과 후에 측정이 되었다. 연구 결과 신체조성에서 운동집단의 체중(p=.003), BMI(p=.002), PWV(p=.017), 낙상위험도지수(p=.037)는 유의하게 감소하였으나 통제집단에서 체중(p=.009), BMI(p=.009)는 유의하게 증가하였다. 따라서 여성노인들은 탄력밴드 저항운동을 통해 체중과 BMI를 감소시키고 혈관탄성에 긍정적인 효과를 얻게 되었다. 그리하여 탄력밴드 저항운동은 노인들의 대사증후군, 심혈관질환, 낙상사고의 발생률을 낮출 수 있는 매우 효과적인 운동이라 할 수 있다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.108-111
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• 1999

Elastic deformation of die has been investigated to improve the accuracy of cold forged parts. In order to improve the accuracy of forged parts we have investigated the elastic deformation of forging die by analysis with commercial. F. E. M code DEFORM and experiments using he strain gages. In the F. E. M analysis two types are used for elastic deformation of die. the one considers die as elastic body and the other considers the die as rigid body. The latter relatively takes a lot of time. The results from the two types are very similar with each other. Considering the results of analysis and experiments it is likely that the elastic strain of forging die is very small.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 춘계학술대회 논문집
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• pp.112-116
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• 2002

In cold forging, the elastic behavior of the die has a direct influence on the accuracy of the forging part. And the die dimension is continuously changed during the loading, unloading, and ejecting stage. In this paper, we evaluated the elastic deflections of cold forging die during loading, unloading, and ejecting stage. Uni-axial strain gauges are used to measure elastic strain of die during each forging stage. Strain gauges are attached on the surface of die. A commercial F.E.M code, DEFORM-2D$\^$TM/ is used to predict elastic strain of die. Two method of F.E.M. analysis are used to compare with measured and calculated elastic strain. One is to regard the die as rigid body over forging cycle. And then, the die sass is analyzed by loading the die with pressure from the forging part. The other is to regard the die as elastic body from forging cycle. The elastic strain of die is calculated and the die is elastically deformed at each strop. The calculated results under the elastic die assumption are well agreed with experimental data using strain gauges.

• 신재생에너지
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• 제7권4호
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• pp.50-57
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• 2011

A wind turbine simulation program for the coupled dynamics of aerodynamics, elasticity, multi-body dynamics and controls of turbine is newly developed by combining an aero-elastic code and a multi-body dynamics code. The aero-elastic code, based on the blade momentum theory and generalized dynamic wake theory, is developed by NREL(National Renewable Energy Laboratory, USA). The multi-body dynamics code is commercial one which is capable of accounting for geometric nonlinearity and twist deflection. A turbulent wind load case is simulated for the NREL 5-MW baseline wind turbine model by the developed program and FAST. As a result, the two results agree well enough to verify the reliability of the developed program.

• The Journal of Korean Physical Therapy
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• 제33권5호
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• pp.217-223
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• 2021

Purpose: This study sought to identify the effects of coordinative locomotor training (CLT) using elastic bands on the flexibility and body alignment of right-handed baseball players in elementary school. Methods: The subjects were 20 instructed right-handed baseball players in elementary school. They were classified into the experimental group with 10 players (n=10) to be given coordinative locomotor training using elastic bands and the control group with 10 players (n=10). Flexibility was measured by the sit and reach exercise. Body alignment was measured using formetric 4D method to measure the trunk imbalance angle (TI), trunk torsion angle (TT), pelvic tilt angle (PTi), pelvic torsion angle (PTo), pelvic rotation angle (PR), kyphotic angle (Ky), and lordotic angle (Lo). Results: There was a significant increase in the flexibility within the experimental group (p<0.05). after the intervention. There was also a significant increase in the difference between the experimental group and the control group (p<0.05). There was a significant decrease in PR during body alignment in the experimental group after intervention (p<0.05). An analysis of the differences between groups showed a significant decrease in the PR of the experimental group compared to the control group (p<0.05). Conclusion: These findings show that coordinative locomotor training using elastic bands would be effective for enhancing the flexibility and pelvic rotation of elementary school right-handed baseball players.

• 한국소음진동공학회논문집
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• 제14권12호
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• pp.1354-1359
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• 2004

This paper is concerned with the application of perturbation method to the dynamic analysis of floating flexible body. In dealing with the dynamics of free-floating body, the rigid-body motions and elastic vibrations are analyzed separately. However, the rigid-body motions cause vibrations and elastic vibrations also affect rigid-body motions in turn, which indicates that the rigid-body motions and elastic vibrations are coupled in nature. The resulting equations of motion are hybrid and nonlinear. We can discretize the equations of motion by means of admissible functions but still we have to cope with nonlinear equations. In the previous paper, we proposed the use of perturbation method to the coupled equations of motion and derived zero-order and first-order equations of motion. The derivation process was lengthy and tedious. Hence, in this paper, we propose a new approach to the same problem by applying the perturbation method to the Lagrange's equations, thus providing a systematic approach to the addressed problem. Theoretical derivations show the efficacy of the proposed method.