• Journal of Korean Public Health Nursing
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• v.25 no.1
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• pp.17-27
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• 2011

Purpose: The study examined the effect of exercise public health center exercise program on strength, balance, body composition and blood pressure in healthy elderly women. Method: Thirty healthy elderly women were divided into three 12-week exercise groups: Tai-Chi (n=10), silver dance (n=10), and band exercise (n=10). The results were analyzed by two-way repeated ANOVA and paired t-test using SPSS 12.0 program. Results: Body weight and body mass index were significantly decreased in the Tai-Chi and silver dance groups. In addition, there was a significant increase in balance time and reduced diastolic blood pressure in Tai-Chi participant. Grip strength was significantly increased in Tai-Chi and silver dance participants, but there was no effect in the band exercise group. Agility was significantly increased in the band exercise group. Conclusion: Tai-Chi and silver dance may be beneficial to improve fitness of elderly people, although the details remain to be elucidated.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.2
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• pp.165-175
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• 2011

Purpose: This study examined the effect of the strengthening exercise and stretching exercise to decrease symptom patellofemoral pain syndrome (PFPS). Methods: The Anterior Knee Pain Scale (AKPS) and Clark's test performed for diagnosis of intrinsic PFPS among young adults. Selected thirty young adults subjects who aged 20~26 years participated in the study. Participants were randomly assigned to strengthening, stretching, or control groups. Strengthening group consisted of quadriceps, hamstring and iliotibia band training used elastic band. Stretching group consisted of quadriceps, hamstring and iliotibia band trainings used stretching exercises program. Participants received 50-minute individualized exercise sessions, 3 times a week for 6 weeks. Results: The results were as follow: there were significantly difference stretching exercise group by all muscles on muscular strength test (p<.05). there were significantly difference both strengthening and stretching exercise group by all muscles on flexibility test (p<.05). There were significantly difference stretching exercise group by all muscles on step-down test (p<.05). There were significantly difference both strengthening and stretching exercise group by all muscles on visual analog scale (p<.05). Conclusion: Results suggest important implications for exercise programs of PFPS that stretching exercise is more improved knee pain, functional performance, patella mobility than strengthening exercise.

• PNF and Movement
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• v.22 no.2
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• pp.233-242
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• 2024

Purpose: The aim of this study was to investigate the effects of different types of unstable loads on core and lower limb muscle activity during squatting. Methods: Nineteen subjects (all females) with resistance experience but no unstable resistance experience participated in the study. Subjects performed squats under three load conditions, and core and lower limb muscle activity was measured during eccentric and concentric contractions. Results: During the eccentric contraction, core and hip flexor activity was significantly higher with the aqua bag than with the barbell or resistance band, and for the quadriceps, the resistance band was significantly higher than the barbell. During the concentric contraction phase, core and hamstring muscle activity was significantly higher with the aqua bag than with the barbell and elastic band (p < 0.05). Conclusion: Squats with an aqua bag increase core and biceps brachii activation and can be recommended as a training method to improve trunk stability.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.295-300
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• 2001

Significant improvements in bond strength between new and existing concrete can be achieved through the modification of the new concrete by latex modification. But, no test method has been adopted as a standard to measure the bond strength between the concrete used to repair and the substrate being repaired. The performance of old and the new concrete construction defends upon band strength between old and the new concrete. Current adhesion strength measurement method is inaccurate method that ignore effect of stress concentration by shape of specimens. Therefore, this research calculates stress concentration coefficient using finite element analysis and direction tensile strength test (pull-off test). The result shows that the required core depth is 2.5 cm. Elastic modulus and overlay thickness do not influence in stress concentration.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.127.2-127.2
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• 2016

연구된 Si위의 흡착원자들의 확산 메커니즘들에 비해 Ge 표면에서의 확산 메커니즘은 잘 알려져 있지 않다. 최근 연구에 따르면, 수소가 덮인 Ge(110) 표면에서 그래핀 결정 핵생성은 비등방적이며, 낟알 둘레없이 웨이퍼 크기로 성장시킬 수 있음을 보였다. 본 연구에서는 VASP(Vienna Ab-initio Simulation Package)의 NEB(Nudged Elastic Band) 방법을 이용하여 수소가 덮인 Ge(110) 표면과 청결한 표면에서 탄소원자의 확산 과정과 확산에 따른 에너지 장벽을 계산 하였다. 계산 결과 수소가 덮인 표면에서의 탄소원자 확산은 체인 방향으로 각각 3.29 eV, 2.67 eV의 에너지 장벽을 가지고 청결한 표면에서는 탄소원자가 게르마늄 연결을 치환하며 확산한다. 이때 에너지 장벽은 0.82 eV이고 치환된 게르마늄이 확산할 때는 각각 0.64 eV, 0.59 eV의 에너지 장벽을 넘어야 한다. 결과적으로 수소가 덮인 표면에서보다 청결한 표면에서 탄소 확산 에너지 장벽이 낮으며, 청결한 표면에서는 탄소가 게르마늄을 치환하고 치환된 게르마늄이 확산할 확률이 높음을 알 수 있었다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.579-584
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• 2002

In press forming of sheet metals, the material sheet is usually subjected to very large plastic strain under in-plane stressing. Moreover, the sheet also very often is subjected to out-of-plane compressive force between tools such as the upper and lower dies, the blank holder and the die, and so forth. In this paper, it is clearly demonstrated theoretically that out-of-plane stress may notably raise the forming limit strain and thus it cm be effectively utilized to avoid earlier fracture of the sheet in press forming.

• Structural Engineering and Mechanics
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• v.36 no.1
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• pp.57-78
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• 2010

A novel flexibility-based 1D element that captures the material nonlinearity and second order P-$\Delta$ effects within a reinforced concrete frame member is developed. The formulation is developed for 2D planar frames in the modified fiber element framework but can readily be extended to 3D cases. The nonlinear behavior of concrete including cracking and crushing is taken into account through a modified hypo-elastic model. A parabolic and a constant shear stress distribution are used at section level to couple the normal and tangential tractions at material level. The lack of objectivity due to softening of concrete is addressed and objectivity of the response at the material level is attained by using a technique derived from the crack band approach. Finally the efficiency and accuracy of the formulation is compared with experimental results and is demonstrated by some numerical examples.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.04a
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• pp.177-186
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• 1999

Dynamic Characteristics of the bridge motions under seismic excitations are analyzed by adopting multi degree - of - freedom system to estimate the effect of restrainers. The applied restrainer is assumed to be a dead - band - system, which has the force clearance and the linear elastic force. The inelastic behaviors of pier and foundation motions are also considered in the study. It is found that the major effect of restrainer is to remarkably decrease the relative displacement between adjacent girders. It is found that restrainers placed on the parts of the bridge system rather than the whole system may increase the unseating failure.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.162-169
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• 2004

In press forming of sheet metals, the material sheet is usually subjected to very large plastic strain under in-plane stressing. Moreover, the sheet also very often is subjected to out-of-plane compressive force between tools such as the upper and lower dies, the blank holder and the die, and so forth. In this paper, it is clearly demonstrated theoretically that out-of-plane stress may notably raise the forming limit strain and thus it can be effectively utilized to avoid earlier fracture of the sheet in press forming.

• Transactions of Materials Processing
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• v.9 no.1
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• pp.59-65
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• 2000

Most studies of failure analysis in ductile metals have been based on the classical plasticity theory using the local constitutive relations. These frequently yields a physically unrealistic solution, in which a numerical prediction of the onset of a deformation localization shows an inherent mesh-size sensitivity. A one way to remedy the spurious mesh sensitivity resulted in the unreasonable results is to incorporate the non-local plasticity into the simulation model, which introduce an internal (material) length-scale parameter into the classical constitutive relations. In this paper, a non-local version of the modified Gurson constitutive relation has been introduced into the finite element formulation of the simulation for plane strain compression of the visco elastic-plastic void material. By introducing the non-local constitutive relations we could successfully removed the inherent mesh-size sensitivity for the prediction of the deformation localization. The effects of non-local constitutive relation are discussed in terms of the load-stroke curve and the strain distributions accross the shear band.