• Journal of Magnetics
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• v.19 no.2
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• pp.181-184
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• 2014

The aim of the present study was to examine whether motor imagery (MI) practice in conjunction with repetitive transcranial magnetic stimulation (rTMS) applied to stroke patients could improve theirgait ability. This study was conducted with 29 subjects diagnosed with hemiparesis due to stroke.The experimental group consisted of 15 members who were performed MI practice in conjunction with repetitive transcranial magnetic stimulation, while the control group consisted of 14 members who were performed MI practice and sham therapy. Both groups received traditional physical therapy for 30 minutes a day, 5 days a week, for 6 weeks; additionally, they received mental practice for 15 minutes. The experimental group was instructed to perform rTMS and the control group was instructed to apply sham stimulation for 15 minutes. Gait analysis was performed using a three-dimensional motion capture system, which is a real-time tracking device that delivers data via infrared reflective markers using six cameras. Results showed that the velocity, step length, and cadence of both groups were significantly improved after the practice (p<0.05). Significant differences were found between the groups in velocity and cadence (p<0.05) as well as with respect to the change rate (p<0.05) after practice. The results showed that MI practice in conjunction with rTMS is more effective in improving gait ability than MI practice alone.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.257-266
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• 1999

This paper presents a method of seismic analysis for a cylindrical liquid storage structure on/in horizontally layered half.space considering the effects of the interior fluid and exterior soil medium in the frequency domain. To capture the essence of fluid-structure-soil interaction effects effectively, a mixed finite element with two-field (u, p) approximation is employed to model the compressive inviscid fluid, while the structure and soil medium are presented by the 3-D axisymmetric finite elements and dynamic infinite elements. The present FE-based method can be applied to the system with complex geometry of fluid region as well as with inhomogeneous near-field soil medium, since it can directly model both the fluid and the soil. For the purpose of verification, dominant peak frequencies in transfer functions for horizontal motions of cylindrical fluid storage tanks with rigid massless foundation on a homogeneous viscoelastic half.space are compared with those by two different added mass approaches for the fluid motion. The comparison indicates that the Present FE-based methodology gives accurate solution for the fluid-structure-soil interaction problem. Finally, as a demonstration of versatility of the present study, a seismic analysis for a real-scale LNG storage tank embedded in layered half.space is carried out, and its member forces along the height of the structure are compared with those by an added mass approach developed by the present writers.

• Journal of Biomedical Engineering Research
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• v.35 no.2
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• pp.26-34
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• 2014

Little information is available about the characteristics in revolution gait of hemiplegic elderly, which is frequently represented in daily life. It is also hard to elucidate purely the characteristics due to hemiplegia because of no consideration of aging factors. The aim of study is to identify the alteration characteristics of lower extremity joint angles in both straight and revolution gaits together due to hemiplegia through comparing healthy with hemiplegic elderly. Following Institutional Review Board approval, twelve healthy and hemiplegic elderly were participated and the center of body mass (COM) and lower extremity joint angles were measured during straight and revolution gaits using a computer-aided video motion capture system. The results showed that the gait characteristics were generally altered in both straight and revolution gaits due to hemiplegia (p < 0.05). The gait characteristics were then different between the straight and revolution gaits each other. This study may be valuable by identifying for the first time the alterations of the lower extremity joint angles in both straight and revolution gaits due to pure hemiplegia through comparing healthy elderly with hemiplegic elderly.

• Physical Therapy Korea
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• v.25 no.3
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• pp.27-38
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• 2018

Background: At present time, smartphones have become very popular and powerful devices, and smartphone applications with the good validity have been designed to assess human balance ability. Objects: The purpose of this study is to evaluate the feasibility of smartphone acceleration in the assessment of postural control ability for six different conditions. Methods: Twenty healthy college-aged individuals volunteered. Static balance ability was measured twice with one-day interval using smartphone application and 3D motion capture system under the six different conditions. Results: Dominant frequencies for each test condition did not show significant differences except for two conditions. The intra-rater correlation coefficient between the first and second tests showed high correlations in six conditions(r>.70, p<.05). Smartphone acceleration and the acceleration calculated from the 3D marker position data showed high correlation coefficient(r>.80, p<.001). Conclusion: Acceleration recorded from a smartphone could be useful assessment variables for balance test in the clinical field.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.3
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• pp.229-236
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• 2016

Magnetic sensors and actuators have been widely used in industry and medical fields. Integrated systems based on sensors and actuators are defined as mechatronics that is the general combination of mechanics and electronics. Recently, magnetic wireless sensors and actuators have been developed and used at a systematic level. In particular, their mechanisms depend on magnetic, such as magnetic material and physical phenomena. However, their research boundary has not been clear. Researchers talk of magnetic micro-robots, magnetic actuators and sensors. Therefore, a new and correct definition is required. In this study, we introduce the advanced and extended concept of mechatronics, which is a magneto-mechantronics for biomedical and rehabilitation. Among various applications, we focused on wireless pump and sensing system for blood vessel rehabilitation and local motion capture, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.309-312
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• 2005

Virtual reality(VR) is both one of the high-technology and main paradime in leading next genaration of 21th century. It's application spectrum is various and lead to numorous revolotion as well as transition in technical aspect. These change is a good procept of it's value and influence effect in global fields of human life. In this paper, a development method of virtual reality simulation system is presented, which is based in the shape research about VR.

• Journal of Biomedical Engineering Research
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• v.32 no.2
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• pp.105-108
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• 2011

The purpose of the present study was to analyze the lower stiffness over the difference between soft and stiff landings during hopping. Five male subjects performed hopping on two legs at 2.5 Hz. During the experiments, 3D motion capture system was used to obtain the kinematic data and two force plates were synchronized to calculate the kinetic data. We determined lower extremity stiffness of the knee and ankle from kinetic and kinematic data. Leg stiffness was approximately 1.2-times significantly higher in stiff landing than in soft landing_ There was no significant difference in knee joint stiffness between soft and stiff landings. Ankle joint stiffness was approximately 1.34-times significantly higher in stiff landing than in soft landing. These results suggest that humans adjust lower extremity stiffness over the comparison of two different landing methods we evaluated.

• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.209-215
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• 2007

The purpose of this study was to investigate gait factor and muscle activity depending on hiking poles-using. Eight healthy men volunteered for this experiment. Each of them performed down-hill walking with hiking poles-using and without poles at speed of 3.5km/h for 45 minutes on a treadmill. The treadmill was set 25% down-hill inclination. Kinematic data collected in 60Hz were recorded and analyzed by using 2D motion capture system to measure step time and step length so on. And the lower extremity muscle activities were simultaneously recorded in 1500Hz and assessed by using EMG. The statistical analysis was the paired t-test with repeated measures to compare between hiking poles-using and without poles. The level of statistical significance for all tests was .05. The results of this study were following : Step time was showed statistically different according to pole conditions. That is, the case of poles-using was longer than without poles in step time. Also, step length was showed statistically different between two conditions. Step length about trials with poles was longer than trials without poles. In the muscle activity, the case of all muscles was not showed statistical significance about pole conditions. However, in most muscles IEMG, there were some decreasing-trend relatively when hiking polesusing.

• Korean Journal of Applied Biomechanics
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• v.23 no.3
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• pp.245-252
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• 2013

The purpose of this study was to analyze the effect that various loads have on the lower limb biomechanics. The following variables were measured and analyzed; performance time for each phase, lower limb moments and joint angles, and ground reaction forces. The kinematic and kinetic data was recorded by 2 force platforms and a motion capture system while 12 healthy adults in their twenties stepped down three steps under loads of 0%, 10%, 20% BW. Results are as follows. First, the different loading conditions did not seem to significantly affect the performance times and the joint angles. Second, the largest ground reaction forces were observed at the 1 step at the 10% BW condition. Finally, at the 0% BW loading condition the right hip extension moment was the smallest and the left hip flexion moment was the largest. The results show that there are not any significant changes in the biomechanics of the lower limbs under loading conditions up to 20% BW. Further investigations including more loading conditions with more weights and more additional steps analyzed are needed.

• Proceedings of the KAIS Fall Conference
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• 2011.12a
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• pp.241-243
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• 2011

인체동작 인식에 대한 연구는 재활치료, 운동선수의 동작 교정 및 모니터링, 3차원 애니메이션 제작등 많은 분야에서 필요로 하고 있다. 동작 인식에 대한 일반적인 방법으로는 반사 마커를 부착하여 여러 대의 적외선 카메라로 관절 운동을 관찰하는 방식이였다. 이러한 방식은 여러 개의 마커를 사용자들이 옷을 벗고 몸에 붙이거나 특수 복장을 착용해야 하는 불편함이 있을 뿐만 아니라 초기 위치 보정에도 많은 시간이 소모된다. 이와 같은 문제점을 해결하기 위하여 본 연구에서는 어떠한 특수 장비를 착용하거나 몸에 부착하지 않고 즉각적으로 인체의 움직임을 트래킹 할 수 있는 마커리스 트래킹시스템을 개발하였다. 이 시스템은 사람의 동작 분석을 하는데 있어 빠르게 측정 및 분석이 가능하고 특수 장비를 착용하지 않아도 됨으로 인해 동작에 방해를 받지 않아서 3차원 영상을 즉각적으로 확인할 수 있는 편리성을 갖추고 있다.