• Journal of Korea Entertainment Industry Association
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• v.14 no.8
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• pp.437-445
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• 2020

The purpose of this study was to examine the effects of whole-body vibration exercise for life care on balance and walking ability in the fall risk stroke patients. 30 stroke patients were divided into two groups, Otago exercise group(n=15) and whole-body vibration exercise group(n=15). Walking ability were measured by 10m walking and Tinetti mobility test with stroke patients and balance ability were measured by BBS and TUG on comparative analysis of pre, post exercise. To compare differences before and after the program, a paired t-test was used and to compare differences between both groups, an independent samples t-test was used. As a result of the test, it was discovered that BBS and Tinetti mobility test of the both groups were increased statistically significantly and TUG and 10m walking test of the both groups were decreased statistically significantly. balance ability and walking ability of the whole-body vibration exercise group were improved statistically significantly in comparison with those of the Otago exercise group. The results of this study showed that whole-body vibration exercise for the improvement of life care had significant effects on improving BBS, TUG, 10m walking and Tinetti mobility test of fall risk stroke patients. Therefore, it is recommended to apply whole-body vibration exercise to improve life-care through improving balance ability and walking ability of fall risk stroke patients.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.10a
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• pp.101-104
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• 2006

전기도금 방법으로 유리기판 위에 제작한 코일과 영구자석을 이용하여 초소형발전기를 제작하였다. 여러 크기의 코일 구조를 설계하여 마스크를 제작하였으며, $4.5\;{\mu}m$, $7\;{\mu}m$ 두께의 코일을 제작하였다. 광학현미경과 SEM(투사전자현미경)을 사용하여 제작된 코일의 구조를 분석하였다. 발생한 전기에너지를 진동주파수의 함수로 측정하였다. 또한 모터의 회전운동을 진동운동과 유사한 선형운동으로 변환하는 시스템을 제작하였고, 초소형 발전기 특성측정에 사용하였다. 1 Hz에서 8 Hz까지 진동주파수를 변화시켜 특성을 측정하였고, 진동에 의해 발생된 전압 값과 채배정류된 전압 값을 비교하였다. 본 연구의 목적은 쓸모없이 버려지는 진동에너지를 유용한 전기에너지로 변환하는 초소형발전기 소자를 제작하는 것이다.

• Journal of Aerospace System Engineering
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• v.17 no.6
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• pp.54-62
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• 2023

Flapping-wing air vehicles, well known for their free vertical take-off and excellent flight capability, are currently under intensive development and research. While most of the studies have explored the effect of various parameters of synchronized motions on the unsteady aerodynamics of flapping wings, limited attention has been given to the effect of nonsynchronous motions on the unsteady aerodynamic characteristics of flapping wings. In the present study, we conducted a numerical analysis to investigate the unsteady aerodynamic characteristics of an airfoil flapping with different frequency ratios between pitch and heave oscillations. We identified the motions and angle of attacks due to nonsynchronous motions. It was found that the synchronous motion produced thrust with zero lift, but the nonsynchronous motion generated a large lift with little drag. The aerodynamic characteristics of the airfoil undergoing the non-synchronous motion were also analyzed using the vorticity distributions and the pressure coefficient around and on the airfoil. When r was equal to 0.5, larger leading and trailing edge vortices were observed compared to the case when r was equal to 1.0, and these vortices significantly affected the aerodynamic characteristics of the airfoil undergoing the nonsynchronous motion. In future, the effect of pitch amplitude on the unsteady aerodynamic characteristics of the airfoil will be studied.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.04a
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• pp.45-50
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• 1994

최근의 로봇 매니퓰레이터는 고정밀, 고생산성, 유연성 자동화를 추구한다. 이에 따라 매니퓰레이터는 운동 정확성, 고속성, 안정성이 더욱 향상되어야 한다. 특히 매니퓰레이터 관절부의 탄성은 동적 변형 및 진동을 유발함으로써 운동 정확성과 안정성을 현저히 저하시킨다. 이러한 복잡하고 불확실한 구조를 갖는 로봇 시스템의 고속, 정확한 운동 제어를 위해서는 보다 효과적인 고급 제어 기법 및 제어 장치의 개발이 요구된다. 본 연구에서는 이러한 문제에 대한 하나의 대응 방법으로 인간의 지식 처리 방법을 모방한 퍼지제어를 적용하여 그 가능성을 본다.

• Computational Structural Engineering
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• v.3 no.1
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• pp.5-8
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• 1990

진동측정은 일반적으로 물체의 상대운동을 변위, 속도, 가속도 등으로 측정한다. 측정방법을 크게 분류하면, 픽업을 진동체 위에 설치하여 진동을 측정하는 방법과 진동체의 외부에 설치한 부동점과 진동체와 상대적 운동을 측정하는 방법으로 분류된다. 이동하는 차량 등의 진동은 외부에 부동점을 설치하는 것이 어렵기 때문에 픽업이 진동체에 붙여지게 된다. 또 구조물에서 비교적 단주기 진동의 경우는 픽업이 직접 진동체에 붙여지나, 주행하중에 의한 교량의 처짐을 측정할 경우 처짐의 변화가 완만하기 때문에 외부에 부동점을 설치하여 측정한다. 그러나 통상 진동측정이라고 하면 전자의 픽업을 사용하는 방법이 대부분이다. 발파 및 항타 등의 건설공사에 의해 야기되는 건설진동의 경우도 픽업을 사용하는 일반적인 진동측정 원리가 보통 이용되고 있다. 본 고에서도 건설진동 측정 및 분석에 픽업을 사용하는 방법을 소개하고자 한다.

• Journal of the Korea Convergence Society
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• v.12 no.3
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• pp.35-41
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• 2021

The purpose of this study was to investigate the effect of prop exercise convergence using vibration on batting speed and batting accuracy in elementary school baseball players. Three times a week for six weeks. The vibration exercise experimental group and the control group were divided into each twenty members. The experimental group performed vibration convergence prop exercise, and the control group performed general exercise. Batting speed and Batting accuracy were measured. The experimental and control groups showed significant differences in the groups of batting speed before and after intervention. There was significant difference between the batting accuracy in the comparison between the experimental group and the control group. Prop convergence vibration exercise may help to improve the batting speed and batting accuracy of elementary school baseball players. In the future, adult and sport injury patient are needed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.10a
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• pp.61-75
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• 1993

이 논문의 제목에 제시한 질문에 답하기 위하여 비선형문제의 전형인 탄성 진자계를 집중적으로 조사하였다. 조화가 전력을 가진 탄성진자계는 비자율 계(원래계)로 나타나는데 다중시간법을 사용하여 이 계를 자율계(근사화계) 로 변환하여 조사하였다. 이 두 계의 해의 Lyapunov지수를 비교한 결과, 근 사화계의 해가 혼돈운동인 매개변수(가진진폭)의 값 근방에서 원래계의 해도 혼돈운동이 된다는 사실을 확인하였다. 이 결과가 애초의 질문에 일반적인 해답이 될 수는 없겠지만 약 비선형 다자유도 진동계의 혼돈운동 해석에 매우 중요한 참고자료가 될 것으로 판단된다.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.5
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• pp.757-762
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• 2013

The purpose of this study is to compare and evaluate the change of Body Mass Index(BMI) and body composition after having performed vibration exercise equipment at different ground conditions. The subjects were divided into 4 groups; Standing Group(SG)(n=10) and Horseback riding Group(BG)(n=10), Four point kneeling Group(FG)(n=10), Complex position Group(CG)(n=11). The period of intervention was for four weeks. Such as BMI and Waist Hip Ratio(WHR), Body Fat Ratio(BFR) were measured before and after exercise. The results from the above three measurements, only the CG showed significant differences. We were able to confirm that obesity change through complex position combines vibration exercise.

• Journal of KSNVE
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• v.7 no.3
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• pp.489-498
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• 1997

In this paper, chaotic motions of a curved pipe conveying oscillatory flow are theoretically investigated. The nonliear partial differential equation of motion is derived by Newton's method. The transformed nonlinear ordinary differential equation is a type of Hill's equation, which has the external and parametric excitation with a same frequency. Bifurcation curves of chaotic motion of the piping systems are obtained by applying Melnikov's method. Numerical simulations are performed to demonstrate theoretical results and show the strange attractor of the chaotic motion.

• The Journal of the Acoustical Society of Korea
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• v.26 no.1
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• pp.1-7
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• 2007

This paper presents a study on acoustic characteristics and sound generation mechanism of Cryptotympana atratas' songs which cause noise problems in summer days. The waveforms & FFT of Cryptotympana atratas' songs in nature were analyzed, and the actions of tymbals were visualized by the high speed camera. In order to know resonance frequency of the abdominal cavity of male Cryptotympana atrata, the sine sweep test was done. It was observed from the experimental results that Cryptotympana atrata's two tymbals act asymmetrically with respect to time & shape, and make a variety of frequencies every time it vibrates. It was also shown that Cryptotympana atratas' have a structure that cause resonances sounds only in a $7{\sim}7.5 kHz$ bandwidth.