• Korean Journal of Applied Biomechanics
• /
• v.18 no.1
• /
• pp.21-30
• /
• 2008

The purpose of this study was to investigate the variability to compare local dynamic stability via a linear and nonlinear analysis during walking. Twenty four elderly males, 12 healthy elderly and 12 patients with osteoarthritise walked on a treadmill for 100 consecutive strides. Lyapunov exponent and correlation dimension and coefficient variation were calculated for the kinematic parameters to determine the dynamic stability during walking. The linear measures indicated that the healthy elderly demonstrated significantly higher variability in the ankle joint displacement. The nonlinear analysis revealed that COD for the knee joint angle were higher in patient with osteoarthritise. There were no coincidence in results between linear and nonlinear techniques over two groups. In light of nonlinear analysis, it was concluded that patients with osteoathritise showed higher local instability during walking.

• Journal of the Korea Convergence Society
• /
• v.11 no.8
• /
• pp.159-163
• /
• 2020

In this study, the flow analyses around according to the existence or non- existence of the trailer's deflector and the shapes were carried out. In the absence of a deflector, the kinetic energy of the turbulence behind the container also generates higher kinetic energy in a wider area than in the presence of a deflector, which adversely affects the vehicle's driving performance. As a trailer's wind deflector-free model has unstable flow rates around the trailer and high kinetic energy of turbulence than a model with a deflector, it can be thought that the increase of fuel economy can be expected by installing a deflector in the trailer. By applying the study result on flow analysis near trailer due to shape of wind deflector, this study is seen to be suitable for the aesthetic convergence.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.10a
• /
• pp.598-601
• /
• 2017

The purpose of this study is to evaluate the effects of Ankle Exercise Program on Muscle Strength and Balance in Middle Aged Woman. Subjects of this study, among the patients who were diagnosed with obesity in the study, for patients total of 8 people have agreed to research. Experimental group 4 people, control group 4 people, was a total of 8 people. Group-specific arbitration method, was applied to Unstable supporting surface exercise program(experimental group) and stable supporting surface exercise program(control group). Each training courses 30 minutes for 6 weeks, examined the changes in Functional Reach Test(FRT) and One Leg Standing(OLST), Dorsi Flexion(DF) and Plantar Flexion(PF) ability to examine a total of 6-week course effectively. The intervention were compared by measuring before and after. There were significant improvements in the subscales of the muscle strength and balance test of those who practiced with the unstable supporting surface exercsie program, while the control group showed no significant changes. Therefore, unstable supporting surface exercsie program is effective in improvement of to improve the muscle strength and balance in woman with obesity.

• Journal of Marine Life Science
• /
• v.1 no.1
• /
• pp.25-30
• /
• 2016

We investigated the possibility of a bio-monitoring system for detecting hypoxic water in coastal area using shell valve movements of Pacific oyster (Crassostrea gigas), which showed most aquaculture production in Korea, with Hall element sensor. In filtrating water to confirm shell valve movement (SVM) under normal condition, it showed spikes which mean a relatively fast closing condition after opened condition of average 5~12 mm, and then the SVM showed back to opening condition slower than closing speed SVM numbers during light period were similar to that of dark period (p<0.05). When dissolved oxygen (DO) concentration was reduced from 7 mg l^-1 to 3 mg l^-1, SVM numbers were increasing with decreasing of DO, and showed abnormality SVMs as compare with normal condition. Moreover, in the condition of 2 mg l^-1, Distance between light and left shell showed gradually decreased, and then we could not detected SVMs due to closed condition. Thus, if we quickly detect abnormal environmental variations as hypoxia water using bio-monitoring of SVM, it may be contribute to increased productivity by dramatically reducing damages in aquaculture.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.12
• /
• pp.1251-1256
• /
• 2015

This study investigates the friction noise characteristic in relation to the corrosion of metal by using the frictional reciprocating and pin-on-disk system. From the experiments, it is found that the corrosion of metal advances the onset time and increases the magnitude of friction noise. Further, it is observed that the effect of corrosion on friction noise stems from the alteration of tribo-surface during repetitive frictional motion. The alteration of the corrosive contact surface induces a negative friction-velocity slope, by which the corrosion of metal can generate dynamic instability faster than non-corrosion of metal.

• The Journal of Korean Academy of Prosthodontics
• /
• v.55 no.4
• /
• pp.451-457
• /
• 2017

Bell's palsy is an acute-onset unilateral peripheral facial neuropathy. For patients with sequelae of facial paresis, the successful rehabilitation of fully edentulous arches is challenging. This case report described the treatment procedures and clinical considerations to fabricate complete dentures of a patient who showed unilateral displacement of mandible, unilateral chewing pattern and parafunctional jaw movement due to sequelae of Bell's palsy. Gothic arch tracing was used to record reproducible centric relation and lingualized occlusion was performed to provide freedom to move between centric relation and the patient's habitual functional area in fabricating satisfactory dentures in terms of function and esthetics.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.22 no.1
• /
• pp.69-74
• /
• 2012

In this research equations of motion of a Wheeled Inverted Pendulum (WIP) which is running on the inclined road and changing its center of gravity. Difference between a conventional cart inverted pendulum and the WIP is also considered. The WIP has small planar size so that it has been used as a mobile platform for several applications which require slender frame in order to travel on the narrow road. The WIP has almost the same unstable properties as conventional inverted pendulums have. There needs an aggressive control scheme for the WIP not to fall down. In order to design a high performance control scheme, equations of motion of the WIP, which is running under various environment and operating conditions, should be derived and considering its properties is necessary.

• Journal of Ocean Engineering and Technology
• /
• v.7 no.1
• /
• pp.13-24
• /
• 1993

The dispersion in the oscillatory flow generated by gravitational waves above the spatially periodic repples is studied. The steady parts of equations describing the orbit of the passive particle in a two dimensional field are assumed to be simply trigonometric functions. From the view point of nonlinear dynamics, the motion of the particle is chaotic under externally time-periodic perturbations which come from the wave motion. Two cases considered here are; (i) shallow water, and (ii) deep water approximation.

• Journal of the korean Society of Automotive Engineers
• /
• v.5 no.4
• /
• pp.10-16
• /
• 1983

액체의 미립화는 기계산업분야 뿐만 아니라, 농약살포, 화학 공학의 분무건조, 반응의 촉진, 분 체제조, 식품공업 등 폭넓게 이용되며 또한 각분야에서 그 필요성이 강조되고 있다. 특히 기계 산업분야에서는 액체연료의 분무연소(boiler, gas turbine, 자동차용engine등) 원자로 노심의 spray cooling, spray drying, spray painting 등 그 이용도는 날로 증가되는 추세에 있다. 액체를 미 립화하는 이유는 각각의 분야나 사용하는 목적에 따라 다르지만, 대별하면 다음과 같다. (1) 액체의 단위 체적당 표면적을 증대시키기 위하여 (2) 직경이 작은 입자의 필요성 (3) 균일한 입경의 액적군을 얻기 위하여 등을 들 수 있다. 액체의 미립화에 대한 요구는 산업의 발당, 대기오염, 생energy 등의 문제가 중요시됨에 따라 다양화되고 있다. 따라서 응용면에서는 atomizer의 성능개선과 설계법, 새로운 미립화방법, 상업에의 분무이용기술, 분무계측법 등의 개발이 필요하게 된다. 액체미립화에서 취급하는 사항은 그 내용에 따라 다음과 같이 분류된다. (1) 액체의 미립화기구 : 기액계면의 불안정성과 분열기구에 관한 것으로, 액체형상으로써 액주, 액막 및 액적으로 나눌 수 있다. (2) 액체의 미립화 방법과 특성 : energy의 종유와 부가방식에 따랄 나누어진다. (3) 합체, 분산, 증발 등 분무의 운동이나 열적거동 (4) 분무입경이나 운동의 계측법과 특성도시 (5) 액체미립화의 각종응용 본보에서는 상기의 각 항목중, 특히 액체의 미립화방법과 분무특성에 대해서만 말하기로 한다.

• Journal of the Korean Society of Physical Medicine
• /
• v.7 no.3
• /
• pp.251-258
• /
• 2012

Purpose : The purpose of this study is to provide an efficient and basis for muscle activity of Quadriceps muscles and balance in anterior cruciate ligament reconstruction patients through unstable surface exercise and stable surface exercise. Methods : This study included 30 anterior cruciate ligament reconstruction patients belonging to A hospital and D orthopedic surgery clinic of province who attended the program for 30 minutes at a time and three times a week for 4 weeks. Of these 15 attended the unstable surface exercise program and 15 the stable surface exercise program. To increase muscle activity (%MVIC) and balance (WPL), the unstable surface exercise. Results : The %MVIC of lower extrmity muscle(RF, VL, VM) increased from before training to after training in the case of the participants who performed the unstable surface exercise, and the whole path length (WPL) decreased from before the training to after the training(p<.05). Conclusion : In conclusion, unstable surface exercise program helps to improve the balancing ability and musle activity in a anterior cruciate ligament recunstruction patients who requires both muscle activity and balance than stable surface exercise program.