• The Journal of Korean Physical Therapy
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• v.21 no.1
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• pp.19-25
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• 2009

Purpose: We investigated the changes that effects of load stimulation (LS) on static balance and muscle activities in normal healthy elders and chronic stroke patients. Methods: Subjects were instructed twenty normal healthy elders (8 men and 12 women) and ten chronic stroke patients (4 men and 6 women). They were tested while standing on a force platform under two conditions; LS, no LS were applied in random order. Prior to testing, adhesive surface EMG electrodes were fastened to the skin overlying the right (non-paralytic side in stroke patient) bellies of tibialis anterior (TA) and lateral gastrocnemius (LG) muscles. They were assessed on postural sway and %MVC (Maximum voluntary contraction) of TA and LG. Results: Participants showed that the application of LS brought about a decrease in postural sway as expressed by average sway path and velocity. %MVC of TA and LG were increased. The application of LS to normal and stroke patients decreases postural sway during quite stance. Conclusion: These findings the application of LS to normal and stroke patients improves static balance.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.3
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• pp.1-9
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• 2017

Numerical computations are performed to investigate the effect of pintle stroke on the performance of an internal pintle thruster. Results show that the thrust control ratio was less than 2% and the aerodynamic load ratio was 22% as the pintle stroke increased. The flow past the nozzle throat rapidly expanding because of the shape of the pintle, and a shock wave was generated. Particularly, at the pintle stroke distance of 4 and 5 mm, the shock wave hit the wall of the nozzle, results in peeling bubbles. Depending on the altitude, the thrust increased and the aerodynamic load decreased, but the difference was as small as 1.5%. In the presence of the bore, the reduction of the pintle tip area resulted in a decrease in aerodynamic load.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1996.03b
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• pp.110-120
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• 1996

A crank-slider mechanism is driven by the rotating disk with are crank-pin guide to be applied to the deep drawing and cold forging presses. Load characteristics for different presses are summarized to see the basics of deep drawing of sheet metal and forging in terms of load-stroke relationship. Several types of conventional deep drawing presses are also shown to be compared with the ratating disk-types press. Kinematic performances by thearc guide driving mechanism are anlayzed in terms of load capaicty, stroke, and slide velocity characteristics, and they are compared with those by conventional driving , e.g. Niagara-typepress and so on. Kinematically better performances is shown by arc guide drive than those by conventional ones. The new driving mechanism is also proven to be one of the best for mass production press in terms of short cycle time. Possible applications of the arc guide press to deep drawing and cold forging work are in terms of kinematics and load capacity.

• PNF and Movement
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• v.16 no.2
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• pp.179-185
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• 2018

Purpose: This study aimed to analyze the visual and spatial elements of the gait of a stroke patient who had diverse ankle weight loads applied, according to weight changes. Methods: The subject was a 57-year-old stroke patient diagnosed and hospitalized with a left intracerebral hemorrhage. A weight equivalent to 0%, 1%, and 2% of his body weight was applied to the area 5cm upward from the ankle using a Velcro strap. He was then trained on a treadmill, receiving a six-minute walk test to evaluate his gait ability. A gait analyzer was used to collect visual and spatial elements, such as gait distance, gait velocity, cadence, step length, stride length, and swing phase, according to a weight load equivalent to 0%, 1%, and 2% of his body weight. Results: According to the results of applying 0%, 1%, and 2% of his body weight on the ankle, except for gait velocity, his gait distance, cadence, step length, stride length, and swing phase were higher when 1% of his body weight was applied compared to 0% or 2% of his body weight. Conclusion: Applying a weight equivalent to 1% of the body weight to the ankle positively affected the visual and spatial element of the gait and heightened the efficiency of exercise during treadmill training, a gait-training tool generally used for stroke patients. However, the result is difficult to generalize because the number of subjects was small with only one subject.

• The Journal of the Korea Contents Association
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• v.12 no.2
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• pp.331-338
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• 2012

The purpose of this study is to investigate the cardiopulmonary function and the energy metabolism of stroke patients and normal persons of graded load exercise using lower ergometer. Targeting 11 normal persons(male: 6, female: 5) and 9 stroke patients (male: 4, female: 5), an graded load exercise was performed with the use of lower ergometer by increasing 25 watts every 6 minute and Quark $b_2$ were used for the cardiopulmonary function and the energy metabolism. With respect to normal persons, there were significant increases in the phase of graded load exercise, maximum oxygen uptake time, exercise time with respect to the cardiopulmonary function. In addition, there was a significant correlation between cardiopulmonary function and energy metabolism, but there was no significant difference energy metabolism. As a result, there were no significant differences between stroke patients and normal persons of the cardiopulmonary function and the energy metabolism within 18 minutes, but it had significant differences between maximum oxygen uptake and exercise time. Moreover, it was possible to identify that the cardiopulmonary function and the energy metabolism of stroke patients and normal persons are related with maximum oxygen uptake.

• Design & Manufacturing
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• v.16 no.3
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• pp.28-33
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• 2022

The recent increasing application rate of advanced high-strength steel(AHSS) for automotive parts makes it difficult to ensure the durability of forming tools. Significant load and friction generated during the piercing process of AHSS increase the wear rate and the damage degree to dies. These harsh process conditions also yield product failures, such as dimensional inconsistency of pierced holes and insufficient quality of hole's sheared edge. This study analyzed the effect of punch wear on the sheared surface of pierced parts and the forming load during the piercing process. Wear-shaped punches showed approximately 20% higher piercing load than normal-shaped punches, and the rollover ratio of the sheared surface also increased. It is considered that the dull edge of wear-shaped punches does not penetrate directly into the material but shears after tensioning it in a piercing direction. In addition, wear-shaped punches experienced compressive load even after completing the piercing process during the down-stroke and tensile load during the up-stroke. This load variation is related to the smaller diameter piercing holes produced by wear-shaped punches compared to normal-shaped punches. Thus, we demonstrated the predictability of the wear level of dies through a comparative analysis of the piercing load pattern.

• Journal of Advanced Marine Engineering and Technology
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• v.17 no.2
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• pp.29-35
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• 1993

Recent marine propulsion diesel engines tend to become slower in speed and longer in stroke for the higher engine efficiency, and in these long stroke and slow speed engines the digital governors are highly recommended to be used. But, in the present digital governors only the feedback of the engine rpm-signal is used for the engine speed control. If the load torque of the engine can be measured or estimated and the torque feedback loop is added to the present digital governor, it is expected that the speed control performance of the digital governor will be highly improved. In this paper, a new method is proposed to estimate the load torque of the diesel engine from the measured signals of fuel oil and rpm. And it is also suggested that the Kalman filter can be used for the estimation of engine torque.

• Journal of Advanced Marine Engineering and Technology
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• v.12 no.4
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• pp.53-61
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• 1988

Speed of a diesel engine is usually controlled by the hydraulic governor which uses the centrifugal force of rotating fly balls for sensing the error speed. But for a recently developed high efficient, low speed and long stroke 2 cycle marine diesel engine, this governor doesn't work well enough because of too much changes of toraring force during one revolution of engine and too long uncontrollable time due to small numbers of cylinder. For improvement of jiggling phenomena and unstability various studies are being carried out, but they are not enough for a steep load change in a small ship's generator plant or at rough sea condition in a propulsion engine. In this paper, authors propose a new method to control a fuel before the change of angular velocity due to load change by feedforward the change of load, and find that the proposed method shows quite a good control performance in comparision to the customary PID control method by simulation using a digital computer for the various load change.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.6
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• pp.35-41
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• 2007

The rate of loading in motor operated valve(MOV) can be defined as a variation of correlation between the actuator torque and the thrust upon the variation of operating load. This paper contains the analysis of characteristic and the validity of loading rate in the opening stroke of gate type motor operated valve. Also, this paper describes the evaluation result of loading rate for 40 MOVs' opening stroke using newly derived methodology in this study. Author has found a result that loading rate of opening stroke gets a negative value when the differential pressure is higher than 150 psi and this value goes up depending on the amount of the differential pressure.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.514-522
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• 2014

A new type of high precision electromagnetic suspension (EMS) which can support heavy tray along long stroke rail is proposed in this paper. Compared with the conventional EMS, the suggested moving-core typed EMS has the levitation electromagnets (EMs) on the fixed rail. This scheme has high load capability caused by iron-core and enables simple tray structure. Also it does not have precision degradation caused by heat generation from EMs, which is a drawback of conventional EMS. With these merits, the proposed EMS can be an optimal contactless linear bearing in next generation flat panel display (FPD) manufacturing process if the ability of long stroke movement is proved. So a special Section Switching Algorithm (SSA) is derived from the resultant force and moment equations of the levitated tray which enables long stroke movement of the tray. In order to verify the feasibility of the suggested SSA, a simple test-setup of the EMS with 2 Section-changes is made up and servo-controlled in the simulation and experiment. The simulation shows the perfect changeover the EMs, and the experiment shows overall control performance of under ${\pm}40{\mu}m$ gap deviations. These results reveal that the newly suggested contactless linear bearing can simultaneously achieve high load capability and precision gap control as well as long stroke.