• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.77.4-77
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• 2002

Communicating devices for the seriously disabled using eye-ball movement or some body movement are proposed. The first one is a device to use image processing, whose input signal is eyeball movement, A feature of this device is that the device can be readily realized using a note-book computer with USB (Universal Serial Bus) interface bus. This device is incorporated with a word processing software called Nearly Ladder. The second one is an emergency call switch which is used by a patient who can move his finger slightly. The patients can switch on the emergency switch only by touching a switch with his finger. The essence of this sensor is a touch sensor. The sensor can be realized using onl...

• Korean Journal of Applied Biomechanics
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• v.20 no.1
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• pp.49-55
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• 2010

The purpose of the study was to analyze kinetic factors required to the three-point jump shot of the basketball games through 3-D analysis and ground reaction force(GRF) analysis. Six university male players participated in this study. The results of the study were showed that (1) resultant velocity in the center of mass(COM) was $0.84{\pm}0.27\;m/s$ since a player didn't shot a ball in the highest peak and shot ball at the moment of going up forward and vertical movement. Therefore, it is necessary to find a proper timing to shot a ball; (2) the angular velocity was largely increased in upper arm and fore arm out of the upper-limb segments and the hands had the largest angular velocity since the body is in a fixed situation and angular speed is rapidly increased by the wrist' snap with the rapid movement of upper arm and forearm at the time of release a ball; (3) it is judged that a player can shot a ball at the accurate and high release point when the player collects power vertically to the maximum by keeping GRF to the right and the rear in a proper way and by keeping the body's balance so that a large power may not be dispersed.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.1940-1942
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• 2001

Magnetic Levitation System(MLS) levitates a steel ball to the desired position in the gravity field using electromagnetic force. MLS consists of light sensor to measure the position of steel ball and an electromagnet to control the position of the ball, that composes a feedback control system. This work does not use a steel ball with constant mass but variable mass steel balls as magnetic levitation targets. Differential equation of electric circuit for electromagnet and motion equation of the movement of steel ball are derived for modeling nonlinear system, that will be linearized at the nominal operating point. We propose a digital control that can levitate a steel ball of which weight is not known for ED-4810 system. Algorithm for estimating ball weight and feedback control are implemented in digital scheme under pentium PC equiped with A/D and D/A converter, ACL-8112, using C-language. Simulation and experimental results are given to show the usefulness of the proposed controller.

• Physical Therapy Korea
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• v.22 no.4
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• pp.79-86
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• 2015

This study examined the effects of trunk stabilization exercise on balance and trunk control in children with spastic diplegia. Four children with ambulatory spastic diplegia participated in the trunk stabilization exercise program using a Both Sides Utilized (BOSU) ball, 30 minutes a day, two times a week for eight weeks. Outcome variables included the pediatric balance scale, trunk control movement scale and multifidus thickness using ultrasound image. After trunk stabilization exercise, there was statistically no significant improvement in pediatric balance scale, trunk control movement scale and multifidus thickness. However, individual outcomes were observed with some positive changes. Balance, trunk control movement, and thickness of multifidus were found to be improved. Trunk stabilization exercise using a BOSU ball could improve trunk control and increase the thickness of multifidus in children with spastic diplegia. Further investigation is needed to evaluate subjects according to type of cerebral palsy and to understand the relationship between postural control and gait.

• Geomechanics and Engineering
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• v.32 no.5
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• pp.463-474
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• 2023

Materials produced with the help of new technology are used in the design of materials used in all science and engineering departments today. A sports engineering and sports equipment department is one of these departments. The use of nanotechnology in sports equipment is one of the most popular uses of this technology today. Nanomaterials have been used in sports equipment for many years, and reputable companies have benefited. Athletes' equipment allows them to display their skills to the fullest extent. It has always been a dream of professional athletes and their coaches to have unique equipment. As a result, engineers have spent all their time and effort solving this problem. Science and engineering can do various things to meet the needs of all sports levels, including specific and detailed designs, the use of appropriate materials, and standardization tests on equipment. However, these aspects must remain aligned with the latest technologies as they develop, just as with other sciences. These technologies, especially nanotechnology, are essential to sports equipment and devices developed today by sports engineers. This article examines the balls that use nanotechnology and can also improve the athlete's performance by using this technology in a specific structure. Using nanotechnology to make nanocomposite poly-hope balls, which makes them lighter and more acceptable, reduces the impact on the ball and increases its movement speed.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.2
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• pp.54-65
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• 1993

The paper describes and alternative method based on a new idea to measure the circular movement of machining centers. ISO has employed three testing methods for the acceptance tests of machine tools; the first is a rotating one-dimensional probe method, the second is a two-dimensional probe and a master circular ring, and the third is a kinematic ball bar. The last two methods were proposed and introduced by W. Knapp and J. B. Bryan, respectively. The newly developed method is superior to above two methods; the rotating angle can be detected and the rotating radius is variable. Circular movement errors of machining centers were investigated by the analysis of data measured by R- .THETA. method. Followint observations are obtained 1) The errors which depend on positions, i.e., periodical errors by the pitch of ball screws, errors by compensation of backlash and errors by perpendicularity of X and Y-axis, were analyzed. 2) The errors which depend on NC control system, i.e., errors by the unbalance of position-loop-gaians, errors by velocity-loop-gains and errors by feed speeds, were quantiatively analyzed. 3) The method of extracting error information, which uses moving technique of averaging angle and fourier's analysis data mesured by the R- .THETA. method, was proposed.

• International journal of advanced smart convergence
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• v.8 no.3
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• pp.78-86
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• 2019

Recently, IoT researches using sensor data based on embedded networks in various fields including healthcare and sports have been continuously attempted. This study analyzes golf ball mobility to support IoT application in golf sports field. Generally, since the difference in density occurs due to the condition of the inner material and the abnormal state at the time of the outer skin joining during the manufacturing of the golf ball, the weight of each subset is equal for any two points with the same radius in the sphere cannot be guaranteed. For this reason, the deflected weight of the sphere has the undesirable effect of hitting the ball in a direction in which the weight of the ball is heavy. In this study, it is assumed that there is a unique center of gravity of the ball, and even if the golf ball cannot be manufactured perfectly, it wants to establish the basic principle to accurately recognize or mark the putting line based on the center of gravity. In addition, it is evaluated how the mobility of the golf ball with a deviation from the center of gravity of the golf ball affects the progress path (or movement direction) and the moving distance (or carry distance) after the golfer hits. The basic model of the mobility of the golf ball can help the golfer exercise model and the correlation analysis. The basic model of the mobility of the golf ball can help the golfer exercise model and the correlation analysis.

• Journal of Sensor Science and Technology
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• v.27 no.6
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• pp.380-385
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• 2018

Recently, interest in baseball has been increasing as the level of international baseball games, the popularity of domestic leagues, and the number of players entering the MLB has increased. In this paper, we propose a pitching system that can be applied to both professional and amateur baseball. The pitching system consists of a control module using MSB764T PLC, a pitching mechanism including AC motors and a ball feed rail, an HMI using the CHA-070WR model, inverter, etc. To pitch the breaking balls, the two AC motors each use an inverter to independently control the speed. The implemented pitching system was experimented on, investigating ball speed and ball movement according to RPM using the BUSHNELL Velocity Speed Gun. Experimental results on ball speed are similar to the theoretical data and the measured data. From the experimental data, it is confirmed that the damping coefficient value for the pitching ball is about 0.98. In the case of the breaking ball, the larger the difference between the speeds on the sides of the ball and the faster the ball speed, the larger the bending degree.

• PNF and Movement
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• v.9 no.2
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• pp.55-63
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• 2011

Purpose : The Purpose of this study was performed to find out back flexibility and strength by Swiss ball and sling exercise. Methods : Subjects were randomly assigned to 3 groups; Swiss ball(n=9), Sling(n=8) and Swiss ball and Sling(n=8). Each groups had the exercise 30 minute per week for 4 weeks. The case of Swiss ball-sling group had 15 minutes for ball exercise and 15 minute for sling exercise. Results : First, sling group among groups significantly increased in flexibility test 1. Second, ball group among groups significantly increased in flexibility test 2. Third, ball-sling group among groups significantly increased in strength test 1 and 2. Fourth, follow-up study after 2 weeks was revealed that flexibility and strength were decreased in all groups. Conclusion : The effect were not consistent with exercise methods. Accordingly, it should be selected for purpose and effect you want.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.6
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• pp.783-790
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• 2013

Circular path generation for ball bar measurement using the simultaneous movement of two axes with at least one rotary axis requires the execution of CAM software. However, a change in the machine type or measurement condition requires a new execution of the CAM software, which is cumbersome. This paper presents a circular path generation technique that does not require CAM software and is applicable to different types of driving axes with an arbitrary structural configuration of machine tools and any ball bar setup condition. Mathematical equations are derived for three cases using the proposed technique. In addition, to inspect the measurement feasibility for avoiding physical interference among the ball bar parts, a tilting angle calculation is proposed. The validity of the proposed technique was verified by performing a ball bar experiment with A and C as the simultaneous axes of a five-axis machine tool.