• Physical Therapy Korea
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• v.3 no.1
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• pp.65-72
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• 1996

The purpose of this study was to introduce rotation-plasty procedure and prosthetic ambulation training. The recent development of chemotherapy and diagnostic facility have permitted the orthopaedic surgeons to try limb saving procedures rather than amputations for the treatment of the malignant bone tumors. If the tumors around the knee joint were treated by mid-thigh amputation or hip disarticulation, it would impose the client with a great handicap for rehabilitation. Rotation-plasty procedure was first done by Borggreve, in 1930 for the congenital short femur. Recently this procedure was used a malignant bone tumor at the distal femur by Kotz and Salzer in 1982. In spite of its cosmetic problem of the distal stump, this procedure has the great functional advantage of converting the above-knee amputation to the below-knee amputation. The inverted foot was also good to control the prosthesis as a below-knee stump and heel functioned as a patella to support the body weight. This 15 years old girl case was had rotation-plasty due to osteosarcoma of the distal femur with 3rd postoperative chemotherapy, and admitted to Yonsei rehabilitation hospital for prosthetic ambulation training. Then, the case had excellent functional results of prosthetic ambulation training with rotaion-plasty after 3 months.

• Journal of the Korea Computer Industry Society
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• v.10 no.5
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• pp.221-226
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• 2009

The closed system's internal rigid body particle rotation motion can be distinguished by a main body that becomes the core of the rotation and the particles that are subjected to the rotation. The instance of particles becoming bounded to the main body as a holonomic system, has till now, been well defined and formulated in the study of Kinetics, and the structure of the formulas relate well to reality. However, when the structure is non-holonomic it deviates from these existing equations. The purpose of this research is to categorize the differences between a holonomic system and a non-holonomic system when rotating, through devices. With a special emphasis on the real phenomenon of the non-holonomic system which will be formulated in the form of a model or computer simulation. With these formulas, the center of mass shift in a closed rotating motion system and confined motion of external friction will be adequately expressed, so that it may be applied to computer graphics motions methods.

• Design & Manufacturing
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• v.11 no.3
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• pp.41-45
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• 2017

Drones can be manipulated in a variety of ways. One of the most common controller is joystick method. But joystick controller uses both hands and takes a long time to learn. Particularly, in the case of 8-character flight, it is necessary to use both front and rear flight (pitch), left and right flight (Roll), and body rotation (Yaw). Joystick controller has limitations to intuitively control it. In particular, when the main body rotates, the viewpoint of the forward direction is changed between the drones and the user, thereby causing a mental rotation problem in which the user must control the rotating state of the drones. Therefore, we developed a motion matching controller that matches the motion of the drones and the controller. That is, the movement of the drone and the movement of the controller are the same. In this study, we used a gyro sensor and an acceleration sensor to map the controller's forward / backward, left / right and body rotation movements to drone's forward / backward, left / right, and rotational flight motion. The motor output is controlled by the throttle dial at the center of the controller. As the motions coincide with each other, it is expected that the first drone operator will be able to control more intuitively than the joystick manipulator with less learning.

• Journal of Animal Science and Technology
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• v.64 no.6
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• pp.1237-1244
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• 2022

Horse breeders suffer massive economic losses due to dystocia, abortion, and stillbirths. In Thoroughbred mares, breeders often miss the foaling process because approximately 86% of the foaling events occur from 19:00 to 7:00; consequently, breeders cannot assist mares experiencing dystocia. To solve this problem, various foaling alarm systems have been developed. However, there is a need to develop a new system to overcome the shortcomings of the existing devices and improve their accuracy. To this end, the present study aimed to (1) develop a novel foaling alarm system and (2) compare its accuracy with that of the existing Foalert^TM system. Specifically, eighteen Thoroughbred mares (11.9 ± 4.0 years old) were included. An accelerometer was used to analyze specific foaling behaviors. Behavioral data were transmitted to a data server every second. Depending on the acceleration value, behaviors were automatically classified by the server as categorized behaviors 1 (behaviors without change in body rotation), 2 (behaviors with sudden change in body rotation, such as rolling over), and 3 (behaviors with long-term change in body rotation, such as lying down laterally). The system was designed to alarm when the duration of categorized behaviors 2 and 3 was 12.9% and that of categorized behavior 3 was 1% during 10 min. The system measured the duration of each categorized behavior every 10 min and transmitted an alarm to the breeders when foaling was detected. To confirm its accuracy, the foaling detection time of the novel system was compared with that of Foalert^TM. The novel foaling alarm system and Foalert^TM alarmed foaling onset respectively 32.6 ± 17.9 and 8.6 ± 1.0 min prior to foal discharge, and the foaling detection rate of both systems was 94.4%. Therefore, the novel foaling alarm system equipped with an accelerometer can precisely detect and alert foaling onset.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.382-389
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• 2001

In the present study, local heat transfer rates for co-rotating disks with two modified hubs having ventilation holes are investigated for Rossby number of 0.04, 0.1 and 0.35 to evaluate the influence of incoming flows through hub holes. A naphthalene sublimation technique is employed to determine the detailed local heat/mass transfer coefficients on the rotating disks using the heat and mass transfer analogy. Flow field measurements are conducted using Laser Doppler Anemometry (LDA) and numerical calculations are performed simultaneously to analyze the flow patterns induced by the disk rotation. The basic flow structure in a cavity between co-rotating disks consists of three regions; the solid-body rotating inner region, the outer region with turbulence vortices and the shroud boundary layer region. The heat/mass transfer. rates on the co-rotating disks are very low near the hub due to the solid-body rotation and those increase rapidly in the outer region due to turbulence mixing. The modified hubs with ventilation holes enhances significantly the heat/mass transfer rates on the region near the hub. The results also show that the heat transfer of Hub-2 is superior to that of Hub-1, but Hub-1 is more profitable for destructing the solid-body rotating inner region.

• Korean Journal of Applied Biomechanics
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• v.22 no.3
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• pp.277-284
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• 2012

The purpose of this study was to find out the changes in beginners' batting movements after taking undergraduate baseball lectures, by comparing and analyzing the speed of bat, the angle of body and its segments, the angular velocity and so on. For this purpose, the author picked up five undergraduates who had not taken baseball lectures, and conducted three-dimension computerized tomography twice on them, that is, before and after taking baseball classes, with eight infrared cameras and two force platforms. The conclusions are, first, the time required for swing was shortened after taking the classes. Second, the maximum velocity of the bat-end was increased. Third, at the time of impact, while the rotation angles of the pelvis and the tip of left foot were increased, the left elbow had more flexion after the classes. Fourth, the size of ground reaction force was increased at the point of swing where the ground reaction force of left foot became maximized. As we can infer from these conclusions, beginners' hitting movements before taking baseball classes tended to swing only with the arms, without waist rotation and weight shift of the lower body, but after the classes, their movements were proved to be corrected into the swing using the lower body. For the future studies, the author expects a research in a close to real environment by using pitching machine.

• The Journal of Korean Academy of Prosthodontics
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• v.27 no.1
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• pp.55-81
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• 1989

Recently the instantaneous center concept has been to understand the biomechanics by which a tissue derangement causes a mechanical derangement in human joint. Therefore, to understand the biomechanics of temporomandibular joint (T.M.J.) as a part of human joint, it is necessary to clarify the instantaneous center of rotation (I.C.R.) in the mandibular movement. Twenty male subjects without T.M.J. disorder and mandibular deviation during the mandibular movement were selected for this study. The habitual opening and closing paths were recorded on the paper of the sagittal metal plate by two pencil markers connected to the resin open clutch attached on the lower teeth, which was designed for this study. The coordinates of the 33-target points and the 109-anatomical landmarks were obtained using a Summagraphic digitizer connected to a 18AT computer. The original raw data of the opening and closing paths were smoothed by B-spline curve fitting technique and then the I.C.R. pathways were determined mathematically by the computer using algorithm for finding the I.C.R. of a planer rigid body model. Also the opening and closing movements of the mandible were simulated according to the determined I.C.R. The results obtained from this study were as follows. 1. At the early opening and the last closing, I.C.R's were almost distributed around the mastoid process outside the mandibular body without the presence in the region of the mandibular condyle. 2. The I.C.R. pathway showed variable patterns to each subject at the opening and closing movements. 3. The K constant with uniform pattern was obtained by the rotation angle times the radius, which was assumed to the index of the mandibular movement. 4. The opening and closing movements of the mandible were simulated by the I.C.R. pathways at the habitual opening and closing movements. 5. The mandibular condyle was rotated or translated accordng to the relative rotation angle and radius of the determinant factors of K contant.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.12 no.2
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• pp.21-25
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• 2006

Objective: The purposes of this study are to provide fundamental data and a rehabilitation program in physical therapy. It has been operated by 30 male college students for lumbar isokinetic exercises. Method : Subjects have been carried out in an experiment by Biodex system operating isokinetic torso rotation. This performance was activated by left rotation after right rotation repeatedly. Results: 1. The mean peak torques at $60^{\circ}$/sec were $95.6{\pm}20.62$ (Rt) and $93.84{\pm}18.41$ (Lt). 2. The mean peak torques/body weight at $60^{\circ}$/sec were $69.28{\pm}28.31$ (Rt) and $67.07{\pm}27.04$ (Lt). 3. The total works in right side at $60^{\circ}$/sec and $180^{\circ}$/sec were $492.21{\pm}92.37$, $1294.97{\pm}278.96$ and in left side at $60^{\circ}$/sec and $180^{\circ}$/sec were $515.78{\pm}109.47$, $1443.74{\pm}329.67$. 4. The work to body weight ratio at $60^{\circ}$/sec was $78.30{\pm}32.37$ (Rt) and $79.93{\pm}37.30$ (Lt). 5. The average powers in right side at $60^{\circ}$/sec and $180^{\circ}$/sec were $76.75{\pm}16.69$, $117.19{\pm}29.94$ and in left side at $60^{\circ}$/sec and $180^{\circ}$/sec were $78.54{\pm}18.58$, $125.39{\pm}32.90$. 6. The work fatigue at $180^{\circ}$/sec was $21.76{\pm}14.82$ (Rt) and $19.66{\pm}26.23$ (Lt). Conclusion: In right side and left side, there was no significant difference in peak torque. peak torque/body weight, work to body-weight ratio, average power of trunk rotators at $60^{\circ}$/sec(p<0.05). However there was a significant difference in the total work of trunk rotators at $60^{\circ}$/sec(p>0.05). Also there was a significant difference in the average of trunk rotators at $180^{\circ}$/sec(p>0.05).

• Korean Journal of Computational Design and Engineering
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• v.15 no.4
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• pp.306-313
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• 2010

In this paper, an acceleration based passenger evacuation simulation is performed. In order to describe a passenger‘s behavior in an evacuation situation, a passenger is modeled as a rigid body which translates in the horizontal plane and rotates along the vertical axis. The position and rotation angle of a passenger are calculated by solving the dynamic equations of motions at each time step. The destination force, the contact force, and the group force are considered as external forces and the moments due to each force are also considered. With the passenger model proposed in this paper, the test problems in International Maritime Organization, Maritime Safety Committee/Circulation 1238(IMO MSC/Circ.1238) are implemented and the effects of passenger rotation on the evacuation time are confirmed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.115-120
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• 2001

A gyroscope is a rotating body possessing one axis of symmetry and whose rotation about the symmetry axis is relatively large compared with the rotation about any other axis. Tuning fork is this type of structure that various modem gyro-sensors are based on. In this paper, dynamic behavior of a cantilevered beam subjected ta a base rotation with respect to the eccentric axis that is parallel to the beam axis is analyzed. The final equations of motion in terms of generalized coordinates can be solved with numerical scheme with various values of angular velocities and angular accelerations of the rotating axis. In contrast to the case of rotating cantilever beam like helicopter blade, the rotational motion with respect to the beam axis has effect to decrease the stiffness of the beam and has unstable region depending on the magnitude of the rotational angular velocity and angular acceleration.