• Journal of Institute of Control, Robotics and Systems
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• v.7 no.8
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• pp.675-679
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• 2001

This paper presents walking algorithm for a quadruped robot that does not have an upper body. Tilting motion is added to the planned walking trajectory instead of using an extra body segment that is independent on walking trajectory. Area and tracking algorithms are proposed as tilting method and compared with that of off-line tilting and that of no tilting. Computer simulation shows that stability of tilted walking is more improved than that of the usual walking algorithm for general walking paths. It also shows that the tracking method guarantees stability and best mobility.

• International Journal of Fluid Machinery and Systems
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• v.6 no.2
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• pp.49-55
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• 2013

Water lubricated guide bearing was newly released and has been applied to actual hydro turbines with vertical shaft. As a result, they can have not only high bearing performance but environmental advantages in meeting the demand for reducing river pollution by oil leakage from oil lubricated guide bearing. The PTFE composite guide bearing was tested by experimental equipment operated under conditions similar to those of actual hydro turbines. Circumferential and axial tilting bearing segments help to improve the bearing performance and efficiency due to low friction loss in the bearing system. Furthermore, bearing cooling systems could be eliminated and maintenance periods could be extended, thus the initial investment and operating costs of the hydroelectric power plant are reduced.

• The korean journal of orthodontics
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• v.46 no.5
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• pp.310-322
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• 2016

Objective: The aim of this study was to determine the optimal loading conditions for pure intrusion of the six maxillary anterior teeth with miniscrews according to alveolar bone loss. Methods: A three-dimensional finite element model was created for a segment of the six anterior teeth, and the positions of the miniscrews and hooks were varied after setting the alveolar bone loss to 0, 2, or 4 mm. Under 100 g of intrusive force, initial displacement of the individual teeth in three directions and the degree of labial tilting were measured. Results: The degree of labial tilting increased with reduced alveolar bone height under the same load. When a miniscrew was inserted between the two central incisors, the amounts of medial-lateral and anterior-posterior displacement of the central incisor were significantly greater than in the other conditions. When the miniscrews were inserted distally to the canines and an intrusion force was applied distal to the lateral incisors, the degree of labial tilting and the amounts of displacement of the six anterior teeth were the lowest, and the maximum von Mises stress was distributed evenly across all the teeth, regardless of the bone loss. Conclusions: Initial tooth displacement similar to pure intrusion of the six maxillary anterior teeth was induced when miniscrews were inserted distal to the maxillary canines and an intrusion force was applied distal to the lateral incisors. In this condition, the maximum von Mises stresses were relatively evenly distributed across all the teeth, regardless of the bone loss.

• Korean Journal of Applied Biomechanics
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• v.13 no.2
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• pp.139-160
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• 2003

The purpose of this study was to suggest the guideline for scientific and quantitative skill acquisition methods of badminton smashing so that the novice could learn the motions of badminton smashing efficiently. The subject participated consisted of total 6 middle school students of the stilled(3) and the unskilled(3). The cinematographical experimental & Analysis equipments used in the study were composed of two Model D-5100 Video Cameras, a control point, a synchronization timer and Kwon3d motion analysis system. The conclusions obtained were as follows, 1. It was necessary for the unskilled to learn the smashing impact phase in situation of max. velocity of COG in order to minimize the timing loss phase. 2. Particularly. The power from segments of Power Zone must participate in utilization in sequence of order of trunk-upper arm- forearm-hand-racket segment in both the skilled and the unskilled.. 3. Therefore it was necessary for the unskilled to do smashing practice for cumulated sum of absolute & relative velocity transfer into shuttle cock after adjusting anterior-posterior tilting angle and max timing, in sequence of segment recruited.

• Journal of KIISE:Software and Applications
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• v.27 no.5
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• pp.510-520
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• 2000

For content-based video indexing and retrieval, it is necessary to segment video data into video shots and then select key frames or representative frames for each shot. However, it is very difficult to select key frames automatically because the task of selecting meaningful frames is quite subjective. In this paper, we propose a new approach in selecting key frames based on visual contents such as region information and their temporal variations in the shot. First of all, we classify video shots into panning shots, zooming shots, tilting shots or no camera motion shots by detecting camera motion information in video shots. Then, in each category, we apply appropriate fuzzy rules to select key frames based on meaningful content in frame. Finally, we control the number of key frames in the selection process by adjusting the degree of detail in representing video shots.

• Korean Journal of Applied Biomechanics
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• v.26 no.3
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• pp.243-248
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• 2016

Objective: The aim of this study was to determine the kinematical characteristics of somersault with twist in the Lou Yun and Akopian motions and to provide useful information to gymnastic athletes in men's vault. Method: The study subjects were 12 male adult top athletes. After 12 trials (7 Lou Yun and 5 Akopian trials) filmed by using two digital high-speed camcorders set at 90 frames/sec, kinematical data were collected through the direct linear transformation (DLT) method. The mean differences in biomechanical variables were compared during the second flight upward phase. The kinematic characteristics of somersault with twist in the Lou Yun and Akopian motions were identified. Results: In Lou Yun motion, the vertical release velocity through horse breaking was not difficult to obtain, so the athletes had enough time to prepare for the twist. Therefore, the Lou Yun motion has an advantage to make a cat twist in the pike posture. In the Akopian motion, obtaining the horizontal velocity through horse pushing was so easy that the Akopian athletes attained a large angular impulse and angular momentum. Therefore, the Akopian motion has an advantage to making a tilt twist in the body tilting posture. Conclusion: This study suggests that gymnastic athletes should control their body segment movements in order to increase the twisting angular velocity of the whole body, which requires regulation of the longitudinal moment of inertia of the body. Moreover, athletes should prepare for the shoulder and hip twists early in order to make the landing position in advance.

• The Journal of Korean Society for Radiation Therapy
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• v.17 no.1
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• pp.33-40
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• 2005

Purpose : We recently perform the latest radiotheraphy (3D conformal, IMRT,etc.) with the development of 3D CT planning technology. However, in case patients with breast cancer, it is difficult to acquire the CT image with the limitation of CT hole size and tilting of breast immobilization device. The Ewha Breast Device(EBD) was constructed to improve the problem in the treatment of patients with breast cancer and we are intend to introduce the procedure of the EBD construction in this study and compare the EBD with conventional breast device in the view point of usefulness. Materials and Methods : We have constructed the EBD with acryl, analyze the skull size with CT data, consider the skin folder in SCL field and evaluated the EBD usefulness from the view point of set-up reproducibility, dose distribution, skin reaction in comparison with conventional breast device. Results : In the case of patients set-up error analysis, the EBD is superior to conventional device in portal film repetition($\%$) check (80pt.), equal to that in simulation & CT image coincidence check(5pt.). There is no difference between the two systems in dose distribution and skin reaction in SCL field is better the EBD than conventional device. Conclusions : The construction of the EBD enable us to perform the latest radiotheraphy in breast treatments, relieve the pains in simulation, and reduce, the skin reaction. In the future, we expect that modification of the EBD is useful in treating for patients with breast cancer.