• Physical Therapy Korea
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• v.12 no.4
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• pp.33-40
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• 2005

The purpose of this study was to define more precisely the anatomy of the thumb flexor pulley system and to determine the relative contribution of each of the pulleys to the biomechanics of thumb motion at the metacarpophalangeal (MP) and interphalangeal (IP) joints. For this, 22 hands from 11 cadavers were used and randomly assigned to two groups. In the first group, the first annular (A1) pulley was cut first followed by the variable annular (Av) pulley and then the oblique pulley. In the second group, the oblique pulley was cut first followed by the, pulley and then the Av pulley. In 7 of 22 hands, it was a transverse structure parallel to the, pulley with a gap between the A1 and Av pulleys, referred to here as type I. In 9 hands, the A1 and Av pulleys were connected without any gap (type II). In 6 hands, the space between the A1 and Av pulleys were triangular in shape with fibers of the Av pulley converging toward the radial side (type III). In biomechanical study of both first and second experiments, there was no significant difference in MCP joint flexion between the all intact, A1 section, A1/Av section, A2 intact (A1/Av/oblique section), and no pulley configuration (p>.05). In occurring displacements less than 10 mm, there was no significant difference in IP joint flexion (p>.05). However, there was a significant decrease in IP joint flexion occurred in both 15 mm and 20 mm excursion (p<.05), when the oblique pulley was resected additionally after cutting the A1 and Av pulleys in first experiment, and when the A1 pulley was resected additionally after cutting the oblique pulley. According to the results, the injury of only the oblique pulley does not decrease thumb motion significantly. The oblique pulley injury with both the A1 and Av pulleys laceration decreased thumb motion significantly. The additional laceration of the A2 pulley does not decrease thumb motion.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.2
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• pp.1-9
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• 2015

In this paper, the RC column-based joint connection part carry out loading test by reinforced hollow or extended Base Plate in order to confirm that RC joint punching shear reinforcement effect of applying the Base Plate. Base Plate thickness, extension length, size, and type as the variable, Base Plate suitable for the stress distribution and shape and dimensions confirmed through experiment and then reinforcing effect was analyzed. Experimentally, vertical load transmitted to the Base Plate from column to foundation is effective to stress distribution and then, type of hollow reinforcement more efficient than a closed. Through experiment, improve performance and ductility due to reinforcement and relative to the thickness of the existing foundation reduced even showed better performance than the existing. The behavior of the reinforced specimens be able to induce from brittle to ductile. Experiment on loading to destroy performed the pattern of cracks, destruction aspect before and after reinforcement.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.26 no.3
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• pp.66-76
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• 2018

Terminal 2 of Incheon in'tl airport had made a grand opening since January 2018. Terminal 2 is currently operated by mainly Korean airline in cooperation with such skyteam members as Delta airline, Air France and Royal Dutch KLM. It is expected another three skyteam member airlines join the separate operation at terminal 2 since this coming winter. It is believed very meaningful research to analyze how separate operation of Global alliance of airlines affects the global brand image of an organization. To find out such effect, researchers have made an empirical analysis of perception of airline staffs working at terminal 2. This paper has focused on how the staffs perceive airline service quality in the changed working environment and on how significantly their perception on service has an effect on airline's global brand image with such moderating variables as organizational efficacy and organizational trust. According to empirical analysis using structural equation modeling, it was proven the variable of responsiveness among perceived airline service qualities had a direct significant effect on formulating airline's global brand image associated with joint venture between Korean airline and Delta airline. However, the other variables had a indirect significant effect on global brand image with moderating effects.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.19 no.1
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• pp.1-8
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• 2013

Background: This study aims to examine the effects of sling exercise and common exercise on the pain level of various body parts. Methods: This study divided the subjects into a sling-exercise group and a common exercise group to for each group across the measurement times after practicing exercises twice per week for 8 weeks (total 16times). To compare the means of the experimental group and the control group on each variable, the ANOVA for repeated measure was used and if there was any significant difference across the measurement times, post-hoc comparisons were conducted for the difference. The T-tests for group difference according to exercise type on each of the variables showed the results as follows. Results: The results of this study suggest that there were significant difference in pain in shoulder pain, but no significant difference could be found in the Thoracic pain & Knee joint pain. There was no significant difference to distinguish between the sling exercise and the common exercise. Conclusions: Currently the sling exercise is not spread out widely in Korea, so that the recognition and studies of the sling exercise is still lacking. Hence, this study can hopefully facilitate popularity of the sling exercise and systematic prospect studies on it in the near future.

• Korean Journal of Applied Biomechanics
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• v.17 no.1
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• pp.53-60
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• 2007

Recently tennis techniques has been changed in stance patterns. Stance is consist of square stance, open stance and semi-open stance. The purpose of this study was to analyze the kinematics variables of racket head velocity during forehand stroke by stance patterns. Eight high school tennis players were chosen for the study who use semi western grip right-handed person more than career 7 years. They performed horizontal swing and vertical swing that it was done each five consecutive trial in the condition of square, open and semi-open stance. The results showed that racket head velocity significant difference was not observed in stance types between swings at impact. Y and Z components of racket head velocity for horizontal and vertical swing at second prior to impact and at impact were that y components velocity was faster horizontal swing than vertical swing and z components velocity was later horizontal swing than vertical swing. Statistically significant variable to racket head velocity and Pearson's correlation were drawn as follows. 1. Z components of racket head velocity in square stance was significant correlation by right knee joint. 2. Y components of racket head velocity in semiopen stance was significant correlation by left hip joint. 3. Y components of racket head velocity in open stance was significant correlation by left ankle joint.

• 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.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.45 no.1
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• pp.9-14
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• 2019

Objectives: This study aimed to evaluate the effect of clinical factors on the outcome of arthrocentesis in the treatment of temporomandibular joint (TMJ) internal derangement. Materials and Methods: Fifty patients with TMJ internal derangement underwent arthrocentesis using ringer's lactate. The present study evaluated the contribution of the clinical variables of age, time since onset, visual analogue scale (VAS) pain level, and range of motion (ROM) on the outcomes of TMJ arthrocentesis: age (${\leq}25\;years$, >25 and ${\leq}40\;years$, >40 and ${\leq}60\;years$), VAS pain level (${\leq}5$, >5 and ${\leq}7$, >7 and ${\leq}10$), and ROM (<25 and ${\geq}25mm$). Odds ratios (ORs) were used to describe the proportional benefit of each variable the on successful outcome of arthrocentesis. For the OR to be clinically relevant or even clinically noticeable, we assumed that the OR would need to be larger than 2. Results: Mean preoperative pain score was $6.49{\pm}1.560$ and at 6 months postoperative was $0.46{\pm}1.147$ with an average decrease of pain score 6 (P<0.001). The mean preoperactive maximum mouth opening was $26.14{\pm}4.969mm$ and mean maximum mouth opening at 6-month inerval was $38.92{\pm}3.392mm$. The mean increase in the mouth opening was a mean difference of 12.78 mm (P<0.001). Logistic regression showed that the maximum benefit occurred in patients aged <25 years (OR, 12.01; P=0.012), a VAS pain level of >7 (OR, 11.25; P=0.039), and a maximum vertical opening of <25 mm (OR, 7.70; P=0.038). Conclusion: Lavage of the superior joint space with ringer's lactate resulted in significant reduction in pain and improvement in mouth opening. Patients with a greater inflammatory component and younger patients benefitted more from arthrocentesis. Evaluation of these clinical variables helped in predictive modelling, which may provide clinicians with the opportunity to identify "at-benefit" patients early and initiate specific treatment.

• Journal of IKEEE
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• v.23 no.3
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• pp.883-892
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• 2019

This study is the method which is adapted to control ankle joint movement for resolving the problem of gait imbalance in intervals where gait environments are changed and slope walking, as applying terrain-adaptive technique to intelligent above-knee prosthesis. In this development of above-knee prosthesis, to classify the gait modes is essential. For distinguishing the stance phases and the swing phase depending on roads, a machine learning which combines decision tree and random forest from knee angle data and inertial sensor data, is proposed and adapted. By using this method, the ankle movement state of the prosthesis is controlled. This study verifies whether the problem is resolved through butterfly diagram.

• Composites Research
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• v.34 no.2
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• pp.101-107
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• 2021

Composite structures have components and joints. Theses connections or joints can be potentially weak points in the structure. The failure mode of the composite bolted joint is designed as a bearing failure mode for structural safety. The load-displacement relation exhibits bearing failure mode shows a nonlinear behavior after the initial failure and progressive failure behavior. In order to accurately predict the failure behavior of composite bolted joints, this study modified the shear damage variable calculation process in the existing progressive failure analysis model. The results of the bearing stress-bearing strain of the composite bolted joint were predicted using the modified progressive failure analysis model, and the modified model was verified through comparison with the previous progressive analysis model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.7
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• pp.1823-1840
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• 2023

In order to improve spectral efficiency and reduce power consumption for reconfigurable intelligent surface (RIS) assisted wireless communication systems, a joint design considering irregular RIS topology, RIS on-off switch, power allocation and phase adjustment is investigated in this paper. Firstly, a multi-dimensional variable joint optimization problem is established under multiple constraints, such as the minimum data requirement and power constraints, with the goal of maximizing the system energy efficiency. However, the proposed optimization problem is hard to be resolved due to its property of nonlinear nonconvex integer programming. Then, to tackle this issue, the problem is decomposed into four sub-problems: topology design, phase shift adjustment, power allocation and switch selection. In terms of topology design, Tabu search algorithm is introduced to select the components that play the main role. For RIS switch selection, greedy algorithm is used to turn off the RISs that play the secondary role. Finally, an iterative optimization algorithm with high data-rate and low power consumption is proposed. The simulation results show that the performance of the irregular RIS aided system with topology design and RIS selection is better than that of the fixed topology and the fix number of RISs. In addition, the proposed joint optimization algorithm can effectively improve the data rate and energy efficiency by changing the propagation environment.