• Korean Journal of Applied Biomechanics
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• v.24 no.1
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• pp.51-57
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• 2014

The purpose of this study was to compare and analyze kinetic variables of lower limbs according to types of ankle taping in drop landing. For this, targeting seven male basketball players (average age: $20.8{\pm}0.74yrs$, average height: $187.4{\pm}3.92cm$, average weight: $79.8{\pm}7.62kg$) with no instability of ankle joints, the drop landing motion was conducted according to three types of inelastic taping (C-type), elastic taping (K-type), and no treatment (N-taping). Based on the result, the next conclusion was reached. First, the effect of taping for the players with stable ankles was minimal and the high load on ankle joints offset the fixing effect of inelastic taping. Thus the inelastic taping for the players with stable ankles did not have an effect on the control of dorsal flexion during one-foot landing. Second, increasing angular velocity by increasing the movable range of knee joints disperses impact forces, yet inelastic taping restricted the range of knee joint motion and at the same time increased angular velocity, adding to a negative effect on knee joints. Third, inelastic taping induced inefficient motion of Lower limbs and unstable impact force control of ankle joints at the moment of landing and produced maximum vertical ground reaction force, which led to an increase of load. Therefore, inelastic ankle taping of players whose jump actions occur very often should be reconsidered. Also, it is thought that this study has a great meaning in proving the problem of inelastic taping related to knee pain with unknown causes.

• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.221-235
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• 2005

The purpose of this study was to analyse badminton players' drop-shots, in order' to make players understand the principles of drop-shot motion in badminton. Three dimensional analysis was used to measure movements such as the time required per section, the change of center of gravity, joint angle and speed, and joint speed. The results of this study revealed as follows: (1) top players are faster than amateurs in the total time required per section; (2) top players moved more in the x-axis and z-axis, while amateurs moved more in the y-axis; (3) the inclination of amateurs was greater than that of top players in all phases; (4) amateurs showed larger angle on the shoulder joints than top players in the first phase, while top players showed larger angle on the shoulder joint than amateurs in the second and third phase. Amateurs' angle was larger on angle joint in the first phase than top players' ones, while top players' angle was larger in the third phase than amateurs; (5) the speed of racket head of top players was faster than that of amateurs; and the velocity of the center of gravity of amateurs was greater than that of the top players. The findings of this study were that gravity decreases during impact and then the velocity increases to perform the follow-through and making the swing fast by increasing the speed of the racket head is most important.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.2
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• pp.224-231
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• 2011

Heating and/or cooling of the channel with pin-fin structure is a promising choice for the efficient heat transfer. Complex pin-fin structure shows highly irregular behavior like porous media. This study shows the numerical analysis on the characteristic of heat transfer and pressure drop of a channel with pin-fin structure. It predicts the experimental data quite well at the high porosity region with large diameter. Low porosity activates the rigorous flow disturbance and, consequently, the enhanced heat transfer. However, the concept of optimum design should be carefully reviewed because the pressure drop is also increased with decreasing porosity at low porosity region.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.12 s.105
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• pp.1370-1377
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• 2005

The bottom structure of an instrumented capsule is a part which is joined at the receptacle of the flow tube in the reactor in-core. A geometrical change of the bottom structure has an effect on the pressure drop and the vibration of the capsule. The out-pile test to evaluate the structural integrity of the material capsule called 04M-17U was performed by using a single channel and a half core test loop. From the pressure drop test, the optimized diameter of the cone shape's bottom structure which satisfies HANARO's flow requirement (19.6 kg/s) is 71 mm. The maximum displacement of the capsule measured at the half core test loop is lower than 1.0 mm. From the analysis results, it is found that the test hole will not be interfered with near the flow tubes because its displacement due to the cooling water is very small at 0.072 mm. The fundamental frequency of the capsule under water is 9.64 Hz. It is expected that the resonance between the capsule and the fluid flow due to the cooling water in HANARO's in-core will not occur. Also, the new bottom structure of a solid cone shape with 71 mm in diameter will be applicable to the material and special capsules in the future.

• Journal of the Korean Home Economics Association
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• v.30 no.3
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• pp.15-32
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• 1992

The purpose of this study was to detect the effect of the lower body type on the shape of flare skirts. The subjects for the wearing test were 50 female students, who were controlled in their hip and waist shapes. The skirts used for wearing test were six types(three flar angles $\times$ two fabric types). The effect of lower body type on the shape of flare skirts was determind by the hemline trace method and the silhouette photography. The data were then analyzed by the repeated measures of analysis of variance and the SNK multiple range test. The results obtained from this study were as follows : 1) When a flare skirt made with larger flare angle and better drapable fabric was worn, the numeric of the nodes increased as the drop value(hip - waist) increased. When a flare skirt made with smaller flare angle was worn, the width of horizontal sectio of hemline increased as the drop value increased. The hemline uneveness decreased on the sides and back as the drop value increased. When a flare skirt made with worse drapable fabric was worn, the sides angle of the flarskirt increased as the drop value increased. 2) When a flare skirt made with larger flare angle was worn, the numeric of nodes increased as the ratio of dropped hip increased. The wave-height increased and the back variation ratio of wave-height was higher than the front variation ratio of wave-height as the ratio of dropped hip increased. The hemiline uneveness decreased on the back as the ratio of dropped hip increased. When a flare skirt made with larger flare angle was worn, the sides angle of the flare skirt increased as the ratio of dropped hip increased.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.5
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• pp.125-133
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• 2008

In this paper, we propose active queue management mechanism (Active-WRED) to guarantee quality of the high priority service class in multi-class traffic service environment. In congestion situation, this mechanism increases drop probability of low priority traffic and reduces the drop probability of the high priority traffic, therefore it can improve the quality of the high priority service. In order to analyze the performance of our mechanism we introduce the stochastic analysis of a discrete-time queueing systems for the performance evaluation of the Active Queue Management (AQM) based congestion control mechanism called Weighted Random Early Detection (WRED) using a two-state Markov-Modulated Bernoulli arrival process (MMBP-2) as the traffic source. A two-dimensional discrete-time Harkov chain is introduced to model the Active-WRED mechanism for two traffic classes (Guaranteed Service and Best Effort Service) where each dimension corresponds to a traffic class with its own parameters.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.4
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• pp.302-306
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• 2006

The improvement of load following operation of the thermal power plant is influenced to the electrical quality. Analysis of boiler, turbine, and governor system, and the study of control algorithm are necessarily preceded. The thermal power plant is operated by various control systems. In the case of faulty governor system, it takes long days to solve the problem and impossible to repair the mechanism without outage. A non-planned outage is taken into consideration because of economical power production. The paper introduces the followings; In case of system-frequency drop during long term, at 500MW thermal power plant, the generator output was drop. To clear this problem, the control logic is modified with analysis of trend and control algorithm. As a result system frequency drop is prevented during the long tenn and the electric grid operation is improved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.2985-2992
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• 2015

In this study, the characteristics of heat transfer and pressure drop was theoretically analyzed by changing longitudinal pitch, bump phase, location of vortex generator about the staggered tube banks by applying SST (Shear Stress Transport) turbulence model of ANSYS FLUENT v.14. Before carrying out CFD (Computational Fluid Dynamics) analysis, It is presumed that the boundary condition is the tube surface temperature of 363 K, the inlet air temperature of 313 K and the inlet air velocity of 5-10 m/s. The results indicated that the heat transfer coefficient is not affected by the longitudinal pitch and the bump phase of circle type was more appropriate than serrated type in the characteristics of heat transfer and pressure drop. Additionally, in case of vortex generator location, the heat transfer characteristics showed that forward location of tube was more favorable 4.6% than backward location.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.782-787
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• 2005

The bottom structure of an instrumented capsule is a part which is joined at the receptacle of the flow tube in the reactor in-core. A geometrical change or the bottom structure has an effect on the pressure drop and the vibration of the capsule. The out-pile test to evaluate the structural Integrity of the material capsule called 04M-l7U was performed by using a single channel and a half core test loop. From the pressure drop test, the optimized diameter of the cone shape's bottom structure which satisfies HANARO's flow requirement (19 6 kg/s) is 71 mm. The maximum displacement of the capsule measured at the half core test loop is lower than 1.0 mm. From the analysis results, it is found that the test hole will not be interfered with near the flow tubes because its displacement due to the cooling water is very small at 0.072 mm. The fundamental frequency of the capsule under water is 9.64 Hz. It is expected that the resonance between the capsule and the fluid flow due to the cooling water in HANARO's In-core will not occur. Also, the new bottom structure of a solid cone shape with 71 mm in diameter will be applicable to the material and special capsules in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5051-5059
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• 2015

Structural behaviour of the front loader for an agricultural tractor was analyzed for three impact test conditions: drop and catch, corner pull, and corner push. Rigid-body dynamic, transient structural, and static structural analyses were conducted using a commercial finite element software. Analysis of the drop and catch test dealt with the case that the bucket located at the maximum elevation was dropped and catched through three steps. Analysis of the corner pull test dealt with the case that the bucket constrained to the ground by a chain at its corner was raised suddenly. Analysis of the corner push test dealt with the case that the corner of the bucket collided with an obstacle. Results of analyses of the three test conditions showed that maximum stress occurs at the geometrically discontinuous location in the mount and is caused from local stress concentration. Results of the present research can be utilized as a guideline to achieve more reliable and safe structural design of the front loaders.