• The Journal of Information Systems
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• v.14 no.1
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• pp.251-275
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• 2005

The advantages of implementing a virtual channel can be derived from the notion of the 'death of distance' that would result from electronic commerce. According to this view, the internet was going to make distance irrelevant, in that firms would no longer need to establish a physical presence in a geographical location in order to do business there. However, on-line firms selling physical products could take advantages of presence in the related off-line(brick and mortar) industrial area. This paper developed a conceptual framework that highlights the various types of synergies by location on-line businesses in the related off-line industrial area. Using data from 96 on-line ventures selling physical products, factor analysis was used to figuring out six synergies including improved customer trust, value-added service, cost savings, personnel and organizational efficiency, sharing products and customer information, relationship with suppliers, and relationship with local government. The six empirically derived critical synergy factors were then used to examine how they improve performance of the on-line ventures measured by Balanced Scorecard(BSC). According to lthe results, we concluded that the on-line firms selling physical products can take advantages of presence in the related off-line industrial area.

• Journal of Institute of Convergence Technology
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• v.5 no.1
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• pp.19-22
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• 2015

Human powered aircraft (HPA) is an airplane that uses only human power for its propulsion. The human power as a power resource and an engine produce the available power that is very crucial to the success of the HPA. In the present paper, the human power characteristics for completing the mission profile are discussed focusing on the take-off and climbing performance. The mission profile is designed by using an athlete's power generation. It is believed that present analysis can be helpful for the mission profile design and athletes exercise program development for the HPA competitions.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.590-593
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• 2005

Unmanned Helicopter has several abilities such as vertical Take off, hovering, low speed flight at low altitude. Such vehicles are becoming popular in actual applications such as search and rescue, aerial reconnaissance and surveillance. These vehicles also used under risky environments without threatening the life of a pilot. Since a small unmanned helicopter is very sensitive to environmental conditions, it is generally known that the flight control is very difficult problems. The nonlinear adaptive fuzzy controller design procedure and its applications for altitude control of unmanned helicopter were described in the paper. This research was concentrated on describing the design methodologies of altitude controller design for small unmanned helicopter acquiring autonomous take off and vertical movement. The design methodologies and performance of the altitude controller were simulated and verified with an adaptive fuzzy controller. Throughout simulation results, I showed that the proposed adaptive controllers have enhanced control performance such as robustness, effectiveness and safety, in the altitude control of the unmanned helicopter.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.335-339
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• 2000

In the weaving process, tension control of the warp is important. The variation of the warp tension cause irregularities of the weft density and low quality of the woven fabrics. Due to the fact that the warp tension varies in depending on the difference between take-up velocity and let-off velocity, it is necessary to regulate the velocity of let-off in relation to that of take-up for keeping the warp tension. Futhermore, the diameter of warp beam changes in the weaving process. The changing diameter of warp beam cause changing inertia of warp beam and the velocity of the let-off. It makes the control of such a system more complex. In this paper, we propose a fuzzy controller for the warp tension control. From the computer simulation, it was observed that a developed fuzzy controller has a better performance than that of conventional PI controller.

• Transactions of the Society of Information Storage Systems
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• v.8 no.2
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• pp.61-66
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• 2012

In HDD industry, many technologies have been developed and investigated as means to increase the areal density of drives. Especially, heat assisted magnetic recording (HAMR) system has been considered as the next generation storage device. Most of the HAMR systems use near field optics as heating mechanism. Therefore, light delivery system is indispensable. We considered the light delivery system with laser diode (LD) mount and optical fiber. Mass and stiffness of the HAMR system using these LD mount and optical fiber are changed. The mass and stiffness of the HAMR system affects the slider dynamic behavior. It is necessary to analyze touch down (TD) and take off (TO). And, we performed the TD-TO experiment with HAMR suspension. Finally, we analyzed the result of TD-TO experiments. And we suggested the design of HAMR suspension to improve TD-TO performance.

• Korean Journal of Applied Biomechanics
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• v.21 no.2
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• pp.131-140
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• 2011

The purpose of this study was to evaluate the kinematic characteristics of 5th hurdle clearance during the 100m hurdle final competition at the 2010 Colorful DaeGu pre-championship meeting. This study was also intended to provide the technical data for better performance for preparing the 2011 world championship. Lee and Jung need to change technical movement by reducing the distance of the take-off point from the hurdle and by decreasing the vertical velocity of the C.G.(center of gravity) at the takeoff. Powell's angle of the take-off leg showed bigger at the touchdown and smaller at the takeoff comparing to Lee's and Jung's. Furthermore, Powell's horizontal velocity of the C.G. was maintained at the takeoff and touchdown. So, Lee and Jung need to change angle of the take-off leg the same as Powell's. Both Lee and Jung need to increase the angle of landing leg at the touchdown. In addition to increasing the angle Jung needs to improve the knee and ankle velocity with the hurdling leg.

• Ocean Systems Engineering
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• v.3 no.3
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• pp.203-217
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• 2013

A PTO (power-take-off) mechanism by using relative heave motions between a floating buoy and its inner mass (magnet or amateur) is suggested. The inner power take-off system is characterized by a mass with linear stiffness and damping. A vertical truncated cylinder is selected as a buoy and a special station-keeping system is proposed to minimize pitch motions while not affecting heave motions. By numerical examples, it is seen that the maximum power can actually be obtained at the optimal spring and damper condition, as predicted by the developed WEC(wave energy converter) theory. Then, based on the developed theory, several design strategies are proposed to further enhance the maximum PTO, which includes the intentional mismatching among heave natural frequency of the buoy, natural frequency of the inner dynamic system, and peak frequency of input wave spectrum. By using the intentional mismatching strategy, the generated power is actually increased and the required damping value is significantly reduced, which is a big advantage in designing the proposed WEC with practical inner LEG (linear electric generator) system.

• Journal of Drive and Control
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• v.12 no.3
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• pp.25-35
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• 2015

The hydraulic power-take-off mechanism (HPTO) is one of the most popular methods in wave energy converters (WECs). However, the conventional HPTO with only one direction motion has a number of drawbacks that limit its power capture capability. This paper proposes an adjustable moving angle wave energy converter (AMAWEC) and investigates the effect of the moving angle on the performance of the wave energy converter to find the optimal moving angle in order to increase the power capture capability as well as energy efficiency. A mathematical model of components from a floating buoy to a hydraulic motor was modeled. A small scale WEC test rig was fabricated to verify the power capture capability and efficiency of the proposed system through experiments.

• Korean Journal of Applied Biomechanics
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• v.18 no.1
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• pp.53-62
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• 2008

The purpose of this research was to analyze the kinematics of the 205B movement in platform diving. For the experiment, 2 athlete from the national diving team were chosen as the subject and two S -VHS video cameras were used. For this diving players preparing for the olympics participated. It was shown that the mean total took $1.112{\pm}0.12s$. In order to perform better, the divers time must be increased, at take off and rotation must be done high up and the horizontal distance must be shorted to main entrance of the water. To enter the water safely, the jump has to be high, the horizontal speed slow and the vertical speed as fast as possible. At E1 the lower limbs change in speed should decrease and after the rotation begins at E2. At take off, the jump is more important than the rotation for the performance of the dive. At take off, the trunk angular velocity was high, and this was needed to jump high for moment of inertia for rotation because for efficient jumping the upper body has to spread out and increase the height of the center of mass.

• Korean Journal of Applied Biomechanics
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• v.15 no.2
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• pp.129-138
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• 2005

The purpose of this study was to investigate the techniques used by long jumpers who recorded over 8meters in 2002 Busan Asian Game and 2003 Daegu Universiade. The kinematic characteristics from the last three stride to takeoff at the takeoff board were analyzed such as velocities, heights and angles. The real-life three-dimensional coordinates of 20 body landmarks during each trial were collected using a Direct Linear Transformation procedure. The conclusion were as follows; 1. The height variation who recorded over 8 meters of center of gravity of the jumpers at the last stride was under 8cm. In order to record over 8meters the national long jumpers should have under 10cm height variation. 2. In the approach phase the horizontal velocity of the jumpers should reach to 10.5m/s in last three strides and 9.79m/s in touch down at take off board. 3. The horizontal velocity at take off board must have over 8.51m/s and the vertical velocity must have 3.75m/s simultaneously in order to record 8meters. 4. The forward body lean angle should have over 20degrees with pushing the take off board in forwarding movement. The appropriate body variation range ratio between take off and touch down should be 1.2 vs 1 and the trunk angle at touch down on the board should be close to the erect posture for higher body flight.