• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.1
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• pp.211-215
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• 2017

The APF (All Pass Filter) method that utilizes the computational power of the controller is most commonly used. However, since the calculation of the filter coefficient is complicated, the calculation is carried out in advance. It is difficult to apply it to the frequency fluctuation environment because the coefficient value is fixed. In this paper, a new control method of single phase PLL that can be usefully used in PWM converter device for electric railway was explained. Comparison and examination of similarities and differences between the conventional APF method PLL controller method and the newly proposed modified MA filter method PLL technique were performed. The possibility of implementation of the modified MA filter method through computer simulation was analyzed. In conclusion, the method proposed as the conclusion was applied to the APU(Auxiliary Power System) of 8200 Series Electric Locomotive and its usefulness was confirmed.

• Journal of Korean Society of Transportation
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• v.20 no.2
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• pp.188-188
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• 2002

• Journal of Korean Society of Transportation
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• v.13 no.4
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• pp.113-113
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• 1995

• Transportation Technology and Policy
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• v.10 no.5
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• pp.62-71
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• 2013

• Journal of Korean Society of Transportation
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• v.19 no.6
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• pp.257-257
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• 2001

• Journal of Korean Society of Transportation
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• v.12 no.3
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• pp.15-27
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• 1994

A mathematical model and its solution algorithm are proposed for computing the capacity of terminal control area. The model is built based on dynamics of aircraft flying on pre-established approach path and its solution algorithm employs a numerical method. The model computes the minimum separation of two aircraft at the entry fix of the terminal control area, which assures that air traffic separation rules are not violated during the approach phase, thereby computes the capacity. The model might be applied for designing approach paths for a new airport, for rearranging paths of an existing airport or establishing approach control procedures.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.1
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• pp.16-23
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• 2018

PM synchronous motor may be rotated to an arbitrary direction and speed by outside wind under natural condition in cases where the fan is applied outside, such as in vehicle radiators and outdoor air-conditioners. Sensorless controls that cannot detect rotor position requires additional sensorless control algorithm because a rotor is rotated by an external load. In this study, the sensorless control of a PM synchronous motor under naturally rotating condition is proposed. The natural rotation conditions are classified as forward high-speed rotation, reverse high-speed rotation, and low-speed rotation. Experiment results verify the performance of the sensorless control, including the rotor speed and position detection at natural rotation mode and switch to the closed-loop sensorless control.

• Structural Engineering and Mechanics
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• v.85 no.5
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• pp.607-620
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• 2023

The classical optimal control (COC) method has been widely used for linear quadratic regulator (LQR) problems of structural control. However, the equation of motion of the structure is incorporated into the optimization model as the constraint condition for the LQR problem, which needs to be solved through the Riccati equation under certain assumptions. In this study, an explicit optimal control (EOC) method is proposed based on the explicit time-domain method (ETDM). By use of the explicit formulation of structural responses, the LQR problem with the constraint of equation of motion can be transformed into an unconstrained optimization problem, and therefore the control law can be derived directly without solving the Riccati equation. To further optimize the weighting parameters adopted in the control law using the gradient-based optimization algorithm, the sensitivities of structural responses and control forces with respect to the weighting parameters are derived analytically based on the explicit expressions of dynamic responses of the controlled structure. Two numerical examples are investigated to demonstrate the feasibility of the EOC method and the optimization scheme for weighting parameters involved in the control law.

• Journal of Korean Physical Therapy Science
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• v.25 no.1
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• pp.62-74
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• 2018

Background: The purpose of this study is intended to evaluate the effectiveness and analyse the change on flexibility, muscular volume and pain of university students with low back pain by stabilization exercise using XCO. Methods: The subjects(N=23) with low back pain are recruited from K university located Chungbuck. The subjects which are divided to 2 group as experimental group(N=12) conducted the stabilization exercise using XCO and control group(N=11) conducted the general stabilization exercise. The flexibility, muscular volume and pain were measured before and after intervention. Results: There were no significant differences(p>.05) in sex, age, height and weight among subjects. Also there were no significant differences(p>.05) in muscular volume and pain between of the experimental group and control group. A significant difference(p<.05) in the flexibility, contraction EO(External Oblique), contraction IO(Internal Oblique), contraction TA(Transverse Abdominal) and pain in the experimental group. There was significant difference(p<.05) in the flexibility, contraction EO(External Oblique), contraction IO(Internal Oblique) and pain in the control group. There was a significant difference(p<.05) in the flexibility of the experimental group between the control group. Conclusion: Based on this study, through a variety of age and various intervention period to apply more subjects conducting Stabilization exercise using XCO should continue.

• The Korean Journal of Food And Nutrition
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• v.37 no.1
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• pp.9-16
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• 2024

To produce super sweet corn sikhye, substituted for sweetener, the ratio of rice and super sweet corn was adjusted and processed with complex enzymes during saccharification, and their physicochemical and sensory properties were analyzed. The soluble solid content of the control and Corn-5 showed significantly high content at 13.50 °Brix, and the reducing sugar content of Corn-5 showed the highest content at 9.45%. The control showed the lowest free sugar content among all the experimental groups, excluding maltose content. In the enzyme-treated corn sikhye group, as the amount of super sweet corn increased, the content of sucrose decreased and the contents of glucose and fructose increased. The content of ascorbic acid and polyphenol compounds increased as the amount of super sweet corn increased. DPPH and ABTS radical scavenging abilities increased with increasing ratio of super sweet corn and enzyme treatment compared to the control. In the case of sensory evaluation, Corn-3, which substituted 30% of super sweet corn for rice and treated with enzymes, showed higher evaluations in taste, sweetness, and overall preference than those of the control.