• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.98-99
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• 2016

The aim of study is to develop a dual driven ship berthing/deberthing system with $360^{\circ}$ steerability. A large ship used bow thruster, side thruster and pod propulsor etc. when approaching to a pier. But as marine leisure boats become large-scaled, the number of accidents is recently increasing what caused a ship to crash into a ship and a ship to crash into mooring facilities during berthing/deberthing on a marina. To solve the problem, the control responsiveness of a joystick connected with two motors and a propeller was checked and torque was increased by the electromagnetic design of magnetic gear. A sea trial test was carried out to investigate a performance of the developed system in the real sea.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.3
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• pp.30-38
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• 2015

As products using LEDs are developed actively, also there has been large request for LED products that can replace traditional lamps like fluorescent lamps and metal halide lamps. But so far there is no proper standard that manufacturer can use and test it. As a result manufacturer can't develop retrofit LED lamps and sell it even they have technology. In this study, by analyzing control gear for fluorescent lamp that is currently used in market which is magnetic or electronic ballast, I'd like to develop proper test method by investigating compatibility between all-type control gear and LED retrofit products.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3633-3640
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• 2010

For a development of non-contact magnet gear which is magnetized as a helical shape, a method of 3-dimensional FEM analysis is used. An elementary technique required for magnetic property analysis and parts design about magnet gear is ensured. In order to test a performance of clean conveyor and turning device which is composed with magnet gear, a clean class 10 environment booth is used for a trial test. It is verified that the magnet conveyor can be acceptable under a condition of clean class 10 by a result of trial test about transfer speed, maximum torque permission, cleanness, maximum transfer weight, existence of hunting and degree of noise.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.11
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• pp.646-654
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• 1999

This paper deals with PWM patterns for harmonic reduction in inverter fed traction motors and the gear changing techniques for the variable speed drive of traction motor. GTOs are used as switching device of inverter because traction motor is a large load. To derive PWM rattern which can minimize the harmonics with the limited switching frequency, the output current and torque characteristic of SPWM and SHE PWM was analyzed. GTO inverter used for traction motor drive includes harmonics in the output current and torque by the limitation of switching frequency. However, the hybrid PWM method that adopt SPWM in the range of low frequency and SHE PWM in upper frequency range can achieve less harmonic characteristics in GTO inverters. If the traction motor is driven in variable speed by the proposed PWM pattern, 7 times of gear changing is needed. At the instant of the mode change, magnetic flux and torque may be altered and the large current flow. To reduce such an undesirable transient behavior, it is also presented the technique for the gear changing of inverter fed traction motor drive operated with the hybrid PWM. The results are verified by simulations and experiments.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.750-751
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• 2015

본 논문에서는 스칼라포텐셜을 계변수로 하는 2차원 공간고조파법을 이용하여 동축 마그네틱 기어의 자계 특성을 해석하였다. 공극자속밀도는 중첩의 원리에 의해 얻어지며 표면 부착형 영구자석을 가지는 고속 회전자 모델과 Inset type의 자속 집중형 저속 회전자 모델로 구분되었다. 공간고조파법에 의한 결과는 유한요소해석과의 비교를 통해 타당성을 검증하였다.

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.3114-3120
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• 2023

A high-accuracy magnetic field measurement device based on a cyclotron is being developed for accelerator mass spectrometry (AMS). In this study, a magnetic field measurement device consisting of a Hall probe sensor, piezo-motor, and step motor was developed to measure the magnetic field of the AMS cyclotron magnet. The Hall probe sensor was calibrated to achieve positional accuracy by using polar coordinates. The measurement results between the ratchet gear and piezo-motor, which are the instruments used for driving the measurement device, were analyzed. The measurement result of the device with a piezo-motor exhibits a difference of 5 Gauss (0.04%) as compared with the simulation result.

• Journal of Aerospace System Engineering
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• v.15 no.1
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• pp.7-18
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• 2021

A semi-active MR damper landing gear is a damper that generates a fluid damping force and a magnetic field control damping force when the MR fluid passes through annular flow paths. In the case of MR fluid passing through annular flow paths, an incompletely developed flow inevitably occurs, causing an error in calculating damper inner forces including the fluid damping force. This error results in an inaccurate design of damper structural parameters and control gain selection, resulting in deterioration of dynamic characteristics and shock absorption performance of the landing gear. In this paper, we derived a mathematical model of an MR damper landing gear considering additional damping force generated in the entrance region of annular flow paths of the MR damper. If the mathematical modeling derived from this paper is applied to the design and optimization process of an MR damper landing gear, excellent performance of the MR damper landing gear is expected.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.425-426
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• 2008

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.433-438
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• 2003

The recent operating trains including the high speed train are mostly moving system on the rail and system use the mechanical propulsion force to drive the gear and wheel by the traction motor. Advanced countries are interested in Magnetic Levitation Vehicle and they have been studying about it continuously. Thus this paper is analyzed the feature of analysis the feature for Linear Induction Motor as the propulsion equipment of Magnetic Levitation Vehicle. And the Magnetic Levitation Vehicle is being developed for the transportation system of next generation using the Finite Element Method

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.39 no.2
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• pp.90-94
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• 2002

This paper is related to remote meter-reading using magnetic sensor. Scan system which is developed recently has week point of temperature, humidity, dust, oscillation To solve these problems, this study used magnetic action to measure the consumption of gas. Gas consumption was detected by interaction of a permanent magnet and hall element. Permanent magnet was pasted on rolling change-gear in normal gas meter and hall sensor was pasted on the external wall of normal gas meter. This experiment proved high accuracy and wasn't influenced by temperature, humidity, oscillation and dust