• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.1
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• pp.190-195
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• 2004

An exhaust brake system is composed of a gate valve, a pneumatic cylinder and an on-off solenoid valve. An on-off solenoid valve which is a key component of the exhaust brake system ought to have characteristics such as high reliability and long life for reducing the foot brake and tires damage, and for driver's fatigue relief of middle/large size vehicles running a long distance. In this paper, an on-off solenoid valve which is used for vehicle brake system was studied. For the performance evaluation of the on-off solenoid, electromagnetic characteristics and dynamic characteristics are analyzed. On the basic study for the performance improvement of exhaust brake system, pneumatic circuit and pneumatic valve of on-off solenoid type were suggested and the performance of pneumatic valve through the test procedure was evaluated.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.39-41
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• 2001

This paper deals with a simulation and a position control for linear synchronous motor with Halbach array (HA) permanent magnet mover. We derived decouple the forces (thrust, normal force) by magnetic field modeling of the electromagnetic field analysis. The results of control simulation for HA-PM having air-core primary are calculated using M Simulink.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.948-950
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• 2005

This paper compared the test data with the loss when a conductor is exposed to the magnetic fieldof reactors after generating external magnetic field in specimen by means of an air core reactor model and the calculation of loss came from a tying the combination of FEM and integral method. It was applied to the loss measurement of transformers due to leakage flux.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1267-1269
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• 2005

This paper presents the design for improving performance of the high-precision Magnetic levitation system. Motor performance on various design schemes such as thickness and magnetizing patterns of the permanent magnets, pole pitch, length of air gap, turn number of windings, and thickness of the aluminum-core has been investigated in detail by using FEM(Finite Element Method) Simulation-based DOE(Design of Experiments) method is also applied in order to reduce the large number of analysis according to each design variable and consider the effect among variables. The design in all aspects is proposed by an optimization algorithm using regression equation derived from the simulation-based DOE.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.285-290
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• 2005

Micro On-Off valves are currently recognized as the core technology in the fields of the micro fluid chip fur medical applications and production lines of semi-conduct chip. Micro valves that operate by compressed air need the high-speed responsibility, repeatability, the absorbability and the uniform pressure by the poppet. In this study, Micro On-Off valves that posses the high-speed responsibility and the high rate of flow have designed and analyzed through the law of equivalent magnetic circuit and Finite Element Method (FEM) respectively. In case of poppet, Flow field characteristic was analyzed by the variation of poppet and it was able to display flow field by changing the location of the poppet. Also, we verified possibility of the design through the static and dynamic pressure and the 3D distribution curve of the force by working the front poppet.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.273-276
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• 2006

To generate electricity from wind energy, wind turbine generally has a rotor blade. Since this rotor blade is a kind of the rotating machinery, the wake from the rotor is very Important role in the side of the aerodynamic performances. Thus the study about wake is essential to analyze wind turbine aerodynamics. In this study wake characteristics are analyzed by hot-wire probe in the K.A.F.A(Korea Air Force Academy) wind tunnel. It is possible to analyze the wake characteristics by hot-wire probe from acquiring the velocity fluctuations at given positions in the flow. This velocity data are arranged by trigger signal at same azimuth of the blade in periodic manner of the rotor blade. From this various wake characteristics are found : radial and axial position of the tip vortex, vortex core characteristics in the flow etc.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.871-872
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• 2009

FDP(Flight Data Processor) is processing of flight data for safety air traffic management. FDPs takes core function in aviation safety. Position estimation of aircraft is a key feature of the FDPs. In this paper, the requirements for position estimation of aircraft was defined.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.833-836
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• 1995

A capacitor discharge impulse magnetizer is used to produce a high current pulse of short duration in a magnetizing fixture for magnets of the various shapes. The problem of designing custom fixtures for magnetization has often been considered more of conventional experience than a scientific theory. Therefore, the design of magnetizingfixture has until recently been a "cut and try" process. It was common to literally blow up one or more fixtures beforeachieving the desired results. Finite element CAD package allow the design of such a fixture. Since magnetizing fixtures come in a variety of sizes and shapes, there is usually no simple analysis method that can be used to estimate the field characteristics of the fixtures. Instead, one typically uses finite element analysis. FEA program MAXWELL is the primary tool used here. The purpose of this study was a examine both theoretically and experimentally the field characteristics inside the fixture. Independent of sizes and shapes of magnetizing fixtures, the desired magnetic field can be obtained with resonable predictability. The experimental results have been achieved using a 1000[V], 22.4[KJ] capacitor discharge magnetizer and iron-core fixtures.

• Electronics and Telecommunications Trends
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• v.37 no.4
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• pp.60-69
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• 2022

So far, artificial intelligence (AI)/machine learning (ML) has produced impressive results in speech recognition, computer vision, and natural language processing. AI/ML has recently begun to show promise as a viable means for improving the performance of 5G mobile telecommunication systems. This paper investigates standardization activities in 3GPP and O-RAN Alliance regarding AI/ML applications on mobile telecommunication system. Future trends in AI/ML technologies are also summarized. As an overarching technology in 6G, there appears to be no doubt that AI/ML could contribute to every part of mobile systems, including core, RAN, and air-interface, in terms of performance enhancement, automation, cost reduction, and energy consumption reduction.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.6
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• pp.127-135
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• 1994

This paper is concerned about a high speed electromagnet of Pressure control solenoid valve. Solenoid valve is controlled by means of Pulse width modulation. The magnetostatic field problem on a solenoid is numerically solved by the 2-D axisymmetric finite element method. And permeance method is adopted for analysing the static and dynamic property of solenoid part theoretically. In addition, in this study, experiments on solenoid part were performed in order to measure the magnetic force and plunger displacement. The numerical results coincided with the experimental results. As a result, the magnetic force has the linear relation with displacement of plunger and the primary factors on the performance of PWM type high speed electromagnet are coil resistance, plunger mass, and the length of air gap between plunger and core.