• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.570-574
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• 1993

This paper proposes a new method of estimating the position and heading angle of a mobile robot moving on a flat surface. The proposed localization method utilizes two passive beacons and a single rotating ultrasonic sensor. The passive beacons consist of two cylinders with different diameters and reflect the ultrasonic pulses coming from the sonar sensor mounted on the mobile robot. The geometric parameter set of beacon is acquired from the sonar scan data obtained at a single mobile robot location using a new data processing algorithm. Form this parameter set, the position and heading angle of the mobile robot is determined directly. The performance and validity of the proposed method are evaluated using two beacons and a single sonar sensor attached at the pan-tilt device mounted on a mobile robot, named LCAR, in our laboratory.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.59-61
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• 2006

The single phase switched reluctance motor(SRM) is simpler in control circuit because the number of switching devices is fewer than the poly phase SRM. The energy density per unit volume is very big because all stator poles are excited simultaneously by a single switching power source. But it must be provided a starting device on account of not being generated the starting torque at specific rotor positions. And also it has some demerits that have a torque ripple, noise and vibration because of being excited by switching pulse power source. Therefore, to make up for these demerits, it is realized many studies for the structure design used by computer and the operating methods by power electronics technique. In this paper, we'll present the comparison of the single phase SRM with the various rotor pole face types, as like stepped rotor pole face type and general rotor pole face type. For the torque characteristics analysis.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.119-121
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• 2008

In underground power cable system, the device for limiting over-voltage is needed when transient over-voltage break out between sheath and ground. For this reason, the SVL(Sheath Voltage Limiter) has been applied on weak points. But the broken SVLs which are installed on the single point bonding system on underground cable are frequently found. In this paper, EMTP(Electromagnetic Transient Program) is utilized to analyze effects on the installation methodology of the parallel ground conductor and SVL for the single point bonding system on the underground cable. The result shows that the proposed installation methodology can be applied for single point bonding system and contribute for power system stabilization.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.482-485
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• 2002

We synthesize a (Y,Sm)BCO(its composition is (Y/Sm123+0.4Y/Sm211)+1wt%CeO$_2$) powders using polymeric complex method. (Y,Sm)BCO powders are prepared as heated at 970$^{\circ}C$. For measurement of this characterization, We measure XRD and SEM. We use TSMG method for fabricatlon of (Y,Sm)BCO single crystal. The manufactured VBCO single crystal is measured by a magnetic distribution device using 0.5 Tesla magnet. As the result of this measurement, we find that a trapped magnet fields are 550 Gauss.

• The Journal of Korean Association of Computer Education
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• v.11 no.6
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• pp.95-102
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• 2008

In this paper through the implementation of cooperative learning using SDG, education puzzle actually applies to computer training. SDG(Single Display Groupware) which one computer display have a multi-input devices can work as a collaborative system. Learners are performing together through SDG-based cooperative learning system. SDG cooperative learning with a multi-input device is superior to traditional learning with individual. We have implementation of the puzzle game with this fact. This system through effective education and raising their children's education participation rate will be able to do.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.166-168
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• 2004

Conventional Switched Mode Power Supplies(SMPS) with diode-capacitor rectifier have distorted input current waveform with high harmonic order contents. Typically, these SMPS have a power factor lower than 0,7. To improve with this problem the power factor correction(PFC) circuit of power supplies has to be introduced. Specially, to the reduce size and manufacture cost of power conversion device, the single-stage PFC converter is increased to demand as necessary of study. In this paper, comparative analysis of Valley-fill, boost and feedforward type single stage power factor correction circuit based on the flyback converter is given. Also, the validity of designed three type of single stage PFC circuit are confirmed by simulation and experimental results.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.2
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• pp.174-179
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• 2005

We have designed a novel single cell gap transflective display associated with dual orientation of the liquid crystal. Owing to hybrid alignment in reflective part, the effective cell retardation value becomes half of cell retardation value in transmissive part where the LCs are homogeneously aligned. This study shows the possibility to manufacture the transflective display with a single gamma curve for reflective and transmissive region. The new device shows a high image quality with relatively easy fabrication.

• Korean Journal of Human Ecology
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• v.7 no.2
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• pp.113-119
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• 1998

The purpose of this study was to investigate the effect of geometrical structure on the heat transfer of insulating nonwovens. Commercially available single and double layered polyester nonwovens have used. Thermal conductivity, k and thermal conductance, h were measured by using a constant temperature sandwich type device at dry and wet state. The results obtained were as follows: 1. Double layered nonwovens showed slightly lower thermal conductance and higher warmability than single layered nonwovens. 2. As moisture regain increased, double layered nonwovens showed higher increasing rate of thermal conductivity than single layered nonwovens.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.05a
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• pp.224-233
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• 2002

A common YBCO powder has been made from a mixture of Y123 and Y211 that heated at different temperatures, respectively. The synthesis temperature of Y211 is lower than Y123. If Y211 has been heated as a synthesis temperature of Y123, a particle size of it may be very coarse. It exist as one of main defects for superconductor. But We simultaneously synthesize a YBCO(its composition is (Y123+0.4Y211)+$lwt%CeO_2$) using polymeric complex method. In the YBCO, the Y123 is synthesized lower temperature than other methodes, and its crystal structure is orthorombic. For measurement of these superconducting properties, we fabricated a YBCO single crystal. The manufactured YBCO single crystal is measured a magnetic distribution device using 0.5Tesla magnet and trapped magnet fields in it are 0.2Tesla.

• Journal of Aerospace System Engineering
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• v.7 no.4
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• pp.12-17
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• 2013

Control Moment Gyroscope(CMG) is one of the most efficient momentum exchange devices for satellite attitude control and essential device for agile maneuver system. This paper presents the details of a designed Single Gimbal CMG with a constant speed momentum wheel and single axis attitude control unstable to stable. In order to keep the naturally unstable equivalent point, it should be controlling the gimbal constantly. The experimental data are compared with theoretical result and requirements are used to verify their performance specifications.