• Journal of Institute of Control, Robotics and Systems
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• v.22 no.9
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• pp.723-732
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• 2016

This paper proposes an approach to fused navigation of an unmanned surface vehicle(USV) and to detection of the outlier or interference of global positioning system(GPS). The method fuses available sensor measurements through extended Kalman filter(EKF) to find the location and attitude of the USV. The method uses error covariance of EKF for detection of GPS outlier or interference. When outlier or interference of the GPS is detected, the method excludes GPS data from navigation process. The measurements to be fused for the navigation are GPS, acceleration, angular rate, magnetic field, linear velocity, range and bearing to acoustic beacons. The method is tested through simulated data and measurement data produced through ground navigation. The results show that the method detects GPS outlier or interference as well as the GPS recovery, which frees navigation from the problem of GPS abnormality.

• Journal of Institute of Convergence Technology
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• v.3 no.1
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• pp.1-8
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• 2013

High-precision surface actuator, in which in-plane motion is realized by not two-dimensional actuator superposing linear actuators but integrated planar actuator, has been developed to cope with the severe target performance like precise motion with large envelope. It is very difficult to accomplish the performance with the traditional actuating principle. So, various methods have been tried to break through the problem. This paper discusses some meaningful trials performed in the Nano Measurement and Precision Motion Control Lab. of Korea National University of Transportation.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.6
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• pp.371-379
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• 2000

The 4-pole linear homopolar synchronous motor (LHSM), so called linear inductor motor, is composed of the figure-of-eight shaped 3-phase armature windings, DC field windings, and the segmented secondary with the transverse bar track. To reduce the calculation time, the simplified 3D finite element model with equivalent reluctance and/or permanent magnet is presented. To obtain a clear understanding, propriety and usefulness of the developed model, we compare with the results of simplified 3D FEA, general 3D FEA and test. Consequently, the results of simplified and 3D FEM analysis are nearly identical, but much larger than that of static test at d-axis armature excitation. Therefore the improved FEA model, such as full model with half slot, is needed for the precise analysis.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.3 s.94
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• pp.293-299
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• 2005

This paper introduces a program by which one can perform measurement, analysis, and simulation of electro-magnetic environment which affects on vehicular AV receivers. An integrated system of EM environment collected, GPS(Global Positioning System) informations, and developed simulation program can be an important evaluating tool for the analysis of automobile AV receivers.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.917-923
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• 2001

This paper presents the fabrication and testing results of a dual stage microactuator system for fine positioning of magnetic heads in hard disk drives. An electrostatic rotary microactuator was newly designed and fabricated. The microactuator was integrated into the head gimbal assembly of a disk drive system and its dynamic characteristics were investigated. Experimental results show that natural frequency and voltage gain of the microactuator are 4.3 KHz and 25 nm/V and the dual stage microactuator system achieves the tracking accuracy of 30 nm.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.3
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• pp.199-204
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• 2007

This paper presents design of interleave configured dc-dc converter for high power distributed power system applications. The multi channel interleaving buck converter with small inductance has proved to be suitable for micro-grid, requiring medium output voltages, high output currents and fast transient response. Integrated magnetic components are used to reduce the size of the converter and improve efficiency. Unlike conventional methods, the distributed approach requires no centralized control, automatically accommodates varying numbers of converter cells, and is highly tolerant of subsystem failures. A general methodology for achieving distributed interleaving is proposed, along with a specific implementation approach. The design and simulation verification of switching frequency 10 kHz system is presented with interleaved clocking of the converter cells. The simulation (simulated by PSIM 6.1) results corroborate the analytical predictions and demonstrate the tremendous benefits of the distributed interleaving approach.

• Journal of the Korean Ceramic Society
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• v.37 no.10
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• pp.1001-1007
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• 2000

스크린 프린트법으로 MMIC(Monolithic Microwave Integrated Circuit)용 YIG 후막을 제조하였고, YIG의 조성과 프린트 조건의 변화가 다결정 $Y_{3-x}$C $a_{x}$ F $e_{5-x}$Z $r_{x}$ $O_{12}$ (x=0~0.3) 후막의 미세구조 및 자기적 특성에 미치는 영향을 고찰하였다. $Ca^{2+}$와 Z $r^{4+}$ 의 치환 첨가량이 0.2인 $Y_{2.8}$ C $a_{0.2}$F $e_{4.8}$ Z $r_{0.2}$ $O_{12}$ 조성의 paste로 제조된 YIG 후막의 경우, 포화 자화값이 최대를 나타내었으며, 강자성 공명 흡수선 폭은 최소를 나타내었다. 또한, YIG 후막의 두께 및 소결 유지시간 등의 제조조건을 제어함에 따라 치밀화 및 자기 특성이 향상됨을 확인할 수 있었다.다.다.

• Radiation Oncology Journal
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• v.36 no.4
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• pp.254-264
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• 2018

This article reviewed new trends and controversial issues, including the intensification of chemotherapy and recent brachytherapy (BT) advances, and also reviewed recent consensuses from different societies on the management of locally advanced cervical cancer (LACC). Intensive chemotherapy during and after radiation therapy (RT) was not recommended as a standard treatment due to severe toxicities reported by several studies. The use of positron emission tomography-computed tomography (PET-CT) and magnetic resonance imaging (MRI) for pelvic RT planning has increased the clinical utilization of intensity-modulated radiation therapy (IMRT) for the evaluation of pelvic lymph node metastasis and pelvic bone marrow. Recent RT techniques for LACC patients mainly aim to minimize toxicities by sparing the normal bladder and rectum tissues and shortening the overall treatment time by administering a simultaneous integrated boost for metastatic pelvic lymph node in pelvic IMRT followed by MRI-based image guided adaptive BT.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.1
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• pp.66-73
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• 2016

An Inertial Measurement Unit (IMU)-based Attitude and Heading Reference System (AHRS) can calculate attitude and heading information with long-term accuracy and stability by combining gyro, accelerometer, and magnetic compass signals. Motivated by this characteristic of the AHRS, this paper presents a Motion-Tracking and Localization (MTL) method for a person or walking robot using multi-AHRSs. Five AHRSs are attached to the two calves, two thighs, and waist of a person/walking robot. Joints, links, and coordinate frames are defined on the body. The outputs of the AHRSs are integrated with link data. In addition, a supporting foot is distinguished from a moving foot. With this information, the locations of the joints on the local coordinate frame are calculated. The experimental results show that the presented MTL method can track the motion of and localize a person/walking robot with long-term accuracy in an infra-less environment.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.281-283
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• 1998

The 4-poles LHSM with transverse bar track was designed on the base of the performance equations and the equivalent circuit model. However, the magnetic shape factors, such as Carter's and Green's coefficients, $B_{min}/B_{max}$ and leakage factors, were important in the design and analysis of LHSM. Consequently, these coefficients were computed from the analytical expressions and examined from FEM analysis in detail.