• 대한기계학회논문집A
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• 제34권1호
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• pp.27-33
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• 2010

본 논문에서는 무전기에 사용되는 마이크로스피커의 누설자속을 최소화하는 설계에 초점을 맞추었다. 진동판표면으로 누설되는 자속을 저감시키고 전자기력을 향상시키기 위한 최적설계로 반응표면법을 적용하였다. 최적설계의 목적함수는 전자기력과 누설자속이며, 폴피스 두께, 마그넷 그레이드, 요크 두께의 세 가지 변수에 의해 결정되어진다. 전자기력과 누설자속은 반응표면법으로 각 조건에서 계산되었고, 평가된 결과에 의해 최적화되었다. 폴피스 두께 0.9 mm, 마그넷 그레이드 N42H, 요크 두께 0.75 mm 일 때, 전자기력은 초기 모델과 동등한 수준을 만족하였고, 자속 누설량은 11.8% 저감되었다.

• 한국지능시스템학회논문지
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• 제21권3호
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• pp.372-377
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• 2011

본 논문에서는 하이브리드 자기베어링 시스템의 효과적인 제어 방안 마련을 위한 기법 제안을 목표로 한다. 자기베어링 시스템에서의 제어 목적이란, 회전자(rotor)의 회전을 외부의 물리적 접촉 없이 자기장의 힘만으로 동작하도록 베어링의 위치를 최대한 센터에 위치케 하는 것이다. 기본적으로 자기베어링 시스템은 비선형적 동적방정식으로 구성되기 때문에, 제어 목적을 달성하기 위한 제어 입력 신호의 설계가 쉽지 않으며, 외부 환경의 영향에 따른 시스템 파라미터 변화율에도 많이 민감한 편이다. 본 논문에서는 자기베어링 시스템의 비선형성에 대한 해석 방안으로 퍼지 모델링을 통해 시스템을 재해석하게 되며, 제어 목적에 대한 설정은 선형행렬 부등식 기반 안정화 문제로 변환하여 제어 입력을 설계하고자 한다. 해당 퍼지 모델링 및 제어 알고리즘의 정당성은 시뮬레이션을 통해 검증된다.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.308-313
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• 2015

This paper describes a technique for complete identification of a two-dimensional scattering object and multiple objects immersed in air using microwaves where the scatterers are assumed to be a homogenous dielectric medium. The employed technique consists of initially retrieving the shape and position of the scattering object using a linear sampling method and then determining the electric permittivity and conductivity of the scatterer using adjoint sensitivity analysis. Incident waves are assumed to be TM (Transverse Magnetic) plane waves. This inversion algorithm results in high computational speed and efficiency, and it can be generalized for any scatterer structure. Also, this method is robust with respect to noise. The numerical results clearly show that this hybrid approach provides accurate reconstructions of various objects.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.153-155
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• 2007

It is as result that study to apply mini magnet nerve curer in peripheral nervous system disease treatment. Design and embodied action power and Control Unit in cylinder form of magnet roof object firstly. Yielded service area about special quality of probe of roof object cylinder style and treatment area dimension and distance of treatment pulse secondly. Embody pulse forming course energy value by Probe's form by third, could embody treatment pulse by disease. Specially, through a special quality experiment, saved Damping pulse form and treatment pulse form etc. variously Lately, embodied this to aid a little in disease treatment that follow that there is no invasion that there is no stimulation by medicine development Go amplitude treatment pulse (traditional magneto-therapy of greatly great that strong.) does curative effect greatest at short time and becomes thought that demand is magnified greatly at the future in this research.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.49-51
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• 2007

It is as result that study to apply mini magnet nerve curer in peripheral nervous system disease treatment. Design and embodied action power and Control Unit in cylinder form of magnet roof object firstly. Yielded service area about special quality of probe of roof object cylinder style and treatment area dimension and distance of treatment pulse secondly. Embody pulse forming course energy value by Probe's form by third, could embody treatment pulse by disease. Specially, through a special quality experiment, saved Damping pulse torn and treatment pulse form etc. variously. Lately, embodied this to aid a little in disease treatment that follow that there is no invasion that there is no stimulation by medicine development. Go amplitude treatment pulse (traditional magneto-therapy of greatly great that strong) does curative effect greatest at short time and becomes thought that demand is magnified greatly at the future in this research.

• 한국자기학회지
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• 제5권5호
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• pp.579-582
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• 1995

The use of amorphous magnetic alloys as tags or targets in electronic article surveillance systems such as antishoplifting desvices is briefly reviewed. Improved tags became possible with the discovery in 1988 of asymmetric magnetization reversal (AMR) in certain amorphous alloys annealed in applied field approximately equal to the earth's field. These asymmetric hysteresis loops are highly unusual, if not unique, and so greatly diminish the probability of false alarms in a detection system. furthermore, the jump field Hj, which is the coercive field in negative applied fields, can be controlled over a useful range by controlling the field applied to the sample during annealing. By applying several tags to an object, each with a different jump field, it is possible to identify the object with a numeric code that can be remotely read by nonoptical means.

• Journal of Magnetics
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• 제21권4호
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• pp.491-495
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• 2016

We developed an embedded Object-Oriented Micromagnetic Frame (OOMMF) script schemes for more flexible simulations for complex and dynamic mircomagnetic behaviors. The OOMMF can be called from any kind of softwares by system calls, and we can interact with OOMMF by updating the input files for next step from the output files of the previous step of OOMMF. In our scheme, we set initial inputs for OOMMF simulation first, and run OOMMF for ${\Delta}t$ by system calls from any kind of control programs. After executing the OOMMF during ${\Delta}t$, we can obtain magnetization configuration file, and we adjust input parameters, and call OOMMF again for another ${\Delta}t$ running. We showed one example by using scripting embedded OOMMF scheme, tunneling magneto-resistance dependent switching time. We showed the simulation of tunneling magneto-resistance dependent switching process with non-uniform current density using the proposed framework as an example.

• 전기의세계
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• 제26권5호
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• pp.74-82
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• 1977

This study is to present a method for reductin of noise and vibration of home electric motors coupled to the mechanical load causing relatively big amplitude of vibration. The noise and vibration factors have been analysed in the divisions such as the pattern related to the armature reaction, the pattern related to the circulating current by induction and the other patterns those are affected by a dditive magnetic field and have an effect on mechanical constants. From the systematic mutual relations between the patterns and daping effects, it is possible to derive the fundamental measure for reduction of noise and vibration. Vibration measurements and analysis were carried out in accordance with the planned experimentation and thre object model was chosen randomly from the production line in a factory where home electric machines were mass-produced. Based on the above-mentioned fundamental measure, suppression effects on noise and vibration have been analysed according to the number of slots, the amount of rotor skew and the way the stator winding connection was series or parallel.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.842_843
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• 2009

본 논문에서는 Magnetic Inductance Tomography System(이하 MIDT System)을 이용하여 대상물체의 위치와 밀도 변화 시의 신호해석에 관한 연구를 하였다. MIDT System은 외부에서 자기장을 인가하고, 인가된 자기장에 의해 변화하는 자기장을 홀센서로 검출한다. MIDT System은 시스템이 간단하고 대상물체에 물리적인 손상을 가하지 않고 측정이 가능하다. 본연구에서는 MIDT System을 직접 구성하여 이론적인 해석신호와 실제 실험을 통한 해석신호의 일치여부를 비교 분석하고 MIDT System을 이용하여 대상물체 위치 변화시의 신호 해석할 수 있는 적합성 여부를 판단하였다.

• Journal of Astronomy and Space Sciences
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• 제34권1호
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• pp.37-44
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• 2017

In this paper, analysis results of the photometric data of DO Dra will be presented. DO Dra had been observed with 1 m LOAO telescope and 0.6 m CBNUO telescope from 2005 through 2014. The data shows kind of periodic oscillation behavior in the orbital period and also in the spin period. It has been found that these QPOs are not observed always and that the periods vary from 30 min to 80 min. We also found that the period variation seems to repeat itself with the period of 13.5 days. It is essential to monitor this object in the future as well as to carry out model calculation in order to have better understanding of these QPO phenomena.