• 조명전기설비학회논문지
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• 제29권10호
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• pp.60-64
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• 2015

Many people think that Electric Vehicles(EVs) is the best method to resolve the problems of running out of fossil fuels. But EVs take long time for charging. So, EVs with battery swapping systems(EVBS) are developed to resolve this problem. Nonetheless, EVBS is not spreaded widely because the method of durability test in couplers is not defined. In this study, the evaluation method of durability test in couplers is defined by some standards and the measurement uncertainty is used to increase the reliability of EV couplers.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.500-501
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• 2007

The method of maintenance in railway is going to be changed to improve reliability on traction equipment. Partial discharge (PD) tests are useful to evaluate the insulation condition of stator winding. This paper describes the use of PD tests with 5 model coils which have the defects such as internal, slot discharge. The PD tests are performed with epoxy-mica coupler 500 pF at various AC voltages. The result of test shows PD pattern can correlate with the species of defects on 5 model coils.

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 하계학술발표회
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• pp.20-21
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• 2003

Erbium doped fiber (EDF) sources are useful devices for characterization of optical components for wavelength division multiplexing (WDM) fiber optic communication system. Therefore, there are many efforts to extend the bandwidth and to increase the power of the light source. Especially, L-band ASE source uses the low inversion state of EDF. It makes the power efficiency very low and needs a lot of fiber as several times as the fiber needed in C-band ASE generation. (omitted)

• 조명전기설비학회논문지
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• 제21권1호
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• pp.148-156
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• 2007

본 논문은 원거리 및 직선구간에 동작되어지는 Stocker 시스템에 대해 설명하고 있다. 파티클 발생을 줄이기 위해 Stocker의 전원은 비접촉 전원장치를 사용한다. 기존 비접촉 전원장치보다 회로구성과 토폴로지를 간략화 하였다. 이를 바탕으로 시제품을 제작하여 상용화에 가능함을 보이고자 한다. 비접촉 전원장치 전체 제어 시스템의 구조는 1차측 전원공급장치와 2차측 전원공급장치간 상호 정보를 광모뎀 통신과 TMS320F243을 사용한 구조이며, 비접촉 전원장치와 출력제어를 위해 주파수 제어를 사용하였다. 본 논문에서는 광모뎀 통신을 사용함으로써 크레인의 이동부(2차측 전원공급장치)와 고정부(1차측 전원공급장치)간 1:1통신으로 제어되는 상용화 Stocker 시스템에 적용하였으며, 향후, Stocker 시스템의 멀티 Crane의 동작을 위해 비접촉 전원장치의 고정부와 이동부간 1:다수가 제어 가능하게 하는 연구가 이루어져야 할 것으로 생각된다.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제11B권3호
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• pp.112-118
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• 2001

In the near future, the voltage of power system for passenger vehicle will be changed to 42V from existing 14V./ Because of increasing power and voltage ratings used in the vehicle the motor drive system has high switching dv/dt and it generates electromagnetic interference (EMI) To solve these problems multi-level inverter system may be used The feature of multi-level inverter is the output voltage to be synthesized from several levels of voltage Because of this feature high switching dv/dt and EMI can be reduced in the multi-level inverter system But as the number of level is increased manufacturing cost is getting expensive and system size is getting large. Because of these disadvantages the application of multi-level inverter has been restricted only to high power drives. The method to reduce manufacturing cost and system size is to integrate circuit of multi-level inverter into a few chips But isolated power supply and signal isolation circuit using transformer or opto-coupler for drive circuit are obstacles to implement the integrated circuit (IC) In this paper a drive circuit of 4-level inverter suitable for integration to hybrid or one chip is proposed In the proposed drive circuit DC link voltage is used directly as the power source of each gate drive circuit NPN transistors and PNP transistors are used to isolate to transfer the control signals. So the proposed drive circuit needs no transformers and opto-couplers for electrical isolation of drive circuit and is constructed only using components to be implemented on a silicon wafer With th e proposed drive circuit 4- level inverter system will be possible to be implemented through integrated circuit technology Using the proposed drive circuit 4- level inverter system is constructed and the validity and characteristics of the proposed drive circuit are proved through the experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1778-1780
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• 2004

Microwave heating system of KSTAR consists of ECH and LHCD. ECH and LHCD offer the reliability of operation in the beginning of plasma formation and non-inductive current drive for long time steady state operation with maintaining MHD stability, respectively. LHCD demands 5 GHz of frequency and consists of c-band waveguide, 4-port circuitor, dry dummy load, dual directional coupler, E-bend, arc detector. Our system is a lineup type pulse modulator that has 45 kV of output pulse voltage, 90 A of pulse current, 4 us of pulse width. 1:4 step-up pulse transformer, 7 stages of PFN and thyratron tube (E2V, CX1191D) are used in this modulator. The purpose of this paper is to show the modulator design and experimental result.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2010년도 추계학술발표논문집 1부
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• pp.172-175
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• 2010

본 논문에서는 GaN HEMT를 이용하여 Jamming용 System에 사용될 수 있는 고효율 및 고출력 특성을 가지는 광대역 Amplifier를 제작하였다. Jamming System에서 핵심이 되는 Amplifier는 넓은 범위의 주파수에서 통상적으로 사용되는 출력 신호에 비해 보다 높은 출력의 신호를 구현하는 것이 중요하다. 본 논문에서는 GaN HEMT에 안정적인 전원 공급을 위한 음 전원 Bias 제어 회로와 Sequence 회로 및 온도에 따른 Gain 보상 회로를 구현하였으며, 500~2500MHz의 광대역에서 동작하면서 50W 이상의 출력을 낼 수 있도록 설계하였다. 출력 전력이 향상과 안정적인 동작을 위해 Main 출력 단은 60Watt 급의 GaN HEMT 소자와 광대역 Coupler를 이용하여 Balanced Structure로 설계하였다. 제작된 광대역 Amplifier는 30V 단일 전원에서 동작하도록 설계되었고, 크기는 140*90mm이다. 동작주파수 대역(500~2500MHz)에서 Small Signal Gain 63dB와 Gain Flatness ${\pm}$2dB, -10dB 이하의 Input Return Loss를 가진다. CW(Continuous Wave) Signal을 이용하여 측정하였으며, 50Watt 이상의 Saturation Power에서 최대 45%, 최소 28% 정도의 효율 특성을 보였다.

• 전자공학회논문지
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• 제50권12호
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• pp.287-291
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• 2013

광섬유 격자소자(FBG)를 이용한 광섬유 수중 음향센서는 기존의 광섬유 센서가 지니고 있는 우수한 장점들을 지니고 있을 뿐만 아니라, PZT센서가 검출할 수 없는 저주파수(30Hz~300Hz)특성에서도 우수한 신호 감지효과를 지니고 있다. 실험에서 $1{\times}3$ 광 커플러 보다, 최근 개발된 hopper lenz WDM을 사용하여, 최대 19KHz까지 고감도 음파신호를 검출하고, 우수한 신호압축율과 초저주파수의 신호검출가능성을 보임에 따라, 정교한 신호해석과 군사용으로 사용될 수 있는 초저주파 신호 검출에 실용화를 기대 할 수 있으며, 센서 어레이(array)를 통하여 고감도 다중화로 발전될 수 있다.

• 제어로봇시스템학회논문지
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• 제8권3호
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• pp.256-263
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• 2002

Optical Multistage Interconnection Networks(OMINs) comprising photonic switches have been studied extensively as important interconnecting building blocks for communication networks and parallel computing systems. A basic element of photonic switching networks is a 2$\times$2 directional coupler with two inputs and two outputs. This paper is concerned with the diagnosis of cross-talk-faults in OMINs. As the size of today's network becomes very large, the conventional diagnosis methods based on tests and simulation have become inefficient, or even more, impractical. In this paper, we propose a simple and easily implementable algorithm for detection and isolation of the single crosstalk-fault in OMINs. Specifically, we develope an algorithm fur the isolation of the source fault in switching elements whenever the single crosstalk-fault is detected in OMINS. The proposed algorithm is illustrated by an example of 16$\times$16 banyan network.

• 한국자동차공학회논문집
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• 제14권5호
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• pp.93-99
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• 2006

Flexible couplers are widely used for exhaust transmitted vibration reduction in vehicles. This paper describes an investigation into the acoustical characteristics of exhaust flexible coupler by the simulation and testing. Computational acoustic simulation is carrying out to investigate resonance frequency and transmission loss of decoupler using the boundary element method and transfer matrix approach. To confirm the acoustical simulation results of exhaust decoupler, we compare with measured experimental results by the test of transmission loss measurement system. In the comparison with simulation results and tests results, there is correctly fit the resonance frequency and the trend of transmission loss. Also, we show that the acoustical structure of decoupler is analogous to the expended tube or side branch resonator. The characteristics of exhaust decoupler have a marked increase in the acoustic attenuation at the specified frequency bend. Therefore the decoupler is applied to develop the exhaust system not only for the vibration isolator but also for the noise attenuator.