• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.2089-2094
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• 2010

The importance of broadband wireless communication implemented at subway tunnels is growing up. At 18GHz wireless video transmission system, the transmitter requires a digital modulation method. At subway tunnel, A 18GHz's influence of the multi-pass padding is strong. OFDM digital modulation that is strong for multi-pass padding is recommended. In this paper, Suitable to a subway wireless video transmission OFDM receiver is designed. OFDM receiver system has 6dB gaion because uses diversity of space diversity and MRC(Maximum Ratio Combining) diversity. The transmitter system use C&ITechnologies's transmitter board. IF frequency of receiver is 480MHz. OFDM modulation parameter is as follow, The bandwidth is 8MHz, The numuber of carrier if 2,000, The modulation methode is QAM16, The guard interval is 1/32.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.150-154
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• 2004

본 연구에서는 멀티 레벨 인버터의 파워 스펙트럼을 광대역으로 분산시키기 위한 멀티 캐리어 Random PWM기법을 제안하였다. PD(phase disposition)방식 및 H(hybrid)방식의 멀티 캐리어 Random PWM을 단상 cascade H-브리지 멀티 레벨 인버터와 3상 hybrid 멀티 레벨 인버터에 적용하였다. 각 방식에 따른 출력 전압/전류 파형 및 고조파 스펙트럼을 PSIM에 의하여 확인 하였으며, 제안된 방식의 타당성을 입증할 수 있었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.153-154
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• 2006

We propose the dynamic channel allocation (DCA) algorithm for multi-cell OFDMA systems to avoid co-channel interference (CCI). The proposed algorithm is utilized not in a centralized, but in a distributed manner which reduces complexity. The simulation results confirm that the number of overlapping allocated subcarriers is reduced and the average SINR of a sub-carrier is increased by this algorithm.

• Journal of Information Display
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• 제8권3호
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• pp.11-16
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• 2007

Theoretical simulations of spatial distribution of charge carriers and recombination rate, and J-V characteristics of the multi-layer organic light emitting diodes are carried out. Drift-diffusion current transport, field-dependent carrier mobility, exponential and Gaussian trap distribution, and Langevin recombination models are included in this computer model. The simulated results show good agreement with the experimental data confirming the validity of the physical models for organic light emitting diodes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 전문대학교육위원
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• pp.82-85
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• 2005

Organic EL has been expected to adopt to a new styles of technology that make flat display after Tang & Vanslyke made good electric luminescence device in late 1980s. Their studies based on multi layer structure that consists of emitting layer and carrier transporting layer using proper organic material. In this study, we made multi layer device using $Eu(TTA)_3(phen)$ as a luminescence material by PVD and investigate luminous properties of each device. But oxidization of organic layer by ITO, energy walls in both pole interface, contaminations of ITO surface, importance of protecting membrane, diffusive dimming of light to cathode organic layer, these causes of degradations are common facts of a macromolecule and micromolecule. We think these degradation caused by the impact of heat and electro-chemical factor, bulk effect and interface phenomenon, and raise a question.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.347-352
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• 2002

The Cut off-type progressive die for U-bending production part is a very specific division. This study reveals the sheet metal forming process with multi-forming die by Center Carrier type feeding system. Through the FEM simulation by DEFORM, it was accepted to u-bending process as the first performance to design of strip process layout. The next process of die development was studied according to sequence of die development, i.e. die structure, machining condition for die making, die materials, heat treatment of die components, know-how and so on. The feature of this study is the die development of scrapless progressive die of multi-stage through the Modeling on the I-DEAS program, components drawing on the Auto-Lisp, CAD/CAM application, ordinary machine tool operating and revision by tryout.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.445-450
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• 2018

Reliable detection and parameter estimation of a radar cross section(RCS) fluctuating target have been known as a difficult task. To reduce the effect of RCS fluctuation, various diversity techniques have been considered. This paper presents a new method for synthesizing a covariance matrix applicable to a coherent multi-input multi-output(MIMO) radar with frequency diversity. It is achieved by efficiently combining covariance matrices corresponding to different carrier frequencies such that the signal-to-noise ratio(SNR) in the combined covariance matrix is maximized. The value of a synthesized covariance matrix is assessed by examining the phase curves of its entries and the improvement on direction of arrival(DOA) estimation.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.882-885
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• 2011

This paper presents testing and self-calibration of RF circuits using MEMS switches to identify process-related defects and out of specification circuits. We have developed a novel multi-tone dither test technique where the test stimulus is generated by modulating the RF carrier signal with a multi-tone signal generated using an Arbitrary Waveform Generator (AWG) with additive white Gaussian noise. This test stimulus is provided as input to the RF circuit and peak-to-average ratio (PAR) is measured at the output. For a faulty circuit, a significant difference is observed in the value of PAR as compared to a fault-free circuit. Simulation is performed for various circuit conditions such as fault-free as well as fault-induced and their corresponding PARs are stored in the look-up table. This testing and self-calibration technique is exhaustive and efficient for present-day communication systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 학술대회 논문집 전문대학교육위원
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• pp.110-113
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• 2002

Organic EL has been expected to adopt to a new styles of technology that make flat display after Tang & Vanslyke made good electric luminescence device in late 1980s. Their studies based on multi layer structure that consists of emitting layer and carrier transporting layer using proper organic material. In this study. we made multi layer device using $Eu(TTA)_3(phen)$ as a luminescence material by PVD and investigate luminous properties of each device. But oxidization of organic layer by ITO. energy walls in both pole interface. contaminations of ITO surface, importance of protecting membrane, diffusive dimming of light to cathode organic layer. these causes of degradations are common facts of a macromolecule and micromolecule. We think these degradation caused by the impact of heat and electro-chemical factor, bulk effect and interface phenomenon. and raise a question.

• 한국표면공학회지
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• 제52권6호
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• pp.321-325
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• 2019

Triso-type coating layers of silicon carbide and graphite on UO₂ paticulate nuclear fuel were prepared by using fluidized bed type chemical vapor deposition and self-propagating high temperature synthesis methods to make a coated nuclear fuel of a power plant for hydrogen mass-production. The source and carrier gases were the mixture of methyltrichlorosilane and propane, and inert argon. Chemical analysis and microstructure observation showed that the coated layers were inner graphite, middle silicon carbide and outer graphite. The elastic modulus and nano-hardness of the silicon carbide layer were 503 [GPa] and 36 [GPa], respectively.