• 전자공학회논문지
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• 제52권5호
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• pp.10-22
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• 2015

이최근, 3GPP (3rd Generation Partnership Project) 에서는 폭발적으로 증가하고 있는 모바일 데이터 트래픽을 수용하기 위하여 사이드홀 (Sidehaul) 시스템을 개발하고 이에 대한 연구가 활발히 진행되고 있다. 사이드홀 시스템은 낮은 PAPR (Peak to Average Power Ratio)을 위해 SC-FDMA (Single Carrier-Frequency Division Multiple Access)를 기반으로 한다. 또한 제한된 공간에서 안테나 배열을 사용함으로써 MIMO (Multiple Input Multiple Output) 전송이 가능하게 한다. 본 논문에서는 사이드홀 시스템에서 ULA (Uniform Linear Array), UCA (Uniform Circular Array) 및 UPA (Uniform Planar Array)에 대한 안테나 배열을 설계하고 성능을 분석한다. 또한, 이웃셀로 부터 간섭의 영향을 줄이기 위하여 새로운 하이브리드 수신기 FSC(Full Suppression Cancellation)를 제안한다. 제안한 수신기는 IRC (Interference Rejection Combining)와 SIC (Successive Interference Cancellation)를 결합하여 간섭을 억제 및 제거 할 수 있다.

• 한국통신학회논문지
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• 제25권10A호
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• pp.1548-1553
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• 2000

In this paper, an effective peak power reduction scheme for a downlink OFDM-CDMA system is proposed. Using the partial parallel transform(PPT) structure, peak-to-average power ratio(PAPR) can be reduced. The patterns of inputs of Inverse Fast Fourier Transform(IFFT) are more randomized in this structure by allotting the subcarriers to each users. At the cost of complexity we can obtain reduced PAPR and multiple access interference(MA) Computer simulations are carried out from the viewpoint of PAPR and demonstrated the improved PAPR performance.

• Journal of the Optical Society of Korea
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• 제13권1호
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• pp.75-79
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• 2009

A four beam interference optical system for laser micro structuring using a pulse laser was demonstrated. The four beam interference optical system using a pulse laser(picosecond laser) can fabricate micro structure on mold material(NAK80) directly. Micro structure on the polymer can be reproduced economically by injection molding of the micro structure on the mold material. The four beam interference optical system was composed by the DOE(Diffractive Optical Element) and two lenses. The laser intensity distribution of four beam interference was explained by an interference optics point of view and by the image optics point of view. We revealed that both views showed the same result. The laser power distribution of a $1{\mu}m$ peak pattern was made by the four beam interference optical system and measured by the objective lens and CCD. A $1{\mu}m$ pitch dot pattern on the mold material was fabricated and measured by SEM(Scanning Electron Microscopy).

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권5호
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• pp.1514-1531
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• 2014

Femtocell provides better coverage and higher spectrum efficiency in areas rarely covered by macrocells. However, serious two-tier interference emerging from randomly deploying femtocells may create dead zones where the service is unavailable for macro-users. In this paper, we present adopting cognitive radio spectrum overlay to avoid intra-tier interference and incorporating spectrum underlay and overlay to coordinate cross-tier interference. It is a novel centralized control strategy appropriate for both uplink and downlink transmission. We introduce the application of proper spectrum sharing strategy plus optimal power allocation to address the issue of OFDM-based femtocells interference-limited downlink transmission, along with, a low-complexity suboptimal solution proposed. Simulation results illustrate the proposed optimal scheme achieves the highest transmission rate on successfully avoiding two-tier interference, and outperforms the traditional spectrum underlay or spectrum overlay, via maximizing the opportunity to transmit. Moreover, the strength of our proposed schemes is further demonstrated by comparison with previous classic power allocation methods, in terms of transmission rate, computational complexity and signal peak-to-average power ratio.

• 대한전자공학회논문지TC
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• 제49권8호
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• pp.39-45
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• 2012

본 논문에서는 주파수 공유 환경에서 일차 사용자가 양방향 중계기 (full duplex relay, FDR)를 사용하는 경우의 이차 사용자의 통신 용량에 대해서 분석한 논문이다. 주파수 공유 시스템에서, 이차 사용자가 일차 사용자의 주파수를 공유하기 위해서는 다양한 일차 사용자의 시스템에 맞는 주파수 공유 기법이 연구되어야 한다. 그러나 기존의 연구들은 오직 일대일 통신 기반의 일차 사용자 시스템만을 고려하였다. 일차 사용자가 FDR을 사용할 때는 일차 사용자의 중계기와 목적지가 이차 사용자로부터 동시에 간섭을 받게 된다. 따라서 기존의 일대일 통신 기반의 주파수 공유 기법 보다 좀 더 엄격한 간섭 제약이 적용되어야 한다. 따라서 본 논문에서는 일차 사용자가 FDR을 사용하는 주파수 공유 시스템에서 평균 및 순시 간섭 파워 제약 조건 하에서의 이차 사용자의 통신 용량을 분석한다. 또한 이러한 시스템에서 간섭 제약을 고려했을 때의 성능 열화를 분석한다. 모의 실험 결과를 통해서 평균 간섭 파워 제약 조건 하에서의 이차 사용자 통신 용량과 일차 사용자의 통신 용량이 순시 간섭 파워 제약 조건 하에서의 통신용량보다 성능이 좋음을 확인하였다.

• 전기학회논문지P
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• 제65권2호
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• pp.114-121
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• 2016

This paper is Instant space vector PWM(Pulse Width Modulation)power conversion devices in switching power semiconductors from my generation to losses and switching when the voltage surge and current surge of electronic noise(EMI: Electro Magnetic Interference / RFI: Radio Frequency Interference)to effectively minimize the power soft-switching power conversion circuit topologies of auxiliary resonant DC tank for the purpose of high performance realization of the electric power conversion system by the high-speed switching of a semiconductor device(AQRDCT simultaneously : an active auxiliary resonance using auxiliary Quasi-resonant DC tank)DC link snubber switch has adopted a three-phase voltage inverter. AQRDCL proposed in this paper can reduce the effective and current peak stress of the power semiconductors of the auxiliary resonant snubber circuit compared to the conventional active-resonant DC link snubber, it is not necessary to install the clamp switch of the auxiliary resonant DC link, DC the peak current and power loss of the bus line can be reduced.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.462-468
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• 2022

The selection and effective utilization of peak-fitting software for conventional gamma-ray spectrum analysis is significant for accurate determination of the mass fraction of elements, particularly in complex peak regions. Majority of the peak-fitting programs can derive similar peak characteristics for singlet peaks, but very few programs can deconvolute multi-peaks in a complex region. The deconvolution of multi-peaks requires special peak-fitting functions, such as left and right-skew distributions. In the this study, 843.76 keV (²⁷Mg) peak area from the complex region (840 keV-850 keV) determined and compared using four different peak-fitting programs, namely, GammaVision, Genie2000, HyperLab, and HyperGam. The 843.76 keV peak interfered with 841.63 keV (^152mEu) and 846.81 keV (⁵⁶Mn). The total Mg concentration was determined through k₀-instrumental neutron activation analysis by applying the isotopic interference correction factor ²⁷Al(n,p)²⁷Mg through the simultaneous determination of Al concentration. HyperLab and HyperGam peak-fitting programs reported consistent peak areas, and resultant concentrations agreed with the certified values of matrix-certified reference materials.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.569-572
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• 2001

Selective. highly stable determination of epinephrine(adrenalin) was achieved in cyclic voltammetric measurement carried out at electrochemically treated conductive boron-doped diamond electrode. Boron-doped diamond electrodes were prepared on single crystal Si wafers by microwave plasma chemical vapor deposition and $B_{2}O_{3}$ was dissolved in acetone/methanol(9:1) mixture solution so that the B/C weight ratio ca. $10^{4}ppm$. Epinephrine is a kind of catecholamines, which secreted from adrenal marrow cells. The serious problem to detection of epinephrine is the interference phenomena of electroactive constituent. including AA. In this study. electrochemical treatment of BDD was carried out to discriminate between epinephrine and AA responses. Experimental results showed that the peak potential of AA oxidation shift to the positive direction and the oxidation peak of epinephrine was unchanged. The effect of electrochemical treatment was maintained up to 40hrs.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.569-572
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• 2001

Selective, highly stable determination of epinephrine(adrenalin) was achieved in cyclic voltammetric measurement carried out at electrochemically treated conductive boron-doped diamond electrode. Boron-doped diamond electrodes were prepared on single crystal Si wafers by microwave plasma chemical vapor deposition and B$_2$O$_3$ was dissolved in acetone/methanol(1:1) mixture solution so that the B/C weight ratio ca. 10$^3$ppm.. Epinephrine is a kind of catecholamines, which secreted from adrenal marrow cells. The serious problem to detection of epinephrine is the interference phenomena of electroactive constituent, including AA. In this study, electrochemical treatment of BDD was carried out to discriminate between epinephrine and AA responses. Experimental results showed that the peak potential of AA oxidation shift to the positive direction and the oxidation peak of epinephrine was unchanged. The effect of electrochemical treatment was maintained up to 40hrs.

• Journal of the Optical Society of Korea
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• 제14권1호
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• pp.33-37
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• 2010

The joint transform correlator (JTC) has been the best known technique for pattern recognition and identification. The JTC optically compares the reference image with the sample image then examines match or non-match by acquiring a correlation peak. However, the JTC technique has some problems such as weak correlation discrimination and noise which originates from the interference fringes in the Fourier transform plane. In order to solve these problems, this paper proposes a new technique of modifications of the interference fringes by adopting special iterative filters. Experimental results are presented to show that the proposed technique can successfully improve the correlation peaks and the level of discrimination.