• 대한교통학회지
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• 제26권1호
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• pp.7-14
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• 2008

교통신호기의 설치목적 중 하나는 교통신호기를 통해 차량의 이동을 명확히 규제하여 교통사고를 사전에 방지하는데 있다. 하지만, 부적절한 신호기 위치로 인해 교차로에 접근하는 운전자가 안전운행에 필요한 행태를 나타내지 못한다면, 교통 안전도를 높이기 위한 방안으로 현장상황에 적합한 설치기준 또는 권고사항이 현장조사 및 분석을 통해서 제시되어야 할 필요가 있다. 이러한 배경에서 본 연구는 도심 신호교차로의 신호기 위치가 교차로에 접근하는 운전자의 운전행태에 미치는 영향을 분석하였다. 분석한 결과, 신호기 위치는 딜레마존을 형성하는 운전자의 감속시작지점과 접근속도에 따른 딜레마존 분포에 영향을 미치며, 더욱이 딜레마존 안전율과 밀접한 관계가 있는 것으로 나타났다. 따라서, 본 연구는 신호교차로의 교통안전도를 향상하기 위한 대안으로 교통신호기를 정지선 근처로 이설 또는 설치하는 방안을 다룬 신호기 설치운영 권고안을 제안하여 현장 활용도를 제고하고자 하였다.

• Journal of Microbiology and Biotechnology
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• 제29권2호
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• pp.304-310
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• 2019

Interleukin-21 is a common ${\gamma}$-chain cytokine that controls the immune responses of B cells, T cells, and natural killer cells. Targeting IL-21 to strengthen the immune system is promising for the development of vaccines as well as anti-infection and anti-tumor therapies. However, the practical application of IL-21 is limited by the high production cost. In this study, we improved IL-21 production by codon optimization and selection of appropriate signal peptide in CHO-K1 cells. Codon-optimized or non-optimized human IL-21 was stably transfected into CHO-K1 cells. IL-21 expression was 10-fold higher for codon-optimized than non-optimized IL-21. We fused five different signal peptides to codon-optimized mature IL-21 and evaluated their effect on IL-21 production. The best result (a 3-fold increase) was obtained using a signal peptide derived from human azurocidin. Furthermore, codon-optimized IL-21 containing the azurocidin signal peptide promoted $IFN-{\gamma}$ secretion and STAT3 phosphorylation in NK-92 cells similar to codon-optimized IL-21 containing original signal peptide. Collectively, these results indicate that codon optimization and azurocidin signal peptides provide an efficient approach for the high-level production of IL-21 as a biopharmaceutical.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.81.2-81
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• 2002

$\textbullet$ Introduction- Concept and meaning of the emotional Recognition $\textbullet$ The feature of 4-emotions $\textbullet$ Pitch(approach) $\textbullet$ Simulator-structure, RNN(learning algorithm), evaluation function, solution search method $\textbullet$ Result

• 한국작물학회:학술대회논문집
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• 한국작물학회 2007년도 춘계학술발표회
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• pp.30-49
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• 2007

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.404-406
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• 2002

We have investigated the contribution of the scattered x rays to the signal imaging in the radiographs acquired with anti-scatter grids of several grid ratios by separating the line spread functions (LSFs) derived from the signal edge image into the primary and the scatter components. By using a 1.0-mm lead plate in the scattering material, the blurred signal edge images were acquired by use of an imaging plate at a tube voltage of 80 kV with the anti-scatter grids of grid ratios for 5:1, 6:1, 8:1, 10:1 and 12:1. The edge profiles of the signal images were scanned and those in relative exposure were differentiated to obtain the LSFs. To investigate the contribution of the scattered x rays to the signal imaging, we proposed a method for separating the LSFs derived from the signal images into the primary and the scatter components, where the scatter component was approximated with exponential function. Our basic approach is to separate the area of the LSFs by ratios of the scattered x-ray exposure to the primary x-ray exposure, which were obtained for the grid ratios by use of a lead disk method. The LSFs and the two components were Fourier transformed to obtain the modulation transfer functions (MTFs) and their two components. As the result, we found that, by using the anti-scatter grids, the scattered x rays were reduced, but the shape of the LSFs of the scatter component hardly changed. The contributions of the scatter component to the MTFs were not negligible (more than 10 %) for spatial frequencies lower than about 1.0 mm$\^$-l/ and that was greater as the grid ratio decreasing. On the other hand, for higher frequencies, the primary component was dominant compared with the scatter component.

• 한국통신학회논문지
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• 제30권4C호
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• pp.223-229
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• 2005

본 논문에서는 디인터레이싱을 위해 제한된 탐색영역을 갖는 확장된 에지기반 라인 평균 방법을 제안한다. 기존의 에지기반 라인 평균 방법들은 화소단위의 상관도를 이용하기 때문에 잡음과 계조도의 변화에 매우 취약하다는 단점이 있다. 그리고 방향성 에지를 탐색할 때, 탐색영역 내에 동일 방향을 갖는 에지들이 다수 존재할 경우 잘못된 에지 방향을 찾게 되고 보간된 영상에 점과 같은 잡음이 발생한다. 이러한 단점을 해결하기 위해 에지 방향 탐색시 탐색영역을 제한하는 블록단위의 에지 기반 라인 평균 방법을 제안한다. 실험 결과 제한하는 방법은 기존의 화소 단위의 에지기반 라인 평균 방법들보다 PSNR 측면에서 약 1 dB 이상 우수한 결과를 나타내었다.

• Journal of Information Processing Systems
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• 제12권1호
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• pp.73-82
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• 2016

In cognitive radio networks (CRNs), the performance of the transmission control protocol (TCP) at the secondary user (SU) severely drops due to the mistrigger of congestion control. A long disruption is caused by the transmission of primary user, leading to the mistrigger. In this paper, we propose a cross-layer approach, called a CR-aware scheme that enhances TCP performance at the SU. The scheme is a sender side addition to the standard TCP (i.e., TCP-NewReno), and utilizes an explicit cross-layer signal delivered from a physical (or link) layer and the signal gives an indication of detecting the primary transmission (i.e., transmission of the primary user). We evaluated our scheme by implementing it onto a software radio platform, the Universal Software Radio Peripheral (USRP), where many parts of lower layer operations (i.e., operations in a link or physical layer) run as user processes. In our implementation, we ran our CR-aware scheme over IEEE 802.15.4. Furthermore, for the purpose of comparison, we implemented a selective ACK-based local recovery scheme that helps TCP isolate congestive loss from a random loss in a wireless section.

• 융합신호처리학회논문지
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• 제12권3호
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• pp.212-216
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• 2011

태양광 발전 시스템의 고장검출은 고장으로 인해 발생되는 기술적 및 경제적 손실을 최대한 줄이기 위한 첨단 기술로 각광을 받고 있다. 본 논문은 푸리에 신경회로망과 확률론적 의사결정법을 이용한 태양광 발전 시스템의 새로운 고장진단 알고리즘을 제안한다. 우선 태양광 시스템의 동적 모델링을 위하여 최급강하 기반 최적화 기법을 통해 신경회로망 모델을 구성하며 GLRT 알고리즘을 이용하여 태양광 시스템의 확률론적 고장검출 기법을 제안한다. 제안한 고장검출 알고리즘의 타당성 검증을 위하여 태양광 고장검출 테스트베드를 제작하여 실시간 실험을 실시하였으며 이 때 태양광으로부터의 신호는 직류 전력선 통신을 이용하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권1호
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• pp.168-186
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• 2016

In this paper, we investigate the degrees of freedom (DoF) of a two-cluster multiple-input multiple-output (MIMO) multiway relay interference channel (mRIC), where there are two relays and two users per cluster. In this channel, users within the same cluster exchange messages among themselves with the help of two relays.We first obtain the DoF upper bound of the considered MIMO mRIC based on cut-set bound. Then, we propose a novel transmission strategy, blind interference neutralization (BIN), to approach the DoF upper bound. This new method utilizes the overheard information at two relays and focuses on the beamforming matrix designs at two relays so that the channel state information (CSI) at users is not required. Through theoretical analysis and numerical simulations, we show that the DoF upper bound can be obtained by using the BIN scheme. From simulation results, we show that the proposed BIN scheme can provide significant performance gain over the conventional time division multiple access (TDMA) scheme in terms of DoF. In addition, we show that the BIN scheme is a superior approach to the existing signal space alignment (SSA) schemes for the considered mRIC.

• 대한의용생체공학회:의공학회지
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• 제29권4호
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• pp.329-336
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• 2008

Recently, causality analysis of source time series extracted from EEG or MEG signals is becoming of great importance in human brain mapping studies and noninvasive diagnosis of various brain diseases. Two approaches have been widely used for the analyses: one is independent component analysis (ICA), and the other is multiple signal classification (MUSIC). To the best of our knowledge, however, any comparison studies to reveal the difference of the two approaches have not been reported. In the present study, we compared the performance of the two different techniques, ICA and MUSIC, especially focusing on how accurately they can estimate and separate various brain electrical signals such as linear, nonlinear, and chaotic signals without a priori knowledge. Results of the realistic simulation studies, adopting directed transfer function (DTF) and Granger causality (GC) as measures of the accurate extraction of source time series, demonstrated that the MUSIC-based approach is more reliable than the ICA-based approach.