• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.9
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• pp.862-876
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• 1991

In this theses, the procedure for finding the equivalent immittance of an n-line coupled structures is presented in terms of the normal mode parameters of the n-line coupled system. The above generalized equations can be applied to the various Coupled structures including directional couplers, DC blocks, bandpass/band elimination filters, and various other uniformly coupled filters. The design equations are based on a simplified TEM(Quasi TEM) mode. The obtained results and the definition of the scattering parameters for a general coupled line four port with arbitrary terminations are used to present the procedure to determine the optimum physical dimensions matching the given load impedances connected to input, output port. Multiple coupled rnicrostrip two-port with three lines circuit designed shows little discrepancy between the conventional method and this one. Four port with five lines were fabricated on teflon substrate($e$r=2.55) with its thickness h=l.588mm designed at the center frequency, 4 GHz. Their measured results are fairly close to the ones by computation.

• Journal of The Geomorphological Association of Korea
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• v.18 no.4
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• pp.261-270
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• 2011

This study is to describe morphological linear anomalies manifested in the geomorphological landscapes of Woongcheon river-basin, situated in the western ends of Charyong Mountainous Range, and to elucidate their morphotectonic significance. The order of decreasing valley scale in the study area is NE-SW, NNE-SSW, NNW-SSE, N-S, and E-W series. The valleys of NE-SW lineament appear as the largest in the study area, having piedmont slope, terraces, low-relif hills. NNE-SSW lineament cross obliquely the geomorphological elements of the precedent lineament. NNW-SSE, N-S and E-W lineament cut the forms of higher orders showing NE-SW and NNE-SSW lineament. Scale of the linear valleys is not correlated with the order of streams. It is paradoxal that great valleys are not associated with the rivers of highest order. It owes to adaption of regional discharge system along the valleys exploiting the fracture resulted from succeeding tectonic accidents.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.91-92
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• 2022

해상 ICT의 발전과 e-Navigation 및 자율운항선 도입에 따라 해상 통신망의 종류와 범위가 확장되어 가상항로표지 서비스의 필요성이 증대되고 있으며, 이러한 서비스 제공을 위해 국가 정책적으로 스마트 항로표지 개발에 관한 연구가 추진되고 있다. 본 논문에서는 e-Navigation 및 자율운항선 도입에 대비하여 디지털 항로표지 정보의 체계적이고 지속적인 제공을 위한 통합가상항로표지 정보서비스 시스템 상세 설계 방안에 대하여 기술하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2021.11a
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• pp.50-51
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• 2021

해상 ICT의 발전과 e-Navigation 및 자율운항선 도입에 따라 해상 통신망의 종류와 범위가 확장되어 가상항로표지 서비스의 필요성이 증대되고 있으며, 이런 서비스 제공을 위해 국가 정책적으로 스마트 항로표지 개발에 관한 연구가 추진되고 있다. 본 논문에서는 e-Navigation 및 자율운항선 도입에 대비하여 디지털 항로표지 정보의 체계적이고 지속적인 제공을 위한 통합 가상항로표지 관리운영 서비스를 설계하여 기술하였다.

• New Physics: Sae Mulli
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• v.68 no.12
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• pp.1281-1287
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• 2018

In this study, $Al_xGa_{1-x}N$ films were grown on (0001) sapphire substrates by using metal-organic chemical vapor deposition (MOCVD). The crystallinity of the grown films was examined with X-ray diffraction (XRD) patterns. The surfaces and the chemical properties of the $Al_xGa_{1-x}N$ films were investigated using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), respectively. The optical properties of the $Al_xGa_{1-x}N$ film were studied in a wide photon energy range between 2.0 ~ 8.7 eV by using spectroscopic ellipsometry (SE) at room temperature. The data obtained by using SE were analyzed to find the critical points of the pseudodielectric function spectra, $<{\varepsilon}(E)>=<{\varepsilon}_1(E)>+i<{\varepsilon}_2(E)>$. In addition, the second derivative spectra, $d^2<{\varepsilon}(E)>/dE^2$, of the pseudodielectric function for the $Al_xGa_{1-x}N$ films were numerically calculated to determine the critical points (CPs), such as the $E_0$, $E_1$, and $E_2$ structure. For the four samples (x = 0.18, 0.21, 0.25, 0.29) between a composition of x = 0.18 and x = 0.29, changes in the critical points (blue-shifts) with increasing Al composition at 300 K for the $Al_xGa_{1-x}N$ film were observed via ellipsometric measurements for the first time.

• Journal of Ocean Engineering and Technology
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• v.33 no.6
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• pp.526-534
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• 2019

The average coastline and the erosion control line introduced as the management coastline, and the average shoreline (MSL) was established from the observed coastline. Also, the median grain size and the wave height of 30-years return period were applied. The erosion control line (ECL) was established through the model, HaeSaBeeN. These two lines set the coastline for evaluation. Based on the observed monitoring data along the coastline, the 1-day variation according to the normal distribution was used to estimate the regional variation, and the width of the erosion was calculated by applying the median grain size (D₅₀) and the wave height of 30-years return period through the high-wave coastal erosion width model, i.e., HaeSaBeeN.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.88.2-88.2
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• 2010

2006년 2월 7일, Gemini North Observatory의 Near-Infrared Integral Field Spectrometer (NIFS)를 사용해 타이탄의 K-band 분광영상을 얻었다. NIFS의 파장분해능은 R~5,000이었고, 타이탄 disk의 적도부분은 약 16 pixel로 분해되었다. 2.0 - 2.1 micron 영역에서 미지의 분광선이 관측됐는데, 그 분광 구조는 전형적인 slightly asymmetric-top molecule의 rotational-vibrational 밴드 구조와 유사하게 나타났다. 또한 N2-N2 Collision-Induced Absorption (CIA)과 H2-N2 dimer에 의한 흡수와 메탄(CH4)가스 흡수를 포함한 분광모델을 만들어 비교한 결과 이 파장영역에는 이러한 흡수선들의 영향이 적은 것으로 확인됐다. 따라서 해당 영역의 저분산 (R~2,000 - 3,400) 스펙트럼을 토대로 액체 또는 고체 상태의 탄화수소가 타이탄에 존재한다고 보는 최근 발표된 주장들은 (e.g., Brown et al. 2008, Nature, v. 454, p. 607; Adamkovics et al. 2009, Planetary and Space Science, v. 57, p. 1586) 보다 신중히 고려돼야 한다.

• Proceedings of the CALSEC Conference
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• 2001.08a
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• pp.401-410
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• 2001

개요 유무선 인터넷 망 연동 무선에서의 ISP (MISP: Mobile ISP) 의미 이동통신사 과점에서 경쟁 체제로 (nTop, magicN, ez-i) MIDC 사업자 출현 (KT, 데이콤, 하나로) WAP, 컨텐트 컨버팅, 과금 서비스 문제점 접속 지점 (IWF, G/W) 접속 대가 접속 대상(중략)

• Journal of the Korean Magnetics Society
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• v.10 no.3
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• pp.106-111
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• 2000

The magnetic thin films can be prepared without vacuum process and under the low temperature (<100 $^{\circ}C$) by ferrite plating. We have performed ferrite plating of M $n_{x}$Z $n_{0.22}$F $e_{2.78-x}$ $O_4$(x=0.00~0.08) films and N $i_{x}$Z $n_{0.22}$F $e_{*}$2.78-x/ $O_4$(x=0.00~0.15) films on cover glass at the substrate temperature 90 $^{\circ}C$. The crystal structure of the samples has been identified as a single phase of polycrystal spinel structure by x-ray diffraction technique. The lattice constant in the M $n_{x}$Z $n_{0.22}$F $e_{2.78-x}$ $O_4$films increases but in the N $i_{x}$Z $n_{0.22}$F $e_{*}$2.78-x/ $O_4$films decrease with the composition parameter, x. The saturation magnetization in the M $n_{x}$Z $n_{0.22}$F $e_{2.78-x}$ $O_4$films does not greatly change, in agreement with observations on bulk samples.k samples.k samples.

• Journal of Ocean Engineering and Technology
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• v.8 no.2
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• pp.141-150
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• 1994

In designing, the strength of tubular joint has been an important problem for integrity of steel structures in which many tubular members are used. This paper presents the results of FEM analysis on stress concentration and fatigue crack initiation life for two types of tubular joints. One is circular and rectangular T type joints which consist of circular brace and rectangular chord. Another is circular and circular T type joints which consist of circular brace and circular chord. FEM analyses were performed under the axial load and in-plane bending moment. The fatigue crack initiation life can be estimated by using $\varepsilon$-N curve and by applying the Palmgren-Miner linear damage rule. According to the results, the stress concentration factor(SCF) of circular and rectangular joints is higher than that of circular and circular joints. The fatigue crack initiation lives of circular-circular joints and circular-rectangular joints were calculated.