• 한국지리정보학회지
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• 제17권2호
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• pp.121-135
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• 2014

최근 픽셀기반분류보다 더 많은 정보를 이용할 수 있는 객체기반에 대한 연구가 활발히 진행 중이다. 따라서, 본 연구는 인제군 Demilitarized Zone(DMZ)지역 일원을 대상으로 객체기반 분류기법을 이용한 토지피복분류를 실시하였다. 분류항목은 환경부 기준의 대분류 항목 7개, 중분류 항목 13개로 선정하였고, 사용된 인자는 분광 값의 평균과 표준편차, Grey Level Co-occurrence Matrix(GLCM)의 Homogeneity를 사용하여 감독분류방법 중 최근린기법을 이용하여 계층적 토지피복도를 구축하였다. 구축된 토지피복도를 이용하여 남방한계선으로부터의 거리와 Digital elevation model(DEM)을 통해 지형특성에 따른 분류항목 별 분포 특성을 분석하였다. 객체기반 분류를 위한 최적 가중치는 Scale 72, Shape 0.2. Color 0.8, Compactness 0.5, Smoothness 0.5로 선정하였고, 가중치 선정과정에서 Scale, Shape, Color가 가장 많은 영향을 주었다. 대분류 토지피복분류는 산림, 초지, 시가지의 순으로 각각 약 92%, 약 5%, 약 2%였으며, 중분류 토지피복분류는 활엽수림, 혼효림, 침엽수림의 순으로 각각 약 44%, 약 42%, 약 6% 순으로 분포하였다. 토지피복형태에 따른 분포특성을 보면, 남방한계선으로부터 2km이내의 지역에서 공공시설 지역과 도로의 이용이 높았으며, 남방한계선 6km이상의 지역에서는 논과 밭, 나지의 형태가 많았다. 산림은 표고 600m, 경사 $30^{\circ}$이상의 지역에서는 면적분포가 높았고, 농업지역과 나지, 초지는 표고 600m, 경사 $30^{\circ}$이하의 지역에서 면적분포가 높았다.

• International Journal of Computer Science & Network Security
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• 제23권10호
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• pp.1-10
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• 2023

This paper proposes a method to extend Inter-Carrier Interference (ICI) canceling Orthogonal Frequency Division Multiplexing (OFDM) receivers for 5G mobile systems to spatial multiplexing 2×2 MIMO (Multiple Input Multiple Output) systems to support high-speed ground transportation services by linear motor cars traveling at 500 km/h. In Japan, linear-motor high-speed ground transportation service is scheduled to begin in 2027. To expand the coverage area of base stations, 5G mobile systems in high-speed moving trains will have multiple base station antennas transmitting the same downlink (DL) signal, forming an expanded cell size along the train rails. 5G terminals in a fast-moving train can cause the forward and backward antenna signals to be Doppler-shifted in opposite directions, so the receiver in the train may have trouble estimating the exact channel transfer function (CTF) for demodulation. A receiver in such high-speed train sees the transmission channel which is composed of multiple Doppler-shifted propagation paths. Then, a loss of sub-carrier orthogonality due to Doppler-spread channels causes ICI. The ICI Canceller is realized by the following three steps. First, using the Demodulation Reference Symbol (DMRS) pilot signals, it analyzes three parameters such as attenuation, relative delay, and Doppler-shift of each multi-path component. Secondly, based on the sets of three parameters, Channel Transfer Function (CTF) of sender sub-carrier number n to receiver sub-carrier number l is generated. In case of n≠l, the CTF corresponds to ICI factor. Thirdly, since ICI factor is obtained, by applying ICI reverse operation by Multi-Tap Equalizer, ICI canceling can be realized. ICI canceling performance has been simulated assuming severe channel condition such as 500 km/h, 8 path reverse Doppler Shift for QPSK, 16QAM, 64QAM and 256QAM modulations. In particular, 2×2MIMO QPSK and 16QAM modulation schemes, BER (Bit Error Rate) improvement was observed when the number of taps in the multi-tap equalizer was set to 31 or more taps, at a moving speed of 500 km/h and in an 8-pass reverse doppler shift environment.

• 자동차안전학회지
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• 제4권2호
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• pp.5-10
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• 2012

Whiplash is the most frequent injury among occupants in low speed rear-end car collision. The aim of this paper is to analyze thecorrelation between influence parameters of head restraints and whiplash injury criteria.In this paper, DFSS (Design for Six Sigma) method is used for optimum design of head restrains. Four control factors of head restraints have selected by function matrix method. The effects of the control factors have been experimentally evaluated by using a sled pulse from 16km/h relative velocity which is suggested by KNCAP (Korean New Car Assessment Program). In order to reduce the noise factors of dynamic tests, whiplash tests were repeated twice. By using DFSS, the correlation between control factors and injury criteria has been comprehended.

• 한국초전도ㆍ저온공학회논문지
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• 제6권1호
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• pp.1-5
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• 2004

Long length of Bi-2223/Ag superconducting wives were fabricated by stacking and drawing process with advanced heat-treatment schedules. Intermediate annealing was carried out to increase the homogeneity and uniformity of the superconducting filaments embedded in the silver matrix. Phase modification from tetragonal to orthorhombic Bi-2212 by pre heat treatment(PHT) was executed to improve the texture and phase transformation of Bi-2223. Drawing stress was measured to predict the sausaging and stress limit. Rolling Parameters such as thickness. width and winding tension were investigated to roll the tape with uniformity. 1 km length of Bi-2223/Ag superconducting wires were fabricated without any breakage. Critical current (Je) of 270 m length of superconducting tapes was measured over than $70 A/cm^2$ continuously after final sintering.

• 한국미생물·생명공학회지
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• 제27권3호
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• pp.208-214
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• 1999

The condition for immobilization of the partially purified agarase from Bacillus cereus ASK202 and the properties of the immobilized enzyme have been investigated. Agarase was immobilized on various supports by entrapment method. The enzyme immobilized on Na-alginate bead showed the highest activity among those studied. The optimal reaction conditions of the immobilized agarase were obtained in 3%(w/v) Na-alginate for the matrix, bead diameter of 2.5mm, 1 unit of agarase solution and 1.0%(w/v) calcium chloride solution. The optimum pH and temperature of the immobilized agarase were pH and temperature of the immobilized agarase were pH 7.0 and 4$0^{\circ}C$, respectively. Km and Vmax values were 0.5mg/ml.min, respectively. The immobilized agarase conerted agar to agarobiose, and their total conversion ratio under the optimal condition was 89%.

• 한국조명전기설비학회지:조명전기설비
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• 제6권2호
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• pp.51-55
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• 1992

In this study as treating to filter silance coupling agent (KM-6030 improving coupling strength between matrix resin (bisphenole-A type epoxy resin) and filler (SiO2), breakdown strength was investigated on cases applying DC voltage to specimen. In the case on DC voltage, breakdown strength was improved bout 12.73% and 10.77% in specimen of 5[wt%] and 50[wt%] of filler content of 10 of epoxy. Therefore, it was investigate the effect that concentration of coupling agent and content of filler was influential on breakdown strength of epoxy resin.

• Structural Engineering and Mechanics
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• 제12권3호
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• pp.267-281
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• 2001

Transient and quasi-steady-state vertical vibrations of a multi-span beam steel bridge located on a single-track railway line are considered, induced by a superfast passenger train, moving at speed 120-360 km/h. Matrix dynamic equations of motion of a simplified model of the system are formulated partly in the implicit form. A recurrent-iterative algorithm for solving these equations is presented. Excessive vibrations of the system in the resonant zones are reduced effectively with passive dynamic absorbers, tuned to the first mode of a single bridge span. The dynamic analysis has been performed for a series of types of bridges with span lengths of 10 to 30 m, and with parameters closed to multi-span beam railway bridges erected in the second half of the $20^{th}$ century.

• 천문학회지
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• 제38권2호
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• pp.59-66
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• 2005

A new ion transport code for planetary ionospheric studies has been developed with consideration of velocity differences among ion species involving ion-ion collision. Most of previous planetary ionosphere models assumed that ions diffuse through non-moving ion and neutral background in order to consolidate continuity and momentum equations for ions into a simple set of diffusion equations. The simplification may result in unreliable density profiles of ions at high altitudes where ion velocities are fast and their velocity differences are significant enough to cause inaccuracy when computing ion-ion collision. A new code solves explicitly one-dimensional continuity and momentum equations for ion densities and velocities by utilizing divided Jacobian matrices in matrix inversion necessary to the Newton iteration procedure. The code has been applied to Martian nightside ionosphere models, as an example computation. The computed density profiles of $O^+,\;OH^+$, and $HCO^+$ differ by more than a factor of 2 at altitudes higher than 200 km from a simple diffusion model, whereas the density profile of the dominant ion, $O_2^+$, changes little. Especially, the density profile of $HCO^+$ is reduced by a factor of about 10 and its peak altitude is lowered by about 40 km relative to a simple diffusion model in which $HCO^+$ ions are assumed to diffuse through non-moving ion background, $O_2^+$. The computed effects of the new code on the Martian nightside models are explained readily in terms of ion velocities that were solved together with ion densities, which were not available from diffusion models. The new code should thus be expected as a significantly improved tool for planetary ionosphere modelling.

• 대한원격탐사학회지
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• 제17권3호
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• pp.275-284
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• 2001

본 연구에서는 강원도 평창군 봉평면 일대의 지역에 대해 2000년 4월 24일에 수신된 IKONOS 위성영상을 이용하여 피복분류를 수행하였다. 피복분류는 임상분류에 중점을 두었으며, 분류에 적용한 분류항목(class)은 현지조사 및 영상을 통하여 상록침엽수, 낙엽송, 활엽수, 나지, 밭, 초지, 수역, 사토지역, 아스팔트지역의 9개로 나누었다. 영상분류는 최대우도법을 적용하여 감독분류를 수행하였다. 정확도는 검정지역에 대한 전체정확도, 생산자정확도, 사용자정확도, k의 항목에 대해 분류오차행렬표를 통하여 평가하였다. 분류 및 분석에는 ERDAS사의 Imagine 8.4와 Purdue 대학에서 개발한 Multispec 소프트웨어를 사용하였다. 분류 결과, 검정지역에 대한 정확도는 전체정확도 94.3%, 생산자정확도 77.0-99.9%, 사용자정확도 71.9-100%, k은 0.93이었다. 나지, 사토지역, 밭 등의 경우 다른 분류항목보다 분류의 정확도가 비교적 낮게 나타난 반면, 임상분류에 있어서는 기존의 중해상도(5-30m) 위성영상보다 향상된 분류결과를 보여주었다.

• 대한토목학회논문집
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• 제40권6호
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• pp.563-569
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• 2020

기상현상 발생에 대한 기존 기상예보 방식에서 벗어나 기상재해가 사회와 인간생활에 끼치는 영향을 제공함으로써 사전에 영향범위에 대한 피해예방 및 행동예방을 취할 수 있는 영향예보를 제공하는 것이 필요하다. 이를 위해 미국, 영국, 프랑스 등 세계 각국에서는 호우, 폭설, 한파 등의 영향예보를 시행하고 있으며, 보다 효율적인 예보방안에 대해 고민하고 있다. 본 연구에서는 여러 기상현상 중 호우에 대한 영향예보를 국내의 실정에 맞도록 개선하고, 적용하기 위해 33개의 호우영향인자(Impact Library)를 격자단위(1 km)로 구축하고, 표준정규분포법을 이용하여 4개의 위험등급(Minimal, minor, significant, severe)의 기준을 산정하였다. 산정된 기준은 호우영향 대상체인 사람, 시설, 농업, 교통을 중심으로 한 6개의 카테고리(Residential, commercial, utility, community, agriculture, transport)에 대한 호우위험영향(Heavy rain risk impact)를 산정하기 위한 지표로 활용된다.