• 한국연소학회:학술대회논문집
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• 한국연소학회 1997년도 제15회 KOSCO SYMPOSIUM 논문집
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• pp.163-173
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• 1997

This article presents an application of a large-scale structural mixing model (Broadwell et al. 1984) to the blowout of turbulent reacting jets discharging perpendicularly into an unconfined cross air-flow. In an analysis of a common stability curve, a plausible explanation can be made that the phenomenon of blowout is related only to the mixing time scale of the two flows. The most notable observation is that the blowout distance is traced at fixed positions at all times according to the velocity ratio R. Measurements of the lower blowout limits in the liftable flame agree qualitatively with the blowout parameter ${\varepsilon}$, proposed by Broadwell et al. Good agreement between the results calculated by a modified blowout parameter ${\varepsilon}^'$ and experimental results confirms the important effect of a large-scale structure in specifying the stabilization feature of blowouts.

• 품질경영학회지
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• 제30권3호
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• pp.38-52
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• 2002

This paper is concerned with the analysis of structural equation model(SEM) with the ordinal data such as Likert scale. The SEM is misused when the arbitrary scores allocated to the Likert scale are treated as quantitative data. The underlying distribution approaches have been studied to solve this problem, and the partial least squares(PLS) Is also tried. In this paper the quantification methods for the Likert scale are proposed to analyze the SEM. We assume that the Likert scale is an observation of the interval of the continuous underlying distribution, and the respondents have their own patterns in the response of some questions. Normal and beta distributions as the response patterns are considered to quantify the Likert scale. To compare the efficiency of the proposed method the bootstrap simulations are tried.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2001년도 창립10주년 제20회 학술발표회
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• pp.201-201
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• 2001

• 천문학회보
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• 제39권2호
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• pp.82-82
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• 2014

One of the subjects in clouds' structure and development is small scale structure of interstellar cloud. The possibility of AU scale structure (Marscher et al. 1993; Moore & Marscher 1995; Roy et al. 2012) is discussed, and this small scale structure is considered as the result of hydrogen volume density (Moore & Marscher 1995), or small-scale chemical and other inhomogeneities (Liszt & Lucas 2000). In order to study this subject with emission line, extremely high resolution is mandatory by VLBI system. However, the alternative method could be observing the absorption line of interstellar cloud on the continuum object. In this case, the resolution would be restricted to the size of the continuum object, if the size of the object is smaller than the resolution of a used telescope. We observed the previous researchers' three objects (BLLAC, NRAO150, B0528+138), whose spectrums are changed from 1993 to 1998 (Liszt & Lucas 2000), with KVN. Through KVN observation, we found the changes of optical depth spectrum compared with the previous spectrums. We will discuss the optical depth spectrum variation by time variation and the meaning of it.

• 아동학회지
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• 제31권3호
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• pp.235-254
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• 2010

The purpose of this study was to examine the feasibility and validity of the Application of Cognitive Function Scale as developed by Lidz and Jepsen (1997). Data were collected from 4 to 5-years-old children. The analysis for item adequacy indicated that the passing rate increases according to age. Futhermore the analysis for test adequacy indicated that internal consistency reliability was .85 in the pre-test and .80 of post-test in terms of the cognitive function scale, and .90 of pre-test and .93 in the post-test in relation to the behavior observation scale. In conclusion, our analysis of the ACFS shows sufficiently high scores in terms of both validity and reliability, so as to indicate that this test is an appropriate way to measure the cognitive function and non-intellective function of young Korean children.

• 환경영향평가
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• 제6권2호
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• pp.81-92
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• 1997

This paper presents the results from the comparison analysis and evaluation between the air pollutant dispersion modeling results and the observation data in the area within a 10 km radius from the Boryong thermal power plants. The observation data used in this study were the air pollutant concentrations which had been continuously measured from 8 locations around the Boryong power plants by TMS(tele-monitoring system) for 3 months from September to November, 1996. The short-term and long-term predictions were carried out using ISC3 model and LPDM(Lagrangian Panicle Dispersion Model). The results of ISC3 modeling in a short-term showed highly as 0.7 in a correlation coefficient, but in a long-term showed just 0.54. On the other hand, LPDM showed 0.78 in a correlation coefficient for a long-term, but in a short-term showed highly value than the observation concentrations.

• 천문학회보
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• 제46권1호
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• pp.36.1-36.1
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• 2021

Galaxy clusters host Mpc-scale diffuse radio emission giving us evidence of large-scale magnetic fields in the Universe. It is relevant to understand magnetic field amplification processes occurring at the center and outskirts of galaxy clusters. Each of these processes are believed to give rise to observed radio haloes and radio relics, respectively. In this work, we focus on studying the continuum and polarised emission in radio relics. We use threedimensional magnetohydrodynamical simulations of merger shock waves propagating through a magnetized, turbulent intracluster medium. Our model includes the diffusive shock acceleration (DSA) of cosmic ray electrons, their spatial advection and energy losses at run-time. We discuss the relation between the mock observation features and the underlying morphology of the magnetic field.

• 대한공업교육학회지
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• 제43권1호
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• pp.114-133
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• 2018

이 연구는 학교 및 발명교육센터 등에서 이루어지는 발명교육활동의 분석과 질적 제고를 위한 관찰 및 분석 도구를 개발하기 위한 것이다. 이 연구를 위해 문헌 고찰을 통해 관찰 및 분석 도구의 초안을 개발하였으며, 이에 대하여 발명교육현장 전문가와 발명교육연구 전문가 10인으로부터 의견 수렴을 통해 타당화 하였다. 전문가 의견수렴은 Fehring(1987)의 내용타당도 지수(CVI)를 근거로 하였다. 이에 따른 연구 결과는 다음과 같다. 첫째, 발명교육활동의 관찰 및 분석의 틀은 관찰대상, 관찰단계 그리고 관찰내용의 3차원으로 구성된다. 둘째, 발명교육활동 관찰 및 분석의 도구는 분석자, 관찰 대상, 관찰 수업 내용, 교사 관찰 및 분석, 학생 관찰 및 분석, 교육환경과 과제 관찰 및 분석으로 구성된다. 셋째, 개발된 도구는 5점 리커트 척도 외에 개별 관찰요소에 대한 의견 및 종합 의견을 기술할 수 있도록 구성하였다. 이를 통하여 향후 발명교육활동에 대한 모니터링을 통해 질적인 평가 외에 교육활동 개선이 이루어지길 기대한다.

• 한국산학기술학회논문지
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• 제18권5호
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• pp.557-564
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• 2017

대한민국 군의 K 계열 전차에 장착되어 있는 열영상장비의 목적은 시계가 제한된 환경에서 외부의 적외선 영역의 정보를 인간이 인지할 수 있는 시각 정보로 변환하는 것이다. 열영상장비의 시계, 배율, 분해능, 변조전달함수, 잡음등가온도차, 최소분해가능온도차 등의 지표 중에서 최소 분해 가능 온도차(MRTD)는 공간주파수와 온도분해능을 복합적으로 표현할 수 있기 때문에, 열영상장비의 성능 표현에 있어 가장 중요한 파라메터이다. 그러나 NATO의 MRTD 표준 측정 방법은 많은 주관적인 요소를 포함하고 있다. 즉, 측정자의 정신 상태, 시력 등의 차이와 측정환경에 따라 측정 결과의 오차가 발생하므로 MRTD의 측정결과는 안정적이지 못하다. 따라서 본 논문에서는 정성적인 MRTD 측정 방법을 gary scale을 바탕으로 이미지 연산을 통한 정량적인 지표로 변환하였다. 흑상과 백상의 Gray scale 차이의 평균을 최소분해가능온도로 변환하여, 국방규격서에서 요구하는 성능요구조건의 충족여부를 판단할 수 있다. 또한 gray scale은 MRTD의 탐지/인지/식별의 판별기준으로 활용할 수 있다. 전차에 열영상장비가 탑재되어 작전을 수행할 때의 탐지 가능 거리를 안개, 폭우, 맑은 날씨 등의 다양한 환경조건에 따라 분석하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2018년도 학술발표회
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• pp.156-156
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• 2018

The subbasin spatial scale can affect a hydrological simulation result. The objective of this study was to investigate an appropriate subbasin spatial scale for reproducing the different flow phases with the Soil and Water Assessment Tool (SWAT). Moreover, this study addressed the total hydrologic model uncertainty using the Generalized Likelihood Uncertainty Estimation (GLUE) method. The hydrologic modelling uncertainty analysis revealed that the courser subbasin spatial scale provided a relatively better coverage of most of the observations by the 95PPU. On the other hand, the finer subbasin spatial scale produced the best single simulation output closer to the observation. Moreover, most of the observed high flows were enveloped by the 95PPU while this did not happen for the low flows. The overall average performance improvement through an appropriate subbasin spatial scale for reproducing the different flow phases in the Yongdam and Gilgelabay watersheds were found to be 36% and 53%, respectively. It is, therefore, a worth that to put more effort in reproducing the different flow phases by investigating an appropriate subbasin spatial scale to improve our understanding about the frequency and magnitude of the different flow phases.