• 한국ITS학회 논문지
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• 제19권4호
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• pp.1-12
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• 2020

본 연구에서는 COVID-19 대유행에 따른 다중밀집시설 중 하나인 서울역 역사를 대상으로 사회적 거리(Social Distance) 유지 및 보행동선체계 구축에 따른 효과분석을 진행하였다. 분석을 위해 서울역 CAD 및 철도역사 이용객 수 조사를 통하여 서울역 보행 Network를 구축하였으며, Social Force Model을 활용하여 사회적 거리(Social Distance)를 유지하는 보행자를 구현하였다. 이를 바탕으로 시나리오 분석을 수행하였다. 분석결과, 보행동선체계 도입 시 현황과 비교하여 평균보행속도가 감소하였으나 평균보행밀도의 경우 보행 서비스수준(LOS) 'C'를 유지하는 것으로 분석되어 보행동선체계의 효과가 입증되었으며, 향후 보행계획 시 보행 시뮬레이션 모델로서 활용이 가능할 것으로 기대된다.

• 대한교통학회지
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• 제35권5호
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• pp.385-395
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• 2017

이 연구는 소규모 회전교차로를 다루고 있다. 이 연구는 회전교차로의 평균지체를 분석하고 효율적인 계획 및 설계기준을 제시하는 데 그 목적이 있다. 이를 위해 이 연구에서는 내접원 지름, 회전차로의 속도 및 진입교통량에 따른 평균지체 분석에 중점을 두고있다. 96개($3{\times}4{\times}8$) 시나리오의 운영효율이 교통시뮬레이션 프로그램 VISSIM (Verkehr In $St{\ddot{a}}dten$-SIMulationsmodell)을 사용하여 분석되었다. 연구의 주요 결과는 다음과 같다. 첫째, 시나리오 분석을 통해 소규모 회전교차로의 적정 설계속도가 도출되었다. 둘째, 서비스 수준 D에 도달하는 진입교통량은 2,180-2,740pcph인 것으로 분석되었다. 셋째, 분석 회전교차로에서 혼잡수준 F로 개선이 요구되는 교통량은 2,780pcph 이상으로 평가되었다. 연구 결과는 효율적인 회전교차로 운영을 위한 대응조치를 제공하는 데 몇 가지 함의를 줄 것으로 기대된다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.376-379
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• 2006

Reaction Wheel Assembly (RWA) is one of the major disturbance sources that have influence upon the Line of Sight (LOS) of payload. A micro-vibration induced by RWA is propagated through the satellite structure and decrease the LOS stability performance of payload. This effect shall be analyzed through the jitter analysis. If a requirement or specification of payload jitter level is found to be not satisfied according to the jitter analysis campaign, some modification or redesign should be done on the satellite structure or a couple of isolator should be attached on the RWA interface in order to reduce the transmitted vibration level of RWA. The purpose of ???RWA isolator test? is to roughly evaluate the performance of vibration suppression level with a passive RWA isolator made of rubber. For this test, actual RWA is used as a vibration source and a couple of cube-shaped rubber mount designed for satellite is used as a passive isolator. There may be several considerations in order to accommodate RWA isolator to spacecraft such as not only vibration reduction performance but also thermal conduction problem, mechanical size, RWA alignment problem, etc. But in this report the feasibility of RWA isolator is analyzed only in a vibration suppression point of view. As a result, high frequency vibration of RWA above 50Hz is perfectly attenuated with isolators, however, first harmonic components below 50Hz became larger due to the additional low frequency resonance modes of roll, pitch, yaw rigid body motion of RWA+bracket.

• 한국통신학회논문지
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• 제34권2B호
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• pp.170-177
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• 2009

본 논문에서는 본 논문에서는 BS(Base Station, 기지국)와 RS(Relay Station, 중계기)가 지향성 안테나를 갖는 multi-tier 기반의 NBTC (Narrow-Beam Trisector Cell)와 WBTC (Wide-Beam Trisector Cell) 구조를 제안하고, 두 시스템에서 동일 채널 간섭 (Co-channel interference)에 의한 용량을 두 개의 채널 모델을 적용하여 분석하였다. 분석을 통해 $2^{nd}$ tier로 구성한 한 클러스터에서 발생하는 총 용량은 LOS(Line of Sight)의 존재 여부에 따라 NBTC 구조 셀과 WBTC 구조 셀의 총 용량이 달라짐을 알 수 있었다. 본 논문의 결과는 향후 차세대 이동통신 및 와이브로 시스템에서 간섭을 고려한 멀티 홉 RS 도입 시에 참고할 만한 가이드라인을 제시할 수 있을 것이다.

• 한국ITS학회 논문지
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• 제13권2호
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• pp.12-26
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• 2014

이 연구에서는 교통사고 영향요인 중 야간의 시인성 저하가 교통사고 발생에 미치는 영향을 진단하였다. 연구를 위해 경기지역의 경부선, 서해안선, 영동선, 서울외곽순환고속도로의 기본구간을 58개의 소구간으로 분할하였고, 2009년에서 2012년 상반기까지 소구간에서 발생한 교통사고 410건을 이용하여 야간의 어두움으로 인한 시인성 저하가 교통사고에 미치는 영향을 진단하였다. 실험방법은 준실험설계를 준용하여 시인성 외 교통사고에 영향을 주는 변인을 통제하고 음이항 회귀분석을 활용하였다. 조사 결과, 맑음 기상조건에서의 LOS A 상태 등 특정조건에서 주간과 야간의 시인성 차이가 교통사고 발생에 유의한 영향을 미치는 것으로 진단되었다. 그리고 진단 결과를 이용하여 교통사고의 유형과 원인에 대하여 다양한 분석을 시도하였다.

• 대한한의진단학회지
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• 제14권2호
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• pp.110-120
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• 2010

Objective: To relate with significant relationship between symptoms and Five Zhang(五臟)symptoms in Five Woon Constitutions and to characterize Five Woons of Asian women who live at Los Angeles area in U.S.A. Methods: 19 diagnostic questions were given to 286 Asian females subjects who were treated for their symptoms at an Asian medical clinic near Los Angeles in USA. The participants were given their constitutions, one of the Five Woons based on their birthdays. The Cross tabulation analysis was also applied to look for the effectiveness of Five Woons on the symptoms. Results: 1. The cross tabulation analysis showed the significant effectiveness of the Five Woons on the five symptoms including dizziness, hot and cold, lower body edema and face fever(p<0.1). 2. The dizziness and the hot and cold were related with Liver diseases, the lower body edema was related with Kidney diseases and the face fever was related to Heart diseases. Conclusions: This study can explain the relationship between the significant symptoms of Five Woons and Five Zhang(五臟)symptoms with reference which is the book by Yoon, ChoChang who lived 1700 years. Further clinical research is necessary to develop more delicate questionnaires and look for ways of characterizing the Five Woons. The diagnosis and corresponding treatment based on the Five Woons should be further studied in view of the Asian medicine.

• 한국항공운항학회지
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• 제10권1호
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• pp.21-34
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• 2002

This study is performed to secure the safety of civil aviation by establishing systematic analysis ability of Flight Data Recorder. Through this study, downloading SSFDR(Solid State Flight Data Recorder) to personal computer, editing interface file, flight data numerical analysis and regulations relayed to the aircraft with changes in destination airport in flight are performed. In the analysis, the flight data of B747-400 model aircraft between Los Angeles(KLAX) and Jeju(RKPC) was selected.

• Journal of Contemporary Eastern Asia
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• 제12권2호
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• pp.19-34
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• 2013

Previous research assessed media reporting on nuclear accidents and risks, whilst studies about the Fukushima accident focused on the impact of the Internet on coverage of the incident. However, little research has addressed news framing or comparisons of the perceptions of journalists in relation to reporting nuclear accidents. The aim of this study is to apply framing analysis to news content in The New York Times, the Los Angeles Times, and USA Today about the Fukushima accident. It explores the question of how journalists view reporting on complex events. Content analysis of these three newspapers shows that conflict, responsibility, and economic consequences were the most frequently used frames. According to the journalists interviewed, the biggest problem was the inability to assess information due to contrary positions held by experts. It is argued that the Fukushima accident was framed as a conflict of experts and officials' opinions, utility and government officials' responsibility, and economic consequences for the United States. Adherence to professional norms of objectivity and impartiality was signified as the best approaches to risk reporting.

• 천문학회지
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• 제37권5호
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• pp.509-515
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• 2004

We present results from an extensive synthetic observation analysis of numerically-simulated radio galaxy (RG) jets. This analysis is based on the first three-dimensional simulations to treat cosmic ray acceleration and transport self-consistently within a magnetohydrodynamical calculation. We use standard observational techniques to calculate both minimum-energy and inverse-Compton field values for our simulated objects. The latter technique provides meaningful information about the field. Minimum-energy calculations retrieve reasonable field estimates in regions physically close to the minimum-energy partitioning, though the technique is highly susceptible to deviations from the underlying assumptions. We also study the reliability of published rotation measure analysis techniques. We find that gradient alignment statistics accurately reflect the physical situation, and can uncover otherwise hidden information about the source. Furthermore, correlations between rotation measure (RM) and position angle (PA) can be significant even when the RM is completely dominated by an external cluster medium.

• Structural Engineering and Mechanics
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• 제54권2호
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• pp.221-237
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• 2015

An integrated method is proposed for structural nonlinear damage detection based on time series analysis and the higher statistical moments of structural responses in this study. It combines the time series analysis, the higher statistical moments of AR model residual errors and the fuzzy c-means (FCM) clustering techniques. A few comprehensive damage indexes are developed in the arithmetic and geometric mean of the higher statistical moments, and are classified by using the FCM clustering method to achieve nonlinear damage detection. A series of the measured response data, downloaded from the web site of the Los Alamos National Laboratory (LANL) USA, from a three-storey building structure considering the environmental variety as well as different nonlinear damage cases, are analyzed and used to assess the performance of the new nonlinear damage detection method. The effectiveness and robustness of the new proposed method are finally analyzed and concluded.