• Title, Summary, Keyword: 종단연구

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Development of a Highway Vertical Alignment Analysis Algorithm and Field Test Using a Vehicle with Multiple Sensors (각종 센서를 장착한 차량을 이용한 종단선형 분석 알고리즘 개발 및 현장 검증에 관한 연구)

  • Yun, Deok-Geun;Seong, Jeong-Gon
    • Journal of Korean Society of Transportation
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    • v.25 no.2
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    • pp.157-165
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    • 2007
  • In this research, a vertical alignment analysis algorithm was developed. The developed algorithm used acquired data from a vehicle with multiple sensors such as a global positioning system (GPS) an inertial navigation system (INS), and a distance measuring unit (DMI) to collect information about vehicle position and altitude. The vertical alignment analysis algorithm includes the identification of vertical tangent sections, the beginning and ending points of vertical curves, and the calculation of length of vortical curves. Also, the algorithm can help build models for vertical tangent sections and vertical curve sections. In order to verify the algorithm, a field survey was conducted at an actual highway section and the result of the field survey was compared to a highway CAD drawing.

Theoretical Proposal and Consideration on Longitudinal Study of Entrepreneurial Gifted Youth (기업영재 종단연구의 이론적 제안 및 고찰)

  • Choi, MinGyeong;Lee, KyungPyo
    • Journal of Gifted/Talented Education
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    • v.23 no.5
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    • pp.793-815
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    • 2013
  • Research on entrepreneurial gifted youth who have immense potential within the national economy in the near future is critical. The purpose of this article is to establish the proper goal and direction of longitudinal study on entrepreneurial gifted youth and to identify substantial research problems. In order to do a theoretical inspection around preceeding research related with the field, longitudinal study of entrepreneurial youth (including gifted education and entrepreneurship) was executed. As a result, the goal, 'the verification of whether entrepreneurs can be cultivated by educational interventions' was derived as an appropriate research direction. Also, 4 major research problems are presented: (1) Description of the features of entrepreneurial gifted youth and their developmental pattern, (2) Explanation of the effects of educational intervention on intensifying entrepreneurial giftedness, (3) Prediction which identifies the factors that influence the youths' success as eminent entrepreneurs, and (4) Control over promoting talented individuals and refining relevant policy and institutions. Implications and further research directions are also discussed.

Study of Terminal Velocity of 2-D Elliptical Object by Sedimentation Characteristics (2차원 타원형 물체의 유체 중 침강특성이 종단속도에 미치는 영향 연구)

  • Jeon, Jae-Yun
    • Proceeding of EDISON Challenge
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    • pp.548-553
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    • 2016
  • 본 연구는 타원형 물체가 유체 중에서 침강할 때 물체의 형상과 밀도에 따른 침강특성을 분석하는 것이며, 이로 인해 종단속도에 미치는 영향을 평가하는 것이다. 복잡한 형태의 물체를 타원기둥으로 단순화하였고, 낮은 Reynolds 수(=0.5~100)에 대하여 연구를 진행하였다. 또한 침강형태가 종단속도에 미치는 영향을 연구하였다. 수치해석 검증을 통해 정확하고 효율적인 격자 크기를 결정하였다. 정확한 분석을 위해 단순히 종단속도의 변화를 본 것이 아니라 진동하지 않은 물체의 이론적 속도와 비교하여 이와 얼마나 차이가 있는지를 확인하였다. 수치해석 결과 장단축비에 따라 물체의 침강특성이 크게 변하였고 그 경향은 밀도비에 따라 다른 양상을 보였다. 또한 각의 진동에 대한 진폭과 진동수가 물체의 침강속도에 영향을 주는 것을 확인하고 그 원인에 대해서도 연구하였다.

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Theoretical Review of Highway Grades Considering Vehicle Performances (차량성능을 고려한 최대종단경사 합리화 연구)

  • Kim, Sang-Yeop;Lee, Seung-Yong;Han, Hyeong-Gwan;Choe, Jae-Seong
    • Journal of Korean Society of Transportation
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    • v.25 no.5
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    • pp.79-90
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    • 2007
  • In determining vertical grades in highway alignment design, engineers usually consider heavy vehicle performances on the upgrade. Heavy vehicles usually experience speed reduction on the upgrade and with recent years weight/horsepower improvements for heavy vehicles the speed reduction shows some change. However, in spite of the weight to horsepower improvements for the design vehicles from 300lb/HP to 200lb/HP in the AASHTO, there was no change in the maximum vertical grades. Therefore, a review of the maximum vertical grade reflecting existing heavy vehicle performances is required. In particular, in South Korea where highways pass through lots of mountaineous terrain, the maximum vertical grades must be reviewed throughly. In this study the amount of heavy vehicle performances during past decades were investigated and their expected impacts on highway vertical alignment designs were subsequently analyzed. A worldwide terrain analysis and international design standards were compared to set South Korean vertical grade standards. Traffic flow simulation Vissim was utilized to simulate vehicular flows on the upgrade and new truck performance curves on the grades were developed. Based on the new curve, it was decided that $1{\sim}2%$ increase of the maximum vertical grades could be allowed.

Standardization of Enhanced Flight Termination System in the U.S. (미국의 차세대 비행종단시스템 표준화 동향)

  • Bae, Young-Jo;Oh, Chang-Yul;Lee, Hyo-Keun
    • Current Industrial and Technological Trends in Aerospace
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    • v.8 no.1
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    • pp.86-95
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    • 2010
  • Flight termination system(FTS) is used to terminate safely the launch vehicle's flight when it faces an emergency situation by transmitting termination command from ground FTS. RCC standard IRIG tone method has been used widely for FTS commands method in foreign ranges and Naro Space Center, but this method has a weakness for security of command signal. Therefore RCC had studied more secured EFTS standard and chose CPFSK digital modulation method. This paper describes basic concept and types of FTS and FTS types which foreign ranges had applied and describes standardization of EFTS in the U.S. based on RCC EFTS study reports.

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Analysis of Achievement and College Major Choice According to Longitudinal Pattern of Awareness of ICT Literacy and Frequency of Computer Use (컴퓨터 활용능력과 빈도의 종단적 패턴에 따른 학업성취도와 대학전공 선택 분석)

  • Shim, Jaekwoun
    • The Journal of Korean Association of Computer Education
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    • v.23 no.1
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    • pp.53-61
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    • 2020
  • In the information society, the ability of learners to use computers to conduct self-directed learning is important. Indeed, the higher the computer's ability to use computers, the more the academic achievement needs to be analyzed. The purpose of this study was to identify longitudinal trajectories of student awareness of ICT literacy and frequency of computer use. We also examined the effects of the longitudinal patterns on academic achievement and college major choice. A non-parametric approach, K-means for longitudinal data(KML) algorithm, was conducted using 9-year longitudinal data from Seoul Education Longitudinal Study (2010-2018). Findings indicated that a pattern presenting a higher awareness of ICT literacy and frequency of computer use showed better academic achievements and was likely to prefer to choose engineering-related majors.

A study on Appropriate Range of Vertical Grade at Urban Road Intersections (상관관계분석을 통한 도시부 평면 교차로의 종단경사 적정범위 연구)

  • Lee, ki-young;Yoon, Byoung-Jo;Jang, Jae-Hun;Yang, Sung-Ryong
    • Proceedings of the Korean Society of Disaster Information Conference
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    • pp.199-200
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    • 2015
  • 도시부 교차로의 설계는 지방부 교차로와 근본적으로 달라야 하나, 현행 도시부 교차로 설계는 지방부 교차로 설계기준을 준용하고 있다. 본 연구는 도시부 및 지방부 교차로의 차이점을 비교 분석하고, 국내외 교차로 종단경사 설계기준을 검토한 후 적정 설계기준(안)을 적용한 후, 이를 통계적 분석기법을 활용하여 검증하여 설계기준을 정립하는 순으로 진행 하였다. 분석결과 정면충돌사고율과 차대차추돌사고율이 종단경사와 상관관계가 있는 것으로 나타났다. 이러한 연구를 통해 적정 교차로 종단경사를 적용한 설계가 이루어져야 함을 확인 할 수 있었다.

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A Study on the Resistor Array Networks for the Optimum Termination of a Modified Large TEM Cell (변형 TEM Cell의 최적 종단 처리를 위한 저항 어레이 망 설계에 관한 연구)

  • 이중근;강문수
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.7 no.2
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    • pp.157-166
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    • 1996
  • This paper presents the optimum termination method of a TEM Cell, which utilizes hybrid distributed termination resistor array networks. Current stream on the septum, and on the terminal end of a TEM Cell is analyzed by numerical analysis. By circuit analysis, the optimum resistor array network is designed based on the result of the analysis, which assures efficient power dissipation, and current stream traveling straight and uniform. Thermovision photos were taken for comparing the conventional termination network on which each resistor is arranged at regular intervals, with the suggested optimum termination network on which each resistor is arranged for current distribution. The comparison of the results of thermovision photos shows a good agreement with those obtained by numerical analysis.

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Sight Distance at Crest Vertical Curves Under Consideration of Construction Errors (볼록형 종단곡선에서 시공오차를 고려한 정지시거에 관한 연구)

  • Lee, Myeong-Han;Kim, Dong-Nyong
    • Journal of Korean Society of Transportation
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    • v.23 no.8
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    • pp.153-162
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    • 2005
  • This study is carried out to evaluate the sight distance change due to construction errors of vertical crest curves. Various design speeds and grades as well as various size of construction errors are incorporated in this study. After showing theoretical methodology numerical results are compared and analysed for the given ranges of parameters. New vertical curve change rate(m/%) is suggested to guarantee minimum sight distance under construction errors. As to the results, the reduction of sight distance are $2.8{\sim}21.3m$ at 120km/h, $2.0{\sim}15.1m$ at 100km/h, $1.4{\sim}10.6m$ at 80km/h, $1.0{\sim}7.5m$ at 60km/h $0.5{\sim}3.9m$ at 40km/h. Vortical curve change rates need to be increased about $6{\sim}25%$ to provide minimum stopping sight distance according to design speed.

A Longitudinal Study of Bibliotherapy with Juvenile Delinquents (비행청소년의 독서경험에 관한 종단연구)

  • Ko, Jung-won
    • Proceedings of the Korean Society for Information Management Conference
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    • pp.59-66
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    • 2014
  • 본 연구는 비행청소년들이 중학생 시절 경험했던 독서활동과 탈비행과의 관련성을 파악하고자 내러티브 탐구를 실시하였다. 청소년들의 탈비행에 미치는 독서활동의 영향을 밝히려는 본 연구의 목적에 따라 실시한 종단연구에 참여한 탈비행청소년은 5명이며, 연구기간은 8년이다. 연구자는 연구참여자들과 독서활동에 대한 탈비행과정을 자유로운 질문으로 면담일지와 내러티브 텍스트를 작성하여 다음과 같은 결과를 얻었다. 연구참여자로 참가한 비행청소년들은 독서활동을 통하여 과거의 상처를 치료하고 현재의 자신과 타인을 이해하게 되어 건강한 성인으로 성숙해 가고 있다. 비행청소년의 탈비행 지속성은 연구자와 연구참여자 사이의 신뢰와 유대감이 선결조건임이 확인되었다.

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