• 한국전산구조공학회논문집
• /
• 제18권1호
• /
• pp.79-91
• /
• 2005

본 논문에서는 프리스트레스를 이용한 가시설 공법(IPS)에 적용되는 띠장의 거동의 해석 및 설계절차에 대한 연구를 수행하였다. 띠장에 초기장력이 도입되는 구조계는 탄성지반위에 놓인 보이론에 의하여 부재력이 산출되고, 토압에 의한 부재력은 장력을 부정정력으로 취하여 부정정 구조해석을 통하여 띠장의 축력 및 휨모멘트를 계산하였다. 지반은 압축력 전담요소, 케이블은 인장력 전담요소를 사용하여 등분포 토압 및 편토압을 받는 띠장의 전산해석을 수행하였다. 기존의 가시설 설계에 적용되는 토압을 적용하여 IPS 띠장설계를 실시하였고, 긴장력과 설계토압에 의한 축력과 휨모멘트를 계산하여 축응력과 휨응력을 도출하고 합성응력검토를 수행하였다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2005년도 춘계학술대회 논문집
• /
• pp.767-775
• /
• 2005

Power Supply System for electric railways is diversified with technical development and is required high technologies. especially, recently there is required many research and development for earthing to ensure safety of people and protection of installations. Generally, leakage resistance is high between rail and ground at tunnel section of subway. because of short circuit of feeding line, earthing interference by transient overvoltage between signals and communication system, and insulation failure, it can damage to human and equipments To minimize these obstacles, earthing equipment is installed at underground section of railway, but it brings about problems in accordance with operate each earthing system to be not enough required protection provisions for electrified railways. This paper proposes effective earthing method to be concerned about installation cost and maintenance. The validity of the proposed earth method is verified by simulation results at underground section of railways.

• 제어로봇시스템학회논문지
• /
• 제14권1호
• /
• pp.27-35
• /
• 2008

A navigation system is one of the important components of an unmanned ground vehicle (UGV). A GPS receiver collects data signals transmitted by (Earth orbiting) satellites. However, these data signals may contain many errors resulting misinformation and depending on one's position (environment), reception may be impossible. The proposed self-driven algorithm uses three low-cost GPS in order to minimize errors of existing inexpensive single GPS's driving algorithm. By using reliable final data, which is analyzed and combined from each of three GPS's received data signals, gathering a vehicle's steering performance information and its current pin-point position is improved even with error containing signals or from a place where signal gathering is impossible. The purpose of this thesis is to explain navigation system algorithm using multiple GPS and compass sensor and prove the algorithm through experiments.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
• /
• pp.573-577
• /
• 2002

The Landsat Program is the longest running enterprise for acquisition of imagery of the Earth from space. The first Landsat satellite was launched in 1972 and the most recent, Landsat 7, was launched on April 15, 1999. The Landsat satellites have acquired millions of images. The Landsat 7 receiving station is installed at more than 25 sites and will be installed in Korea. This paper will address the work being carried out for the development of image receiving and processing system for the Landsat 7 image data, which will be used at ground station of Landsat 7 in Korea.

• 한국지구과학회지
• /
• 제39권1호
• /
• pp.103-116
• /
• 2018

이 연구의 목적은 초등학교 6학년 학생들의 달의 위상 변화에 대한 학습 발달과정을 천문학적 시스템 사고를 기반으로 탐색하는 것이다. 선행 연구 결과 분석을 통해 서답형 문항을 개발하고 가설적 학습 발달과정을 설정하였으며, 이를 토대로 문항 분석틀을 개발하였다. 달의 위상 변화에 대한 수업을 실시하기 전과 후에 서답형 문항을 이용한 검사 자료를 수집하였으며, 평가 결과를 이용하여 가설적 학습 발달과정의 타당성을 검증하였다. 이를 통하여, 상향식으로 지구-달 계에 대한 학습 발달과정을 탐색할 수 있었다. 연구 결과, 초등학생들은 지구 기반 관점과 우주 기반 관점 사이의 사고 전환에 어려움을 겪는 것으로 보인다. 또한, 달의 위상 변화에 대한 초등학생들의 학습 발달과정을 근거로 할 때, 달의 위상 변화의 개념은 교육과정 상에서 초등학교의 학습 내용으로 다소 높은 수준인 것으로 판단된다.

• 대한지구과학교육학회지
• /
• 제8권1호
• /
• pp.87-97
• /
• 2015

This study is to find out that the effect of class applied Jigsaw cooperative learning to self-directed learning skills and task commitment. This study has been aimed at 2 class 66 students pre-service teachers who take "Science and study of teaching materials I" enrolled in B University of Education located in B city. This study targets to 2009 revision of elementary school science curriculum of changes in earth's surface(3-1), the volcano and earthquakes (4-1), the solar system and the stars (5-1), the motion of the Earth and the Moon (6-1) sections. Clarify the subject of study for implementing a research topics are as follows. First, What is the effect of class applied Jigsaw cooperative learning to self-directed learning skills? Second, what is the effect of class applied Jigsaw cooperative learning to task commitment? Third, what is awareness of class applied Jigsaw cooperative learning? Results of the study were as follows: First, class applied Jigsaw cooperative learning was effective in improving self-directed learning skills. Second, class applied Jigsaw cooperative learning was effective in improving task commitment. Third, in the course of discussion, students got consideration for others with leadership in their discussion was good in the class applied Jigsaw cooperative learning discussion. There was a response that they would like to do the class continually.

• 한국대기환경학회지
• /
• 제24권1호
• /
• pp.1-15
• /
• 2008

Chemical Accident Response Information System (CARIS) which has been designed for the efficient emergency response of chemical accidents produces the real-time atmospheric fields through the Regional Atmospheric Modeling System, RAMS. The previous studies were emphasized that improving an initial input data had more effective results in developing prediction ability of atmospheric model. In a continuous effort to improve an initial input data, we replaced the land-use dataset using in the RAMS, which is a high resolution USGS digital data constructed in April, 1993, with the latest land-use data of the Korea Ministry of Environment over the South Korea and simulated atmospheric fields for developing a real-time prediction in dispersion of chemicals. The results showed that the new land-use data was written in a standard RAMS format and shown the modified surface characteristics and the landscape heterogeneity resulting from land-use change. In the results of sensitivity experiment we got the improved atmospheric fields and assured that it will give more reliable real-time atmospheric fields to all users of CARIS for the dispersion forecast in associated with hazardous chemical releases as well as general air pollutants.

• 한국전자통신학회논문지
• /
• 제16권4호
• /
• pp.643-652
• /
• 2021

송·배전시스템에서 사고나 장애는 결코 완벽하게 피할 수 없으며, 단락 및 지락사고는 계통운영자의 노력에도 불구하고 발생한다. 최근 대용량 신재생 분산전원의 송·배전계통에 연계가 급증하여 계통 운영에 다양한 영향을 주고 있어, 이를 최소화하기 위해 FRT(Fault-Ride-Through)와 같은 연계기준을 마련하여 풍력터빈 또는 태양광 인버터가 계통의 중대 장애 시 연계유지 또는 신속한 계통분리 등을 원활히 수행하여 운영자가 안정적으로 계통을 운영할 수 있도록 지원을 하여야 한다. 본 논문에서는 대표적인 신재생 분산전원의 계통연계 기준인 FRT 조건의 충족여부를 적절하게 판단하기 위하여 동기페이저 측정을 하는 PMU(Phasor Measurement Unit)를 사용한 검출 시스템을 설계 및 구축하고 발전기 탈락으로 인한 계통사고 사례를 기반으로 제시한 시스템을 분석하고 평가한다.

• 자원환경지질
• /
• 제30권6호
• /
• pp.567-586
• /
• 1997

Concentrations of several heavy metals in soils derived from black shale and slate have been reported to be higher than the average concentrations in non-polluted soils. This study describes and characterizes soil minerals, and investigates the distribution of heavy metals in soils, and then examines their relationship. Soils in the study area are mainly consist of guartz and feldspars with minor amount of kaolin, illite, vermiculite, chlorite and illite-vermiculite interstratified minerals. Mineral compositions are similar in mountain-, farmland-, and paddy-soils. The residual soils derived from sandy phyllites contain less illites than those from black shale and black slate. Heavy metals appear to be more concentrated in soils than in rocks. The concentrate ratios in soils to rocks ranges 1.1 times for Cr, 2 for Cu, 1.4 for Ni. The contour maps of Cd, Zn, Pb, Cu contents using 0.43N $HNO_3$-extraction imply that these elements are highly concentrated in the soils near the past uranium exploration region, coal seams, black slate beds and tailings than other parts of the study area. The proportions of the day in most soils are less than 10%. In spite of small proportions of the clay, the concentrations of heavy metals from clay fractions to the total concentrations are high: 1~2.4 times for Co, 1.4~2.5 for Cu, 1.2~2.6 for Ni, 1~5 for Pb, 1~2.7 for Zn and 1.6~1.8 for Cr and V. The contents of organic carbons in clay fractions are also 1.5~3.9 times higher than in silt and sand fractions. Cu, Pb and organic carbons show positive relationship in all size fractions. In the size-fractionated soil profile samples, the contents of heavy metals and organic carbons show analogous trends with depth. For the clay fractions of soil profile samples, the contents of heavy metals with depth have analogous trends to abundances of vermiculites, which have the high CEC in main clay minerals.

• 자원환경지질
• /
• 제49권6호
• /
• pp.433-444
• /
• 2016

백령층군의 사암에서 분리한 쇄설성 저어콘에 대해 LA-MC-ICPMS를 이용하여 U-Pb 연령을 측정하였다. 저어콘 연령은 주로 중원생대와 고원생대말의 기간인 약 1100-1800 Ma의 범위에 집중된다. 그러나 하부고생대 조선누층군이나 상부고생대 평안누층군의 쇄설성 저어콘들에서 흔히 나타나는 1800-2000 Ma 또는 약 2500 Ma의 고원생대 연령은 거의 나타나지 않는 특징을 보인다. 이러한 특징은 북한의 신원생대 상원계 퇴적암과 동일하며, 백령층군이 상원계의 남서쪽 연장부에 해당함을 시사한다. 군산 인근에 분포하는 임피층이 백령층군과 아주 비슷한 쇄설성 저어콘의 연령분포를 보이는 것은 임피층 역시 상원계에 대비될 가능성을 시사한다. 따라서 옥천변성대의 황강리층, 태백산 분지의 묘봉층, 삼방산층, 세송층 등 여러 퇴적층에서 보고된 중원생대 연령의 쇄설성 저어콘들은 중원생대의 저어콘을 갖는 한반도 내의 암석으로부터 유래하였을 가능성이 있다.