• Journal of the Korean earth science society
• /
• v.25 no.7
• /
• pp.532-544
• /
• 2004

The purpose of this study is to analyze the concept concerned with Earth's rotation as passed by tenth graders whose interest in earth's rotation and learning styles were varied. To examine student's interest in the Earth's rotation, 4students (visual-verbal learning style student with much interest, visual learning style student with much interest, visual learning style student with little interest, and verbal learning style student with little interest) were chosen for study. Personal interview was used for this study. To probe students' conception in varied ways, they were allowed to make gesture and draw pictures through data collection process, except for interviews. And the data were analyzed one by one. The result of this study were as follows: First, the student with much interest was faster to answer the questions about Earth's rotation than the one with little interest. Also he comprehended better and was able to explain reasons coherently. Second, there was little difference according to student's learning style. Third, one of the repeated misconception was direction. For thinking that is the right side is the east side, students have misconception that the sun goes from right to left and stars in north sky move clock-wise.

• Journal of Korea Spatial Information System Society
• /
• v.12 no.1
• /
• pp.66-75
• /
• 2010

The authors argues that the current road updating system based on traditional aerial photograph or multi-spectral satellite image appears to be non-user friendly due to lack of the frequent cartographic representation for the new construction sites. Google Earth are currently being emerged as one of important places to extract road features since the RGB satellite image with high multi-temporal resolution can be accessed freely over large areas. This paper is primarily intended to evaluate optimal threshold of RGB pixel values to extract road features from Google Earth. An empirical study for five experimental sites was conducted to confirm how a RGB picture provided Google Earth can be used to extact the road feature. The results indicate that optimal threshold of RGB pixel values to extract road features was identified as 126, 125, 127 for manual operation which corresponds to 25%, 30%, 19%. Also, it was found that display scale difference of Google Earth was not very influential in tracking required RGB pixel value. As a result the 61cm resolution of Quickbird RGB data has shown the potential to realistically identified the major type of road feature by large scale spatial precision while the typical algorithm revealed successfully the area-wide optimal threshold of RGB pixel for road appeared in the study area.

• 한국지구과학회:학술대회논문집
• /
• 2003.09a
• /
• pp.106-107
• /
• 2003

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2007.05a
• /
• pp.33-38
• /
• 2007

This paper presents a experimental evidence of the generation of the earth potential and communication line noise from the electric railway. There is a critical measurement err in case of measuring the electrical power induced noise voltage and degree of cable balance in the field of earth potential generated. As a results, it has been found that the conventional cable has more noise immunity than shielded cable near the railway where the earth current flows through the sheath layer.

• Proceedings of the KSR Conference
• /
• 2004.10a
• /
• pp.1168-1173
• /
• 2004

The alignment design is one of the most influencing elements in earth work for the railway design. The amount of earth work mostly depends on the route, and the construction cost for railway construction largely depends on it. For this reason. it is necessary to develop a program for the construction cost estimation by route alternatives. This study introduces a program for the estimation of the earth work amount including the logics and the way to use.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.2
• /
• pp.496-498
• /
• 2009

• Proceedings of the KSEEG Conference
• /
• 2003.04a
• /
• pp.186-188
• /
• 2003

The Suryun gold-silver mine is one of precious metal occurrences discovered in the Hapcheon mineralized district on which lies the western margin of the Cretaceous Gyeongsang Basin, Korea. The district hosts deposits that include the early to late Cretaceous (108 ～ 88 Ma) Au-Ag-bearing vein systems (So et al. 1989; Shelton et al. 1990). (omitted)

• Journal of The Korean Astronomical Society
• /
• v.29 no.spc1
• /
• pp.439-440
• /
• 1996

The Chinese ancient accounts of timing observations of 48 lunar eclipses and the secular variation of the Earth's spin speed are discussed. A series of ${\Delta}$T expressing the secular deceleration of the Earth's rotation was obtained. The average increase rate of length of the day is about 1.5 milliseconds per century.

• 전기의세계
• /
• v.22 no.6
• /
• pp.33-51
• /
• 1973

To lower the earth resistance shall be one of the most effective method for the prevention of lightening damage on power transmission line. In this report, in order to investigate various characteristic necessary to lowering the earth resistance, the following experiments have been made at 154KV U1San-PoHang T/L, 154KV YoSu-SoonChun T/L and so on. 1. Measurement of Earth specific resistance, 2. Efficiency of Earthing of concrete foundation for steel structure., 3. Efficiency of Earthing with counter poise., 4. Compound impulse test with foundation of steel structure and counter poise. With the above investigate a guidance have been prepared for the effective work-performance of steel structure.

• Proceedings of the KSEEG Conference
• /
• 2007.04a
• /
• pp.235-235
• /
• 2007

See Full Text