• The Bulletin of The Korean Astronomical Society
• /
• v.34 no.1
• /
• pp.154.2-154.2
• /
• 2009

• Journal of the Korean earth science society
• /
• v.30 no.1
• /
• pp.49-57
• /
• 2009

We studied a structure of the Kunsan basin in the Yellow Sea using ship-borne magnetic data and altimetry satellite-derived gravity data provided from the Scripps institution of oceanography in 2006. The gravity data was analyzed via power spectrum analysis and gravity inversion, and the magnetic data via analytic signal technique, pseudo-gravity transformation, and its inversion. The results showed that the depth of bedrock tended to increase as we approached the center of the South Central Sag in Kunsan basin and that the maximum and minimum of its depth were estimated to be about 6-8 km and 2 km, respectively. Inaddition, the observed high anomaly of gravity and magnetism was attributed to the intrusion of igneous rock of higher density than the surrounding basement rock in the center of South Central Sag, which was consistent with the interpretation of seismic data obtained in the same region.

• Journal of the Korean earth science society
• /
• v.38 no.1
• /
• pp.1-10
• /
• 2017

The symbiotic star AG Peg is a nebulous binary system that consists of giant star (GS) and white dwarf (WD). We investigated the HI Balmer emission lines of the symbiotic nova AG Peg, observed in 1998, 2001, and 2002 at Lick Observatory. The $H{\alpha}$ and $H{\beta}$ line profiles consist of blue-shifted, red-shifted, and broad components of which intensities and width showed notable changes. The HI emission line profiles that represent the kinematics of the gaseous nebula appear to be mainly from an accretion disk in relatively large radius from the WD. Considering the line of an observer's sight, both GS and WD are located at the sky plane side by side during the 1998 observation, while the WD is in front of GS during 2002 but the WD in rear during 2001. Such a relative position and the spectral line intensity variation imply that a fairly constant outflow occurs into WD from GS which caused to maintain the rotating thick accretion disk structure responsible for the observed spectral lines.

• Journal of the Korean earth science society
• /
• v.30 no.2
• /
• pp.176-184
• /
• 2009

The purpose of this study is to develop and apply the web contents about the optical characteristics of rock forming minerals. The web contents developed in this study are fundamentally made up so as to show clearly the learning objective and the teaching and learning contents, and to review one content easily and search for another content freely. In addition to the web contents, the photos and moving images of the optical characteristics of rock forming minerals cited in the middle and high school textbooks are demonstrated for the students to recognize the mineral characteristics on the screen. The analysis on the quality level and teaming effect of teaching and teaming materials based on the investigation of the MALSAM after the application of the web contents to the class, showed that most students evaluated were effective for understanding the optical characteristics of the rock-forming minerals. About 62% of the students who used the web contents were able to identify the rock-forming minerals on the thin section under the polarizing microscope.

• Journal of the Korean earth science society
• /
• v.39 no.5
• /
• pp.436-457
• /
• 2018

In this study, we apply a three-dimensional circulation model, MOHID (MOdelo $HIDrodin{\hat{a}}mico$), and reproduce oceanic variation around the East Asian seas including Korea in 2016. Simulation results are verified by using objective analysis fields (EN4, ARMOR3D, AVISO, and SIO products) and in-situ observation data (serial oceanographic and buoy data). Verification results show that general characteristics of the water temperature, sea level anomaly, surface velocity, and mixed layer depths simulated by MOHID are similar with those of the objective analysis fields in the East Asian seas. Especially, when buoy data in the coastal areas are compared, correlation coefficients of sea surface temperature and sea level anomaly are both over 0.8 and normalized standard deviations are between 0.85 and 1.15, respectively. However, it is analyzed that additional improvement would be necessary in the representation of thermocline structure in the East Sea and strong stratification phenomena in the Yellow and South Sea in summer.

• Journal of the Korean earth science society
• /
• v.24 no.6
• /
• pp.508-523
• /
• 2003

This study has developed the test tool to measure the level of spatial concept in the astronomy education for high school students. The items of the test tool are composed of basic elements (spatial position, spatial reasoning, spatial variation) forming spatial concepts in the astronomy. The test tool was applied to the 274 high school students. As a result of item analysis, the test tool showed that the content validity was 98%, the reliability (KR 20) was 0.84, the measure the level of astronomical spatial concept for the high school students.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2005.05a
• /
• pp.209-214
• /
• 2005

In the present age, the quality of MT(magnetotellurics) data highly depends on the level of industrial interference in data. We analyzed the correlation between the spatial distributions of man-made EM noise source and the characteristics of MT data. The noise source analysis shows the correlation between the noise source density and the power spectral density of measured magnetic field in the frequency band of 60 Hz harmonics. In the MT 'dead band', the strong polarization observed on the magnetic field reveals that the severe artificial noises are caused by the adjacent metropolis.

• Journal of the Korean earth science society
• /
• v.23 no.2
• /
• pp.119-131
• /
• 2002

Constructivism is defined in a variety of ways (e.g., constructivist research paradigm, sociological constructivism, and philosophical constructivism) and applied in vastly different contexts. Among the various usages and interpretations of constructivism, one is educational constructivism that embodies an epistemological view of knowledge and learning that is an alternative to naive empiricism or classical behaviorism. To represent the full range of stances taken by educational constructivists, three versions of educational constructivism were considered in this study: individual constructivism originating in the work of Piaget, the radical version of constructivism associated with von Glasersfeld, and the social constructivism of Vygotsky. I investigated preservice teachers' meaning construction about constructivist epistemology as they went through their preservice teacher education program using in-depth interviews. This preservice teacher education program employs constructivist aspects of teacher education and generates applications of constructivism to the practice of teaching. Features of preservice teachers' internalized meanings of educational constructivism include: (1)traditional pedagogy as the default, (2) Literal interpretation of constructivism, (3) Individual constructivism as conceptual change learning, (4) Radical constructivism as a strong individualistic philosophy, (5) Social constructivism as being too ideal to be practical. A compilation of the teachers' own statements about how to implement conceptual change learning and their projected role as constructivist teacher is also provided.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2006.06a
• /
• pp.35-38
• /
• 2006

The polarized direction of MT field was analyzed using the MT dataset measured in the Korean Peninsula. The atmospherics above 1 Hz has a large dispersion of polarized direction, whereas the Schumann resonance near 8 Hz exhibits the predominant direction ranging from $N20^{\circ}W$ to NS. The electromagnetic field variations below 0.1 Hz, induced by magnetic pulsations, show a strongly polarized direction of nearly NS. It results from the regular pulsations since the regular pulsation fields, driven by Alfv.n's wave in the magnetosphere, has a worldwide predominant direction of NS. The MT field strongly polarized along NS direction causes the poorly behaved XY impedance.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2007.06a
• /
• pp.42-47
• /
• 2007

We have studied feasibility of the geostatistical approach to enhance the result of analysis of the sparsely obtained MT(Magnetotelluric) data by combining with gravity data. We have attempted to use geostatistics for integrating the MT data along with gravity data. To evaluate the feasibility of this approach, we have studied about interrelation between geological boundary and density distribution, and corrected density distribution for conversion to more sensitive to geological boundary by minimization of difference between z-directional variogram values of resistivity distribution obtained MT inversion and density distributions. Then, this method has been tested on model and field data. In model test, the results obtained were good agreement with real model. And in a real field data, the result of analysis demonstrate convincingly that our geostatistical approach is effective.