• Journal of Advanced Navigation Technology
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• v.8 no.2
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• pp.155-162
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• 2004

Recently, significant interest is shown to creation rather inexpensive global systems communications on base of Low-Earth-Orbit Satellite Networks (LEOSN). One of problems of design and creation LEOSN is development of the stream control methods and estimation it's efficiency in such networks. The given problem is complicated, that the topology of the satellite networks varies in time. It essentially hinders the analytical decision of the given problem. An effective way of overcoming of these difficulties is simulation modeling. For realization of research experiments on learning the information streams routing algorithms in LEOSN a special program complex SANET was developed. In the given paper principles of development of LEOSN simulation models and architecture of the manager by the process of a simulation modeling of the unit are considered. Methods of promotion of modeling time and architecture of a simulator complex offered in the article allow to boost essentially efficiency of simulation analysis and to ensure simulation modeling of the satellite networks consisting of several hundreds space vehicles.

• Ocean and Polar Research
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• v.43 no.4
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• pp.371-374
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• 2021

Triglopsis quadricornis Linnaeus, 1758 (Cottidae) is distributed in the Atlantic and Arctic and has four unique bony protuberances on its head. Here, we report the complete, circular, and annotated mitochondrial genome of T. quadricornis. The complete T. quadricornis mitochondrion was sequenced by high-throughput Illumina HiSeq platform. The sequences are 16,736 bp in size and contains 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, a control region, and large and small ribosomal subunits. The overall genomic structure of T. quadricornis mitochondrion was conserved with the gene arrangement of Megalocottus and Myoxocephalus species, and phylogenetic analysis supports their sister relationships. Most PCGs consist of TAA or TAG as a termination codon, whereas COII, ND4, and CYTB have T-- as a stop codon. This complete mitochondrial DNA information of T. quadricornis will provide an essential genomic resource to elucidate the phylogenetic relationship and evolutionary history of the family Cottidae.

• Journal of the Korean earth science society
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• v.40 no.4
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• pp.329-339
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• 2019

Arctic warming is a global issue. The sea ice in the Arctic plays a crucial role in the climate system. We thought that a recent abnormality in many countries in the northern hemisphere could be related to the effects of shrinking sea ice in the Arctic. Many research groups monitor sea ice in the Arctic for climate research. Satellite remote sensing is an integral part of Arctic sea ice research due to the Arctic's large size, making it difficult to observe with general research equipment, and its extreme environment that is difficult for humans to access. Along with monitoring recent weather changes, Korea scientists are conducting polar remote sensing using a Korean satellite series to actively cope with environmental changes in the Arctic. The Korean satellite series is known as KOMPSAT (Korea Multi-Purpose Satellite, Korean name is Arirang) series, and it carries optical and imaging radar. Since the organization of the Satellite Remote Sensing and Cryosphere Information Center in Korea in 2016, Korean research on and monitoring of Arctic sea ice has accelerated rapidly. Moreover, a community of researchers studying Arctic sea ice by satellite remote sensing increased in Korea. In this article, we review advances in Korea's remote sensing research for the polar cryosphere over the last several years. In addition to satellite remote sensing, interdisciplinary studies are needed to resolve the current limitations on research on climate change.

• Journal of the Korean earth science society
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• v.23 no.8
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• pp.697-706
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• 2002

Authigenic siderite grains, ranging 100 to 250-${\mu}$m in diameter, are abundant in an about 8,600-year-old sediment layer in Namyang Bay, west coast of Korea. The siderites exhibit the aggregated spherulitic morphology with well-developed rhombs on the grain surfaces. They consist mostly of FeCO$_3$ (average, 65%) and MnCO$_3$ (average, 22%) with low Mg/Ca ratio (less than 0.4) in their bulk composition. A series of compositional ternary discrimination diagrams, together with high Mn and low Mg contents, show that only meteoric porewater was involved in siderite precipitation, assuming that depositional environment of host sediment is an organic-rich freshwater system. Considering a series of results such as radiocarbon age, authigenic Mn-rich siderite and lithological features, siderite-hosting sediment (unit Tl) is interpreted as freshwater swamp or bog deposition, infilling the topographic depressions that locally existed before the formation of mid-to-late Holocene tidal deposits. Center-to-margin compositional variation within individual grain is very systematic; Mn and Ca decrease towards the margin of a siderite grain, while Fe and Mg increase. It suggests that the spherulitic siderites were precipitated in this sedimentary layer in a series during the early diagenesis of MnOx-FeOx reduction under steady-state.

• The Journal of Engineering Geology
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• v.27 no.1
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• pp.91-101
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• 2017

Fault materials has various properties depending on their areas, rock types, and components because they are formed by heterogeneous and complicated mechanisms. In this study, to understand the physical and mechanical properties of fault materials, 109 fault materials distributed in South Korea were collected to conduct various laboratory tests with them and analyze their physical and mechanical properties (unit weight, specific gravity, porosity, gravel content, silt/clay content, clay mineral content, friction angle, and cohesion) according to areas, rock types, and components. As for the physical and mechanical properties by rock type, gneiss shows the highest medians in the unit weight ($17.1kN/m^3$) and specific gravity (2.73), granite does so in the porosity (45.5%), schist does so in the gravel content (20.0 wt.%) and cohesion (38.1 kPa), and phyllite does so in the silt/clay content (54.4 wt.%), clay mineral content (30.1 wt.%), and friction angle ($38.2^{\circ}$). With regard to the physical and mechanical properties by component, fault gouge was shown to have lower values than cataclasite and damage zones in all factors other than porosity and silt/clay contents.

• Journal of the Mineralogical Society of Korea
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• v.28 no.2
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• pp.109-126
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• 2015

Because fault gouge developed at the center of fault is recognized as one of the most important weak sites, it is evident that clay mineralogy and physical properties greatly affect the rock stability. The purpose of this study is to establish the relationship of mineralogy and physical factors that control rock stability in fault zones. We analyzed a total of 51 samples from 16 main faults which were selected from a Korea fracture map, using XRD, SEM, and physical analyses like unit weight, friction and cohesion properties. Though it is considered that the most common clay minerals comprising fault gouge are kaolinite, illite and smectite, clay mineralogy slightly varies depending on lithology: illite > smectite > kaolinite and chlorite in volcanic rocks, kaolinite and chlorite > illite > smectite in sedimentary rocks, and illite > smectite > kaolinite and chlorite in abundance, respectively. Friction angle decreases with increasing clay content. Cohesion increases with increasing clay content below the 45 % region while it decreases with increasing clay content at the region higher than 45%, with some scatters in the data. It is likely that these results are ascribed to the physical heterogeneity of fault gouges with varying content of different clay minerals.

• The Journal of the Petrological Society of Korea
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• v.17 no.3
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• pp.166-178
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• 2008

The modal analyses on the phenocryst phases and the normative mineralogies from the bulk chemical analyses record that the volcanic rocks related to the Yangsan caldera might been derived from compositionally zoned magma. The volcanic rocks show linearly continuous mineralogical gradients, not only totally in the relations between $SiO_2$ and proportion of phenocryst content, but also within each rock unit in the relations between total phenocryst content and the proportion, Q-Ab-Or and Q-An(Ab-Or) diagrams. The roughly gradational modal variations of the phenocryst phases are shown upward within each rock unit. However, the contents and proportion of the phenocrysts in the Yangsan Tuff and the Hwajeri Formation represent the zigzaggedly undulatory variations. The continuous mineralogical gradients without large gaps define a large zoned magma system in the pre-eruptive, later precollapse and postcollapse magma chambers respectively. The zigzagged variations reflect the intermittent eruptive pulses representing any time gaps.

• Journal of Environmental Science International
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• v.18 no.8
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• pp.885-897
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• 2009

In order to make sure the impact of spatial resolution of wind energy map on the estimation of wind power density in the Korean Peninsula, the comparison studies on the characteristics of wind energy map with three different spatial resolutions were carried out. Numerical model used in the establishment of wind map is MM5 (5th generation Mesoscale Model) with RBAPS (Regional Data Assimilation and Prediction System) as initial and boundary data. Analyzed Period are four months (March, August, October, and December), which are representative of four seasons. Since high spatial resolution of wind map make the undulation of topography be clear, wind pattern in high resolution wind map is correspond well with topography pattern and maximum value of wind speed is also increase. Indication of island and mountains in wind energy map depends on the its spatial resolution, so wind patterns in Heuksan island and Jiri mountains are clearly different in high and low resolutions. And area averaged power density can be changed by estimation method of wind speed for unit area in the numerical model and by treatment of air density. Therefore the studiable resolution for the topography should be evaluated and set before the estimation of wind resources in the Korean Peninsula.

• Journal of the Korean earth science society
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• v.29 no.6
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• pp.487-494
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• 2008

The purpose of this study was to investigate the effects of MBL experiment instruction on the 7th graders' scientific inquiry skills and graph construction and interpretation ability in the unit "Elements and movement of sea water". Results are as follows: First, this study analyzed the influence on students' scientific inquiry skill after having six MBL instructional classes. The result showed a significant difference in the scientific inquiry skills between the experimental group and the control group, which implies that the instruction using MBL was an effective way to improve students' scientific inquiry skills. Second, this study also analyzed the influence on students' abilities to construct and interpret graphs. The result did not show any significant differences between the experimental group and the control group in the ability to construct graphs. But it showed significant differences in the ability to interpretgraphs, which means that instruction using MBL was an effective way to improve students' ability to interpret graphs.

• Journal of the Korean earth science society
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• v.25 no.8
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• pp.663-673
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• 2004

This study has developed an interactive WBI to enhance learning effects on 'the Moon motion' for middle-school students. The quality of this examined by applying it to 20 science teachers and 49 middle school students 49. As a result, over 85% of the test subjects gave an affirmative response in the interest induction, the curiosity solving, and the degree of learning participation category, the degree of difficulty item. Response of the students with negative perception on science have changed positively(p<.05) after this WBI learning. In addition, we compared the learners' of knowledge prior and subsequent to 'the Moon motion'. As a result, it was found that the case of 'no concept' was enhanced more than the case having 'partly or ambiguously concept' for 'the Moon motion'.