• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.6 s.58
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• pp.176-182
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• 2009

Other damage can occur due to the preexisting dull structure and installation of nonenvironmental-friendly concrete structure, lack of function for preventing coastal erosion. Increase of personal income and fast spread of the concept of waterfront casued the initiation of many project to improve aging coastal ports. However, none of environment-friendly structure has been developed and pre-existing solid block, igloo block, tunnel block are used commonly. In piers and lighter's wharf where the ships are mooring, resonance by the generation of a reflected wave caused by penetration wave in the port and port wave increases wave heights in the port and makes difficult to maintain the temperature, causes problems in mooring ships and cargo-working, and eventually increase the occurance of damages of the small ships by the collision. Therefore, development of new types of blcok is necessary. To apply Coastal Environments block developed for this reason, it requires allowable bearing capacity evaluation of shear key. For this study, we made test specimen for connecting part of C.E. Block, and conducted friction test of boundary surface. Data obtained by the experiment was analyzed by finite element analysis and assessed the coefficient of friction between C.E. Block and boundary surface.

• Journal of the Korean earth science society
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• v.28 no.7
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• pp.762-774
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• 2007

The purpose of this study was to investigate misconceptions about plate tectonics which spread widely among freshmen at high school with drawing. For this, we chose 6 conceptions about plate tectonics by analysis of 7th curriculum and of 11 kinds of science textbooks. Questionnaire of drawing about plate tectonics were developed depending on them. Data was collected from 134 students who was freshmen at high school in Daegu. The result of this study was as follows. First, In structure of plate, 'upper mantle type' and 'crust type' misconceptions were more than half of the respondents. Second, In distribution of plate, 'cracked earthquake zone type' and 'earthquake frequency type' misconceptions were more than half of the respondents. Third, In formation of ocean ridge at oceanic crust- oceanic crust divergent plate boundary, 'divergence type' and 'collision type' misconceptions were more than half of the respondents. Fourth, In formation of mountain ridge at continental crust- continental crust convergent plate boundary, 'collision type' misconceptions were more than half of the respondents. Fifih, In formation of mountain ridge at oceanic crust- continental crust convergent plate boundary, 'subduction type' and 'fault type' misconceptions were more than half of the respondents. Sixth, In transform-fault at oceanic crust- oceanic crust transform-fault boundary, 'direction type' and 'section type' misconceptions were almost half of the respondents. In this study, students' drawings about plate tectonics showed similar misconceptions. This imply that drawing conceptions can be used by the strong evidence of misconceptions which spread widely among students. Furthermore, this study has a significance that this conclusion is useful to teachers as basic teaching-teaming materials of plate tectonics.

• The Journal of the Petrological Society of Korea
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• v.21 no.2
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• pp.151-171
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• 2012

The Permo-Triassic Songrim orogeny in the Korean peninsula was a major tectonic event involving complicated continental collisions at the eastern margin of Eurasia. Based on the previous studies on the metamorphic and deformations features of the Songrim orogeny, this paper presents metamorphic and structural characteristics and timing of the Songrim orogeny in the Taebaeksan basin, and discuss about correlation of the tectono-metamorphic evolution of the Taebaeksan basin with the Okcheon basin and the Imjingang belt with a combined analysis of bulk crustal shortening direction, metamorphic P-T and T-t (time) paths. The metapelites in the Pyeongan Supergroup in the northeastern margin of the Taebaeksan basin have experienced lower-temperature/medium-pressure (LT/MP) regional metamorphism followed by high-temperature contact metamorphism due to the Jurassic granite intrusion. The earlier LT/MP regional metamorphism produced two loops of clockwise P-T-d (deformation) paths combined with four deformation events ($D_1-D_4$). The first loop concomitant with $D_1$ and $D_2$ occurred at $400-500^{\circ}C$, 1.5-3.0 kbar, and related with growth of syn-$D_1$ chloritoid and andalusite, post-$D_1$ margarite, Ca-rich syn-$D_2$ or post-$D_2$ plagioclase. The second loop accompanying $D_3$ and $D_4$ occurred at $520-580^{\circ}C$, 2.0-6.0 kbar, and associated with the growth of syn-$D_3$ garnet and staurolite, and syn-$D_4$ and/or post-$D_4$ andalusite porphyroblasts. Furthermore the syn-$D_1$ chloritoid and andalusite porphyroblasts grew during E-W bulk crustal shortening, whereas the syn-$D_3$ garnet and staurolite, and the syn-$D_4$ and/or post-$D_4$ andalusite porphyroblasts have grown under N-S bulk crustal shortening. The similarity in the characteristics and timing of the metamorphism and bulk crustal shortening directions between the Okcheon and Imjingang belts suggest that the peak metamorphic conditions tend to increase toward the western part (Imjingang belt and southwestern part of the Gyeonggi Massif) from the eastern part (Taebaeksan basin). The E-W bulk crustal shortening influenced the eastern part of the Okcheon belt, whereas the N-S bulk crustal shortening resulted in strong deformation in the Imjingang and Okcheon belts. Consequently, the Permo-Triassic Songrim orogeny in the Korean peninsula is probably not only related to collision of the North and South China blocks, but also to the amalgamation of terrane fragments at the eastern Eurasia margin (e.g., collision of the Sino-Korean continent and the Hida-Oki terrane).

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.251-252
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• 2012

Recently, the growing interest in organic microelectronic devices including OLEDs has led to an increasing amount of research into their many potential applications in the area of flexible electronic devices based on plastic substrates. However, these organic devices require a gas barrier coating to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency OLEDs require an extremely low Water Vapor Transition Rate (WVTR) of $1{\times}10^{-6}g/m^2$/day. The Key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required ($1{\times}10^{-6}g/m^2$/day) is the suppression of defect sites and gas diffusion pathways between grain boundaries. In this study, we developed an $Al_2O_3$ nano-crystal structure single gas barrier layer using a Neutral Beam Assisted Sputtering (NBAS) process. The NBAS system is based on the conventional RF magnetron sputtering and neutral beam source. The neutral beam source consists of an electron cyclotron Resonance (ECR) plasma source and metal reflector. The Ar+ ions in the ECR plasma are accelerated in the plasma sheath between the plasma and reflector, which are then neutralized by Auger neutralization. The neutral beam energies were possible to estimate indirectly through previous experiments and binary collision model. The accelerating potential is the sum of the plasma potential and reflector bias. In previous experiments, while adjusting the reflector bias, changes in the plasma density and the plasma potential were not observed. The neutral beam energy is controlled by the metal reflector bias. The NBAS process can continuously change crystalline structures from an amorphous phase to nano-crystal phase of various grain sizes within a single inorganic thin film. These NBAS process effects can lead to the formation of a nano-crystal structure barrier layer which effectively limits gas diffusion through the pathways between grain boundaries. Our results verify the nano-crystal structure of the NBAS processed $Al_2O_3$ single gas barrier layer through dielectric constant measurement, break down field measurement, and TEM analysis. Finally, the WVTR of $Al_2O_3$ nano-crystal structure single gas barrier layer was measured to be under $5{\times}10^{-6}g/m^2$/day therefore we can confirm that NBAS processed $Al_2O_3$ nano-crystal structure single gas barrier layer is suitable for OLED application.

• Convergence Security Journal
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• v.12 no.1
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• pp.97-107
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• 2012

Our nation, of which the term of dispatching troops is winded up at the end of this year, is facing presidential election time including the nuclear security summit meeting in March, opening of EXPO in May, and the general election. Hence, the possibility to select our nation at the strategy forming public opinion of military withdrawal through Taliban's terror is high. It coincides with public affair strategy of Taliban terror and learning effect by the past cases. If the possibility of terror threat of Taliban along with this is summarized, the period of threat will concentrate on and be heightened in the first half when the nuclear security summit meeting and EXPO open in our nation, and target and method have high possibility of collision terror of bomb carrying vehicle and suicide bomb on national government organizations or American facilities, and etc, and possibility of kidnapping on our people such as oversea tourists, missionaries, and so on. Terror groups joining the criminal act is to use Islam illegal aliens who already acquire base in our nation or entry maneuver of specialized terrorists connected to Al-Qaeda. Pretext of such terror is withdrawal of our military and western allies stationed in Afghanistan. Therefore, publicity terror of Taliban against our people living overseas and security measure of international events such as the world nuclear security summit meeting, Yeosu EXPO, and etc in the first half of this year should be thoroughly prepared, domestic illegal aliens' movement should be comprehended, and measure blocking international terrorists' relating to Taliban infiltration into our nation should be sought for. Also, there is need of early announcement of government's political will on our military stationed in Afghanistan.

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.472-477
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• 2011

The concentration of selenium in grain samples was determined using isotope dilution method in ORC-ICPMS. The experimental conditions were optimized to $H_2$ mode and the flow rate was $4.0\;mL\;min^{-1}$. ORC in $H_2$ mode proved to eliminate most of polyatomic interferences except $BrH^+$ when Br is present in sample matrix. Chemical removal of Br was very difficult and the mathematical correction was successfully employed. The fraction of $BrH^+$ generated from Br at the current experimental condition was 14.1%. The signal on m/z 82 was corrected and calculated for isotope dilution. The analytical reliability of the propose method was successfully evaluated by analyzing the certified standard reference material NIST SRM 1566 and 1567. The method was applied to real samples and the results are $0.034{\pm}0.001\;{\mu}g\;g^{-1}$ for white rice, $0.059{\pm}0.002_5\;{\mu}g\;g^{-1}$ for brown rice, $0.029{\pm}0.001_4\;{\mu}g\;g^{-1}$ for black rice, and $0.034{\pm}0.002\;{\mu}g \;g^{-1}$ for barley. The detection limits ($3\sigma$) for Se was $0.012\;ng\;g^{-1}$.

• Journal of Digital Convergence
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• v.16 no.8
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• pp.71-79
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• 2018

This study discussed the meaning of a drone, and especially drone journalism and legal and ethical issues around that, at an introductory dimension, which is used in various social bases, but is still just an academic discussion at the beginning stage. As a methodology, content analysis was used. It seems that drone journalism has high diffusibility as a technology with high 'relative advantage', 'compatibility', 'trial ability' and 'observability' and low 'complexity' in terms of the diffusion of innovation theory. However, it will be very likely that controversies will be raised, such as safety issue due to collision and crash, a dispute over violation of privacy that may seriously infringe privacy like individual portrait rights and a controversy about the accuracy and source of information as drone filming low price and ease of use. Suggest solutions to legal and ethical issues based on existing research. Technical stability is required. Also, it is necessary to change the awareness of journalists about the drones coverage and to educate ethics, and it is necessary to establish social public opinion on issues such as privacy violation and establish system and legal measures through it. Future research is expected to carry out empirical research including journalists and public awareness surveys.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.1
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• pp.28-38
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• 2016

Cooperative-Intelligent Transport Systems (c-ITS) has emphasized a real-time traffic safety service in urgent situations among highway infrastructure and four-wheeled vehicles, while two-wheeled vehicles, e.g. bicycles and motorcycle, sharing highway space and endangering highway safety, have yet been out of its interest. This paper delivers the results of a study conducted to analyze the patterns of two-wheeled-vehicle traffic accidents experienced in the past, the last three years (2011~2013), and to propose the types of service enhancing the safety of the riders of those. It was found from the analysis of historical accident data that the side collision on a link section should be taken care of for further safety treatment, while the old female drivers need additional care to decrease their fatality rate. By combining the services proposed for bicycles and motorcycles, this paper proposes (1) eight different bicycle-to-everything (B2X) services which can be eventually provided in c-ITS and (2) three of those that would be available in the near future with the current communication technologies.

• Journal of The Korean Association For Science Education
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• v.31 no.5
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• pp.734-744
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• 2011

The purpose of this study was to identify middle school students' mental models on plate tectonics and to compare the mental models of verbal-learning-style students with those of visual-learning-style students. 94 student participants in 9th grade were requested to draw and explain three topics; generation of magma, the formation of the mountain range and the interior of the Earth. The criterions for analyzing the mental models are derived from the data of the drawing task. The research results were as follows: The mental models on the generation of magma were classified as 'unstable model,' 'partial casual model,' 'causal model,' and 'conceptual model.' On the other hand, the mental models on the interior of the Earth were classified as 'static unstable model,' 'dynamic unstable model,' and 'conceptual model.' Students holding 'unstable model' were unable to relate the plate collision and the magma generation. They showed a variety of alternative conceptions of study areas, such as 'magma is generated from the core' and 'the mountain is formed by rising of the plates themselves.' Also, visual-learning-style students showed higher proportion of conceptual models and lower proportion of unstable mental models than verbal-learning-style students on three topics. The findings revealed that the students tend to have different concepts on the plate tectonics depending on their learning style.

• The Journal of the Acoustical Society of Korea
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• v.30 no.1
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• pp.9-16
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• 2011

When a hydrofoil ship plies at high speed, there exist possibilities of collision with ocean mammals dwelling near the surface. An active sonar located within the immersed hydrofoil structure that provides the lift for the vessel, can be used for early warning of their presence. The proper functioning of the active sonar system depends on its ability to reject noise and pick up the target signal. In this article, we measured the noise on a hydrofoil of an operating ship with two flush-mounted hydrophones. The measurements were conducted for the purpose of (1) identifying the effect of operating state of machinery likes engine, cooler and generator (2) observing the change of noise depending on the measuring position (3) observing the change of noise with increasing ship speed. To verify our experiment, experiments were performed three times and the measured results are compared with other investigations and they show similarity to each other. The results are analyzed with frequency domain in order to apply to operating active sonar detecting system and focus on high frequency band within sonar's operating frequency region. Through these experiments and analysis, it is expected that we can identify the generated noise around hydrofoil where active sonar is installed and these results lead us to design active sonar that could distinguish target signal from noise more effectively.