• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.4
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• pp.1033-1040
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• 1995

To simulate strength reliability and durability of ceramic parts under gas turbine application environments, particle impact damage behaviors in silicon carbide oxidized at 1673 K and 1523 K for 200 hours in atmosphere were investigated. The long-term oxidation produced a slight increase in the static fracture strength. Particle impact caused a spalling of oxide layer. The patterns of spalling and damage induced were dependent upon the property and impact velocity of the particle. Especially, the difference in spalling behaviors induced could be explained by introducing the formation mechanism of lateral crack and elastic-plastic deformation behavior at impact sit. At the low impact velocity regions, the oxidized SiC showed a little increase in the residual strength due to the cushion effect of oxide layer, as compared with the as-received SiC without oxide layer.

• BMB Reports
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• v.49 no.4
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• pp.199-200
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• 2016

Gene regulation in the brain is essential for long-term plasticity and memory formation. Despite this established notion, the quantitative translational map in the brain during memory formation has not been reported. To systematically probe the changes in protein synthesis during memory formation, our recent study exploited ribosome profiling using the mouse hippocampal tissues at multiple time points after a learning event. Analysis of the resulting database revealed novel types of gene regulation after learning. First, the translation of a group of genes was rapidly suppressed without change in mRNA levels. At later time points, the expression of another group of genes was downregulated through reduction in mRNA levels. This reduction was predicted to be downstream of inhibition of ESR1 (Estrogen Receptor 1) signaling. Overexpressing Nrsn1, one of the genes whose translation was suppressed, or activating ESR1 by injecting an agonist interfered with memory formation, suggesting the functional importance of these findings. Moreover, the translation of genes encoding the translational machineries was found to be suppressed, among other genes in the mouse hippocampus. Together, this unbiased approach has revealed previously unidentified characteristics of gene regulation in the brain and highlighted the importance of repressive controls.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.343-346
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• 2008

Unsteady 3D flowfields generated by transverse fuel injection into a supersonic mainstream are simulated with a DES turbulence model. Comparisons are made with experimental results in term of the temporal eddy position and eddy formation frequency. Results indicate that the DES model correctly predicts the convection characteristics of the large scale eddies. However, it is also observed that the numerical results slightly overpredict the eddy formation frequency.

• International Journal of Aeronautical and Space Sciences
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• v.11 no.4
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• pp.351-359
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• 2010

This paper proposes a linear system control algorithm with collision avoidance in multiple satellites. Consideration of collision avoidance is augmented by adding a weighting term in the cost function of the original tracking problem in linear quadratic control (LQC). Because the proposed algorithm relies on a similar solution procedure to the original LQC, its inherent advantages, including gain-robustness and optimality, are preserved. To confirm and visualize the derived algorithm, a simple example of two-vehicle motion in the two-dimensional plane is illustrated. In addition, the proposed collision avoidance control is applied to satellite formation flying, and verified by numerical simulations.

• Journal of the Korean Institute of Rural Architecture
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• v.13 no.3
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• pp.11-20
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• 2011

The present age demands a change in attitude based on a differentiated life value from city. It will provide to a fundamental solution for the gap of living level in the farming and fishing communities and recreate distinguishing comfortable communities. The purpose of this study was to deduct the formation characteristics of the townscape of Korean slow city according to analyze resources and structure of landscape. Planning of slow city's townscape is a process of imagification of filtrate unique meaning. The glob share synchronic unique values by slow city's network. Therefore instead of putting emphasis on promoting tourist business for short-term revenue, it will be under control to raise the standard of living and to be not forfeited and diluted the rights for sustainable slow city's status. Participation of resident needs in this process. Accordingly it need a strategy of landscape formation design and a interdepartmental practice system for a continuous slow city's image by renewal of disharmonious townscape in the built-up area.

• Journal of Technology Innovation
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• v.23 no.4
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• pp.89-121
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• 2015

Recently, national energy policy tends to be approached with the long-term perspective because it became harder to cope with various energy issues fundamentally only through the short-term and piecemeal approaches. To deal with energy policy from a long-term perspective, we need new governing approach that differs from established short-term perspective. In this context, research efforts to apply transition management theory to long-term energy policy are receiving attention. In this paper, we suggest extended transition management model based on case study of Dutch energy transition model and review the transition management traits of long-term energy policy of Korea. We conclude that transition thinking and approaches are diffusing widely in the long-term energy policy formation processes, but also can find various issues that are needed to be addressed for effective transition management especially in the energy policy implementation processes.

• Journal of Engineering Education Research
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• v.19 no.2
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• pp.26-33
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• 2016

A camp program where the theory of inventive problem solving TRIZ is applied to real problems of the industry was developed and taught at a five-day seminar apart from the standard curriculum at a university D in Gyeonggido. This study focuses on the educational effect that the TRIZ method has on the engineering students when their creative problem solving skills are required to solve industry problems on their own with the knowledge from their courses. For five days, the students were educated about TRIZ and assigned a real industry problem "Removal of friction caused by bubble formation in water heating pipelines". By applying TRIZ to the problem, the students developed an "Air removing Air Arrester" which received the evaluation, "with understanding the system architecture and the task objective causes and formation of the problem could be handled which directly helps the company's R&D". In this case, TRIZ offers the students a guideline and knowledge on how to approach problems and as a result the students provided a practical solution. During the process, the TRIZ method instilled confidence in the students and proved to be a motivation. It becomes obvious that this short-term program has a positive effect on students' way of thinking creatively and increasing their problem-solving abilities.

• Journal of Fashion Business
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• v.19 no.5
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• pp.157-174
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• 2015

This research intends to observe the effects of social capital regarding fashion social enterprises on the community sense of participating consumers, and verify the relationship of the effects that such social capital and community sense have on sustainability formation variable(shared values, suitability of values, behavioral flow, cognitive belief and long-term relationship orientation) of social enterprises. For such analysis, a sample of 400 consumers with experience of purchasing products of fashion social enterprises more than once was utilized, and path analysis was conducted utilizing AMOS 20.0. As a result of this research, first, information sharing, social participation among the characteristic factors of social enterprises' social capital had a meaningful impact on shared values, and self-pursuit and significance meaningfully affected the suitability of values. Second, mutual influence, sense of belonging, satisfaction of needs and emotional bond among the characteristic factors of community sense between social enterprises and consumers meaningfully affected shared values, whereas mutual influence, sense of belonging and emotional bond substantially influenced suitability of values. Third, shared values and suitability of values affected the relationship between behavioral flow and cognitive trust, and behavioral flow and cognitive trust both had meaningful impact on long-term relationship orientation.

• Journal of Astronomy and Space Sciences
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• v.25 no.2
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• pp.71-76
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• 2008

Study of terrestrial impact craters is important not only in the field of the solar system formation and evolution but also of the Galactic astronomy. The terrestrial impact cratering record recently has been examined, providing short- and intermediate-term periodicities, such as, ${\sim}26$ Myrs, ${\sim}37$ Myrs. The existence of such a periodicity has an implication in the Galactic dynamics, since the terrestrial impact cratering is usually interpreted as a result of the environmental variation during solar orbiting in the Galactic plane. The aim of this paper is to search for a long-term periodicity with a novel method since no attempt has been made so far in searching a long-term periodicity in this research field in spite of its great importance. We apply the cepstrum analysis method to the terrestrial impact cratering record for the first time. As a result of the analysis we have found noticeable peaks in the Fourier power spectrum appear ing at periods of ${\sim}300$ Myrs and ${\sim}100$ Myrs, which seem in a simple resonance with the revolution period of the Sun around the Galactic center. Finally we briefly discuss its implications and suggest theoretical study be pursued to explain such a long-term periodicity.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.2
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• pp.179-189
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• 2003

The concentration of gaseous elemental mercury (Hg) was measured concurrently with relevant environmental parameters from Yang-Jae monitoring station in Seoul during Sept. 1997 to June 2002. Although data collection was disrupted for certain periods, the grand mean concentration of Hg for this five year period was found at 5.32 $\pm$ 3.53 ng m$^{-3}$ (N = 27,170). Because of short resolution of data acquisition, we were able to examine the temporal variability of Hg at varying time scale. The diurnal variability of Hg, when investigated for each of those five years, indicated consistently the dominance of nighttime over daytime. If examined at seasonal scale, Hg level was systematically higher during winter/spring than summer/fall period. The results of this short-term variability were best explained by the combined effects of such factors as meteorological conditions (formation of inversion layer and seasonal changes) and anthropogenic source processes. However, examination of long-term variation Pattern was much more complicated to explain. Thus, extension of our study is needed to diagnose the future direction in long-term trend of Hg behavior.