• Journal of The Korean Astronomical Society
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• v.36 no.spc1
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• pp.37-44
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• 2003

In this paper, we review recent studies on the magnetic helicity changes of solar active regions by photospheric horizontal motions. Recently, Chae(200l) developed a methodology to determine the magnetic helicity change rate via photospheric horizontal motions. We have applied this methodology to four cases: (1) NOAA AR 8100 which has a series of homologous X-ray flares, (2) three active regions which have four eruptive major X-ray flares, (3) NOAA AR 9236 which has three eruptive X-class flares, and (4) NOAA AR 8668 in which a large filament was under formation. As a result, we have found several interesting results. First, the rate of magnetic helicity injection strongly depends on an active region and its evolution. Its mean rate ranges from 4 to $17 {\times} 10^{40}\;Mx^2\;h^{-1}$. Especially when the homologous flares occurred and when the filament was formed, significant rates of magnetic helicity were continuously deposited in the corona via photospheric shear flows. Second, there is a strong positive correlation between the magnetic helicity accumulated during the flaring time interval of the homologous flares in AR 8100 and the GOES X-ray flux integrated over the flaring time. This indicates that the occurrence of a series of homologous flares is physically related to the accumulation of magnetic helicity in the corona by photospheric shearing motions. Third, impulsive helicity variations took place near the flaring times of some strong flares. These impulsive variations whose time scales are less than one hour are attributed to localized velocity kernels around the polarity inversion line. Fourth, considering the filament eruption associated with an X1.8 flare started about 10 minutes before the impulsive variation of the helicity change rate, we suggest that the impulsive helicity variation is not a cause of the eruptive solar flare but its result. Finally, we discuss the physical implications on these results and our future plans.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.307.2-308
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• 2002

Acharan sulfate. a new glycosaminoglycan(GAG) isolated from the giant African snail Achatina fulica. was shown to have antitumor activity in vivo. To elucidate the mechanisms for the antitumor activity. we examined its impact on professional antigen presenting cells such as macrophages and dendritic cells (DCs). Acharan sulfate stimulated cytokine production (TNF-a and IL -1b). nitric oxide release. and morphological changes in a dose dependent manner on a macrophage cell Line Raw 264.7 cells. The differentiation-inducing activity of acharan sulfate was examined on immature DCs. Immature DCs were generated from mouse bone marrow (BM) cells by culturing with GM-CSF and IL-4, and then stimulated with acharan sulfate. The resultant DCs were then examined for funcional and phenotypic properties. It was found that acharan sulfate could induce functional maturation of immature DCs as determined by increased allogenic mixed lymphocyte reaction (MLR) and IL-12 production. Phenotypic. analysis for the expression of class II MHC molecules and major co-stimulatory molecules such as B7-1, B7-2 and CD40 also confirmed that acharan sulfate could induce maturation of immature DCs. These results suggest that that the antitumor activity of acharan sulfate is at least in part due to activation adn induction of differentiation of professinal antigen presenting cells. (omitted)

• IMMUNE NETWORK
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• v.5 no.3
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• pp.150-156
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• 2005

Background: Dendritic cells (DCs) playa critical role not only in the initiation of immune responses, but also in the induction of immune tolerance. In an effort to regulate immune responses through the modulation of antigen presenting cell (APC) function of DCs, we searched for and characterized APC function modulators from natural products. Methods: DCs were cultured in the presence of propolis components, WP and CP, and then examined for their ability to present exogenous antigen in association with major histocompatibility complexes (MHC). Results: WP and CP inhibited class I MHC-restricted presentation of exogenous antigen (cross-presentation) in a DC cell line, DC2.4 cells, and DCs generated from bone marrow cells with GM-CSF and IL-4. The inhibitory activity of WP and CP appeared to be due not only to inhibition of phagocytic activity of DCs, but also to suppression of expression of MHC molecules on DCs. We also examined the effects of WP and CP on T cells. Interestingly, WP and CP increased IL-2 production from T cells. Conclusion: These results demonstrate that WP and CP inhibit MHC-restricted presentation of exogenous antigen through down-regulation of phagocytic activity and suppression of expression of MHC molecules on DCs.

• Journal of the Korea Fashion and Costume Design Association
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• v.11 no.3
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• pp.1-15
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• 2009

The purpose of this study was to provide Apparel Industries producing the school uniform with the information on manufacturing the school uniform, and the students with the information of reasonable life of garments. Differences of reforming condition and satisfaction of the school uniform have been researched. The data were collected from 764 middle and high school girl students living in Daegu. Except for psychological aspect of wearing the uniform, most of satisfaction of wearing the uniform in the survey has been studied as lower ones. in line with these, overall improvement of aesthetic, economic, handling, class symbolic, movable aspects are requested to meet the needs of the students. A majority response of reforming the school the uniform once have come from middle school students, and another response of reforming the uniform twice coming from high school students are as follows : fitness of the uniform, trend, movability, expression of personality, and those of high school students are fitness of the uniform, expression of personality, trend, movability. Opportunities to have an education on how to wear school uniform appropriately have not been offered to students, and a number of the students in the survey have replied that they need to have adequate school uniform wearing education.

• Journal of Arbitration Studies
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• v.24 no.2
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• pp.137-160
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• 2014

These days, in line with the increase of opportunities in our country's firms to do transaction, large-scale M&A and investment with foreign firms incorporating arbitration clauses in the contracts have become general practice. Recently, Singapore has come to the fore as a place of arbitration and, particularly, Singapore International Arbitration Center (SIAC) was assessed as the favored international arbitration institution uniquely in Asia at the 2010 International Arbitration Survey: Choices in International Arbitration, along with the ICC, LCIA, and AAA/ICDR. Therefore, the country's firms need to understand properly the international arbitration procedure of Singapore. This study examines the international arbitration system of Singapore, focusing on the arbitration procedure of the SIAC. The Center revised arbitration rules twice in 2010 and 2013, and established the Court of Arbitration of SIAC in April 2013 for the first time in Asia in pursuit of stricter neutrality and promptness. It further seeks to run the arbitration procedure fairly by selecting a third country's people as an arbitrator, while its arbitration expenses are cheaper than those of the ICC. The study believes that for the country's international arbitration institutions such as the KCAB to jump forward as a world-class international arbitration institution, the Korean government should render positive support to them, learning from Singapore which does not spare any political and financial assistance to cultivate international arbitration institutions. On the other hand, KCAB should also try hard to improve in the aspects of neutrality, fairness, and promptness and to be selected as a trustworthy international arbitration institution by firms in Asian countries.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.1
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• pp.12-28
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• 2013

The purpose of this study was to develop storytelling Instructional model for promote problem-solving in a Blended learning Environment. To achieve the purpose, the study was performed by dividing into two stages. First, the draft of storytelling Instructional model was proposed by performing a literature survey and a case study. Second, the draft model was applied to the actual work. And the draft was modified and developed to the final model on the basis of the draft model's strength and implemented to 28 students who were the sophomore of child care education department and enrolled the profession class of at S University for 6 weeks. From the implementation result of the model, it was obtained that there was the positive reaction on applying storytelling technique to the beginning stage of learning. Instructional model storytelling consists phases Preparing to perform Storytelling, Building the team and role sharing team, Problem providing, Planning for problem solving, Brend Story structuralization, Cooperative Learning and Problem solving, announcement of the results and evaluating and reflection of general. And then learning supporting components for a facilitator and a learner were prepared for each process. Established in a Blended learning Environment was created based on all-line, how to teach and learning supporting organization. Final Model was suggested as a blueprint for stages actual learning which was consisted of a introductory storytelling part, an main storytelling part and a post storytelling part.

• Journal of the Korean Society for Railway
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• v.15 no.5
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• pp.429-435
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• 2012

The HEMU-430X is a world-class railway vehicle which aimed the maximum speed of 430km/h and the operation speed of 370km/h. To maintain high-speed operation condition over 300km/h, various requirements for satisfy exist. However, one of the most important things is a reliable supply of electricity. Especially, the dynamic interaction between the pantograph and overhead contact line at high-speed is a significant matter to pre-evaluate. In this paper, using the dynamic interaction analysis program, current collection performance of the HEMU-430X was investigated. Firstly, based on the international standard, performance of the original specifications was evaluated. In addition, through study on changes in tension and span length, improvement of the performance was considered.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2000.10a
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• pp.116-122
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• 2000

The molecular modification of antiepileptic drugs and direct synthesis of new drugs with the predetermined antiepileptic properties are perspective. New neurochemical attacking to solve the problem including prevention and inhibition of seizures seems to be related to ginsenosides and ginseng polypeptides. The main study based on the severity of febrile convulsions of rat pups has been done from the earlier investigations of antiepileptical action of ginsenosides between KGTRI and MSU (Chepurnov, Park et al., 1995) with different kinds of experimental models of epilepsy. From the cultured cell line DAN25 of ginseng root, the extracts of ginsenosides made in "BIOKHIMMASH" were studied by the project of preclinical anticonvulsant screening (Stables, Kupferberg, 1997). The inhibition of severity of convulsions, decrease of seizures threshold, decrease of audiogenic seizures in rats of different strains and normalization of cerebral blood flow (measured by hydrogen test) were demonstrated in rats after i.c.v., intraperitoneally and orally administration, respectively. The antiepileptical effects by the combination of compounds from ginseng; were compared with the iuluence of Rg1, Rb1, Rc and with the well known antiepileptical drugs such as carbamazepine, valproic acid. The base for the research is obtained by using the WAG/Rij strain (Luijtelaar, Coenen, Kuznetcova), an excellent genetic model for human generalized absence epilepsy. The improving action of gensinosides was effectively demonstrated on the model of electrical kindling of amygdala of WAG/Rij rats with genetically determined absences, and the influences of ginsenosides on the slow wave discharges have also been being investigated. The different characteristics of a kindling process exerted in the sex-different region of the amygdala and demonstrated that the level of sex steroids and content of neurosteroids in amygdaloid tissue can modify the development of seizures. The chemical structures of ginsenosides not only have some principal differences from well-known antiepileptical drugs but the Plant Pharmacology gives us unique possibility to develop new class of antiepileptic drugs and to improve its biological activity.

• Journal of the Korea Convergence Society
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• v.9 no.2
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• pp.85-90
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• 2018

The purpose of this study is to analyze the effect of flipped learning strategy, which is an online offline convergence learning strategy becoming a hot issue, on students' learning styles..Ultimately, the goal is to analyze the academic achievements and learning attitudes by applying the flipped learning strategy considering the preferred learning styles of Korean students. By assuming that Korean students are accustomed to traditional lecture class, it is assumed that the students would have difficulty in applying the flipped learning strategy which involves information gathering and problem solving through discussion. In order to analyze whether the application of flipped learning strategy is effective, it is necessary to identify students' preferred learning style and to develop appropriate teaching strategies accordingly.

• Journal of English Language & Literature
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• v.55 no.5
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• pp.907-936
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• 2009

Quite arguably, W. E. B. Du Bois is the first figure in the history of black nationalism who engaged most persistently and systematically with the dominant ideology of racism and white supremacy. It is not too much to say that, by contending with the Eurocentric but taken-for-granted concept of the 'Negro' in the turn of the century, Du bois has laid the theoretical and ideological cornerstone of postcolonialism today. But his concept of race varied over time and was even contradictory in the same writings. The early Du Bois defined race as something historically made rather than biologically given and determined. Yet he didn't utterly deny the significance of physical traits and skin color in constructing racial identity. His notion of the 'Negro' was not unambiguous, either. While drawing on the 'soul' of 'black folk' to undermine the Eurocentric dichotomy of white/mind and black/body, Du Bois argued that there is some kind of 'spiritual' differences between whites and blacks, differences that are essentially inherent and hereditary in the 'Negro.' Such essentialist notion of race and the 'Negro' was on the wane in the later Du Bois, especially after his encounter with Marxism. He came to think of race merely as a discourse of racism that can be subverted and even appropriated for anti-racist practices. Following the Marxist assumption that 'the color line' is a class conflict on the international level, Du Bois contended that the 'Negro' is an outcome of slavery which is in turn a subsystem of Western capitalism. He also argued that, since the 'Negro' is not a biological essence but a sociocultural formation, the identity of the 'Negro' can and must be reconstructed according to historical change. For Du Bois, therefore, the resistance against colonialism and capitalism became a resistance against racism. This is why his Pan-African movement shifted its gear from the American program in the initial phase to a truly 'Afrocentric' and socialist one.