• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.236-236
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• 2006

Time-resolved photoluminescence spectroscopy measurements of oligofluorenes with various side chains were studied. With extremely pure oligofluorenes, two kinds of red-shifted green emission were observed which have different origins; aggregate formation and on-chain chemical defect. The green emission around 490 nm was largely dependent upon the intermolecular interaction of oliglfuorene molecules. Moreover, by using oligofluorene with high-order liquid crystalline phase, we observed that the green emission was strongly dependent upon the molecular packing in solid films.

• Journal of Korean Society of Transportation
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• v.8 no.1
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• pp.55-71
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• 1990

The behavioral mechanism underlying the traffic assignment model is a choice, or decision-making process of traveling paths between origins and destinations. The deterministic approach to traffic assignment assumes that travelers choose shortest path from their origin-destination pair. Although this assumption seems reasonable, it presumes that all travelers have perfect information regarding travel time, that they make consistently correct decision, and that they all behave in identical fashion. Stochastic user equilibrium assignment relaxes these presumptions by including a random component in traveler's perception of travel time. The objective of this study is to compare "A Model of Deterministic User Equilibrium Assignment" with "Models of Stochastic User Equilibrium Assignment" in the theoretical and practical aspects. Specifically, SUE models are developed to logit and probit based models according to discrete choice functions. The models were applied to sioux Falls net ork consisting of 24 zones, 24 nodes and 76 links. The distribution of perceived travel time was obtained by using the relationship between speed and traffic flow.

• Journal of the Ergonomics Society of Korea
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• v.22 no.3
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• pp.93-111
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• 2003

This research extends a general theory of cognition to address cognitive constraints on complex command production and allows us to make system design recommendations. The research described in this paper addresses the cognitive origins of problems user have producing sequence-dependent command strings while interacting with the UNIX operating system. We describe an empirical and theoretical analysis of user difficulties, and then show how our analyses lead to design recommendations. In addition, we summarize results from testing the impact of our design recommendations on system usability

• Korean Parent-Child Health Journal
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• v.18 no.1
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• pp.39-45
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• 2015

Purpose: This study aimed to analyze the women's health nursing curriculum in Korean nursing baccalaureate education. Methods: This study was conducted with women's health nursing curriculum from one nursing school. Data were collected through one nursing school in A city, Korea from November to December, 2014. Data were analyzed using 4 domain of Posner's curriculum analysis. Results: Curriculum documentation and origins were based on the nursing standard from Korean Accreditation Nursing Board Education and the learning goal of maternal nursing from Korean Nursing Association. The purpose and content of the curriculum were composed with cognitive, affective, and psychomotor domains. The curriculum was organized deductively and multidisciplinary. Conclusion: The continuity, sequence, integration, and articulation were advantage of the curriculum. The concept map of women's health nursing curriculum can contribute to share the objectives between teachers and learners.

• International Commerce and Information Review
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• v.6 no.3
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• pp.373-384
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• 2004

While the bilateral trade volume between China and U.S. has been growing rapidly, the trade deficits of U.S. to China has also been expanding. This growing trade deficit of U.S. to China has several reasons: the increase of foreign direct investment to China, the transfer of trade deficit origins, the intervention of U.S. domestic politics to China-U.S. trade relations, and U.S. direct control on export to China. However, the increased U.S. trade deficit to China does not mean that U.S. is in a disadvantaged position in its economic relations with China, or its international competitiveness is deteriorating. When U.S. surplus in service trade to China is included, the picture would be very different. Also, as internationalization progresses and China's industrial structure adjusts, the trade deficit of U.S. to China would narrow.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1334-1339
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• 2020

This paper presents an empirical and comprehensive forecasting analysis of the uranium price. Prices are generally difficult to forecast, and the uranium price is not an exception because it is affected by many external factors, apart from imbalances between demand and supply. Therefore, a systematic analysis of multiple forecasting methods and combinations of them along repeated forecast origins is a way of discerning which method is most suitable. Results suggest that i) some sophisticated methods do not improve upon the Naïve's (horizontal) forecast and ii) Unobserved Components methods are the most powerful, although the gain in accuracy is not big. These two facts together imply that uranium prices are undoubtedly subject to many uncertainties.

• Korea-Australia Rheology Journal
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• v.21 no.4
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• pp.245-268
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• 2009

Recent developments in dilute polymer solution rheology are reviewed, and placed within the context of the general goals of predicting the complex flow of complex fluids. In particular, the interplay between the use of polymer kinetic theory and continuum mechanics to advance the microscopic and the macroscopic description, respectively, of dilute polymer solution rheology is delineated. The insight that can be gained into the origins of the high Weissenberg number problem through an analysis of the configurational changes undergone by a single molecule at various locations in the flow domain is discussed in the context of flow around a cylinder confined between flat plates. The significant role played by hydrodynamic interactions as the source of much of the richness of the observed rheological behaviour of dilute polymer solutions is highlighted, and the methods by which this phenomenon can be incorporated into a macroscopic description through the use of closure approximations and multi scale simulations is discussed.

• Journal of the Korean earth science society
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• v.36 no.5
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• pp.447-459
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• 2015

Dok island comprises Pliocene volcanic products such as a series of volcanoclastic rocks and lavas ranging in composition from alkali basalts, and trachyandesites to trachytes. Compositional variation of the basaltic rocks can be attributed to fractional crystallization of olivine, clinopyroxene, plagioclase, and magnetite. Chemical variations among the trachyandesites are caused by fractionation of clinopyroxene, plagioclase, and magnetite with minor amphibole, while trachytes are controlled mainly by feldspar fractionation. Incompatible element abundance ratios and chondrite normalized LREE/HREE ratios (e.g., (La/Yb)c: 24.8 to 32.8 for basalts, 15.6 to 31.2 for trachyandesites) suggest that the origins of the basalts and trachyandesites involve both different degrees of partial melting and subsequent fractional crystallization processes. Trace element ratios of the basalts from Dok island are characterized by high Ba/Nb, La/Nb, Ba/Th and Th/U and isotopic ratios (Tasumoto and Nakamura, 1991) that are similar to the EM 1 type of oceanic island basalts such as Gough and Tristan da Cunha basalts.

• The Korean Journal of Ceramics
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• v.7 no.2
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• pp.63-69
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• 2001

We investigated strength degradations from cyclic contact fatigue in self-toughened glass-ceramics. Hertzian indentation was used to induce cyclic contact load. Dynamic fatigue was also performed with changing stress rates from 0.01 to 10000 MPa/sec. After that, strength data and fracture origins were analysed. As the number of contact cycles increased or stressing rate decreased, severe strength degradation occurred by as much as 50% because of radial cracks developed from microcrack coalescence.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.688-691
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• 2000

Ferritin, an iron-storage protein, is found in bacteria and some animal tissues such as liver, spleen, and bone marrow. It is more effective and causes less side reactions than the traditional ferrous sulfate, and thus has been used primarily to treat iron deficiency in pregnancy anaemia. Currently, the ferritin extracted from the bovine and equine spleens are sold as a commercial product. Its market is estimated as several hundreds of million US dollars. However, because of the recent warnings against the viral diseases of animal origins such as mad cow disease, a safer ferritin is sought after. Our research team has successfully developed a production process for recombinant human ferritin. Its expression titer from yeast is high enough to be economically viable, and its particle formation characteristics are as effective as well.