• Clinical and Experimental Pediatrics
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• 제53권2호
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• pp.129-135
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• 2010

Human rhinoviruses (HRVs) is a nonenveloped, single stranded RNA virus belonging to the family Picornavirudae. Transmission by direct contact such as hand-to-hand, hand-to-nose, and hand-to-eye has been readily demonstrated in experimental settings. HRV are the most frequent causes of common cold infection, however, they are also known to replicate in the lower respiratory tract and associated with more severe respiratory illnesses such as asthma. New technique such as reverse transcriptase polymerase chain reaction and molecular typing in HRV has been developed and our understanding of the importance of these respiratory viruses. HRVs consisted of 101 serotypes that are classified into groups A and B according to sequence variations. And there is a newly identified set of HRVs, called Group C, and it is currently under investigation. In recent study using PCR techniques, HRVs accounted for approximate 50-80% of common colds and 85 % of childhood asthma exacerbations and in more than half of adult exacerbations. However, the mechanisms of HRV- induced asthma exacerbations are poorly understood. This review discusses the association between HRVs and childhood asthma.

• 대한수학회보
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• 제57권3호
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• pp.677-690
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• 2020

In this article, we study a reaction-diffusion system with homogeneous Dirichlet boundary conditions, which describing a three-species food chain model. Under some conditions, the predator-prey subsystem (u₁ ≡ 0) has a unique positive solution (${\bar{u_2}}$, ${\bar{u_3}}$). By using the birth rate of the prey r1 as a bifurcation parameter, a connected set of positive solutions of our system bifurcating from semi-trivial solution set (r₁, (0, ${\bar{u_2}}$, ${\bar{u_3}}$)) is obtained. Results are obtained by the use of degree theory in cones and sub and super solution techniques.

• E2M - 전기 전자와 첨단 소재
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• 제10권9호
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• pp.876-880
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• 1997

In this paper we investigated the transcription of liquid crystal (LC) alignment method by using memory effect of nematic(N) LCon polymide(PI) surface with side chain as for non-rubbing alignment techniques. That the monodomain alignment of aligned NLC is observed by microscope textures in the cells on PI surface with side chain. We obtained that the pretilt angle of NLC are generated about 3.7$^{\circ}$on PI surface. We suggest that the LC alignment by using transcription alingnment method is attributed to memory effect of NLC on PI surface.

• Communications for Statistical Applications and Methods
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• 제7권3호
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• pp.773-788
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• 2000

Statistical process control (SPC) and engineering process control (EPC) are based on different strategies for processes quality improvement. SPC reduces process variability by detecting and eliminating special causes of process variation. while EPC reduces process variability by adjusting compensatory variables to keep the quality variable close to target. Recently there has been needs for a process control proceduce which combines the tow strategies. This paper considers a combined scheme which simultaneously applies SPC and EPC techniques to reduce the variation of a process. The process model under consideration is an integrated moving average(IMA) process with a step shift. The EPC part of the scheme adjusts the process back to target at every fixed monitoring intervals, which is referred to a repeated adjustment scheme. The SPC part of the scheme uses an exponentially weighted moving average(EWMA) of observed deviation from target to detect special causes. A Markov chain model is developed to relate the scheme's expected cost per unit time to the design parameters of he combined control scheme. The expected cost per unit time is composed of off-target cost, adjustment cost, monitoring cost, and false alarm cost.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권2호
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• pp.628-646
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• 2016

This paper proposes a novel channel assignment scheme that is based on finite projective plane (FPP) theory. The proposed scheme involves using a Markov chain model to allocate N channels to N users through intermixed channel group arrangements, particularly when channel resources are idle because of inefficient use. The intermixed FPP-based channel group arrangements successfully related Markov chain modeling to punch through ratio formulations proposed in this study, ensuring fair resource use among users. The simulation results for the proposed FPP scheme clearly revealed that the defined throughput increased, particularly under light traffic load conditions. Nevertheless, if the proposed scheme is combined with successive interference cancellation techniques, considerably higher throughput is predicted, even under heavy traffic load conditions.

• Bulletin of the Korean Chemical Society
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• 제25권3호
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• pp.351-356
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• 2004

Selected MPEG-b-PDLLA block copolymers have been synthesized by ring-opening polymerization with systematic variation of the chain lengths of the resident hydrophilic and hydrophobic blocks. The size and shape of the micelles that spontaneously form in solution are then controlled by the characteristics of the block copolymer template. All the materials prepared in this study showed the tunable pore size of 20-80 ${\AA}$ with the increase of hydrophobic chain lengths and up to 660 $m^2$/g of specific surface area. The formation mechanism of these nanoporous structures obtained by controlling the micelle size has been confirmed using both liquid and solid state $^{13}C\;and\;^{29}Si$ NMR techniques. This work verifies the formation mechanism of nanoporous structures in which the pore size and wall thickness are closely dependent on the size of hydrophobic cores and hydrophilic shells of the block copolymer templates.

• 한국경영과학회지
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• 제25권2호
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• pp.11-22
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• 2000

The unit of competition is not a single firm any more but group of firms. They make a supply chain and compete with other chains. In this study we investigate success factors of supply chains from the supplying firms perspective. We consider various success factors such as commitmet trust communication confilct re-solving techniques vendor selection process and incentive systems. A set of hypotheses is tested based on the data collected from the electronics and automobile part manufacturers. Samples are divided by the length of the relationship between the vendor and assembler. joint problem solving under the long-term relationship plays an important role for the success of the supply chain. The findings offer insight into how to better manage the sup-ply chains.

• International Journal of Naval Architecture and Ocean Engineering
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• 제1권2호
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• pp.70-77
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• 2009

Today, many middle-sized shipbuilding companies in Korea are experiencing strong competition from shipbuilding companies in other nations. This competition is particularly affecting small- and middle-sized shipyards, rather than the major shipyards that have their own support systems and development capabilities. The acquisition of techniques that would enable maximization of production efficiency and minimization of the gap between planning and execution would increase the competitiveness of small- and middle-sized Korean shipyards. In this paper, research on a simulation-based support system for ship production management, which can be applied to the shipbuilding processes of middle-sized shipbuilding companies, is presented. The simulation research includes layout optimization, load balancing, work stage operation planning, block logistics, and integrated material management. Each item is integrated into a network system with a value chain that includes all shipbuilding processes.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.268-270
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• 2013

The construction project can be defined as a network combined between elements which are engineering, procurement, construction, start-up, and has a plenty of subjects and partners. For the successful project management in construction industry, it is necessary to adopt various management methods, such as lean production, information network system, SCM(Supply Chain Management), which can increase the efficiency of project management. During recent years, even though various management techniques have been applied, the SCM system has not formulated in construction industry. Especially, the Nuclear Power Plant Construction which requires high regulations of the safety and security has not applied SCM. Therefore, this study aimed to propose technology area of SCM in Korean Nuclear Power Plant Construction.

• 한국전기전자재료학회논문지
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• 제13권5호
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• pp.411-419
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• 2000

In this paper we have investigated the surface degradation by ultraviolet-irradiation in high-temperature vulcanized silicone rubber. Through the measurement of surface potential decay by corona-charging and of contact angle it is found that the change of surface electrostatic properties and the decrease of contact angle under UV-radiation. For the changes in micro-morphological and chemical structure of the UV-treated silicone rubber we utilized several analytical techniques such as SEM, ATR-FTIR,XPS. From this study it is shown that the chemical reactions(scissoring of side chain(S-$CH_3$) cross-linking and branching) occur on the surface of silicone rubber during the UV-irradiation. Also we obtained the results of the loss of low molecular weight chain by cross-linking and oxidation reaction.