• Journal of the Korean BIBLIA Society for library and Information Science
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• v.31 no.1
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• pp.237-255
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• 2020

Pareto principle states that, for many events, roughly 80% of the effects come from 20% of the causes. This study clarified if there is Pareto principle in Korean universities' academic information resource sharing network and calculates the Gini efficient about inequality in sharing academic resources. As a result, top 20% libraries led 80% of performance and inequality degree showed 0.8 as very serious condition. Relative Gini efficient which is recalculated considering scale of each libraries stay 0.7 that is adjusted slightly down. It means that such phenomenon is not caused by the difference of each universities scale with high contribution of big university and low contribution of small university. And in comparison of inequality between university's types, inequality between community colleges and private universities is more serious than four-year-course college and national university respectfully. Finally, as a result of visualizing the distribution of participating libraries, there were libraries with overwhelming contributions, and libraries with small but relatively high contribution levels were also distributed.

• Journal of the Korea Institute of Building Construction
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• v.18 no.3
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• pp.305-312
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• 2018

This study is about the development of a non-sintered binder (NSB) which does not require a sintering process by using the industrial by-products Phosphogypsum (PG), Waste Lime (WL) and Granulated Blast Furnace Slag (GBFS). In this report, through SEM analysis of the NSB paste hardening body, micropore analysis of paste using the mercury press-in method and microstructure observation were executed to consider the influence of the formation of the pore structure and the distribution of pore volume on strength, and the following conclusions were reached. 1) Pore structure of NSB paste of early age is influenced by hydrate generation amount by GBFS and activator. 2) Through observing the internal microstructure of NSB binder paste, it was found that the strength expression at early age due to hydration reaction was achieved with a large amount of ettringite serving as the frame with C-S-H gel generated at the same time. It was confirmed that C-S-H gel wrapped around ettringite, and as time passed, the amount generated continually increased, and C-S-H gel tightly filled the pores of hardened paste, forming a dense network-type web structure. 3) For NSB-type cement, the degree of formation of gel pores below $10{\mu}m$ had a greater influence on strength improvement than simple pore reduction by charging capillary pores, and the pore size that had the greatest effect on strength was micropores with diameter below $10{\mu}m$.

• Geomechanics and Engineering
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• v.5 no.1
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• pp.17-36
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• 2013

Settlement of the piled raft can be estimated even after years of completing the construction of any structure over the foundation. This study is devoted to carry out numerical analysis by the finite element method of the consolidation settlement of piled rafts over clayey soils and detecting the dissipation of excess pore water pressure and its effect on bearing capacity of piled raft foundations. The ABAQUS computer program is used as a finite element tool and the soil is represented by the modified Drucker-Prager/cap model. Five different configurations of pile groups are simulated in the finite element analysis. It was found that the settlement beneath the piled raft foundation resulted from the dissipation of excess pore water pressure considerably affects the final settlement of the foundation, and enough attention should be paid to settlement variation with time. The settlement behavior of unpiled raft shows bowl shaped settlement profile with maximum at the center. The degree of curvature of the raft under vertical load increases with the decrease of the raft thickness. For the same vertical load, the differential settlement of raft of ($10{\times}10m$) size decreases by more than 90% when the raft thickness increased from 0.75 m to 1.5 m. The average load carried by piles depends on the number of piles in the group. The groups of ($2{\times}1$, $3{\times}1$, $2{\times}2$, $3{\times}2$, and $3{\times}3$) piles were found to carry about 24%, 32%, 42%, 58%, and 79% of the total vertical load. The distribution of load between piles becomes more uniform with the increase of raft thickness.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11B
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• pp.709-717
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• 2007

Pricing a network service aims for congestion control of the network as well as economic efficiency. A monopolistic supplier providing users with a network service on a shared link needs a pricing schedule that maximizes revenue under the link's bandwidth constraint and guarantees the bandwidth purchased by the users. In that case, nonlinear pricing is an efficient scheme which meets both requirements. This study reviews how nonlinear pricing can be applied to the network service under the constraint and shows that the nonlinear pricing may result in a fixed unit price of bandwidth as linear pricing when demand characteristics of the users follow a power law. Also, the way how the provider with incomplete information on the demand distribution seeks for the optimal pricing from the degree of the network congestion is introduced and the relationship between the development direction of the Internet and internet pricing is considered based on the results of the study.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.4
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• pp.246-251
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• 2003

The blood-brain barrier (BBB) is composed of the brain capillaries, which are lined by endothelial cells displaying extremely tight intercellular junctions. Several attempts at creating an in vitro model of the BBB have been met with moderate success as brain capillary endothelial cells lose their barrier properties when isolated in cell culture. This may be due to a lack of recreation of the in vivo endothelial cellular environment in these models, including nearly constant contact with astrocyte foot processes. This work is motivated by the hypothesis that growing endothelial cells on one side of an ultra-thin, highly porous membrane and differentiating astrocyte or astrogliomal cells on the opposite side will lead to a higher degree of interaction between the two cell types and therefore to an improved model. Here we describe our initial efforts towards testing this hypothesis including a procedure for membrane fabrication and methods for culturing endothelial cells on these membranes. We have fabricated a 1 $\mu\textrm{m}$ thick, 2.0 $\mu\textrm{m}$ pore size, and 55% porous membrane with a very narrow pore size distribution from low-stress silicon nitride (SiN) utilizing techniques from the microelectronics industry. We have developed a base, acid, autoclave routine that prepares the membranes for cell culture both by cleaning residual fabrication chemicals from the surface and by increasing the hydrophilicity of the membranes (confirmed by contact angle measurements). Gelatin, fibronectin, and a 50/50 mixture of the two proteins were evaluated as potential basement membrane protein treatments prior to membrane cell seeding. All three treatments support adequate attachment and growth on the membranes compared to the control.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.4
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• pp.31-45
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• 2020

This study suggested the planting models of Carpinus turczaninowii community to make in Badahyanggi Arboretum and was carried out to the structure of C. turczaninowii commnity in Daebu-Yeongheung Islands. In order to identify the current ecological environment, this study set to 13 plots(i.e. 100㎡) for analysing detailed structure of plant communities. The research methodology was qualitative analysis. It used TWINSPAN, PCA and Indicator Species Analysis tools which are performed well in several comparisons of classification techniques and one of the ordination techniques showed that the plant communities. The results were classified into 3 communities that C. turczaninowii-Pinus densiflora community(I), C. turczaninowii-Quercus serrata community(II) and C. turczaninowii-Platycarya strobilacea community(III). In all of communities, C. turczaninowii was dominant species in canopy layer and understory layer, the degree of closure was high. Proposed the planting models that are I~II communities based on planting status in Badahyanggi Arboretum(Island Plant Botanical Garden), the structure of plant communities, indicator species and individual distribution by DBH classes. Also, The multi-layer planting plans are necessary, such as P. strobilacea, Lindera erythrocarpa, Viburnum carlesii, V. dilatatum, Ligustrum obtusifolium, Zanthoxylum schinifolium and so on.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.4 s.163
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• pp.507-518
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• 2007

This study aimed to investigate the competitive advantages of Chinese fashion industry and firms to Korean fashion industry by applying the generalized double-diamond theory. Data collection was done by internet and fax survey. Questionnaires were distributed to the Korean textiles and apparel firms who entered China for production anuor distribution. List of firms were provided by KOFOTI, KOTRA, and Korea Apparel Industry Association. Total 198 questionnaires were distributed, and 77 questionnaires were used for final analysis. The results were follows. Korea's competitiveness scores of double-diamond model were higher in every aspects, such as demand condition, infra/supportive industry, firms's strategy and competition except factor condition. Glottalization score in double diamond model measured by the degree of glottalization which was determined by international diamond factors which make firm's multinational/international activities possible. Chinese fashion industry's globalization score of factor condition was significantly higher than Korea, but for the rest of aspects, Korean fashion industry showed higher scores. Therefore, Korean fashion firms can overcome comparative disadvantage of factor condition by utilizing Chinese fashion industry no matter what type of entry. In addition, considering the growth rate of Chinese fashion industry and its power of influence in the world market, the entry to the global market of the Korean fashion industry can be possible.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.1
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• pp.3-10
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• 2002

Quantifying the settling velocities of fine-cohesive sediments is very essential in the study of ocean pollutions as well as sedimentations. Settling properties of fine-cohesive sediments are influenced largely by aggregation which occurs as a consequence of interparticle collision and cohesion of particles. Since the degree of cohesion of fine-cohesive sediments depends on physico-chemical properties such as grain size distribution, percentage of organic materials, and mineralogical compositions, and these physico-chemical properties varies regionally, the settling velocities of fine-cohesive sediments for a specific site should be determined through field or laboratory experiment. Recently, settling velocities of fine-cohesive sediments in Saemankeum coasts and Kunsan Estuary have been measured through laboratory experiments. Using these data, the previously proposed well-known settling velocity equations for fine-cohesive sediments are examined and a new equation is developed for better representation of the measured data in this study. The newly developed settling velocity equation is simpler in the form and easier in determining the related coefficients than the previous well-known equations.

• Analytical Science and Technology
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• v.13 no.1
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• pp.89-95
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• 2000

Three grades of activated carbon fibers (ACFs) were prepared from various precursors of plantic, synthetic, and mixed fabrics of viscose rayon and cotton. The ACFs an exhibited type I isotherms on the adsorption of nitrogen or argon. Micropore analysis revealed that the ACFs have uniform micropore size distribution in which their peak diameters were in the range of $5.6{\pm}0.3{\AA}$. The BET surface area of ACFs up to $1600m^2g^{-1}$ was proportional to the adsorption capacity of iodine. The BET values of the ACFs prepared were proportional to the burn-off degree of the products.

• Analytical Science and Technology
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• v.18 no.6
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• pp.483-490
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• 2005

Mass resolution of the time of flight aerosol mass spectrometer for an aerosol component analysis depends on the initial direction and the initial energy of the ions. We have found that the shape of the optimum post focusing electric field is not linear. The maximum electric potential should be applied to the ions whose initial direction is 90 degree. To check on the post focusing effects, we have installed a laser ablation mass spectrometer. By using this LA-MS, we have found that the average energy distribution of the laser ablated ions is 8 eV. To establish the optimum mass resolution, a time delay and a high voltage are needed, and the results of the study show that 1500 nsec, and 3.7 kV are the optimum parameters for our system respectively. The isotope mass signals of copper show a good resolution.