• Journal of KIISE:Computing Practices and Letters
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• v.10 no.2
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• pp.134-145
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• 2004

With rapid growth in the amount of data transferred on the Internet, traditional storage systems have reached the limits of their capacity and performance. SAN (Storage Area Network), which connects hosts to disk with the Fibre Channel switches, provides one of the powerful solutions to scale the data storage and servers. In this environment, the maintenance of data consistency among hosts is an important issue because multiple hosts share the files on disks attached to the SAN. To preserve data consistency, each host can execute the disk I/O whenever disk read and write operations are requested. However, frequent disk I/O requests cause the deterioration of the overall performance of a SAN cluster. In this paper, we introduce a SANtopia global buffer manager to improve the performance of a SAN cluster reducing the number of disk I/Os. We describe the design and algorithms of the SANtopia global buffer manager, which provides a buffer cache sharing mechanism among the hosts in the SAN cluster. Micro-benchmark results to measure the performance of block I/O operations show that the global buffer manager achieves speed-up by the factor of 1.8-12.8 compared with the existing method using disk I/O operations. Also, File system micro-benchmark results show that SANtopia file system with the global buffer manager improves performance by the factor of 1.06 in case of directories and 1.14 in case of files compared with the file system without a global buffer manager.

• The Journal of Engineering Geology
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• v.26 no.2
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• pp.251-260
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• 2016

Groundwater flow due to hydraulic gradients across a geologic barrier surrounding a dam reservoir can cause swamps or wetlands to form on the downstream side of the dam, thereby restricting land use. The difference in head between the reservoir level and the downstream groundwater level creates a hydraulic gradient, allowing water to flow through the geologic barrier. We constructed a drainage system at the Daecheong dam to study the effects on groundwater levels and soil moisture contents. The drainage system consisted of a buried screened pipe spanning a depth of 1-1.5 m below a land surface. Groundwater levels were monitored at several monitoring wells before and after the drainage system was installed. Most well sites recorded a decline in groundwater level on the order of 1 m. The high-elevated site (monitoring well W1) close to the reservoir showed a significant decline in groundwater level of more than 2 m, likely due to rapid discharge by the drainage system. Soil moisture contents were also analyzed and found to have decreased after the installation of the drainage system, even considering standard deviations in the soil moisture contents. We conclude that the drainage system effectively lowered groundwater levels on the downstream side of the dam. Furthermore, we emphasize that water seepage analyses are critical to embankment dam design and construction, especially in areas where downstream land use is of interest.

• Applied Microscopy
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• v.42 no.2
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• pp.67-76
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• 2012

The biomimetic approach on the cuticular spinning nozzles of the major ampullate silk glands in the golden-web spider Nephila calvata has been attempted using various visualizing techniques of light and electron microscopes to improve the design of spinning nozzle for producing synthetic nanofibers spun from electrospinning apparatus. The major ampullate spigot which has the most effective nozzle system to produce nanofibers for dragline silk with high strength and elasticity is connected via the bullet type spigot on anterior spinneret with flexible terminal segment. The excretory duct which transports the liquid silk feedstock from ampulla to spigot is divided into 3 limbs by loops back on itself to form an S-shape morphology that is bundled in connective tissue. Final diameter of the nanofibers at nozzle was dramatically reduced by gradual narrowing of duct cuticle less than 10 times comparing to its original size of funnel region. Moreover, the funnel has a characteristic cuticular organization with porous microstructure which seems to be related to water removal from feedstock of silk precursors. High magnification electron micrographs also reveal the presence of the spiral grooves on the surface of the cuticular intima near the valve which presumed to reduce friction during rapid flow of liquid silk.

• Clinical and Experimental Reproductive Medicine
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• v.23 no.3
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• pp.351-355
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• 1996

Objective: To analyze the direct effect of nitre oxide, generated from sodium nitroprusside, on sperm motility and reactive oxygen species. Design: Human sperm samples were treated to allow swim-up and washing. And the samples were devided into four aliquots. Each aliquot was incubated with either concentration at 0, 100nM, $10{\mu}M$, 1mM of nitroprusside. Intervention: Samples were measured chemiluminosence for reactive oxygen species of each aliquot with concentrations at 0, 100nM, $10{\mu}M$, 1mM of nitroprusside at allowing swim-up and washing of sperm. Main Outcome Measures: Percent motion parameters and viability were asse-ssed at 0, 3, 6, 12, 24 hours incubation. Results: The percent viablity was lower slightly in control group (50.2%) than that in sperm treated with 100nM of nitroprusside(57.5%) at 24 hours after incubation, while was reduced significantly in sperm with concentra-tion of $10{\mu}M(42.1%)$ and 1mM(21.3%)of nitroprusside at 6 hours after incubation. And the sperm treated with 1mM of nitroprusside was immotile totally at 6 hours after incubation. The straight line$(35.3{\pm}5.6%)$, the rapid forward$(37.2{\pm}6.4%)$ and the weak curvilinear velocity$(9.6{\pm}2.4%)$were more favorable comparing with those ($32.4{\pm}4.2%$, $30.0{\pm}7.8%$ and $18.0{\pm}4.6%$ respectively) in control group at 3 hours after incubation, but reduced significantly in sperm treated with $10{\mu}M$ and 1mM of nitroprusside. The levels of reactive oxygen species in control(700 c.p.m.) is lower significantly than that in each experimental groups of sperm treated with nitroprusside. And the levels of reactive oxygen species were 2200 c.p.m. in 100nM, 6200c.p.m. in $1{\mu}M$ and 12800c.p.m. in 1mM respectively. Conclusion: These results suggested that the concentration of 100nM of nitroprusside on sperm is beneficial to the maintanance of viablity and motile velocity, but detriment in high concentration of $10{\mu}M$ or 1mM of nitroprusside.

• The Journal of Natural Sciences
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• v.8 no.2
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• pp.289-321
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• 1996

After the two big wars (Imjin Woeran and Byungia Horan), the Lee Dynasty confronted rapid transitional periods in almost all aspects of the society. Corruption of the governmental system by the wars and disordered social structures also caused confusion in the social position system. In addition, development of the commercial economic system and monetary economy brought up a new rich middle-class, "Joong in Gyegeup". In ideological aspects, Confucianism indulged in and stick to isms and ics, and the Confucian morality slackened, thus a more pragmatic ideology, "Silhak Sasang", developed. And the emergence of the modern literature and art of the 'common people' was followed by the appearance of the common-people class including those having the common-people concept among the noble-class "Yangban Gyegeup". This evoked a new common costume culture and the fashion appeared. The public could no longer find the power and appeal from the preexisting ruling classes due to the changed role and sense of value. Thus, they sought a new symbolic leader group that would to be the new standard of the newly changed society. That was a group of people called as "Kisaeng" liberal and independent. They were performing social activities, enjoying poetry, music and dancing, and classy dressers, having physically attractive bodies. The erotic as well as luxurious mode proposed by them reflected the trend of that time. It concurred well with the concept and taste of the public, so it was accepted with a good response. That is, by following these leaders, the public achieved their identification and tried to share the prestige of the leaders. For this reason, the Kisaeng group attracted the public attention and led the taste of the public, thereby becoming the influential fashion leaders of that age.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.1-12
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• 2016

Rapid growth of information and communication technology and changes in college student characteristics require for university instructors to diversify instructional improvement efforts. Technological Pedagogical Content Knowledge (TPACK) is a capacity that instructors need to build for making instructional design based on consolidated technology. Accordingly this study explores instructors' awareness of the importance and performance of TPACK and to inquire into their relationships with epistemological beliefs and social support as relevant factors through a survey carried out with 264 instructors. The study has shown that there is a significant difference between college instructors' awareness of the importance of TPACK and their awareness of its performance. Furthermore, it has shown that the awareness of importance and performance of TPACK is significantly related to the social support, and that among the sub-factors of the social support, significant influences are observed from the emotional support on their awareness of the importance of TPACK and from the informational support on their awareness of the performance of TPACK. These results provide fundamental data for measures to develop and support TPACK capacity of college instructors, suggesting that it requires a teaching support strategy to enhance social support for instructors above all things.

• Applied Biological Chemistry
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• v.19 no.3
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• pp.145-154
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• 1976

Studies have been carried out to design a suitable consumer size package from flexible packaging material to hold 100 grams of Chilli powder and 250 grams of whole chilli which are moisture and color sensitive. 1. Sorption characteristics of the chilli powder has revealed that moisture sorption is rapid above 55 per cent R.H., and the product is fairly hygroscopic. Further, an equilibrium moisture content of about 15 per cent at 70 per cent R.H., appears to be critical from the point of microbial spoilage of chilli powder. 2. Studies on the colour (Capsanthin) changes of chilli powder equilibriated to different moisture content, have revealed that colour changes during storage is greatly influenced by the moisture content and temperature decreases the capsanthin content of chilli during storage. 3. From the studies, it can be inferred that the sunlight exhibits pronounced effect in bleaching of colour and brings about maximum discolouration of the red pigment in chilli. 4. From the packaging and storage studies of chilli powder in different flexible films, it can be concluded that for long-term storage, the aluminium foil laminate is unique in offering maximum protection from various physico-chemical changes. For short-term storage and for fairly good moisture and colour protection, amber or black polyethylene, high-density polyethylene and Saran/Cello/Saran poly laminate pouches appear to be suitable alternatives.

• Journal of Distribution Science
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• v.11 no.1
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• pp.55-63
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• 2013

Purpose - As the members of the baby boomer generation have retired in earnest, the start-up market has received more attention than ever before. According to recent statistical data, an increasing number of entrepreneurs are in their fifties. There has been a continuous increase in promotional materials on small business issues published by start-ups. This means that senior start-ups have increased in number. A number of support systems have been established for youth start-ups, but there are few government support policies in place for the senior start-up market. Thus, this study suggests a number of constructive alternatives from the perspective of government policy and marketing strategy for entrepreneurs, in order to generate competitiveness in the start-up process, through examining the current state of the senior start-up and by diagnosing extant problems. Research design, data, methodology - This study gives a number of options regarding the government's support policies and the securing of competitiveness in order to vitalize senior business start-ups. As for the government's support policies, funding support policy, publicizing business start-up policies, and operating systematic mentoring policies before retirement have all been covered. In particular, in order for senior business start-ups to become competitive, development through mutual relations with diverse policies is urgently needed. The aging population is becoming an issue in Korea, so businesses for the aged, and the creation of jobs for these people, will become a social issue. Senior business start-ups are playing an important role in expanding enterprise productivity, in addition to enhancing national competitiveness. Expanding senior business start-ups is important, because they also serve to expand the national infrastructure. Productivity increase through continuous expansion is thus recommended. Results - In order to expand the competitiveness of business start-ups, marketing-related observations and learning in regard to customers are necessary for the baby boomer generation, and competitiveness for seniors is urgently needed. Conclusions - Studies on the business start-up policies for the domestic baby boomer generation are almost non-existent, and systematic studies on small businesses are necessary. Only the government is providing statistical studies for small businesses, and such research remains at a general level for entrepreneurs. Therefore, a support system that can actually assist entrepreneurs is essential. Continuous business start-up studies with respect to the baby boomers should be vitalized, to invigorate studies on competition. In order to supplement and strengthen foundational support, senior business start-ups must develop various competitive capabilities with a focus on the customer. The government and the various stakeholder agencies and organizations involved with start-up businesses must find ways to offer support to founders. Such support should include access to knowledge and legal and consultancy services in order to incubate the rapid increase in start-ups founded by seniors. Government support projects should be expanded to meet this end.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.1
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• pp.1-11
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• 2005

Several Solid Freeform Fabrication Systems(SFFS) are commercialized in a few companies for rapid prototyping. However, they have many technical problems including the limitation of applicable materials. A new method of agile prototyping is required for the recent manufacturing environments of multi-item and small quantity production. The objectives of this paper include the development of a novel method of SFFS, the CAFL/sup VM/(Computer Aided Fabrication of Lamination for Various Material), and the manufacture of the various material samples for the certification of the proposed system and the creation of new application areas. For these objectives, the technologies for a highly accurate robot path control, the optimization of support structure, CAD modeling, adaptive slicing was implemented. However, there is an important problem with the conventional 2D lamination method. That is the inaccuracy of 3D model surface, which is caused by the stair-type surface generated in virtue of vertical 2D cutting. In this paper, We design the new control algorithm that guarantees the constant speed, precise positioning and tangential cutting on the 5DOF SFFS. We develop the tangential cutting algorithm to be controlled with constant speed and successfully implemented in the 5DOF CAFL/sup VM/ system developed in this paper. Finally, this paper confirms its high-performance through the experimental results from the application into CAFL/sup VM/ system.

• Journal of the Earthquake Engineering Society of Korea
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• v.16 no.2
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• pp.47-60
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• 2012

Based on the Korean Building Standard Law, a building less than 3-stories and $1000m^2$ in area is defined as a small-level building and, as a result, this type of building has been excluded from the requirement to comply with seismic design. In order to prevent the loss of life and property under earthquake loadings, the small-scale building should satisfy the seismic performance specified in the current code through a seismic retrofit. In this study, a seismic retrofit scheme of a Buckling-Restrained Knee Brace (BRKB) was developed for non-seismic 2-story steel buildings, including small-scale buildings, using a fragility contour method. In order to develop an effective retrofit scheme of the BRKB for the building, a total of 75 BRKB analytical models were used to achieve the desired performance levels and analyzed using the fragility contour method. The seismic performance of the retrofitted building was evaluated in terms of the weight of the developed BRKB systems. This study shows that the fragility contour method can be used for rapid evaluation and is an effective tool for structural engineers.