• Journal of Electrochemical Science and Technology
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• v.15 no.2
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• pp.207-219
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• 2024

Metal-N-C (MNC) catalysts have been anticipated as promising candidates for oxygen reduction reaction (ORR) to achieve low-cost polymer electrolyte membrane fuel cells. The structure of the M-N_x moiety enabled a high catalytic activity that was not observed in previously reported transition metal nanoparticle-based catalysts. Despite progress in non-precious metal catalysts, the low density of active sites of MNCs, which resulted in lower single-cell performance than Pt/C, needs to be resolved for practical application. This review focused on the recent studies and methodologies aimed to overcome these limitations and develop an inexpensive catalyst with excellent activity and durability in an alkaline environment. It included the possibility of non-precious metals as active materials for ORR catalysts, starting from Co phthalocyanine as ORR catalyst and the development of methodologies (e.g., metal-coordinated N-containing polymers, metal-organic frameworks) to form active sites, M-N_x moieties. Thereafter, the motivation, procedures, and progress of the latest research on the design of catalyst morphology for improved mass transport ability and active site engineering that allowed the promoted ORR kinetics were discussed.

• Journal of Korean Society of Transportation
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• v.24 no.5 s.91
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• pp.89-108
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• 2006

Korea has been entering the ageing society as the population of age over 65 shared over 7% since the year 2000. The ageing society needs to have transportation facility considering elderly people's travel behavior. This study aims to understand the elderly people's travel behavior using recent data in Korea. The activity schedule approach begins with travel outcomes are part of an activitv scheduling decision. For tho?e approach. used discrete choice models (especially. Nested Logit Model) to address the basic modeling problem capturing decision interaction among the many choice dimensions of the immense activity schedule choice set The day activity schedule is viewed as a sot of tours and at-home activity episodes tied togather with overarching day activity pattern using the Seoul Metropolitan Area Transportation Survey data, which was conducted in June, 2002. Decisions about a specific tour in the schedule are conditioned by the choice of day activity pattern. The day activity scheduling model estimated in this study consists of tours interrelated in a day activity pattern. The day activity pattern model represents the basic decision of activity participation and priorities and places each activity in a configuration of tours and at-home episodes. Each pattern alternative is defined by the primary activity of the day, whether the primary activity occurs at home or away, and the type of tour for the primary activity. In travel mode choice of the elderly and non-workers, especially, travel cost was found to be important in understanding interpersonal variations in mode choice behavior though, travel time was found to be less important factor in choosing travel mode. In addition, although, generally, the elderly was likely to choose transit mode, private mode was preferred for the elderly over 75 years old owing to weakened physical health for such things as going up and down of stairs. Therefore. as entering the ageing society, transit mode should be invested heavily in transportation facility Planning tor improving elderly transportation service. Although the model has not yet been validated in before-and-after prediction studies. this study gives strong evidence of its behavioral soundness, current practicality. and potential for improving reliability of transportation Projects superior to those of the best existing systems in Korea.

• Journal of the Korean Society for Railway
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• v.10 no.1 s.34
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• pp.23-37
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• 2007

Since 1964, HSR, which was opened in Japan, has had a hoge impact on the world. Historically, HSR has similar characteristics to the Roman Road, which promoted rapid movement and hada great influence on international society as transport infrastructure. Recently the development of HSR has become more rapid because of economic, environmental and external cost concern, emphasizing Environmentally Sustainable Transport(EST). In particular, the external cost has become more important factor for justifying HSR. The successful factors of HSR are high demand and cost minimal construction costs. There are two successful HSR models, the Japanese and the French. The former operates based on high demand oriented and the latter focuses on its minimizing costs. The demand orientated model means HSR carries over 100,000 passengers per day as in Japan and Far East Asian countries. The cost minimized model focuses on lower operation and construction costs as in France. In particular, Germany carries both passengers and freight on HSR. The construction costs in Germany are in between those of Japan and France. In future, Korea, Taiwan and China HSR will follow Japan's successful model because of high population density and concentration of economic activity along railway lines. This paper supports Vickerman's argument that HSR is justified where there is a demand of between 12 million and 15 million railway passenger a year(about 40thousand persons/day) between two urban center. This will be shown in the future in Korea, in Taiwan and China. Finally, this paper reviews that HSR activates at 250km/h for dedicated new lines and 200km/h for upgraded lines. In particular, it is successful in area of high population density and cost minimizing technology.

• Korea Journal of Hospital Management
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• v.25 no.4
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• pp.76-93
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• 2020

Purpose: In this study, the general characteristics of subjects who spent more than a certain amount of cost for general medical examination at the general hospital health promotion center, and the characteristics of disease, family history, and lifestyle (smoking, alcohol, physical activity, oral care) significantly differed in cost expenditure. We intend to provide basic data for establishing an appropriate marketing strategy for comprehensive examination. Method: It was conducted for users who received comprehensive checkups at a health promotion center at a general hospital in Seoul. The research data collection period is for 979 people who performed comprehensive examinations from January 2019 to December 2020. In order to carry out a comprehensive examination, a questionnaire before the examination was distributed to the subjects who visited the hospital to prepare, and the investigation was conducted in a way that the subjects of the investigation directly filled in. Results: There was a significant influence on the difference in expenditure for comprehensive examination according to the gender, age, and type of health insurance of the subject. In addition, there were significant differences in expenditure according to the presence or absence of disease and the type of family history. Weight loss, smoking history, smoking period, smoking frequency, drinking history, and drinking frequency all had significant effects on cost expenditure. Also, strength training and oral treatment management showed a significant effect on the cost of comprehensive examination. The number of flossing and interdental brushing was also found to have a significant effect. According to the results of multiple regression analysis, disease history (t=2.683, p<.01) and mean smoking frequency (t=4.315, p<.001) appeared to have the most significant effect on expenditure statistically. In other words, when the subject has a history of disease and when the average number of smoking is large, it means that the comprehensive examination cost is remarkably large. Conclusion: By using these contents, hospitals can further refine the marketing of the examination center. In addition, a more convenient and specialized process should be used by patients by linking the general medical department and the examination center well. In terms of management of operating medical institutions, this can be expected to create patients and increase profits.

• Animal Bioscience
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• v.34 no.6
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• pp.1049-1060
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• 2021

Objective: This study assessed the effect of different levels of xylanase, β-glucanase and phytase on intestinal enzyme activities and tibia bone development in broiler chickens fed wheat-based diets. Methods: Twelve experimental diets were formulated using a 3×2×2 factorial design (three doses of phytase and two doses of both xylanase and β-glucanase) and offered to 648 day-old Ross 308 male chicks having 6 replicates groups with 9 birds per replicate and lasted for 35 days. Results: An interaction between the enzymes products improved (p<0.01) the activity of chymotrypsin. Protein content at d 10 was highest (p<0.001) with addition of phytase while general proteolytic activity (GPA) (p<0.02) and lipase activity (p<0.001) were decreased. At d 24, there were improvements in protein content (p<0.01) and lipase (p<0.04) with supplementation of superdose phytase. Addition of superdose phytase decreased in chymotrypsin (p<0.02), trypsin (p<0.01) and GPA (p<0.001). The optimum dose of xylanase decreased the chymotrypsin activity (p = 0.05), while the GPA (p<0.001) was increased with the optimum level of β-glucanase. Superdose phytase supplementation at d 10 improved maltase (p = 0.05), sucrase (p<0.001) and alkaline phosphatase (p<0.001) activities in the jejunum while aminopeptidase activity was highest (p<0.005) with the low level of phytase. Protein content of jejunum mucosa was bigger (p<0.001) in birds fed superdose phytase while maltase activity (p<0.001) at d 24 was reduced by this treatment. Sucrase (p<0.04) and aminopeptidase activities (p<0.001) improved when diets supplemented with low levels of phytase. Tibia bone breaking strength was highest (p<0.04) with addition of low level of superdose phytase or optimum level of β-glucanase. Bone dry matter content decreased (p<0.04) when diets supplemented with phytase. Conclusion: From the results obtained in this study, supplementation of superdose phytase was the most effective, however, the cost-benefit analysis of the use of such a dose needs to be evaluated.

• Journal of Digital Convergence
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• v.13 no.10
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• pp.245-254
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• 2015

This research aims to look into correlation between Korea's childbirth promotion policy caused from women's maternity leave and economic activity. For the purpose, 300 surveys were distributed to mothers using postnatal care centers located in Seoul. Listed postnatal care centers such as Babe Glory, Shinsegae, Happy, Miznomall and out of 260, 222 surveys were selected for the research. Several advanced studies regarding child birth promotion policy backed up by current government and related domestic and overseas documents were used as reference. Decisive factors including social insurance, tax, cost for child birth and rearing service, social culture were derived as trait elements for child birth promotion. Mentioned factors along with economic activity by childbearing women were used when setting up the research model and hypothesis. Relation with material leave was employed as parameter for this study of which purpose lies in empirical analysis and investigation.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.4
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• pp.461-467
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• 2015

119 Integrated Emergency Management System, 119 IEMS hereinafter, is specialized command and control system for fire H.Q., that supports effective response activity at Fire, Rescue, and First Aids; it covers the emergency call taking, dispatch command delivery and situation control after dispatch command. While the efficiency of emergency response activity of call-taker and dispatcher is directly linked to the capability of qualified response in protecting the life and properties at real-time emergency condition, there is not any similar simulator system that can be used for training purposes for newly allocated personnel or beginner of emergency call taking and dispatch activity - 119 IEMS in fire H.Q. is the operation system that cannot be shared with other purposes, and they're highly expensive ICT system and infrastructure to be used as training and education. 119 Integrated Emergency Management Simulator System, 119 IEMS Simulator, was developed to be utilized in low cost for the training of 119 emergency call taker and dispatcher, and it can be used in training of various types of disaster and emergency handling, spans to emergency call taking, dispatch command, and field report and situation control after dispatch command.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.77-82
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• 2004

Quantifying rates of microbial processes under subsurface conditions is difficult, and is most commonly approximated by laboratory studies using aquifer materials. In this study a single-well, 'push-pull' test method is adapted for the in situ determination of denitrification rates in groundwater aquifers. The rates of stepwise reduction of nitrate to nitrite, nitrous oxide, and molecular nitrogen were determined by performing a series of push-pull tests at an experimental well field of Korea University. A single Transport Test, one Biostimulation Test, and four Activity Tests were conducted for this study. Transport tests are conducted to evaluate the mobility of solutes used in subsequent tests. These included bromide (a conservative tracer), fumarate (a carbon and/or source), and nitrate (an electron acceptor). At this site, extraction phase breakthrough curves for all solutes were similar, indicating apparent conservative transport of the solutes prior to biostimulation. Biostimulation tests were conducted to stimulate the activity of indigenous heterotrophic denitrifyinc microorganisms. Biostimulation was detected by the simultaneous production of carbon dioxide and nitrite after each injection. Activity tests were conducted to quantify rates of nitrate, nitrite, and nitrous oxide reduction. Estimated zero-order degradation rates decreased in the order nitrate '||'&'||'gt; nitrite '||'&'||'gt; nitrous oxide. The series of push-pull tests developed and field tested in this study should prove useful for conducting rapid, low-cost feasibi1ity assessments for in situ denitrification in nitrate-contaminated aquifers.

• Journal of Korea Multimedia Society
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• v.12 no.11
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• pp.1530-1538
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• 2009

KISTI-ACOMS ver. 2.0 has been distributed to more than 340 academic societies and used by more than 130 academic societies for 4 years since 2005 and still is desired for use by lots of other academic societies. But contrary to the desire and requests for system upgrades of academic societies, ACOMS has not been improved for last 3 years and some academic societies began to use domestic or foreign similar pay online peer review systems. In this paper, a new integrated portal service system is suggested in order to attempt national production cost-saving and quality improvement of academic information by creating and collecting high quality scientific and technologic academic information inexpensively. We come up with methodology of integration and utilization of a personal academic activity portal system interoperable with other services of KISTI, an open citation reference database automatically constructed by authors' activity and a journal evaluation system based on impact factor.

• The Journal of the Korea Contents Association
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• v.20 no.10
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• pp.167-176
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• 2020

The automated fish feed system currently used in Korea supplies a certain amounts of feed to water tanks at a certain time. This automated system can reduce the labor cost of managing aqua farms, but it is very difficult to control intelligently and appropriately the amount of expensive feed that is critical to aqua farm productivity. In this paper, we propose the FIIFF Inference Model( Fuzzy Inference-based Intelligent Fish Feeding Model) that can solves the problems of these existing automatic fish feeding devices and maximizes the efficiency of feed supply while properly maintaining the growth rate of fish in aqua farms. The proposed FIIFF inference model has the advantage of being able to control feed amounts appropriately since it computes the amount of feed using the current water environments and fish activity state of the aqua farms. The result of the feed amount yield experiment with the proposed FIIFF Inference Model represents the effect of saving 14.8% over the eight months of actual feed amount in the aqua farm.