• Proceedings of the KSR Conference
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• 2007.11a
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• pp.517-528
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• 2007

Domestic or international existing researches regarding rail damage factors are focused on laying, vehicle conditions, driving speed and driving habits and overlook characteristics of track structure (elasticity, maintenance etc). Also in ballast track, as there is no special lateral spring stiffness of track also called as ballast lateral resistance in concrete track, generally, existing study shows concrete track has 2 time shorter life cycle for rail replacement than ballast track due to abrasion. As a result of domestic concrete track design and operation performance review, concrete track elasticity is lower than track elasticity of ballast track resulting higher damage on rail and tracks. Generally, concrete track has advantage in track elasticity adjustment than ballast track and in case of Europe, in concrete track design, it is recommended to have same or higher performance range of vertical elastic stiffness of ballast track but domestically or internationally review on lateral spring stiffness of track is very minimal. Therefore, through analysis of service line track on site measurement and analysis on performance of maintenance, in this research, dynamic characteristic behaviors of commonly used ballast and concrete track are studied to infer elasticity of service line track and experimentally prove effects of track lateral spring stiffness that influence curved rail damage as well as correlation between track elasticity by track system and rail damage to propose importance of appropriate elastic stiffness level for concrete and ballast track.

• Economic and Environmental Geology
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• v.38 no.5 s.174
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• pp.547-561
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• 2005

General characteristics of groundwater contamination by As were reviewed with several recent researches, and its occurrence in groundwater of Korea was investigated based on a ffw previous studies and a groundwater quality survey in Nonsan and Geumsan areas. In Bangladesh, which has been known as the most serious arsenic calamity country, about $28\%$ of the shallow groundwaters exceeded the Bangladesh drinking water standard, $50{\mu}g/L$, and it was estimated that about 28 million people were exposed to concentrations greater than the standard. Groundwater was characterized by circum-neutral pH with a moderate to strong reducing conditions. Low concentrations of $SO_4^{2-}$ and $NO_3^-$, and high contents of dissolved organic carbon (DOC) and $NH_4^+$ were typical chemical characteristics. Total As concentrations were enriched in the Holocene alluvial aquifers with a dominance of As(III) species. It was generally agreed that reductive dissolution of Fe oxyhydroxides was the main mechanism for the release of As into groundwater coupling with the presence of organic matters and microbial activities as principal factors. A new model has also been suggested to explain how arsenic can naturally contaminate groundwaters far from the ultimate source with transport of As by active tectonic uplift and glaciatiion during Pleistocene, chemical weathering and deposition, and microbial reaction processes. In Korea, it has not been reported to be so serious As contamination, and from the national groundwater quality monitoring survey, only about $1\%$ of grounwaters have concentrations higher than $10{\mu}g/:L.$ However, it was revealed that $19.3\%$ of mineral waters, and $7\%$ of tube-well waters from Nonsan and Geumsan areas contained As concentrations above $10{\mu}g/:L.$. Also, percentages exceeding this value during detailed groundwater quality surveys were $36\%\;and\;22\%$ from Jeonnam and Ulsan areas, respectively, indicating As enrichment possibly by geological factors and local mineralization. Further systematic researches need to proceed in areas potential to As contamination such as mineralized, metasedimentary rock-based, alluvial, and acid sulfate soil areas. Prior to that, it is required to understand various geochemical and microbial processes, and groundwater flow characteristics affecting the behavior of As.

• Journal of Animal Environmental Science
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• v.18 no.3
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• pp.207-220
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• 2012

There are around 7,500 manure tanks to treat the manures from pigs in Korea. In the tank, there are too much sediments deposited on the base and wall, which causes low efficiency of stock capacity and manure fermentation. In order to minimize sediments and to ferment manure effectively, we developed a 2-fluid jet mixer for mixing sediments in liquid livestock manure tank. For developing the prototype, we tested a factorial experimental system with various nozzles, and simulated CFD models with two kinds of nozzle arrangement. From the results of factorial experiment and CFD simulation, we concluded the dia. ratio of primary : secondary nozzle should be 1:2 and the nozzles should be arranged at the same distances toward to the circumferential direction. With this results, we manufactured a 2-fluid jet mixer which is consists of four 2-phase nozzles, centrifugal slurry pump and root's type air blower. And, we carried out the performance test of the prototype in the round shaped liquid manure tank in the farm. The performance test results showed that the uniformity of TS (Total Solid) and VS (Volatile Solid) was raised from 21.3 g/L, 13.3 g/L In steady state to TS and VS to 23.0 g/L, 14.1 g/L in the mixing operation. Therefore, we could conclude that the prototype of 2-fluid mixer could make the solid material which could be sediments in the tank not to be deposited in the tank and to be contacted to air bubbles which could enhance the efficiency of the fermentation of livestock manure.

• Korean Security Journal
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• no.11
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• pp.203-226
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• 2006

A highly sophisticated expertise and systematic and integrated management of security operation are essential for a crowded stadium. a special object of security guarding. Nonetheless, the recent incident in a singing concert hall reveals the overall problem like the lacking safety management system. lacking deployment of professional security personnel, absence of safety manuals and safety measures, as well as the lack of professionalism of private sector security companies. In this study, we presented three categories that needed improvement, like the legal and institutional improvement, improvement of policy and improvement of operation which are required to set up the model to operate the optimal private sector security duties. For the revision of law and institution for a better and more desirable method, we discussed the revision of related laws and regulations pursuant to the security operation at places where events are held, including the revision of law on security guarding work, regulation on common housing management, uniformity of security guarding, and law on performance. For the improvement of policies, we discussed the introduction of security consultants, strengthening the security instructor system, expansion of relevant organizations, establishment of mutual cooperation, privatization of profitable events, improvement of awareness about the security activities provided by private sector, policy for the professionalism of private security operation, expansion of security exhibition and seminar. For the improvement of operation. we discussed professional security techniques. such as the technique of security consulting, the application of CPTED technique, the technique for the integration of system, the method of operation, the establishment of a system to support public security operations and volunteers, establishment of a manual for security guarding performance, modernization and high tech-oriented equipment, organization of security guarding entity in which the industry, academic society and government participates together.

• Journal of agricultural medicine and community health
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• v.20 no.1
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• pp.39-49
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• 1995

This study was attempted to investigate the acceptive status of 428 persons who had taken the vasectomy and the tubal ligation and the intra-uterine device(IUD, copper-T). It defined the complications after the contraceptive procedures and the effects of the supporting of the government for contraception. The target population was identified from the list of the 105 females taken tubal ligation, and 109 males vasectomized, 214 IUD acceptors covered by Gumi Health Center from January 1990 to December 1992. Data was collected from the target population by the questionnaire and medical records between March 1 and April 30, 1993. Among the study subjects, 56.0% of vasectomized males was between 30 and 34 years of age and the highest percentages of tubal ligation and IUD acceptors were between 25 and 29 years of age. The highest percentage of occupation of vasectomized males was officials and that of tubal ligation and IUD acceptors was in no occupational status. 81.2% of respondents were more than high school in educational level, educational level of vasectomized males was more higher than that of females. The percentage contraceptive acceptors with one or two children was 90.8% for vasectomized males, 80.1% for females with tubal ligation, and 93.9% for IUD acceptors. The most people accepted the contraception as they felt the need rather than other's persuasion. The major reasons of contraception were having the wanted children and alleviating the economic burden for the raising and the educating their children. Among the vasectomized males, 11.0% complained the side reaction and the most common symptoms were the inflammation around the wound and sexual declination. Among the tubal ligation females, 46.7% complained the side reaction and the most common symptoms were vaginal discharge, the menorrhagia, back pain and lethargy. The IUD acceptors were similar to them. The regretting rate of tubal ligation and the IUD acceptors was higher than the vasectomized males. The major reason of their regretting was the side reaction in the tubal ligation and the IUD. But the vasectomized males had the insecurity that they couldn't have their own children any more, and sexual declination. The main reason of the females accepted the tubal ligation and the IUD were the fears about toward induced abortion. The most contraceptive acceptors(83.2%) wanted to be offered by the government, but if they pay the expense in their own money, they would accept the contraception in 86.9%.

• The Journal of Small Business Innovation
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• v.19 no.4
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• pp.1-17
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• 2016

The purpose of this study is to suggest an efficient way for ventures to achieve innovation performance through R&D cooperative arrangements. Achieving innovation is one of the critical factors for the survival of ventures. Unlike established firms, ventures often do not have the specialized assets necessary to take technological developments to the product and market stages. Young and resource-constrained firms can achieve innovation by finding and accessing to the complementary resources from R&D cooperation. In the current business environment, many firms are likely to engage in multiple simultaneous R&D cooperations with different partners. Recent research stream addresses the importance of efficient cooperation management from the holistic portfolio perspective. Since maintaining the multiple cooperative relations require substantial amount of time and effort, managing cooperative relationships play a more important role to resource-constrained firms. In order to find an efficient composition of R&D cooperative partners, we mainly focus on the diversity of partner type and dependence level in partnership. We analyze the data on Korean manufacturing ventures collected in the Korean Innovation Survey (KIS) which was conducted by the Science and Technology Policy Institute (STEPI). The KIS questionnaire assesses the existence of cooperative relationships with different types of partners respectively. The types of cooperating partners are affiliated companies, suppliers, clients & customers, competitors or other firms in the same industry, consulting firms, universities, and research institutes. We confirm that ventures obtain relatively higher benefits from R&D cooperation compared with established firms in terms of innovation performance. The results show that a moderate level of diversity in cooperative partner type composition increases innovation. Moreover, diversity of cooperation dependency among the partners enhances innovation performance. Likewise, concentrating on the quality aspects of cooperative composition, such as diversity of partners and degree of dependencies, this study offers some implications for ventures in managing partners from an integrative perspective.

• Journal of Mushroom
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• v.2 no.1
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• pp.15-20
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• 2004

Pleurotus ostreatus, the oyster mushroom, is one of the most widely cultivated and important edible mushrooms in the world. In order to study the developmental process of P. ostreatus and its regulatory mechanism, a new culturing method needs to be established for inducing the fruiting body and sporulation in the laboratory. In this study, we have examined whether the fruiting body of P. ostreatus can be formed on the plastic petri dish which are commonly used for cell culture in the laboratory. The strain was cultured on $60{\times}15mm$ plastic petri dish with potato dextrose agar media at $28^{\circ}C$ for mycelial growth and then at $18^{\circ}C$ for the formation of primordia and fruiting bodies within plant growth chamber. The development of primordia into fruiting bodies was achieved on cultured dishes under air ventilation. At the primordia stage, the normal formation of fruiting body was blocked by sealing the plastic dish with parafilm. The periods requiring for the formation of primordia and fruiting bodies were examined on the dish culture. About 96% and 76% of cultured samples formed primordia and fruiting bodies under the optimal conditions during ten weeks of culture, respectively. These culturing periods, however, were changed by the mechanical injury treatment to mycelia. As other factors affecting the fruiting body formation, the effects of light and cold shock have been tested. No fruiting formation was observed on the cultured dishes under the dark. The cold shock treatment by storing cultured dishes for one day at $4^{\circ}C$ did not have any significant effects in the fruiting body formation. Spores of fruiting bodies acquired from the petri dishes could be germinated on culture media at $28^{\circ}C$. These results suggest that the fruiting bodies of P. ostreatus can be formed on the experimental petri dish and this dish-culturing method is useful for understanding of the developmental process of P. ostreatus in the laboratory. Furthermore, the dish-culturing method is able to shorten the life cycle of P. ostreatus without requiring large area and expensive device.

• Journal of Nutrition and Health
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• v.50 no.4
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• pp.313-324
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• 2017

Purpose: The purpose of this study was to examine the association between intake of antioxidant vitamins and prevalence of metabolic syndrome (MetS) among Korean adults. Methods: A total of 614 subjects aged 30~60 years were recruited from those who received a medical checkup at a general hospital in South Korea between 2009 and 2012. Presence of MetS was determined based on criteria issued by the NCEP ATP III. Intakes of antioxidant vitamins (vitamin A, retinol, carotenoids, vitamin C, and vitamin E) were estimated by combining 3-day diet records with an antioxidant vitamin database for common Korean foods. We used multiple logistic regression analysis to assess the association between dietary intakes of antioxidant vitamins and MetS. Results: Men in the highest tertile for retinol (OR = 0.40, 95% CI = 0.23~0.71, P for trend = 0.0009), carotenoids (OR = 0.57, 95% CI = 0.32~1.00, P for trend = 0.0470), and vitamin E (OR = 0.52, 95% CI = 0.30~0.92, P for trend = 0.0190) intakes had a lower likelihood of having Mets than those in the lowest tertile. The OR of high fasting blood glucose among men in the highest tertile for vitamin A (${\mu}g$ RE: OR = 0.55, 95% CI = 0.32~0.97, P for trend = 0.0417, ${\mu}g$ RAE: OR = 0.52, 95% CI = 0.29~0.92, P for trend = 0.0211), carotenoids (OR = 0.41, 95% CI = 0.23~0.73, P for trend = 0.0036), and vitamin E (OR = 0.47, 95% CI = 0.26~0.82, P for trend = 0.0080) intakes was lower than those in the lowest tertile. In women, subjects in the highest tertile of retinol intakes had a lower prevalence of MetS than those in the lowest tertile group (OR = 0.55, 95% CI = 0.30~0.98). The OR for abdominal obesity was lower among women with the highest vitamin A (${\mu}g$ RE) intakes compared to those in the lowest tertile (OR = 0.51, 95% CI = 0.28~0.93, P for trend = 0.0293). Conclusion: These results suggest that dietary intakes of antioxidant vitamins might be associated with reduced risk of having MetS among Korean adults.

• Korean Journal of Animal Reproduction
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• v.24 no.1
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• pp.69-76
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• 2000

This study was carried out to improve of effective culture system on development of IVM/IVF/IVC bovine embryos. The cumulus-oocyte-complexes (COCs) collected from Korean cattle ovaries harvested at a local abattoir were matured in 50 ${mu}ell$ of TCM199 supplemented with 10% fetal bovine serum (FBS) and hormones (35 $\mu\textrm{g}$/$m\ell$ FSH, 10 $\mu\textrm{g}$/$m\ell$ LH, 1$\mu\textrm{g}$/$m\ell$ estradiol 17 $\beta$ under paraffin oil at 39$^{\circ}C$ in a humidified atmosphere of 5% $CO_2$in air. At 24 hrs after culture, matured oocytes were fertilized in vitro for 22~24 hrs with motile semen in which obtained by centrifugation of a frozen thawed semen on Percoll-density gradients (45% vs. 90%) at 500 g for 20 min. The presumptive zygotes were divided into three experimental groups. Single egg (Group 1), 25 (Group 2) or 50 eggs (Group 3) were cultured on cumulus cell in 50 ${mu}ell$ TCM199 supplement with 10% FBS for 6~9 days after fertilization. In vitro developmental rates into the blastocysts in the groups 2 and 3 were significantly (P＜0.05) higher than those of group 1 (37,27 vs. 6%, respectively). Cell number of blastocysts obtained in groups 2 and 3 at day 8 were significantly (P${mu}ell$) resulted in higher developmental competence and cell number of bovine blastocysts produced in vitro than those the culture of single embryos with cumulus cells.

• Korean Journal of Environmental Agriculture
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• v.31 no.4
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• pp.313-317
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• 2012

BACKGROUND: Citrus is usually propagated by grafting onto a rootstock. In Korea, As trifoliate orange (Poncirus trifoliata) has dwarf and strong cold hardness, it is widely used as the rootstock of satsuma mandarin. Because 'Shiranuhi' ((Citrus unshiu ${\times}$ C. sinensis) ${\times}$ C. reticulata), a kind of citrus, also, generally is grafted onto a trifoliate orange, most of farmer has been recognized that 'Shiranuhi' root is naturally trifoliate orange. Meanwhile, reduction of flowering in 'Shiranuhi' orchard has been issued among the farmers and researchers over past few years and they guessed it was occurred by severe prune, oversupply of fertilization, overfruiting and temperature of growth period. However, a few researchers strongly assumed that it would be caused by scion rooting of 'Shiranuhi'. So, this study was carried out to identify the existence of scion rooting in 'Shiranuhi' tree in Korea. METHODS AND RESULTS: To identify the existence of scion rooting in 'Shiranuhi' tree, we randomly selected six 'Shiranuhi'orchards and we surveyed three to four trees, which flowering was not enough, from six 'Shiranuhi' orchards respectively. We took the root samples of 'Shiranuhi' mandarin, and then separated the two group which were non-scion rooting (Trifoliate orange), and scion rooting ('Shiranuhi' mandarin). To identity the scion rooting, we used primer set of three types which were a F2/R15, F4/R15 and F5/R15 primer set. As a result, when we conducted the DNA analysis, fourteen tree in less bloomed twenty tree was proved as tree with the scion rooting of 'Shiranuhi' mandarin. CONCLUSION(S): Scion roots of 'Shiranuhi'mandarin were usually observed in a deeply planted tree, and xylem of 'Shiranuhi' root indicated more white color than a case of trifoliata orange. 'Shiranuhi' tree by scion rooting was more vigorous but less flowering than trees grafted onto trifoliata orange. When we used F2/R15, F4/R15 and F5/R15 primer set for discriminance of 'Shiranuhi'mandarin root and trifoliate root, we identified the existence of scion rooting in 'Shiranuhi', From our results, it is suggested that the influence of scion root should be reviewed in 'Shiranuhi'orchards.