• Journal of Wetlands Research
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• v.6 no.4
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• pp.59-69
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• 2004

Constructed wetlands are regarded as an important water treatment system for agricultural water quality improvement and management. The purpose of this study is to evaluate the application of subsurface flow wetland(SFW), using the Pharagmites australis as macrophytes, and to clarify the basic and essential factors to be considered in the construction and management of constructed wetlands. This study was carried out relatively short hydraulic residence time(HRT), 6hr ~ 72hr (3days), using eutrophic reservoir water with relatively low concentrations of influent and large quantity to be treated. The effluent satisfied the criteria of agricultural water quality. Removal efficiencies of Biochemical oxygen demand(BOD), Chemical oxygen demand(COD), Suspended solids(SS) and Chlorophyll a(Chl-a) were high in HRT 24hr, not any more significant increasement of removal efficiencies in HRT 48hr and 72hr. However, removal efficiencies of nitrogen and phosphorus increased as HRT increased, showing the highest efficiency at the 72hr of HRT in nitrogen, and 48hr in phosphorous. The SFW was very effective system for reservoir water quality improvement, and had the advantages of the reduction of purchasing cost to land required, lack of odors, and harmful insects, especially mosquito, the improvement of the scenic beauty and minimal risk of public exposure. Therefore, it was evaluated that the SFW was very available water treatment system for the water quality improvement of agricultural reservoir. However, it was need to consider with application of the SFW in high cost of construction and troublesome of management.

• Microbiology and Biotechnology Letters
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• v.20 no.4
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• pp.377-383
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• 1992

Seven strains of Bacillus thuringiensis were isolated from soil in Korea and characterized. The isolates were named HL-8, 10, 12, 13, 14, 15 and 16 which produced parasporal crystals and endospores in their cells. The biochemical characteristics of the seven isolates were only minor different in specific chracteristics to the known serotypes of Bacillus thuringiensis. The number of the plasmid DNA elements from the isolates were studied. The computerized molecular weights of the six plasmid elements in the HL-8 and HL-lO strains were from 3.01 to 15.1 Md, four plasmid elements in the HL-12 were from 5.4 to 21.9 Md, four plasmid elements in HL-13 were from 5.1 to 20 Md, three plasmid elements in HL-15 were from 3.4 to 11.3 Md and three plasmid elements in the HL-16 were from 2.4 to 20.1 Md. The seven isolates showed resistances to ampicillin, bacitracin, cephalothin, methicillin and penicillin G. The strains of HL-8, HL-lO, HL12, HL-14, HL-15 and HL-16 showed lethalities against Culex pipiens 3rd instar larvae. The HL8 and 14 strains showed 100% lethality to the larvae within 48 hours. HL-13 strain did not have toxicity against the larvae.

• Journal of the Economic Geographical Society of Korea
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• v.18 no.4
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• pp.415-430
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• 2015

Since the late 1990s Vinacafe has gone through strategic changes in corporate governance and managements due to an increase in the introduction of coffee MNCs, a growth of global demands in sustainable coffee, aging coffee tree, and the deterioration of coffee production with climate changes in Vietnam. Vinacafe has attempted to cope with these kinds of changes through strategies for equitization. Therefore, the main aim of this paper is to identify strategies for enhancing the competitiveness of the Vietnamese coffee industry by investigating changes in corporate governance and processes of coffee production and distribution. The equitization of Vinacafe has led to the enhancement of coffee competitiveness in two perspectives. Firstly, as it has decentralized decision-making from headquarter, subsidiaries have become able to strength their competitiveness themselves by introducing new technologies, improving coffee quality, and encouraging the introduction of eco-friendly production methods through cooperative relationships with stakeholders involved in coffee production and distributions in Vietnam. Secondly, it has also enhanced competitiveness through the diversification and effectiveness of coffee managements by intensifying the flexibility of contract with coffee farmers and diversifying coffee sales and supply chains in Vietnam.

• The Journal of the Convergence on Culture Technology
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• v.6 no.2
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• pp.437-447
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• 2020

The purpose of this study is to research the countermeasures and expected effects through the use of drones in the field of disaster prevention as a drone-based smart quarantine performance method. The environmental, market, and technological approaches to the review of the current quarantine performance task and its countermeasures are as follows. First, in terms of the environment, the effectiveness of the quarantine performance business using drone-based control is to broaden the utilization of forest, bird flu, livestock, facility areas, mosquito larvae, pests, and to simplify and provide various effective prevention systems such as AI and cholera. Second, in terms of market, the standardization of livestock and livestock quarantine laws and regulations according to the use of disinfection and quarantine missions using domestic standardized drones through the introduction of new technologies in the quarantine method, shared growth of related industries and discovery of new markets, and animal disease prevention It brings about the effect of annual budget savings. Third, the technical aspects are (1) on-site application of disinfection and prevention using multi-drone, a new form of animal disease prevention, (2) innovation in the drone industry software field, and (3) diversification of the industry with an integrated drone control / control system applicable to various markets. (4) Big data drone moving path 3D spatial information analysis precise drone traffic information ensures high flight safety, (5) Multiple drones can simultaneously auto-operate and fly, enabling low-cost, high-efficiency system deployment, (6) High precision that this was considered due to the increase in drone users by sector due to the necessity of airplane technology. This study was prepared based on literature surveys and expert opinions, and the future research field needs to prove its effectiveness based on empirical data on drone-based services. The expected effect of this study is to contribute to the active use of drones for disaster prevention work and to establish policies related to them.

• Journal of the Economic Geographical Society of Korea
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• v.3 no.2
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• pp.43-61
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• 2000

This study investigate the spatial characteristics and corporate networks of foreign business service firms in Korea. Specifically intrafirm and extrafirm organization of foreign firms are addressed utilizing the corporate network perspective. For this purpose, this study conducted questionnaire and interview surveys for the foreign firms. Parent-subsidiary relationships are focused on the mechanisms by which Transnational Corporations (TNCs) headquarters control and coordinate their foreign affiliates and subsidiaries in order to achieve investment purpose in Korea (overseas market expansion). But extrafirm networks of foreign business services firms in Korea do not appear to play an important role in regional development to date. A low proportion of foreign firms is engaged in academics-industry linkages, and a low number o( foreign firms is formally linked with government organizations, research institutes, and trade associations. To conclude, Foreign direct investment firms in business services in Korea are characteristics by globalized intrafirm networks and localized interfirm and extrafirm networks. It is understood that regional development can be vitalized when Korean local firms have close relationships with technologically advanced foreign firms in tacit knowledge capacity. Foreign firms are able to play an important role in the development of business services in Korea. This study suggests that regional foreign direct investment policy should be targeted towards the corporate networking with foreign firms and domestic firms and incrementation of the potential of foreign firms as a knowledge-intensive industry.

• Journal of the Korean association of regional geographers
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• v.21 no.1
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• pp.114-136
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• 2015

Manufacturing FDI is mainly conducted by establishing production firms in the host country. The foreign branch facilities which are closely connected to headquarters in the home countries through the global supply chain have decisive effects on the integration of global production system and on the pattern changes in international logistics. Therefore, the study on the development process of manufacturing supply chain through FDI can be the key factor to understand the global production and international logistics system. This study analyzes the spatial and temporal patterns of direct investments in China by Korean companies in the manufacturing sectors. The results show a great deal of differential in periods and regions in investment. At the early period of Korean manufacturing FDI, the coast provinces in China which are adjacent to Korean peninsula were main investment target regions. However recently, coastal and inland provinces far away from Korea have been important for attracting Korean manufacturing capital. If further affiliated studies are done, the results of this study would be more beneficial to understand the logistics flows of regional supply chain based on the manufacturing FDI.

• Journal of Navigation and Port Research
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• v.44 no.3
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• pp.244-252
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• 2020

The 2008 global financial crisis was triggered by the Lehman Brothers crisis caused by the sub-prime mortgage crisis in the United States This crisis has had an impact on the globe's dry bulk shipping market by reducing dry bulk cargo volume. An oversupply of dry bulk carriers caused a serious recession in the globe's dry-bulk shipping industry and shipbuilding industry. In this situation, the Korean dry-bulk shipping companies were victims of the quagmire of a long recession since the global financial crisis and could not overcome this crisis. This condition forced them into severe financial risk Thus, it caused many shipping companies to file for bankruptcy. In this study, we classified Korean ocean-going dry-bulk shipping companies into two groups, that is, the solvent group and the insolvent group. We also separated the research period before and after the 2008 global financial crisis. Then we investigated the differences in the major financial ratios of the two groups by t-test and found that some financial ratios such as profitability ratios and growth ratios showed the difference between the two groups with statistical significance. The significance of this study is as follow. First, the shipping company management is also crucial for the systematic management of financial strength and business strategy, it is crucial to manage cargo which a high profitable freight. Second, the shipping company should be managed as a company with continued growth through efficient operation and management of ships.

• Journal of Sericultural and Entomological Science
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• v.54 no.1_2
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• pp.17-22
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• 2016

Rearing environment direct effects on oviposition preference of black soldier fly(Hermetia illucens). In this study, the number of egg-filled flutes was surveyed according to the size of adult rearing cages and oviposition media of black soldier fly (BSF). The height of the adult rearing cages were fixed at 2 m and provided different sizes of width and length and released 20,000 BSF adults in the rearing cages. The mean number of BSF egg-filled flutes was 895.4 at $4{\times}4m$ cage, 876.3 at $2{\times}1m$ cage and 62.3 at $1{\times}1m$ cage. Comparison of egg-filled flutes was according to cages material of adult BSF. The mean number of egg-filled flutes were 820.7 and 604.3 at different cage materials such as mosquito net and green house film. The mean numbers of egg-filled flutes were 326.6 in green floral form, 135.2 in green corrugated cardboard and 41.0 in brown corrugated cardboard. And the mean number of egg-filled flutes were similar floral form with the corrugated cardboard was overlapped by floral form such as 57.7 and 64.7. The mean number of egg-filled flutes was 29.0 and 48.2 in 6 mm and 4 mm diameter of oviposition hole.

• Pediatric Infection and Vaccine
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• v.16 no.1
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• pp.54-60
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• 2009

Purpose : Yellow fever, a mosquito-borne viral hemorrhagic fever, is one of the most lethal diseases. Recently there have been an increasing number of Korean children who have travelled to yellow fever endemic zones and were administered yellow fever vaccine (YFV). Therefore, we carried out this study to provide child travelers with safety information of YFV. Methods : This study was conducted at the International Clinic of National Medical Center in Seoul between April 2007 and June 2008 for the evaluation of adverse events of YFV. One hundred twenty-five children received YFV (17-DD) and were prospectively monitored for adverse events through telephone interviews on day 3, 6, 9, 16, 23 and 30 after vaccination. Results : Adverse events were observed in 31 (24.8%) of 125 child travelers who received the YFV. The mean age was 12.5${\pm}$5.0 years. Sixty-six of the child travelers (52.8%) were males. The common adverse events were pain in 11 (8.8%), swelling in 8 (6.4%) and redness in 7 children (5.6%) at the injection site. The systemic adverse events included mild fever in 5 (4.0%), headache in 5 (4.0%), cough in 4 (3.2%), abdominal pain in 3 (2.4%), and vomiting in 2 children (1.6%). Most of the adverse events were detected within 7 days of administration and there were no differences in adverse events by gender or age. All travelers who had complained of symptoms improved spontaneously or following symptomatic treatment. Conclusion : This study showed that YFV is well-tolerated and there were no reports of severe adverse events. Studies are ongoing to clarify the cause and risk factors for rare adverse events.

• Current Research on Agriculture and Life Sciences
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• v.4
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• pp.127-131
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• 1986

In order to know the effects of iron the lipid characteristics in common feed, vitamin E and free unsaturated fatty acid concentrations were determined using feeds with(uncommon) and without(common) water added. The vitamin E concentrations in common feed(P<.05) and uncommon one (P<.01) showed statistically continuous decreasing figure from 1.75mg/g(1 day) to 0.25mg/g(11 days). The free unsaturated fatty acid concentrations in common feed showed also statistically continuous decreasing figure from 23.8mg/g(control group) to 17.6mg/g(20% ferrous sulfate group) (p<.01). On the mean time, quantitative values in uncommon feed have shown statistically continuous decreasing figure from 23.9mg/g(control group) to 17.4mg/g(20% ferrous sulfate group) (P<.01). The concentrations of vitamin E and free unsaturated fatty acid in common feed was higher than those in uncommon one, but significant difference was not recognized. The interactions between time lapse and ferrous sulfate were recognized in respect to the vitamin E and free unsaturated fatty acid in common and uncommon feed.