• Journal of Korean Society of Forest Science
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• v.105 no.3
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• pp.284-293
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• 2016

In order to assess th changes in vegetation characteristics over time in the forest-lands which is isolated by urbanization, vegetation surveys based on the Braun-Blanquet phytosociological method was carried out in 1996 and 2015 on Mt. Hwangyeong located in the center of Busan metropolitan city, South Korea. The number of vegetation types based on floristic composition showed no significant changes, the vegetation units under the community levels was more or less represents the difference. the average total vegetation cover and average number of species per unit area ($100m^2$) was increased 16% and 2 species, respectively. The relative importance value (RIV) for each tree species, Quercus spp. like as Q. mongolica and Q. serrata was decreased, while the warmth-tolerant trees, evergreen broad-leaved trees, and mesophyte like Lindera erythrocarpa, Styrax japonica, Osmanthus heterophyllus, and Stephanandra incisa was increased significantly. Changes of the life form spectrums of vascular plants did not substantially, hemicryptophyte(H) and therophyte (Th) was decreased, while nanophanerophyte(N) was increased significantly. Also through the creating of large-scale vegetation map (based on physiognomic vegetation types) was compared the spatial distribution characteristics of each vegetation types.

• Journal of Korean Society of Forest Science
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• v.109 no.2
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• pp.124-135
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• 2020

Alder (Alnus japonica) forests are representative of the wetland in East Asia, including Korea. In the past, alder forests were relatively common in various habitats such as mountains, riversides, back marshes, and alluvial plains. However, this plant community has recently become rare due to increasingly arid habitats and the influence of various land uses. In this study, we identify the synecological characteristics of alder (A. japonica) forests distributed naturally in the mountainous wetlands of Korea and provide basic data for their systematic conservation and management in the future. Based on vegetation survey data collected from 66 alder forests, community types were classified using the methods of the Zürich-Montpellier School of Phytosociology and two-way indicator species analysis. There were eight community types: Styrax obassia, Weigela subsessilis-Fraxinus mandschurica, Spiraea fritschiana, Viola verecunda, Impatiens textori-Spiraea salicifolia, Glyceria leptolepis, Molinia japonica, and Lindera obtusiloba-Quercus acutissima. These community types constituted a vegetation unit hierarchy of two communities, four subcommunities, and eight variants. In addition, the ecological characteristics of each community type were compared (including total coverage per 100 square meter, importance value index, constancy class, life-form composition, diversity indices, community similarity coefficient, and indicator species).

• Journal of fish pathology
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• v.6 no.2
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• pp.133-142
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• 1993

Vitamin B6(pyridoxine, pyridoxamine. and pyridoxal) is a dietary requirement in relatively small quantities for growth, health, and function in animals and fish. The metabolically active B6 is pyridoxal-5-phosphate(PLP). It does function as a coenzyme in number of enzymes(PLP-dependent enzymes) in which amino acids are metabolized, including decarboxylases, aminotransferases, sulfhydrases, tryptophanase, and hydroxylases. Vitamin B6 requirement is higher for fish because fish are fed much higher protein diet than land animals. B6 is also involved in metabolism of carbohydrates and lipids and essential for the synthesis of heme and serotonin. Deficiency signs in fish develop quickly, in cluding nervous disorders, convulsions, poor swimming coordination, skin lesions, edema, exophthalmos, and tetany. The conversion of vitamin B6 to metabolically active form(PLP) is catalyzed by pyridoxal kinase and pridoxine(pyridoxamine) oxidase. In this review, we summarized in detail the enzymatic studies on vitamin B6 metabolism and about the mechanisms and properties of a PLP-dependent enzyme.

• The Journal of the Korea Contents Association
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• v.20 no.7
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• pp.56-65
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• 2020

The purpose of this research is to study the excellence and originality of the Joseon artillery(Jungwan-gu) through an effective restoration. Jungwan-gu that was used during the Japanese Invasion of Korea in 1592 was able to maintain its maritime dominance based on cutting-edge technology of its time. Joeson artillery(Jungwan-gu) was used in major naval/land battles during the Japanese Invasion of Korea in 1592 and is an important cultural heritage that provides a glimpse into Joeson people's will to defend the nation from foreign invasion. For further historical verification such as operational method of Jungwan-gu, extensive research in various fields including size, proportions, structure, materials, and casting method were required. Accordingly, for a more effective research on Jungwan-gu, cutting-edge technologies such as 3D scanning and 3D printing were utilized. Firstly, 3D scanning, modeling, and printing technology were applied to identify the morphological characteristics of Jungwan-gu. Through this, we were able to reach our research objective of identifying the size, internal structure, and proportionality of Jungwan-gu. In addition, by studying the form, operation, casting methods, and other characteristics, the restoration of Jungwan-gu provided us with an important opportunity to verify the dominance and originality of the Joeson era's science and technology during the Japanese Invasion of 1592. This reaserch subject participated in the "4th 3D printing BIZCON Contest" and won the Minister Prize of Science and Technology Information and Communication.

• Journal of Korea Water Resources Association
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• v.43 no.10
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• pp.883-891
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• 2010

More recently, there have been significant changes in the forms of channels due to runoff characteristics driven by climate changes and other alterations in basin/channel environments. Particularly, increasing local deposition in major channels is being observed nationwide. Of such phenomena, it is noteworthy that flood-plains show unidirectional growth and lowering of channels within compound channels in the form of a high-flow plain. These changes are supposed to affect management of the river ecology as well as flood control. In this study, the research on channels in Korea confirmed that the phenomenon of local deposition in those channels is actually taking place, rendering a problem to be urgently addressed. Previous studies on bed changes have been focused on low channels based on bed materials distributed over the channels. However, this research has proved that surface-layer deposition of a high-flow plain is closely related with changes in the conditions of ground surfaces and, ultimately, affects the bed of the entire channel as well. According to the intensive research on the condition of the high-flow plain of the mouth of the Han River, the silt deposited in the high-flow plain was the main cause of settlement/growth of vegetation. And this leads to landforming along with woods-forming, disturbing flood control as well as the normal river ecology.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.649-657
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• 2019

An essential part of the development of an autonomous ship is supporting technology that can effectively check and diagnose the operational status of the ship form the shore control center on land. This development has recently occurred in the shipbuilding and shipping industries. In this paper, we present a smart ship solution that operates, as a single system, a data collection platform that gathers ship operation data and a service platform that provides various services. When this smart ship solution was applied to an operating ship, it was determined that a variety of high-quality data could be collected compared to existing ship data collection systems. In addition, it was shown that of the operation data collected, analysis of parameters related to the main engine can be used to determine the overall state by deriving valid results and visualizing patterns. In conclusion, it was suggested that a ship's operation status could be checked more effectively and a comprehensive evaluation could be possible at the shore control center if the results of this study were extended to various ship equipment and analyzed together with the operational environment data.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.721-724
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• 2008

The present study was to develop a dry PFB method similar to the existing gypsum board construction method in order to apply the existing wet PFB method that uses fire.resistant adhesive. It was found that the existing wet method can produce concrete compressive strength of 80MPa and fire resistance of 3 hours with 30mm PF boards. The goal of development in this study was fire resistance of 3 hours through dry construction of 15mm fire resistant boards. The results of fire resistance test showed an increase in thermal durability and thermal strain. It is believed that inorganic fiber reduces thermal strain, and lowers heat insulation performance by 15% or less. This suggests that heat insulation performance was improved by the change in the inner composition of PF board resulting from the adjustment of Al:Si mol ratio, high temperature molding, and dry curing. According to the results of fire resistance test, when the dry PF method was applied, the temperature of the main reinforcing bar was 116$^\circ$C in 15mm, 103.8$^\circ$C in 20mm, and 94$^\circ$C in 25mm, and these results satisfied the current standards for fire resistance control presented by the Ministry of Land, Transport and Maritime Affairs. When a 3 hour fire resistance test was performed and the external properties of the specimen were examined, the outermost gypsum board hardly remained and internal PF board maintained its form without thermal strain.

• Strategy21
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• s.43
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• pp.5-28
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• 2018

The tensions between the U.S and China, which form the two pillars of the G2 era, seem to have persisted even after the Trump administration inaugurated. The strong confrontation between the two in recent foreign security issues may drive to develop an inadvertent military conflict, and it is high likely to occur in the maritime are. The purpose of this study is not only to analyze the balance of modernized naval forces in the PLAN through naval strategy changes and weapons system modernization trend, but also to predict the impact of the geographical proximity difference on the balance of naval forces in the disputed areas. It examined the impact of distance and geography on naval power by assessing the modernization pattern of the PLAN and capabilities in the context of two scenarios at different distances from China by 2020: one centered on Taiwan and the other on the Spratly Islands. The PLAN's strategy had impact on operational concept and forces construction. First, from the viewpoint of operation operational concept, it can be seen that the passive defense is changing into active defense. Second, in terms of power construction, it can threaten the surface and submarines of U.S power from a distance. And they generated follow three features; The ocean is not the focus of Chinese submarines, Horizontal and vertical expansion of Chinese naval vessels, The improvement of the suppression ability as the Chinese naval modernization ratio increases. The strength of the PLAN is dominant over the U.S in terms of reserves, and it can complement the qualitative deterioration by utilizing nearby bases in the vicinity of the mainland, such as the Taiwan Strait. However, due to the shortage of aircraft carriers, there is a possibility that it will take some time to secure the advantage of air and ocean in the amphibious operation. Therefore, as the dispute is prolonged, China may fail to achieve its original goal. In addition, the lack of cutting edge Commanding Ships may bring to weaken the C2 capabilities. At results, it is expected that PLAN will not be able to have a superiority in the short term due to lagging behind U.S advanced technology. Nevertheless, PLAN has strengthened its naval power through modernization sufficiently and it is highly likely to use force. Especially, it is more likely in the region where the naval power operation like the Taiwan Strait is possible with the almost equality to that of the United States. China will continue to use its naval forces to achieve a rapid and decisive victory over U.S in the close area from the land.

• Strategy21
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• s.41
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• pp.52-84
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• 2017

After finishing Cold War, the U.S. Navy's ability to Sea control has been gradually eroded last 15-20 years. The global security environment demands that the surface Navy rededicate itself to sea control, as a new group of potential adversaries is working to deny U.S. navy command of the sea. China has been increasing their sea denial capability, such as extended anti-surface cruise missile and anti-surface ballistic missile. To cope with this situation, the U.S. Naval Surface Forces Command has announced Surface Forces Strategy: Return to Sea Control. It is a new operating and organizing concept for the U.S. surface fleet called 'distributed lethality'. Under distributed lethality, offensive weapons such as new ASCMs are to be distributed more widely across all types of Navy surface ships, and new operational concept for Navy surface fleet's capability for attacking enemy ships and make it less possible for an enemy to cripple the U.S. fleet by concentrating its attack on a few very high-value Navy surface ships. By increasing the lethality of the surface ships and distributing them across wide areas, the Navy forces potential adversaries to not only consider the threat from our carrier-based aircraft and submarines, but they now consider the threat form all of those surface ships. This idea of using the distributed lethality template to generate surface action groups and adaptive force package and to start thinking about to increase the lethal efficacy of these ships. The U.S. Navy believes distributed lethality increases the Navy's sea control capability and expands U.S. conventional deterrence. Funding new weapons and renovated operating concept to field a more lethal and distributed force will enable us to establish sea control, even in contested area. The U.S. Navy's Surface Forces Strategy provides some useful implications for The ROK Navy. First the ROK Navy need to reconsider sea control mission. securing sea control and exploiting sea control are in a close connection. However, recently the ROK Navy only focuses on exploiting sea control, for instance land attack mission. the ROK Navy is required to reinvigorate sea control mission, such as anti-surface warfare and anti-air warfare. Second, the ROK Navy must seek the way to improve its warfighting capability. It can be achieved by developing high-edge weapons and designing renewed operating concept and embraced new weapon's extended capabilities.

• Strategy21
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• s.41
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• pp.174-207
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• 2017

Human history shows diverse strategies for survival and prosperity. This study introduces the concept of the expansion of wealth as a key to explain choice and behavior of political entities. American scholar, -Bruce Bueno de Mesquita-, offers theoretical grounds for this concept in that the cores of selectorate theory is settled. The political entity consists of two groups, -the winning coalition that has power to replace leader and non-winning coalition that has not. Leaders implement policies serving for the welfare of winning coalition in return for their loyalty. Both internal problems caused by demographic changes and external ones of climate changes, epidemic disease, or invasion compel leader and winning coalition to adopt policies of expansion that they believe may lead to the acquisition of wealth needed to counter those problems. The process starts by occupying one spot where other entities reside and then connecting it to its own. The line between spots functions as a foothold to form a new line to other spots. By repeating this process, a space is created in which new laws and orders are instated. In the early stage of expansion, war is hardly avoidable. Once finished successfully, the political circumstance tilts to encourage economic activities in order to generate national revenues to strengthen political power of winning coalition. However, as scale of economic activities grows, so does political power of civic classes in production and trade. To gain financial support required to run the political entity, delegation of power or bestowing autonomy to non-winning coalition is inevitable. Thus, expansion is not the ultimate solution, only to prolong the political survival if succeed. Maritime power came to attractive option when overland expansion had become obstructed. It offered much greater advantages in terms of political risks and financial burdens in exploring new regions of precious commodities than overland expansion. Each political entity around world have been, for the first time in human history, connected by maritime means since 15th century. It is worthy of noting that land conditions propelled people out to sea. Political and economic situations created opportunities to exploit geographical position in pursuit of wealth. In the 21st century, we witness the operation of international winning coalition that presides over the rules of expansion. Competing for market is synonymous to the expansion in this era, the cause and aim of it has not been changed though. Energy and dollars are key factors of expansion since the end of the 2nd world war. No matter what the forms and conditions change, naval power is still the most relevant means for expansion as it retains unique characters of maneuver, flexibility, continuity, display and projection of power. The strategy for using naval power should be in line with two different approaches for expansion: Approaches to the international winning coalition by making contribution to world order, and approaches to the non-international winning coalition by enhancing military diplomatic activities. The former will serve our share of winning coalition while the latter will open chances to acquire further prosperity.