• Journal of Korea Water Resources Association
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• v.52 no.spc2
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• pp.791-799
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• 2019

This study explained the historical changes in the habitat structures based on the aerial photographs (1948, 1967, 1973, 1989 and 2010) of the mid-stream reach of the Mangyeong River. The habitat structure was divided into landforms and aquatic habitats. The landform was classified into bare land, vegetated land, water surface, farmland and artificial land. The aquatic habitat was classified into natural riffle, artificial riffle, run, head wando, tail wando, mid wando, pond and chute channel. The ratio of bareland decreased, and water surface and vegetated land increased after the excavation in 1970s and since the construction of weir in 1980s. As historical changes of aquatic habitat, ratio of run decreased sharply while mid wando increased sharply. aquatic habitats such as head wando, tail wando, and pond located on bars decreased dramatically.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.5
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• pp.734-741
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• 2019

Objective: The objective of the study was to determine the relationship between plasma and salivary cortisol concentrations in beef cattle that were subjected to handling prior to sampling. Methods: Twenty-one Nguni cows of three age categories; 5 to 7 yr (n = 7), 8 to 10 yr (n = 6), and 11 to 13 yr (n = 8) were handled for five consecutive weeks. In the pen, a human avoidance test was performed and cattle responses to restraint in the chute and crush were observed. In addition, rectal temperature readings were taken and, faecal samples were collected and analysed for glucocorticoid metabolites. Through the handling and restraint process, excretory and vocalisation behaviour, as a sign of stress were observed and recorded. Thereafter, six cows were randomly selected and subjected to an adrenocorticotropic hormone (ACTH) challenge. Blood and saliva samples were extracted to determine cortisol concentrations. Results: Repeated handling affected (p<0.05) faecal glucocorticoid metabolites, rectal temperatures, avoidance distance, crush scores as well as urination and defaecation behaviour. Acclimation to handling was variable based on each respective parameter. Saliva cortisol concentrations increased and decreased significantly (p<0.001). A peak value of $136.78{\pm}15.869nmol/L$ was observed 30min after administration of ACTH, from a baseline value of $8.75{\pm}15.869nmol/L$. Plasma cortisol concentrations did not differ (p>0.05) across the time of sampling. A low and insignificant correlation (r = 0.0131, p>0.05) between plasma and saliva cortisol was therefore observed. Conclusion: We conclude that if beef cows are subjected to handling prior to sampling, a weak relationship exists between plasma and salivary cortisol levels.

• Journal of The Geomorphological Association of Korea
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• v.27 no.2
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• pp.29-46
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• 2020

In this study, changes in the fluvial landforms of the Yeoju section of the Han River, which was made up of the Han River Restoration Project, were examined through existing previous research data, government's environmental impact assessment data, satellite images, and field observations. For example, In the vicinity of Dori Island, the most upstream part of the study section, the location of the confluence of the Han River and Cheongmi Stream was changed, and it was found that a significant portion of the sand sedimentary layer disappeared. In the Bawuinupgubi area, the wetland, which is the first class in the ecological nature, was greatly modified, and the elevation of the ground rose as Gangcheon island and it was completely separated from the river by dredging The confluence of Geumdangcheon and the point bar of Yeonyang-ri in the south were also dredged, turned into an artificial waterfront park, and a chute channel remained in the form of a wetland was also developed as a recreational park. The deposional forms around Baekseok-ri islands also disappeared as dredging was carried out. Among the areas adjacent to the confluence of Bokcheon and Yangchon-ri Island, some sedimentay forms remains, but the abandonned channel between Yangchon-ri and the northern river bank has been changed into a riverside reservoir through dredging and embankment construction, and the waterway of the tributary river(Yazoo) has been greatly changed.

• Journal of Korea Port Economic Association
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• v.27 no.1
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• pp.281-304
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• 2011

In the energy-climate era, pollution emissions from port activities have a significant issue in international shipping and port community. Thus international organization such as IMO and developed countries are seeking to develop various reduction strategies against air pollution. However Korea has recently conducted several studies concerning air pollution in port industry. The main purpose of the paper is to suggest emission reduction strategies for bulk terminal in Port of Incheon, which handles large amount bulk cargoes as a gateway for the metropolitan area. For this aim, the clean air strategies of the world major ports were considered and air pollution reduction strategies were suggested. The main findings of this paper are as follows. First, the emission reduction strategies for container terminal are should be integrated based on technologies changes, operational changes and market-based measures. Second, the emission reduction strategies for bulk terminal can be effective when use innovative measures during loading, unloading and storage process such as telescopic cascade trimming chute, snake sandwich equipment, dry fog system and dome structure. Finally, investigation on actual conditions of air pollution in Korean ports and development of environmental evaluation scheme for persisting monitoring should be conducted.

• Fire Science and Engineering
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• v.34 no.4
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• pp.52-58
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• 2020

The number of medical welfare facilities caring for the elderly with paralysis and dementia has been increasing rapidly because of the change in the way of supporting the elderly, stemming from an increase in the number of the elderly and working couples. These medical welfare facilities are usually installed all over the city and are gradually becoming high-rise. Few inmates are capable of making their own decisions in case of fire at night and when there are no escape routes such as ramps for evacuation, leading to massive casualties. This study aimed to identify problems in evacuation in the medical welfare facilities for the elderly in Goyang city. This city has the largest number of medical welfare facilities for the elderly per unit area. The following strategies could aid in better evacuation: secure ramps or bed escape elevators; the bedrooms of the inmates should have one-hour fire resistance; the stairs should have the structure of an enclosed stairway; the necessary apparatus for evacuation, such as an escape chute, should be installed; and, to conclude, a business agreement with neighboring agencies to help inmates escape during the fire. The state should implement necessary measures to protect the lives and property of the people. Rapid implementation of this proposal is necessary for the evacuation safety of an increasing number of medical welfare facilities for the elderly.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3370-3377
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• 2015

FMECA(Failure Mode, Effects and Criticality Analysis) techniques to make quantitative evaluation of failure effects severity and criticality have been applied to systematic failure analysis for reliability improvement of train which should provide regular service and secure high level of safety as a mass transportation system. These FMECA techniques do not fully reflect the inherent train operation and maintenance circumstances because they are based on the FMECA standards devised for other industries such as automobile industry and FMECA standard dedicated to train industry has not been established yet. This paper analyzes FMECA standards for various industries, and suggests a FMECA technique dedicated to train industry which makes failure effect analysis and criticality analysis step by step and makes criticality analysis placing emphasis on the severity of the failure effect. The proposed technique is applied to FMECA of high-speed current breaker which is a core safety device of train using field failure data for 15 years of train maintenance. The FMECA results show that breakage of arc chute has the highest risk with 3rd severity class and 5th criticality class among all the components of high-speed circuit breaker. Damage and poor contact of electronic valve, and cylinder breakage with 3rd severity class and 4th criticality class are followed by. These results can be applied to improvement of design and maintenance process for high-speed circuit breaker of train.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.1
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• pp.2206-2217
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• 1971

Spillway and discharge channel of reservoirs require the Control of Large volume of water under high pressure. The energies at the downstream end of spillway or discharge channel are tremendous. Therefore, Some means of expending the energy of the high-velocity flow is required to prevent scour of the riverbed, minimize erosion, and prevent undermining structures or dam it self. This may be accomplished by Constructing an energy dissipator at the downstream end of spillway or discharge channel disigned to dissipated the excessive energy and establish safe flow Condition in the outlet channel. There are many types of energy dissipators, stilling basins are the most familar energy dissipator. In the stilling basin, most energies are dissipated by hydraulic jump. stilling basins have some length to cover hydraulic jump length. So stilling basins require much concrete works and high construction cost. Flip bucket type energy dissipators require less construction cost. If the streambed is composed of firm rock and it is certain that the scour will not progress upstream to the extent that the safety of the structure might be endangered, flip backet type energy dissipators are the most recommendable one. Following items are tested and studied with bucket radius, $R=7h_2$,(medium of $4h_2{\geqq}R{\geqq}10h_2$). 1. Allowable upstream channel slop of bucket. 2. Adequate bucket lip angle for good performance of flip bucket. Also followings are reviwed. 1. Scour by jet flow. 2. Negative pressure distribution and air movement below nappe flow. From the test and study, following results were obtained. 1. Upstream channel slope of bucket (S=H/L) should be 0.25<H/L<0.75 for good performance of flip bucket. 2. Adequated lip angle $30^{\circ}{\sim}40^{\circ}$ are more reliable than $20^{\circ}{\sim}30^{\circ}$ for the safety of structures.