• Journal of Korea Water Resources Association
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• v.41 no.10
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• pp.1045-1058
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• 2008

Drought is a natural phenomena caused by long time lack of precipitation causing varying damages in several regions which increases yearly. Specifically, in 1994$\sim$1995 and 2001 severe drought occurred in almost every region of Korea. Small and medium sized water supply reservoirs exposed their bottoms and also raised considerable economic losses. In spite of this fact, damages and impacts from the drought can still be minimized by well defined drought management plans with optimal management of water supply facilities. Throughout this research, integrated drought information system is proposed to used in monitoring the drought of Korea in real time. And the expert system for the management of water supply facilities has developed using Shared Vision Model (SVM) to enable the Virtual Drought Exercise (VDE). To find a better way to manage water during drought and to develop the enhanced abilities to respond to drought, virtual drought exercise is the most effective approach and process. The proposed process of virtual drought exercise using integrated drought information system can be used as an effective tool to prepare the optimal water supply plans during the drought.

• Journal of Korean Society of Transportation
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• v.31 no.1
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• pp.37-46
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• 2013

Lane closure in freeway work zone due to maintenance and repair of freeway facilities results in abrupt change of traffic flow. Sudden change of traffic flow results strong interactions among vehicles, and reduces capacity compared to the ordinary traffic condition. Such capacity reduction is likely to cause congestion, traffic queues, and economic loss cost. This study aims to determine the base capacity for a short-term freeway work zone that can be used to establish a work zone schedule in advance without any traffic impact. First, the research collected detector data and schedule data of road works on all freeways in Korea. Second, the research determined 23 study sites finding the capacity values of work zone after matching two kinds of data. All study sites had varying characteristics regarding traffic flow being adjacent to work zone during road works. The capacity values were reviewed in terms of lane closure configuration, the types of work, and design speed. Finally, research proposed capacity values for a short-term freeway work zone with the design speeds of 100 kph, 120 kph and 1,700 pcphpl, 1,750 pcphpl, respectively.

• Journal of Korean Society of Transportation
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• v.34 no.4
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• pp.318-329
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• 2016

There has been a growing interest on the effect of volcanic eruption on the aviation safety, air travel and economy especially after the eruption of Eyjafjallajokull in Iceland. Since volcanic eruption is influential on a large geographic region, the effect usually extends to other neighboring countries. Korea also has an active volcano named Mountain Baekdu. Hence, the need to estimate in advance the quantitative impact of the potential eruption of Mt. Baekdu on South Korean air transportation system. However, previous studies with quantitative estimation were confined to the calculation of the direct economic loss from shut down of the airports, grounding of airlines, and trade deficits caused by the eruption. Therefore, this paper introduces a new approach to assess more accurate impact simultaneously considering volcanic ash dispersal and aviation routes. This approach is then applied to a virtual scenario to predict the damage to air traffic. With further development, this method can help estimate the damage in the air transportation industry in more accurate and faster ways. Prediction outcomes can also be utilized in setting up the emergency response plan for the air transportation industry and contribute to the creation of more proactive and predictive measures in the future.

• Korean Journal of Microbiology
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• v.54 no.3
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• pp.254-265
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• 2018

Avian influenza recently damaged the poultry industry, which suffered a huge economic loss reaching billions of U.S. dollars in South Korea. Transmission routes of the pathogens would help plan to control and limit the spread of the devastating biological tragedy. Phylogenetic analyses of pathogen's DNA sequences could sketch transmission trees relating hosts with directed edges. The last decade has seen the methodological development of inferring transmission trees using epidemiological as well as genetic data. Here, I reanalyzed the DNA sequence data that had originated in the highly pathogenic avian influenza H5N8 outbreak of South Korea in 2014. The H5N8 viruses spread geographically contiguously from the origin of the outbreak, Jeonbuk. The Jeonbuk origin viruses were known to spread to four provinces neighboring Jeonbuk. I estimated the transmission tree of the host domestic and migratory wild birds after combining multiple runs of Markov chain Monte Carlo using a Bayesian method for inferring transmission trees. The estimated transmission tree, albeit with a rather large uncertainty in the directed edges, showed that the viruses spread from Jeonbuk through Chungnam to Gyeonggi. Domestic birds of breeder or broiler ducks were estimated to appear to be at the terminal nodes of the transmission tree. This observation confirmed that migratory wild birds played an important role as one of the main infection mediators in the avian influenza H5N8 outbreak of South Korea in 2014.

• Pediatric Infection and Vaccine
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• v.9 no.1
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• pp.74-78
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• 2002

Purpose : Proper diagnosis of group A streptococcal pharyngitis that may cause chronic diseases in childhood is not easy because its signs and symptoms would be nonspecific. Because results of classical throat culture delays for one to two days, we'd like to determine whether early antibiotics would be introduced with according to the clinical score system. This study was undertaken to evaluate of clinical usefulness of scoring system based on the clinical and laboratory findings. Methods : From Jan. 1998 to Dec. 2000, 10 clinical items based on modified 9 items by Breese in 1977 were checked in patients with pharyngitis who visited on outpatients clinic of pediatrics, Kyunghee University Hospital. We compared the results of throat culture with the points of clinical score system. Results : Out of 45 cases, the positive culture for Group A Streptococcus was 20 and negative culture was 25. When we applied more than 30 points of score, which correspond to 70 percentile of study population, the sensitivity and specificity were 35.0% and 96.0%, respectively. Conclusion : Although sensitivity was relatively low this scoring system, but the high specificity may be useful diagnostic tool in the areas where the rate of isolation of Group A Streptococcus is low.

• Korean Journal of Organic Agriculture
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• v.23 no.3
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• pp.567-582
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• 2015

Botrytis cinerea infects stems, leaves and fruits of greenhouse tomato and can cause serious economic losses. This study was conducted to develop organic farming control method against tomato gray mold. Twenty two organic farming materials including mineral and plant extracts were screened for the suppressive activity against Botrytis cinerea, in vitro and in vivo. Among the organic farming materials, sulfur, copper, Chinese twinleaf extract and rhubarb extract decreased by 51.7-90% of the spore germination of Botrytis cinerea. Also, gray mold incidence was reduced more than 90% on tomato stems by treating sulfur, seaweed extracts, rhubarb root extracts and Chinese twinleaf extract. After the selected four organic farming materials were applied on tomato cultivated in greenhouse, their control effects against the tomato gray mold were tested. When the water soluble sulfur was foliar-sprayed on the tomato leaves infected by artificial inoculation with spore suspension of Botrytis cinerea, it showed 87.9% of control value. Also, control activity of the water soluble sulfur was paralleled with chemical fungicide, diethofencarb+carbendazim. The above mentioned results indicate the sulfur formulation can be used as chemical fungicide alternatives for controlling tomato gray mold in the greenhouse.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.1
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• pp.27-39
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• 2008

Landslides cause enormous economic losses and casualties. Korea has mountainous regions and heavy slopes in most parts of the land and has consistently built new roads and large-scale housing complexes according to its industrial and urban growth. As a result, the damage from landslides becomes greater every year. In summer, landslides frequently occur due to local torrential rains and storms. It is critical to predict the potential areas of landslides in advance and to take preventive measures to minimize consequences and to protect property and human life. The previous study on landslides mostly focused on identifying the causes of landslides in the areas where they occurred, and on analyzing landslide vulnerability around the areas without considering rainfall conditions. Thus there were not enough evaluations of the direct risk of landslides to human life. In this study, potentially risky areas for landslides were identified using the GIS data in order to evaluate direct risk on farmlands, roads, and artificial structures that were closely connected to human life. A map of landslide risk was made taking into account rainfall conditions, and a land use map was also drawn with satellite images and digital maps. Both maps were used to identify potentially risky areas for landslides.

• Journal of fish pathology
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• v.26 no.3
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• pp.193-206
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• 2013

The ark shell, Scapharca broughtonii is a marine bivalve mollusks belonging to the family Arcidae and important seafood for Korean and Japanese, and southern coast is brisk bays for the ark shell aquaculture. However, productivity of ark shell from these regions were rapidly reduced during the last decade due to mass mortality. The reason of this great damage has not yet been identified. To overcome this economic loss, diverse investigations were focused on environmental factors that affects in the physiology of S. broughtonii, but microbiological researches were performed insufficiently. Hemoglobin is one of the major blood component of ark shell and is damaged by some species of bacterial toxins. We concentrated on this red pigment because hemolysis could be the cause of ark shell mortality. In this study, we analyzed microbial diversity of underwater sediments in coastal regions and also existences in the body of S. broughtonii. We investigate about 4,200 isolates collected from June to September for microbial diversity of sediments and ark shell. We screened all of culturable microorganisms, and identified 25 genera 118 species, 24 genera 89 species, 30 genera 109 species and 39 genera 141 species, and selected 140 unique colonies for identification and challenge assay.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.4
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• pp.15-22
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• 2003

Seismic design codes developed taking into account the strong earthquakes may result in unnecessary economical loss in the low seismic area, and the importance of the performance based design considering the soil-structure interaction is recognized for the reasonable seismic design. In this study. elastic and inelastic seismic response analyses of a single degree of freedom system on the soft soil layer were performed considering the nonlinearity of the soil for the 1 weak earthquakes scaled to the nominal peak accelerations of 0.07g and 0.11g. The seismic response analyses were performed in one step applying the earthquake motions to the bedrock, utilizing a pseudo 3-D dynamic analysis software of the soil-structure system. The study results indicated that seismic response spectra of a system assuming the rigid base or the linear soil layer does not represent the true behavior of a structure-soil system, and it is necessary to take into account the nonlinear soil-structure interaction effects and to perform the performance based seismic design for the various soil layers, having different characteristics, rather than to follow the routine design procedures specified in the design codes for the reasonable seismic design. The nonlinearity of the soft soil excited with the weak seismic motions also affected significantly on the elastic and inelastic seismic response spectra of a system due to the nonlinear soil amplification of the earthquake motions, and it was pronounced especially for the elastic response spectra.

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.1
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• pp.147-155
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• 2015

The existing field survey and aerial photography involve the waste of manpower and economic loss in the coastline survey. To minimize these disadvantages, the digitization for efficient coastline extraction was conducted in this study using the points extracted from the standard coastline of the approximate highest high water and the diverse satellite images (KOMPSAT-3, SPOT-5, Landsat-8 and Quickbird-2), and the comparative accuracy analysis was conducted. The differences between the standard coastline points of the approximate highest high water and the coastline of each satellite were smallest for KOMPSAT-3, followed by Quickbird-2, SPOT-5 and Landsat-8. The significant probability from between the multipurpose applications satellite and Quickbird-2 (significant probability two-tailed) was statistically significant at 1% significance level. Therefore, high-resolution satellite images are required to efficiently extract the coastline, and KOMPSAT-3, from which images are easily acquired at a low cost, will enable the most efficient coastline extraction without external support.