• Weed & Turfgrass Science
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• v.3 no.2
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• pp.121-129
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• 2014

We investigated turfgrass diseases and inoculum density at nationwide turfgrass cultivation sites in year of 2013. Occurrences of large patch and rust disease appeared in September. Brown patch recorded in September to October at Namhea and Pythium blight disease occurred outbreaks in early July at Namhea site. Some sites in Namhea damaged 3% area of total cultivation field by Sclerotinia homoeocarp. In Daepyeong (Gyeongnam), Fairy ring and large patch were recorded. Severe takeall and fairy ring have been observed in Gochang-si. Multi-site in Cheongju-si, brown patch was observed in pandemic level. Interesting enough, a cool-season turfgrass cultivate sites in Pyeongtaek-si brown patch, leaf blast, summer patch, and Curvularia leaf spot were investigated during the surveys period. Inoculum densities (Rhizoctonia spp.) at turfgrass cultivations sites were increased as cumulatively in all survey sites. The investigation result indicated that the disease occurrence and pathogens are similar as diseases in golf courses.

• Journal of Digital Convergence
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• v.14 no.2
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• pp.65-72
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• 2016

This study built the theoretical frameworks for empirical analysis based on the analysis of the relationship among the concepts of risk of information privacy, the experience of information privacy, the policy of information privacy and information control via the provision intention studies. Also, in order to analyze the relationship among the factors such as the risk of information privacy, intention to offer the personal information, this study investigated the concepts of information privacy and studies related with the privacy, established a research model about the information privacy. Followings are the results of this study: First, the information privacy risk, information privacy experience, information privacy policy, and information control have positive effects upon the information privacy concern. Second, the information privacy concern has the negative effects upon the provision intention of personal information.

• Journal of Korean Society of Disaster and Security
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• v.15 no.4
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• pp.47-56
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• 2022

Along with high-rise buildings, complex buildings used by many unspecified people, such as various buildings and underground-linked buildings, are increasing. In particular, high-rise buildings are accompanied by a number of casualties and a lot of property damage in the event of a disaster, so reinforced integrated disaster management is necessary. The High-Rise Disaster Management Act stipulates that a general disaster manager is appointed and requires stricter safety management tasks than other buildings. Therefore, this study aims to analyze and present item factors for a preliminary survey of job satisfaction of general disaster managers through literature research and expert verification.

• Journal of Internet Computing and Services
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• v.25 no.1
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• pp.137-146
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• 2024

drones are used in a variety of fields, including business, leisure, lifesaving, and war. Various research using drones is being conducted in the military. In particular, the use of drones in 『Manned-Unmanned Complex combat performance plan』, powered by various unmanned vehicles deployed in the Army TIGER system, is expected to be a major factor realizing the Army's future combat performance that minimizes damage to ally combat troops while causing maximum damage to the enemy. As the deployment of various systems progresses, combat performance methods utilizing each system are evolving, but there is a lack of research to identify and resolve limitations in the perspective of unmanned vehicle operators. Based on the Ukrainian military's FPV drone combat case, we would like to make suggestions from the operator's perspective on overcoming perspective limitations through the introduction of FPV and the designation of military drone frequency.

• Journal of Energy Engineering
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• v.28 no.4
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• pp.29-34
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• 2019

In this study, a quantitative risk assessment was carried out for a hydrogen complex station. The complex fueling station to be evaluated was hydrogen-LPG, and the components of each station were analyzed and the risk was evaluated. The final risk is assessed by individual and societal risks, taking into account the impact of damage and the frequency of accidents. As a result of individual risk calculation for the hydrogen-LPG fueling station that is the subject of this study, the hydrogen-LPG type fueling station does not show the unacceptable hazardous area (> 1 × 10E-3) proposed by HSE. The level of individual risk for both the public and the worker is within acceptable limits. In societal risk assessment, the model to be interpreted shows the distribution of risks in an acceptable range(ALARP, As Low As Reasonably Practicable). To ensure improved safety, we recommend regular inspections and checks for high-risk hydrogen reservoirs, dispensers, tube trailer leaks, and LPG vapor recovery lines.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.151-163
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• 2021

This paper is dealt with railway slope stability for slope reinforcement using a geosynthetic concrete composite mat(GCCM). Recently, according to a change in weather caused by global warming, train operation has been restricted by the loss of backfill slope at the roadbed, which is consists of gravel, due to typhoons and heavy rainfall. In addition, the amount of damage is getting more significant than the cost of restoration, and the safety of workers is worried. In order to improve this limitation, a slope stability analysis was applied with a rapid hardening composite mat so that it can quickly secure a construction surface with increased workability and work stability and reduce maintenance costs by preventing re-loss in case of heavy rain and fundamentally blocking vegetation. As a result of the analysis, it was confirmed that the increase in safety factor was confirmed when the rapid harding composite mat was applied.

• Composites Research
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• v.21 no.2
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• pp.8-14
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• 2008

Decrease of strength in composite material is generally caused by water absorption. It makes fracture of material, and loss of money or human lives. The objective of this study is to investigate the causes of decrease in strength by water absorption. Mechanism of water absorption was supposed as three steps. This mechanism is consisted of absorption into resin, absorption between resin and surface treatment agent, and delamination between fiber and resin. Conditions of test were supplied differently; kinds of fiber and resin, immersion time etc. Both of reversible reaction and irreversible reaction occurred simultaneously. Most of decrease in strength was finished at 2.5% water absorption, and the strength was recovered. At 4% water absorption, most of decrease was caused by irreversible reaction, therefore, there was a tendency not to be recovered in strength.

• Journal of Korean Society of Forest Science
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• v.101 no.1
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• pp.121-129
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• 2012

The edge area with burn severity is known as significant factor that has great effects on the ecosystem recovery. However, there is little study on the edge area and its effects in the South Korea. Thus, this study aimed to analyze immediate responses of vegetation following forest fires due to combined effect of burn severity and edge-interior effect. Burn Severity (BS), or ${\Delta}NBR$ values were computed using satellite images of pre and post-forest fire in Samcheock areas. The burn forest was classified 231 $1-km^2$ girds and these grids were further reclassified into 4 groups by BS type (low BS and high BS areas) and forest areas (edge areas and interior areas). These four groups of grids including low BS-interior (group A), low BS-edge (group B), high BS-interior (group C) and high BS-edge (group D). Post-fire vegetation responses measured with (${\Delta}NDVI$) among four groups were then compared and tested by T-test. The results indicated that group C (${\Delta}NDVI$=0.047) and D (${\Delta}NDVI$ = 0.059) showed considerably greater vegetation regeneration than those of low BS areas including group A (${\Delta}NDVI$ = -0.039) and group B (${\Delta}NDVI$ = -0.036). It was also observed that edges areas showed greater vegetation regeneration than interior areas when BS is the same. Group B (${\Delta}NDVI$ = -0.036) showed greater (${\Delta}NDVI$) values than group A (${\Delta}NDVI$ = -0.039) in low BS condition. Similar relationship is observed between group C and group D in high BS condition. Thus adequate restoration practices for burned areas might need to pay close attention to interior areas with low BS to minimize the secondary damages and to rehabilitate the burned forests.

• Korean journal of applied entomology
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• v.24 no.2 s.63
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• pp.65-70
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• 1985

The locational preference of the brown planthopper (BPH) Nilaparvata lugens ($St{\aa}l$) and the whitebacked plant hopper (WBPH) Sogatella furcifera(Horvath) was studied on rice cultivars IR22 and IR36 as an integral part of subsequent research on insect-fungal pathogen relationships. The BPH was observed to stay consistently on the basal portion while the WBPH showed a general preference for the upper portion regardless of varieties, rice growth stages and insect population density levels. The habitat preference of both species (BPH and WBPH) was found not to be affected by the presence of the other species when both species are present on the same host plant Five rice cultivars with different reactions to BPH biotype 2 were used in the study on BPH-Rhizoctonia solani relationship: IR22 and TN1 (susceptible); Triveni and ASD7 (moderately resistant); and IR42 (resistant). Test plants were inoculated with R. solani (Kuhn) $3{\sim}4$days after insect infestation. Sheath blight disease severity/incidence was significantly higher in the treatment where BPH+R. solani were together than in the treatment with only the pathogen. Symptom expression of the disease in the BPH-pathogen combination was faster and mycelial growth was more profuse inducing the formation of more infection structures. Regardless of varietal reaction to BPH biotype 2, the degree of hopperburn was significantly higher in the combination of the two pests as compared with that of BPH alone. There could be a synergistic relationship between the insect pest and the pathogen indicated by a positive interaction between the two species.

• Korean Journal of Organic Agriculture
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• v.25 no.3
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• pp.587-602
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• 2017

Correlations of soil and leaf nutrients and growth of young 'Enterprise' apple (Malus ${\times}$ domestica Borkh.) trees were analyzed with tree damage, such as Japanese beetle (JB; Popillia japonica Newman)-damaged leaves, vole damage to trunk, tree mortality, and weed density in a certified organic orchard in warm and humid environment of Southern USA. Interaction treatments of four mulch and three fertilizers were applied around trees as follows: mow-and-blow (MB), shredded paper (SP), wood chips (WC), and green compost (GC) as a mulch, with no fertilizer (NF), poultry litter (PL), and commercial organic fertilizer (CF) as a fertilizer applied in April. Vole damage to trunk and weed density were little correlated with mineral nutrients and tree growth. JB-damaged leaves were highly stimulated to 26.5% in GC-treated plots while tree mortality were increased by MB treatments. Biomass production per tree was approximately 3,700 g on the WC- and GC-treated plots, which was two times higher than those values observed on the other two mulch plots. JB-damaged leaves tended to get worse when nutrients in soil and leaf increased through the correlation analysis, with a strong positive relationship ($r^2=0.585$) observed between JB-damaged leaves and trunk cross sectional area, a vegetative indicator. Tree mortality was more negatively associated with nutrient contents and growth of trees than those of soil nutrients. Wood chips was considered for a local organic mulch materials to increase organic matter contents and to produce healthy young trees in Southern USA, with control insect, such as beetle, and vole density in an orchard habitat.