• Korean Journal of Plant Resources
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• v.20 no.5
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• pp.424-436
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• 2007

In this paper, it was discussed situations and necessities of conservation management strategy for the woody plants resources in Jeju Island. Out of 320 taxa of the woody plants distributed in Jeju, there were 62 families, 136 genus, 279 species, 28 varieties and 13 forma. Conifers, gymnosperms, were 3 families, 5 genus and 7 species as holding 2.2% of total woody plants. Broad leaves, angiosperms, were 59 families, 131 genus, 272 species, 28 varieties and 13 forma that were 313 taxa. Evergreens were 84 taxa consisting of 31 families, 45 genus, 72 species, 7 varieties and 5 forma that make up 26.8% out of total angiosperms. Deciduous were 229 taxa(73.2%) consisting of 42 families, 93 genus, 200 species, 21 varieties and 8 forma that were 122 trees(38.1%), 177 shrubs(55.1%) and 21 vine plants(6.8%). Life form spectra by dormancy, disseminule, radicoid and growth form were analysed. Thirty eight taxa including 17 families, 21 genus, 14 species and 16 varieties out of 320 taxa growing Jeju were endemic to Korea and 22 taxa of them were endemic to Jeju. The specific plant species among the woody plants in Jeju were 10 taxa in V grade, 24 taxa in IV grade and 53 taxa in III grade. These are correspondence to those of nations as 12% of V grade, 7.6% of IV grade and 17.2% of III grade.

• Ecology and Resilient Infrastructure
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• v.8 no.4
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• pp.165-178
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• 2021

We studied driftwood behaviors including generation and deposition in a tsunami using a numerical simulation. We used an integrated two-dimensional numerical model, which included a driftwood dynamics model. The study area was Sendai, Japan. Observation data collected by Inagaki et al. (2012) were used to verify the simulation results by comparing them with driftwood deposition patterns. A simplified model was developed to consider the threshold of driftwood generation by the drag force of water flows. To consider the volume of driftwood generated, we estimated the total wood number in the study area using Google Earth. Therefore, we simulated more than 13,000 pieces of driftwood that were generated and transported inland from approximately 300,000 trees that were growing in the forest. The final distribution of the driftwood was similar to the observation data. The reproducibility of the generation and deposition patterns of driftwood showed good agreement in terms of longitudinal deposition pattern. In the future, a sensitivity analysis on driftwood parameters, such as the size of the wood, boundary conditions, and grid size, will be implemented to predict the travel patterns of driftwood. Such modeling will be a useful methodology for disaster prediction based on water flow and driftwood.

• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.437-445
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• 2018

IMO (International Maritime Organization) has been strengthening the regulations of ship emission gas such as sulfur oxides (SOX), nitrogen oxides (NOX) and carbon dioxides (CO2) to protect the marine environment. Especially, ECA (Emission Control Area) has been set and operated in the USA and US. As a countermeasure against these environmental regulations, the demand for environmentally, friendly and highly efficient vessels has led to a growing interest in technology related research with respect to electric propulsion systems capable of reducing exhaust gas. Container ships were excluded from the application coverage of the electric propulsion systems for reasons of operation at economical speed. However, in the future, the need for electric propulsion system is expected to rise, because it is easy to monitor and control so that it can be an applicate to smart ship which are represented by fourth industrial revolution technology. In this study, research was carried out to design a generator and battery capacity through the load analysis of the 6,800TEU container ship to apply the electric propulsion system of the container ship. A capacity design based on the load analysis has an advantage that the generator can be operated in a high efficiency section through the load distribution control using the battery.

• Korean Journal of Plant Resources
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• v.32 no.1
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• pp.45-52
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• 2019

In the process of adapting climate change, the government needs to provide policy and technical support necessary for growing promising crops imported from abroad. Therefore, this study was conducted to survey and analyze the conditions of growth of imported foreign crops and to derive response tasks. As a result, tropical and subtropical vegetables were cultivated 18 crops in 920 farms in 321 ha area (in 2015 year). The cultivation scale decreased in the order of Curcuma aromatica, Momordica charantia, Asparagus aethiopicus, Allium hookeri and Herbs. Tropical and subtropical fruits were cultivated 9 crops in 264 farms in 106.5 ha area (in 2015 year). Special and medicinal crops introduced abroad cultivated 10 crops in 753 farms in 276.3 ha area (in 2015 year). The cultivation scale decreased in the order of Curcuma longa, Glycyrrhiza uralensis, Lepidium meyenii and Moringa oleifera. For the stable settlement of domestic growth of tropical and subtropical crops introduced abroad, there should be safety and economic feasibility in terms of the cultivation environment according to the domestic culture adaptation test. Consideration needs to be given to the use of locally grown products in Korea, the securing of distribution and sales markets, and the competitiveness of imported products.

• The Journal of the Korea Contents Association
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• v.19 no.8
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• pp.115-122
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• 2019

The companion animal related businesses are rapidly growing as the pet population increases in Korea. In this study, we analyzed the market trends of companion animal food and products to offer basic information that can be used in related policies and industries. The data were collected using Nielsen Korea's wholesale/retail distribution channels. As a result, in the case of companion dog food, PB products of domestic companies showed the highest market share with 24.6%, and the ratio of domestic companies(54.8%) was higher than that of import companies(45.2%). Domestic PB products also had the highest market share(16.5%) in companion cat food, however, the ratio of import companies(71.6%) was higher than that of domestic companies(28.4%). In the case of the market share of the companion animal products(toys, oral and bath supplies), Nosework mats from domestic companies were top ranked in the toy category(28.0%). Oral products(62.5%) and bath products(59.5%) from domestic companies were also having a higher market share than import companies. Our research may help domestic companion animal product companies to steadily increase market share and the amount of their export.

• Journal of the Korean Regional Science Association
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• v.35 no.2
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• pp.19-31
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• 2019

There have been a growing number of studies that show huge discrepancies between individuals' perceptions of relative economic position and the economic position based on the reported income in the survey. If this is the case, it is expected that the impact of perceived income status on individual happiness can be different from that of objective income status based on the reported income. The aim of this study is to investigate the factors affecting the discrepancies between perception and reality with respect to relative income status, focusing on the 'Reference group theory'. This study also tries to extend existing knowledge of the relative status on the happiness level of individuals, by examining how individual's happiness can be changed by providing the accurate information about their objective income level. There are systematic biases in perceived income status. A majority of people who actually rank in the lower part of income ladder place themselves in higher positions, while a significant portion of rich individuals underestimate their actual income status. Secondly, the misperception about the income distribution is affected by a variety of individual, household characteristics and reference group income. Thirdly, providing individuals with accurate information has a considerable effect on their happiness level.

• Sleep Medicine and Psychophysiology
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• v.25 no.2
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• pp.82-91
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• 2018

Objectives: Synchronous electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) has been used to explore sleep stage dependent functional brain networks. Despite a growing number of sleep studies using EEG-fMRI, few studies have conducted network analysis on whole night sleep due to difficulty in data acquisition, artifacts, and sleep management within the MRI scanner. Methods: In order to perform network analysis for whole night sleep, we proposed experimental procedures and data processing techniques for EEG-fMRI. We acquired 6-7 hours of EEG-fMRI data per participant and conducted signal processing to reduce artifacts in both EEG and fMRI. We then generated a functional brain atlas with 68 brain regions using independent component analysis of sleep fMRI data. Using this functional atlas, we constructed sleep level dependent functional brain networks. Results: When we evaluated functional connectivity distribution, sleep showed significantly reduced functional connectivity for the whole brain compared to that during wakefulness. REM sleep showed statistically different connectivity patterns compared to non-REM sleep in sleep-related subcortical brain circuits. Conclusion: This study suggests the feasibility of exploring functional brain networks using sleep EEG-fMRI for whole night sleep via appropriate experimental procedures and signal processing techniques for fMRI and EEG.

• Journal of the HCI Society of Korea
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• v.14 no.2
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• pp.31-39
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• 2019

This research examined the changes that fast-growing voice-based devices would bring in the media multitasking environment. Based on the theoretical background that information processing efficiency improves when performing multiple tasks requiring different resource structures at the same time, we conducted an experiment where participants searched for information with voice-based or screen-based devices while performing an additional visual task. Results showed that both task performance environment and interface modality had significant main effects on cognitive load. The overall cognitive load level was higher in the voice interface group, but the difference in cognitive load between the two groups decreased in a multitasking environment where the additional visual resources was required. The visual task performance was significantly higher when using the voice interface than the screen interface. Our findings suggest that voice interfaces offered advantages in the cognitive load and task performance by distributing two tasks to the auditory and visual channels. The results of this study imply that voice-based devices have the potential to facilitate efficient information processing in the screen-centric environment where visual resources collide. We provided theoretical evidence of resource distribution using multiple resource theory and tried to identify the advantages of the voice interface more specifically based on the threaded cognition model.

• The Journal of the Korea Contents Association
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• v.20 no.12
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• pp.492-497
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• 2020

Today, banks around the world are making great efforts to adapt to the rapidly changing internal and external environment changes caused by the development of IT technology and to gain a competitive advantage in the market. In particular, in line with the rapid growth of smartphone usage, financial services are also provided in a variety of ways using Fintech, and one of the fastest growing areas is mobile simple payment. Mobile payment service is a financial service that pays the purchase price using a portable mobile device. As fintech, a convergence of financial services and information technology, it is recently used not only in financial services, but also in various industries. It is used in all fields where payment functions such as distribution are available. In the case of mobile cards, it shows that the usage rate of people in their 20s and 30s is increasing very much, so it can be said that the use of mobile payment services will continue to increase in the coming future. We know that simple payments are being used. However, it can be said that the research on the use of mobile payment services by these teenagers is somewhat incomplete. Therefore, this study investigated what factors are important for Korean teenagers to use mobile payment services. As a result, among the five hypotheses presented in this study, all hypotheses were adopted except for , which states that cash usage habits have no effect on innovation.

• Research in Plant Disease
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• v.28 no.1
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• pp.39-45
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• 2022

Patterns of occurrence of tomato yellow leaf curl virus (TYLCV) and tomato chlorosis virus (ToCV) with whitefly on summer-cultivated tomato in Gwangju-si, Gyeonggi Province were surveyed using multiplex reverse transcription-polymerase chain reaction in 2020. In addition, distribution of the whiteflies species and their viral transmission rates were investigated throughout the tomato growing season. The infection rates of TYLCV and ToCV increased sharply during harvest, and the single infection rates were 30.9% and 5.0%, respectively, with a mixed infection rate of the two viruses being the highest at 52.2%. Single infection with TYLCV and double infections with TYLCV and ToCV accounted for the majority with 83.1%. Bemisia tabaci were dominant over Trialeurodes vaporariorum in greenhouse grown plants, and all of the investigated B. tabaci biotypes were identified as Mediterranean (MED, formerly known as Q biotype). The transmission rate of TYLCV, detected in every sampled B. tabaci MED population, was 21.4%, and the mixed transmission rate with ToCV was 35.5%. Viruliferous MED whiteflies with ToCV showed a higher rate than that of T. vaporariorum. In the transplant stage, viruliferous rate of both TYLCV and ToCV of B. tabaci was 42.7%; this rate was highest in the harvest stage. In examination of tomato yield, the increase in the mixed infection rate of TYLCV and ToCV led to complete yield loss. When the mixed infection rate increased by 10%, the yield decreased by 405.4 kg/10a.