• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.2
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• pp.179-192
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• 2019

Additional frequencies are allocated in maritime digital data exchange to alleviate overload of the VHF data link. The shipborne ad-hoc network (SANET) for this frequencies was subsequently proposed, which provides various IP-based services to ships on behalf of satellite communications. In SANET, a ship should determine its own IP address to achieve IP connectivity to the shore. Accordingly, this paper proposes a SANET configuration (SANETconf) protocol as an IP configuration protocol. SANETconf propagates non-overlapping IP addresses across the network from the shore to ships. A ship obtains its IP address by exchanging Request and Response messages with its neighbors. Therefore, SANETconf eliminates the process of DAD and managing the movement of ships. Extensive simulations were performed to verify the applicability of SANETconf. Based on results, 85% of the ships can determine their own IP address within one frame. Also, SANETconf has a high resource efficiency by using 0.024 percent of resources for IP configuration.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.520-529
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• 2019

This paper has made an empirical research on airline staff working at Incheon international airport, who perceived safety culture in their organization and delivered safety information while the staff were providing service against passengers. The purpose of this paper was to analyze the relationship among safety culture, service quality and service provider efficacy to find out which factor of safety culture had a significant effect on both service quality and service provider efficacy. Following the results from empirical research, this paper would provide administrative implications which could be applied to improve airline's service quality and to manage effectively the airline staff at field. According to research, it was found fairness culture among safety cultures had a positive and significant effect on both service quality and service provider efficacy. However, reporting/studying culture had a negative effect on them. In other words, it would decrease airline service quality and prevent active service provider's efficacy at airport if a airline management focused reporting/studying culture of safety. It is important to settle down fairness culture of safety to motivate and improve service quality.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.483-488
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• 2019

This study first examines whether the high matching principle reduces the cost of equity, and then examines the effect on discretionary accruals and capital cost. According to previous studies, the higher the response to revenue cost, the higher the earnings quality. The higher the quality of earnings, the lower the information risk, and the lower the information risk, the lower the capital cost of enterprise. Discretionary accruals can play two roles in opposing each other. One is that managers use the discretionary accruals to provide private information about the future of the corporation to the market, thus enhancing the usefulness of the earnings. The other is that managers can use the discretionary accruals opportunistically to distort earnings and provide misinformed information to investors, thus reducing the usefulness of earnings. The results of this study represents that the higher the responding to the revenue cost, the less the cost of equity. In the case of firms with high revenue response, we examine whether discretionary accruals reduce the cost of equity capital. As a result of the study, the higher the responding to the revenue cost, the lower the cost of equity capital. Companies with higher matching principle have been shown to reduce their capital costs by using discretionary accruals.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.187-192
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• 2019

Hybrid power storage system with emergency power function for demand management and power outage minimizes the investment cost in the building of buildings and factories requiring emergency power generation facilities, We propose a new business model by developing technology that can secure economical efficiency by reducing power cost at all times. Normally, system power is supplied to load through STS (Static Transfer Switch), and PCS is connected to system in parallel to perform demand management. In order to efficiently operate the electric power through demand forecasting, the EMS issues a charge / discharge command to the ESS as a PMS (Power Management System), and the PMS transmits the command to the PCS controller to operate the system. During the power outage, the STS is rapidly disengaged from the system, and the PCS becomes an independent power supply and can supply constant voltage / constant frequency power to the load side. Therefore, it is possible to secure reliability through verification of actual system linkage and independent operation performance of hybrid ESS, By enabling low-carbon green growth technology to operate in conjunction with an efficient grid, it is possible to improve irregular power quality and contribute to peak load by generating renewable energy through ESS linkage. In addition, the ESS is replacing the frequency follow-up reserve, which is currently under the charge of coal-fired power generation, and thus it is anticipated that the operation cost of the LNG generator with high fuel cost can be reduced.

• Journal of Wetlands Research
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• v.24 no.4
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• pp.213-223
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• 2022

This study was conducted to establish a Habitat Suitability index (HSI) based on literature research and field surveys on ecology and habitat of 'Hynobius leechii'. And this study will be used as basic data for qualitative evaluation of habitat environment. The survey sites were divided into natural habitats close to the prototype habitat and artificial restoration areas where Hynobius leechii was monitored. So the types of habitats were diversified. Hynobius leechii is a vulnerable species to climate change because it is affected by the microhabitat and has low mobility. HSI variables of Hynobius leechii were extracted through domestic and overseas literature, and standards were extracted from literature research and field survey. The standards were presented as a value of the physical allowable category in consideration of realization. To verify the study, an in-depth consultation was conducted by amphibians experts. HSI variables of Hynobius leechii were included 9 variables such as Overstory canopy cover(%), Understory cover(%), Water-pH, Soil-pH, Soil relative humidity(%), Leaf litter depth(cm), Rock substrates (%), Type of Coarse woody, Distance from Street or Pollutant(m).

• Journal of Korean Society of Forest Science
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• v.100 no.3
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• pp.466-475
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• 2011

This study purposed to analyze the spatial pattern and the amount of carbon emission at the deforestation area based on the administrative and GIS data. The total size of deforestation area in last nine years (2000-2008) was about 649 ha, and it was occurred annually about 72 ha. The occurrence rate of deforestation per administrative area in Wonju was about 0.74%. It was 0.34% higher than that of Kwangwondo, and 0.06% less than that of National rate. On the other hand, the forms of deforestation by purpose were not related to the administrative district unit. The number of deforestation forms was highest at settlements. second most frequent form is other land. Grassland showed the lowest score. In addition, the deforestations were more occurred which is closed to the existing housing and building rather than roads. The number of deforestation was 1.2 times higher based on 300m. Seventy percent of deforestation was occurred which is less than 0.5 ha in size, and it increased to 91% when the size is less than 1ha. The total size of theoretical carbon emission based on deforestation area was estimated at 23,424 tc, and average annual carbon emission was estimated by 2,603 tc. Carbon emission per ha was 36.1 tC/ha. This study results will be useful to construct the greenhouse gas statistical verification system against the Post-2012 by GIS.

• Smart Media Journal
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• v.9 no.4
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• pp.66-72
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• 2020

As the online education market expands, educational contents with various presentation methods are being developed and released. In addition, it is imperative to develop content that reflects the usability and user environment of users who use this educational content. However, for qualitative growth of contents that will support quantitative expansion of markets, existing model analysis methods are urgently needed at a time when development direction of newly developed contents is secured. In this process of content development, a typical model for setting development goals is needed, as the rules of the prototype affect the entire development process and the final development outcome. It can also provide a positive benefit that screens the issue of performance dualization between processes due to the absence of communication between a single entity or between a number of entities. In the case of AR-based educational content which is effective to secure data necessary for development by securing samples of similar categories because there are not enough ready-made samples released. Therefore, a big data statistical analysis service is needed that can easily collect data and make decisions using big data. In this paper, we would like to design analysis services that enable the selection and detection of intuitive multidimensional factors and attributes, and propose big data-based statistical analysis services that can assist cooperative activities within an organization or among many companies.

• Journal of the Korea Society for Simulation
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• v.30 no.1
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• pp.113-126
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• 2021

The future energy consumption pattern will show a very different pattern from the present due to the increase of distributed power sources such as renewable energy and the birth of the concept of prosumers, etc. Accordingly, it can be predicted that the direction of establishment of an appropriate production and supply plan considering the stability and consumption efficiency of the entire power grid will also be different from now. This paper proposes a simulation model that can test a new operational strategy when faced with a number of possible future environments. Through the proposed model, it is possible to simulate and analyze power consumed and supplied in a future Smart Grid environment, in which a large amount of new concepts including energy storage service (ESS) and distributed energy resources (DER) will be added. In particular, it is possible to model complex systems structurally by using DEVS formalism among the ABM (Agent-Based Model) methodologies that can model decision-making for each agent existing in the grid, and several factors can be easily added to the grid. The simulation model was verified using given dataset in the current situation, and scenario analysis was performed by simply adding an ESS, one of the main elements of the smart grid, to the model.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.1
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• pp.49-57
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• 2022

In order to efficiently analysis the stability of a slope, measuring the shear strength of soil is needed. The Standard Penetration Test (SPT) is not appropriate for a slope inspection due to cost and weights. One of the ways to effectively measure the N-value is the Dynamic Cone Penetration Test (DCPT). This study was performed to develop a minimized multi-function sensors that can easily estimate CPT values and Volumetric Water Content. N value with multi-fuction sensor DCPT showed -2.5 ~ +3.9% error compared with the SPT N value (reference value) in the field tests. Also, the developed multi-fuction sensor system was tested the correlation between the CPT test and the portable tester with indoor test. The test result showed 0.85 R2 value in soil, 0.83 in weathered soil, and 0.98 in mixed soil. As a result of the field test, the multi-function sensor shows the excellent field applicability of the proposed sensor system. After further research, it is expected that the portable multi-function sensor will be useful for general slope inspection.

• Microbiology and Biotechnology Letters
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• v.50 no.2
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• pp.301-309
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• 2022

Helicobacter pylori (H. pylori) establishes infection in the human gastric mucosa for a long time and causes severe gastric diseases such as peptic ulcer and gastric cancer. When H. pylori is exposed to the antibacterial agents or inhibitors, the expression of pathogenic associated genes could be altered. In this study, we analyzed the transcriptional changes of H. pylori genes induced by zerumbone treatment. RNA expression changes were analyzed using next-generation sequencing (NGS), and then reverse transcription-polymerase chain reaction (RT-PCR) was performed to verify the results. As a result of NGS analysis, a total of 23 out of 1,632 genes were differentially expressed by zerumbone treatment. RT-PCR confirmed that zerumbone treatment regulated the expression level of 14 genes. Among the genes associated with DNA replication, transcription, virulence factors and T4SS components, 10 genes (dnaE, dnaQ, rpoA, rpoD, secA, flgE, flhA, virB5, virB8 and virB9) were significantly down-regulated and 4 genes (flaA, flaB, virB4 and virD4) were up-regulated. The results of our current study imply that zerumbone might be a potential therapeutic agent for H. pylori infection by regulating factors related to various H. pylori pathogenicity.