• Journal of the Korean Wood Science and Technology
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• v.32 no.5
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• pp.12-19
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• 2004

This study was performed to investigate the optimum condition of protease production from submerged culture of oak mushroom (Lentinula edodes, Sanlim No. 5) and its enzymatic features. Among several combinations of media, the combination of wheat bran, corn flour, water and corn oil (WB+CF+W+ CO) yielded 84.8 U/g of maximum protease activity. This combination of ingredients, in spite of not being particularly protein-rich in comparison to the other media, allowed for good growth of the fungus and maximal protease production. Comparison of different growth medium liquids indicated that demineralized water afforded the best growth of the fungus and the highest protease activity. Acetate buffer and acidified water negatively affected The protease production peaked around 72 hr of incubation, and decreased thereafter. The molecular weights of produced protease were about 45,000 by Sephadex G-75 chromatography. The pH optimum for protease activity was 4, while maximal activity incubated at 37℃ for 1 hr was observed between pH 4~6. The optimum temperature of this protease was 55℃, and the enzyme was active over a broad temperature range (30~60℃), indicating that this protease would be suitable for a wide range of applications where. different pH and temperature are necessary, such as digestive aids, food industry, beer and tannery industries.

• Journal of Navigation and Port Research
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• v.46 no.6
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• pp.554-561
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• 2022

Technology development related to maritime autonomous surface ships (MASS) is actively progressing around the world. However, since there are still many technically unresolved problems such as communication, cybersecurity, and emergency response capabilities, it is expected that it will take a lot of time for MASS to be commercialized. In this study, we proposed a ship group navigation system in which one leader ship and several follower ship are grouped into one group. In this system, when the leader ship begins to navigate, the follower ship autonomously follows the path of the leader ship. For path following, PD (proportional-derivative) control is applied. In addition, each ship navigates in a straight line shape while maintaining a safe distance to prevent collisions. Speed control was implemented to maintain a safe distance between ships. Simulations were performed to verify the ship group navigation system. The ship used in the simulation is the L-7 model of KVLCC2, which has related data disclosed. And the MMG (Maneuvering Modeling Group) standard method proposed by the Japan Society of Naval Architects and Ocean Engineering (JASNAOE) was used as a model of ship maneuvering motion. As a result of the simulation, the leader ship navigated along a predetermined route, and the follower ship navigated along the leader ship's path. During the simulation, it was found that the three ships maintained a straight line shape and a safe distance between them. The ship group navigation system is expected to be used as a navigation system to solve the problems of MASS.

• Journal of Digital Policy
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• v.1 no.2
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• pp.25-40
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• 2022

This study analysed the effect of inheritance tax on households in reality and to improve it if there is an unreasonable aspect compared to countries around the world. The study conducted a one-on-one face-to-face survey on adults living in major cities across the country for 31 days from 1^st of September to 10^th of October, 2022. The collected data was analysed using SPSS 25.0 version and noted that 1) they preferred the abolition of inheritance tax, but hoped to improve it when maintaining it, 2) it was necessary to expand the deduction limit, abolish spouse deductions, and 3) prefer the inheritance acquisition tax system. Finally, it was found that they wanted to Extension of installment period of inheritance tax and introduce the tax deferred system.. This suggests that there is a perception that the overall revision of the inheritance tax system is necessary to maintain the inheritance tax. The significance of the study is to provide the basis for discussions on the improvement of the inheritance tax system in Korea, which does not reflect reality.

• Korean Journal of Materials Research
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• v.32 no.4
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• pp.200-209
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• 2022

In this study, defects generated in the YSZ coating layer of the IN738LC turbine blade are investigated using an optical microscope and SEM/EDS. The blade YSZ coating layer is composed of a Y-Zr component top coat layer and a Co component bond coat layer. A large amount of Cr/Ni component that diffused from the base is also measured in the bond coat. The blade hot corrosion is concentrated on the surface of the concave part, accompanied by separation of the coating layer due to the concentration of combustion gas collisions here. In the top coating layer of the blade, cracks occur in the vertical and horizontal directions, along with pits in the top coating layer. Combustion gas components such as Na and S are contained inside the pits and cracks, so it is considered that the pits/cracks are caused by the corrosion of the combustion gases. Also, a thermally grown oxide (TGO) layer of several ㎛ thick composed of Al oxide is observed between the top coat and the bond coat, and a similar inner TGO with a thickness of several ㎛ is also observed between the bond coat and the matrix. A PFZ (precipitate free zone) deficient in γ' (Ni₃Al) forms as a band around the TGO, in which the Al component is integrated. Although TGO can resist high temperature corrosion of the top coat, it should also be considered that if its shape is irregular and contains pore defects, it may degrade the blade high temperature creep properties. Compositional and microstructural analysis results for high-temperature corrosion and TGO defects in the blade coating layer used at high temperatures are expected to be applied to sound YSZ coating and blade design technology.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.40 no.2
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• pp.59-66
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• 2022

The purpose of this study was to suggest the landscaping repair work classification, the standard for securing the independence of and establishing the scope of landscaping repair works. Standard construction specifications currently specify the landscaping repair work classification around the planting construction, while standard work estimate does not include the field of landscaping. The landscaping construction specifications and the standard work estimate in the construction industry should be, however, applied, so it is difficult to specifically understand what is the landscaping repair work classification in the cultural heritage industry. From 1961 to 1980, not only the tree planting but also a variety of landscaping facilities had been specified as the landscaping repair works, and it was found that all of these work classifications are established as the landscaping repair work classifications in the construction industry. A total of 20 work classifications were verified by comprehensively arranging those specified in notices of tender for working drawing services for cultural heritages during three years, from 2018 to 2020, except for those for the maintenance and Dancheong of architectures, plant protection and conservation. All 20 work classifications corresponded to the landscaping work classifications in the construction industry. On the basis of the landscaping work classifications in the construction industry, this study divided the landscaping repair work classifications into site-building and shaping, planting work, facility construction, paving work, ecological landscape architectural construction and vegetation maintenance, by considering the specialty of cultural heritage space.

• Korean Journal of Culture and Social Issue
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• v.28 no.4
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• pp.597-625
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• 2022

This study aimed to examine the hypothesis that intrapersonal, interpersonal, and environmental self-awareness would alleviate the association between sSchadenfreude and cyberbullying. 300 middle and high school students answered survey questionnaires including sSchadenfreude, cyberbullying behavior, (intrapersonal. interpersonal, and environmental) self-awareness, depression, and anxiety. After controlling depression and anxiety, theThe results reveal that first, Schadenfreude predicts cyberbullying behavior, so those who have a high level of Schadenfreude commit more online cyberbullying behavior. Second, intrapersonal and interpersonal self-awareness moderated the association between schadenfreude and cyberbullying, and those who were above average on intrapersonal and interpersonal self-awareness were more liable to commit cyberbullying, but those below average did not show a significant moderation effect. Third, whereas environmental self-awareness did not show a significant moderation effect. Specifically, those who know well what they think and do and what they look like in interpersonal relationships perpetrate more cyberbullying when their schadenfreude was high. However, knowing well about what was happening around them was not related to the likelihood of schadenfreude that lead to cyberbullying. The results of this study revealed that Schadenfreude, which deals with emotions on expecting the misfortune of others and the possibility of having antisocial characteristics, lead to actual cyberbullying behaviors of adolescents. Also, this study identified that intrapersonal and interpersonal self-awareness are harmful in causing cyberbullying in those with high Schadenfreude. Finally, the implication and the limitation of this study were discussed.

• Geomechanics and Engineering
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• v.35 no.1
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• pp.29-39
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• 2023

As the intensity of urban underground space development increases, more and more tunnels are planned and constructed, and sometimes it is inevitable to encounter situations where tunnels have to underpass the river embankments. Most previous studies involved tunnels passing river embankments perpendicularly or with large intersection angle. In this study, a project case where two EPB shield tunnels with 8.82 m diameter run parallelly underneath a river embankment was reported. The parallel length is 380 m and tunnel were mainly buried in the moderate / slightly weathered clastic rock layer. The field monitoring result was presented and discussed. Three-dimensional back-analysis were then carried out to gain a better understanding the interaction mechanisms between shield tunnel and embankment and further to predict the ultimate settlement of embankment due to twin-tunnel excavation. Parametrical studies considering effect of tunnel face pressure, tail grouting pressure and volume loss were also conducted. The measured embankment settlement after the single tunnel excavation was 4.53 mm ~ 7.43 mm. Neither new crack on the pavement or cavity under the roadbed was observed. It is found that the more degree of weathering of the rock around the tunnel, the greater the embankment settlement and wider the settlement trough. Besides, the latter tunnel excavation might cause larger deformation than the former tunnel excavation if the mobilized plastic zone overlapped. With given geometry and stratigraphic condition in this study, the safety or serviceability of the river embankment would hardly be affected since the ultimate settlement of the embankment after the twin-tunnel excavation is within the allowable limit. Reasonable tunnel face pressure and tail grouting pressure can to some extent suppress the settlement of the embankment. The recommended tunnel face pressure and tail grouting pressure are 300 kPa and 550 kPa in this study, respectively. However, the volume loss plays the crucial role in the tunnel-embankment interaction. Controlling and compensating the tunneling induced volume loss is the most effective measure for river embankment protection. Additionally, reinforcing the embankment with cement mixing pile in advance is an alternative option in case the predicted settlement exceeds allowable limit.

• Journal of The Geomorphological Association of Korea
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• v.17 no.1
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• pp.49-57
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• 2010

To evaluate physical characteristics of open rainfall in Korea, terminal velocity of raindrop and drop size distributions (DSD) were continuously measured using by laser-optical disdrometer around Gosam reservoir, Anseong-si, Gyeonggi-do during three rainfall events from 2008 to 2009. The relationships between kinetic energies (KE, Jm^-2mm^-1; KER, Jm^-2h^-1) and rainfall intensity were obtained, respectively. Moreover, we compared the rainfall intensity from a disdrometer with the rainfall intensity from a tipping bucket raingauge to transform the kinetic energy of rainfall using the data from a tipping bucket raingauge. Therefore, the established relationships between kinetic energies (KE and KER) and rainfall intensity could be a useful model to consider the kinetic energy of raindrop using the rainfall intensity below 40mmh^-1 of max 5-min rainfall intensity in the middle of South Korea. However, to better examine the relationship between kinetic energy and rainfall intensity, further measurement will be required.

• Journal of the Korean Geotechnical Society
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• v.23 no.10
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• pp.5-11
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• 2007

This paper is to investigate the removal of the smear at elevated temperatures. This study utilized both small cylinder cell and large consolidometer apparatus to investigate the combination of PVD with heat and without heat. Two types of heaters are used in this study. The heater drain made of copper tube is used for all tests except large consolidometer and flexible wire heater is used for large consolidometer. Specimens demonstrated volume contraction upon heat and without heat. This contraction is dependent on temperature magnitude. When the specimen is heated, the magnitude of settlements is higher and rate of consolidation is faster. After treatment using PVD combined without heat and with heat for undisturbed specimens the $C_h$ values obtained were $3.45m^2/yr$ and $3.83m^2/yr$, respectively, from $3.2m^2/yr$ before treatment. The $K_h/K_s$ ratios were 3 for the specimen without heat and 2 for the specimen with heat. Similarly, in reconstituted specimens without heat and with heat, the $C_h$ values were $2.1m^2/yr$ and $2.5m^2/yr$ with $K_h/K_s$ ratios of 1.75 and 1.5, respectively.

• Journal of Navigation and Port Research
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• v.46 no.1
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• pp.42-56
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• 2022

Due to the 4th Industrial Revolution announced at the Davos Forum, the World Economic Forum, in 2016, industrial trends around the world are changing rapidly and intelligently. Among them, the digital twin is drawing attention from all industries as a groundbreaking technology that reduces unnecessary costs and trial and error by implementing real objects, systems, and environments in the same way in the real virtual world and using them to perform simulation analysis. In particular, there is a lot of interest in the application of digital twin technology in solving ports safety and efficiency challenges at once. However, there is a lack of in-depth research for the application of digital twin technology in the port, and in particular, there is a lack of research on measurable data for the implementation of the digital twin in ports. The purpose of this study was to increase granularity and connectivity through measurable data investigation for the application of digital twin technology at container ports. Based on the study results, data factors for container port application were classified into crane data, operational data, physical data, and transportation data, and factor composition, correlation with factors, and fitness were confirmed through confirmatory factor analysis.