• Journal of the Korean Society of Visualization
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• v.19 no.1
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• pp.62-67
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• 2021

Selective catalytic reduction(SCR) is an exhaust gas reduction device to remove nitro oxides (NOx). SCR operation of ship can be controlled through valves for minimizing economic loss from SCR. Valve in SCR-high pressure (HP) system is directly connected to engine exhaust and operates in high temperature and high pressure. Long-term thermal deformation induced by engine heat weakens the sealing of the valve, which can lead to unexpected failures during ship sailing. In order to prevent the unexpected failures due to long-term valve thermal deformation, a failure prediction system using autoregressive integrated moving average (ARIMA) was proposed. Based on the heating experiment, virtual data mimicking temperature range around the SCR-HP valve were produced. By detecting abnormal temperature rise and fall based on the short-term ARIMA prediction, an algorithm determines whether present temperature data is required for failure prediction. The signal processed by the data collection algorithm was interpolated for the failure prediction. By comparing mean average error (MAE) and root mean square error (RMSE), ARIMA model and suitable prediction instant were determined.

• Journal of Ecology and Environment
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• v.45 no.1
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• pp.10-16
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• 2021

Background: Ranavirus is an emerging infectious disease which has been linked to mass mortality events in various amphibian species. In this study, we document the first mass mortality event of an adult population of Dybowski's brown frogs (Rana dybowskii), in 2017, within a mountain valley in South Korea. Results: We confirmed the presence of ranavirus from all collected frogs (n = 22) via PCR and obtained the 500 bp major capsid protein (MCP) sequence from 13 individuals. The identified MCP sequence highly resembled Frog virus 3 (FV3) and was the same haplotype of a previously identified viral sequence collected from Huanren brown frog (R. huanrenensis) tadpoles in South Korea. Human habitat alteration, by recent erosion control works, may be partially responsible for this mass mortality event. Conclusion: We document the first mass mortality event in a wild Korean population of R. dybowskii. We also suggest, to determine if ranavirus infection is a threat to amphibians, government officials and researchers should develop continuous, country-wide, ranavirus monitoring programs of Korean amphibian populations.

• Journal of the Korean Society of Visualization
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• v.19 no.3
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• pp.115-122
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• 2021

Oral cancer surgery typically consists of resection of lesion, neck dissection and reconstruction, and it has an impact on the position of hyoid bone. Therefore, morphological change of airway can occur since the geometric parameter of airway is correlated with the hyoid bone. Airflow is affected by geometry of the airway. In this study, flow characteristics were compared between pre- and post-surgery models by both particle image velocimetry (PIV) and numerical simulation. 3D model of upper airway was reconstructed based on CT data. Velocity is accelerated by the reduced channel area, and vortex and recirculation region are observed in pre- and post-surgery models. For the post-surgery model, high pressure distribution is developed by significantly decreased hydraulic diameter, and the longitudinal flow stream is also interrupted.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.554-564
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• 2022

The natural circulation phenomena occurring in fully integrated nuclear reactors are associated with a unique formation mechanism. The phenomenon results from a structural feature of these reactors involving upward flow from the core, located in the central-bottom region of a single vessel, and downward flow to the steam generator in the annulus region. In this study, to understand the natural circulation in a single vessel involving a multi-layered flow path, single-phase and two-phase natural circulation tests were performed using the SMART-ITL facility, and validation analysis of the TASS/SMR-S code was performed by comparing the corresponding test results. Three single-phase natural circulation tests were sequentially conducted at 15%, 10%, and 5% of full-scaled core-power without RCP operation, following which a two-phase natural circulation test was successively conducted with an artificial discharge of coolant inventory. The simulation capability of the TASS/SMR-S code with respect to the natural circulation phenomena was validated against the test results, and somewhat conservative but reasonably comparative results in terms of overall thermalhydraulic behavior were shown.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.826-833
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• 2022

A two-phase natural circulation test using SMART integral test loop (SMART-ITL) was conducted to explore thermo-hydraulic phenomena of two-phase natural circulation in the SMART reactor. Specifically, the test examined the natural circulation in the primary loop under a stepwise coolant inventory loss while keeping the core power constant at 5% of the scaled full power. Based on the test results, three flow regimes were observed: single-phase natural circulation (SPNC), two-phase natural circulation (TPNC), and boiler-condenser natural circulation (BCNC). The flow rate remained steady in the SPNC, slightly increased in the TPNC, and dropped abruptly and maintained in the BCNC. Using a natural circulation flow map, the natural circulation characteristic in the SMART-ITL was compared with those in pressurized water reactor simulators. In the SMART-ITL, a BCNC regime appeared instead of siphon condensation and reflux condensation regimes because of the use of once-through steam generators.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.3
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• pp.251-258
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• 2023

This study (1) explored spatio-temporal population distribution patterns in Jeonju by using emerging hot spot analysis and (2) identified the influential factors to determine the spatio-temporal patterns by using multinomial logit model. The major findings are as follows. First, the results of emerging hot spot analysis indicated that the 100*100m grid in the urban area of Jeonju was found to have a category of hot spots, whereas most of the cold spot series was concentrated in the outskirts of the city. Also, new towns such as Jeonju Eco City, Jeonbuk Innovation City, and Hyocheon District were persistent or intensifying hot spots, Third, the results of multinomial logit model revealed that the factors influencing deterrmining the spatio-temporal patterns were accessibility to schools, hospitals, parks, and walfare services. This study offered a deeper understanding of urbanization and regional changes in Jeonju, and important information for urban planning.

• Journal of Educational Research in Mathematics
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• v.23 no.3
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• pp.335-351
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• 2013

This research assumes that abduction is so important as much as all the creative plausible reasoning to be based upon. We expect it to be deeply appreciated and be taught positively in school mathematics. We are noticing that every problem solving process must contain some steps of abduction and thus, we believe that those who are afraid of abduction cannot solve any newly faced problem. Upon these thoughts, we are looking into the middle school mathematics textbooks to see that how strongly various abductions are emphasized to solve problems in it. We modified types of abduction those were suggested by Eco(1983) or by Bettina Pedemonte, David Reid (2011) and investigated those books to see if, we may regard, various types of abduction be intended to be used to solve their problems. As a result of it, we found that more than 92% of the problems were not supposed to use creative abduction necessarily to solve it. And we interpret this as most authors of the textbooks have emphasis more on the capturing and understanding of basic knowledge of school mathematics rather than the creative reasoning through them. And we believe this need innovation, otherwise strong debates are necessary among the professionals of it.

• Journal of Venture Innovation
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• v.6 no.3
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• pp.95-109
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• 2023

In light of the world grappling with diverse environmental issues due to climate change, the prominence of the 'pre-cycling' movement has grown. This movement strives to curtail or eliminate waste generation even before product purchases, garnering more attention than conventional eco-friendly practices. Consequently, this study employs experiments to delve into effective message strategies for promoting pre-cycling behaviors, which serve as preventive measures against the escalating environmental challenges posed by worsening waste problems. This study investigated the effects of message framing and temporal distance on pre-cycling behavioral intention. In terms of message frame, suggestive messages increased pre-cycling behavioral intention more than coercive messages, and temporal distance had no direct effect on pre-cycling behavioral intention. Assertive messages were associated with higher pre-cycling behavioral intentions when the target was interpreted as near future and suggestive messages were interpreted as distant future. Although temporal distance did not directly affect pre-cycling behavioral intention, it positively influenced consumers' pro-environmental behavioral intention by reducing their antipathy toward assertive messages. The implications of this study extend to the realm of management, offering insights into steering consumer behavior in response to pro-environmental messages.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.4
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• pp.172-181
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• 2011

Recently, Urban has been innovated through u-City and Smart City. Urban facility management system is developing using the latest IT technology for real-time monitoring and prevention. In this paper, we propose an UOID(Unique Object IDentification), a standard location-based ID system for urban facility object and develop the UOID service system based on network for innovation of urban facility management system. The system has been tested through Test-bed for connectivity and stability. We wish that the proposed UOID and network service system manages u-City facilities effectively and also provides various ubiquitous services to the citizen, one of the integrate service of u-City platform.

• Management & Information Systems Review
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• v.29 no.2
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• pp.53-73
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• 2010

SCEM is the concept of reducing environmental effect on the outside of purchasing and manufacturing process, delivery, and distribution process. An ultimate aim of SCEM are obtaining environmental stability and energy/materials operational efficiency. Although the importance of greening supply chain was highlighted, former researches were often based on case studies of specific industry and didn't provide clear definition of environmental supply chain management which includes fundamental notions for business practitioners. This study focuses on findings how the SCEM system practically run and what the characteristics of SCEM is in Korean firms through case studies. It is suggested that SCEM is more effective for environmental management rather than by making limited eco-innovation. Korean firms have considered that an international environmental regulation is more important than customers' needs for environmental goods for implementing SCEM.