• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2591-2603
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• 2023

Simulating the Corrosion-Related Unidentified Deposit (CRUD) on the surface of fuel assemblies is necessary to predict the axial offset anomaly and the localized corrosion induced by the CRUD during the operation of nuclear power plants. A new CRUD model was developed to predict the formation of the CRUD deposits, considering the deposition and erosion mechanisms. The heat transfer and capillary flow within the CRUD were also considered to evaluate the boiling amount within the CRUD layer. This model predicted a CRUD deposit thickness of 44 ㎛ during a one-cycle operation of the Seabrook nuclear power plant. The CRUD deposition tended to accelerate and decelerate during the simulation, by being related to boiling mechanism on the deposits surface. Additionally, during a three-cycle operation corresponding to the refueling period, the CRUD deposition was saturated at a thickness of 80 ㎛, which was in good agreement with the suggested thickness for CRUD buildupin pressurized water reactors. Surface boiling on the thin CRUD deposits enhanced the acceleration of the deposition, even when the wick boiling properties were not favorable for CRUD deposition. To ensure the certainty of the simulation results, sensitivity analyses were conducted for the porosity, chimney density, and the constants employed in the proposed model of the CRUD.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.26 no.4
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• pp.280-295
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• 2022

This paper contains an introduction to industrial problems, solutions, and results conducted with the Korea Association of Machinery Industry. The client company commissioned the problem of upgrading the method of identifying global supply risky items. Accordingly, the factors affecting the supply and demand of imported items in the global supply chain were identified and the method of selecting risky items was studied and delivered. Through research and discussions with the client companies, it is confirmed that the most suitable factors for identifying global supply risky items are 'import size', 'import dependence', and 'trend abnormality'. The meaning of each indicator is introduced, and risky items are selected using export/import data until October 2022. Through this paper, it is expected that countries and companies will be able to identify global supply risky items in advance and prepare for risks in the new normal situation: the economic situation caused by infectious diseases such as the COVID-19 pandemic; and the export/import regulation due to geopolitical problems. The client company will include in his report, the method presented in this paper and the risky items selected by the method.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.28-31
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• 2006

It is require to construct geothermal database to develop geothermal energy as renewable energy policy. It must be consist of geologic data, borehole data and geophysical data for geothermal database. In aspect of geology, there are included the distribution of geology, structural geology, geological time, rock name, density of rock, porosity, thermal diffusivity, specific capacity and thermal conductivity In order to calculate the heat general ion, it is needed to analysis the radioactivity elements as U, Th and K of rock. In aspect of borehole data, there are included temperature of depth, surface temperature and geothermal gradient And also there is geotherrnornetry using chemical components of groundwater as Na Ca, K and $SiO_2$. In aspect of geophysical data, there are some thematic map as booger gravity anomaly data and magnetic survey data and etc. In addition, it is important to descript the distribution of hot spring and water temperature.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.169-174
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• 2019

This paper propose a system to notify the user that detects failure of malfunction of smart farm ICT devices. As the fourth industrial revolution approaches, agriculture is also fused with ICT technology to improve competitiveness. Smart farming market is rapidly growing every year, but there is still a lack of standardization and certification systems. Especially, smart farm devices that are widely used in Korea are different in product specifications, software and hardware are developed separately, and quality and compatibility are poor. Therefore, a system that can recognize the abnormality of the equipment due to the frequent damage of farmers using low cost smart farm equipment is needed. In this paper, we review smart farm domestic and overseas policy trends and domestic smart agriculture trends, analyze smart farm failure or malfunctions and proactively prevent them, and propose a system to inform users when problems occur.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.6
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• pp.1087-1101
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• 2020

Various security devices are used to protect internal networks and valuable information from rapidly evolving cyber attacks. Firewall, which is the most commonly used security device, tries to prevent malicious attacks based on a text-based filtering rule (i.e., access control policy), by allowing or blocking access to communicate between inside and outside environments. However, in order to protect a valuable internal network from large networks, it has no choice but to increase the number of access control policy. Moreover, the text-based policy requires time-consuming and labor cost to analyze various types of vulnerabilities in firewall. To solve these problems, this paper proposes a 3D-based hierarchical visualization method, for intuitive analysis and management of access control policy. In particular, by providing a drill-down user interface through hierarchical architecture, Can support the access policy analysis for not only comprehensive understanding of large-scale networks, but also sophisticated investigation of anomalies. Finally, we implement the proposed system architecture's to verify the practicality and validity of the hierarchical visualization methodology, and then attempt to identify the applicability of firewall data analysis in the real-world network environment.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.234-237
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• 2003

The Korean housing supply have been provided by the Pre-construction sales system. The Pre-construction sales system contributed to large housing supply. But it followed by the market anomaly. Along the housing market is changing to tile market for consumers, it requires new policy and regulations. This market changes and needs to modify the policy make a discussion about introducing the Post-construction sales system. it concerns to change the time to sale. This paper analyzes the present feasibility study and makes a tool to predict construction cashflow considering changed sales point. The sales timing leads to decide the amount of financial costs in the construction project and that cost affects to the feasibility. The accurate cashflow prediction is required for a successful apartment construction delivery.

• KDI Journal of Economic Policy
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• v.34 no.1
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• pp.29-52
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• 2012

During the global financial turmoil in 2007-2008, deviation from the covered interest parity (CIP) between the Korean won and US dollar through the foreign exchange swap has escalated in its magnitude beyond 1,000bp in November 2008, and it still persists around 100bp level. In this paper, we examine a newly developed margin based asset pricing model using Kalman filter approach and show that the escalation of the CIP deviation is found to be significantly related to the global dollar funding illiquidity and country-specific funding conditions. Furthermore, we find evidence that the poor funding conditions (or higher margins) are driven by the general money market illiquidity and may lead to higher funding illiquidity, which suggests the reinforcing effects of the liquidity spiral. We also show that the supply of dollar liquidity and improved funding conditions help alleviate the deviations from the parity, however the persistent anomaly is found to be related to the high level of volatility in the FX swap market.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1077-1086
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• 2013

Recent huge losses of both life and property have occurred by unexpected natural disasters. We studied snow damages, an important natural disaster issue because it happens more frequently in recent years. This study tries to select vulnerable areas of snowfall in advance and then establish climate change adaptation policy for minimizing unexpected snowfall damage. Busan, where is our study area, has hilly in downtown areas so that topography characteristics of the roads such as slope, elevation and aspect are vulnerable to snowfall. The sudden snowfall in Busan causes traffic jam and causes some schools in hilly to close some schools. At this moment, the adaptation policy has to be established for infrastructure (such as roads) in advance, because prediction of anomaly climate due to global warming is so difficult beside the damage of natural disaster is huge. Therefore, the purpose of this study is contribute to selecting and assessing vulnerable zones of snow damage focusing topography characteristics of the roads and then evaluating the degree of risk of vulnerable zones.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.2
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• pp.15-23
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• 2021

This study investigates the presence of the day-of-the-week anomaly in exchange rate for 30 developing countries with free floating exchange rate regimes using daily data from January 2, 2011 to December 31, 2019. First, we apply the GARCH panel to estimate the intraday effect for all the sampled countries. Second, we run poolability test to check whether the coefficients of the GARCH panel are the same for all countries sampled. The result of poolability test rejects the homogeneity assumption. This implies that our sample countries contain heterogeneity. Third, we apply mean-group estimation by averaging the coefficients for all individual GARCH estimations. Fourth, we divided our sample of developing countries into three groups based on capital restriction index for the reason that the effect of monetary policy on the exchange rate depends on the degree of capital account liberalization. The empirical evidence for the return equation suggests that Mondays are connected with lower volatility whereas Thursdays experiences higher return compared to Tuesdays. The lowest estimated coefficient for full sample, group 1 and group 2, is Friday, but for group 2 is Thursday. We find similar result for the volatility equations, which show that Monday returns are lower compared to Tuesday.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.168-169
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• 2022

The continuous development of science and technology since the Industrial Revolution and the development of human civilization are based on the use of fossil fuels. However, the use of fossil fuels is increasing the greenhouse gas, the main cause of global warming, and global warming is an extreme climate anomaly that is rapidly increasing human and material damage. Therefore, efforts are being made worldwide to return greenhouse gases to pre-industrial levels. In Korea, 2050 carbon neutrality has been set as a major policy and efforts are being made to curb carbon emissions in the overall industry. Carbon emission suppression is based on the minimization of fossil fuel use, and research and development are underway on building a zero-emission house that minimizes the energy used in buildings in the construction field. Therefore, in this study, as part of the zero-emissions water system construction, waste resources generated at industrial sites were utilized and an integrated lightweight concrete solar panel grafted with a concrete lightweight panel and solar panel was manufactured and the possibility of its use was evaluated.