• Convergence Security Journal
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• 제18권3호
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• pp.123-132
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• 2018

North Korea's cyber warfare capability is becoming a serious security threat to Korea because most of the operational systems of social infrastructure and advanced weapons system are all networked. Therefore, the purpose of this article is to examine what the Korean government should do to strengthen cyber security capabilities toward North Korea. For this purpose, this article analyzed North Korea's cyber attack cases against Korea by categorizing according to threat type and purpose. The research findings are as follows. It is necessary first, to have aggressive cyber protection and attack capabilities; second, to establish an integrated cyber security control tower that can be overseen by the national government; third, to need to legislate domestic cyber- related laws; fourth, to build a multilateral & regional cyber cooperation system. The implication of these findings are that it needs to be strengthened the cyber security capability from the cyber threats of North Korea by minimizing the damage during the peacetime period and for the complete warfare in case of emergency.

• Ocean Systems Engineering
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• 제9권2호
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• pp.191-218
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• 2019

The tower-platform interface and mooring system of floating offshore wind turbines (FOWTs) are some of the most critical components with significant influences on overall project costs. In addition to satisfying strength requirements, it is typical and vital to meet fatigue criteria for a service life of 25 years or more. Wind spectra characteristics considered in analysis can penalize fatigue designs, leading to unnecessary costs. The International Electrotechnical Commission (IEC, 2009) recommends the use of site-specific wind data (spectrum, turbulence intensity, etc.) in design of FOWTs, but for offshore sites it is often the case that such data is unavailable and land-based data are used as surrogates in design. For such scenarios, it is worth investigating whether such alternative approach is suitable and accurate, and understanding the consequence of the selection of wind spectral characteristics on fatigue design. This paper addresses the impact of the subsequent selection on fatigue responses of towerbase and mooring system in a FOWT, as a sequel to the paper by Udoh and Zou (2018) which focused on impacts on strength design. The 5 MW semi-submersible FOWT platform with six mooring lines implemented in the preceding study is applied in analysis. Results indicate significant variations in resulting fatigue life with considered wind parameters. Thus, it is critical to apply proper wind spectra characteristics for analysis and design of FOWTs to avoid unnecessary conservatism and costs. Based on the findings of this study, more explicit guidance on the application of turbulence intensities for IEC-recommended models in offshore sites could lead to more accurate load estimates in design of FOWTs.

• International journal of steel structures
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• 제18권4호
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• pp.1191-1199
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• 2018

Concepts of submerged floating tunnels (SFTs) for land connection have been continuously suggested and developed by several researchers and institutes. To maintain their predefined positions under various dynamic environmental loading conditions, the submerged floating tunnels should be effectively moored by reasonable mooring systems. With rational mooring systems, the design of SFTs should be confirmed to satisfy the structural safety, fatigue, and operability design criteria related to tunnel motion, internal forces, structural stresses, and the fatigue life of the main structural members. This paper presents a feasibility study of a submerged floating tunnel moored by an inclined tendon system. The basic structural concept was developed based on the concept of conventional cable-stayed bridges to minimize the seabed excavation, penetration, and anchoring work by applying tower-inclined tendon systems instead of conventional tendons with individual seabed anchors. To evaluate the structural performance of the new type of SFT, a hydrodynamic analysis was performed in the time domain using the commercial nonlinear finite element code ABAQUS-AQUA. For the main dynamic environmental loading condition, an irregular wave load was examined. A JONSWAP wave spectrum was used to generate a time-series wave-induced hydrodynamic load considering the specific significant wave height and peak period for predetermined wave conditions. By performing a time-domain hydrodynamic analysis on the submerged floating structure under irregular waves, the motional characteristics, structural stresses, and fatigue damage of the floating tunnel and mooring members were analyzed to evaluate the structural safety and fatigue performance. According to the analytical study, the suggested conceptual model for SFTs shows very good hydrodynamic structural performance. It can be concluded that the concept can be considered as a reasonable structural type of SFT.

• Plant Journal
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• 제17권2호
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• pp.32-41
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• 2021

Recently, air environmental issues such as fine dust have rapidly emerged as national issues, and intensive environmental regulations are being applied to coal-fired power plants. This study introduces the case of improving the performance of desulfurization facilities for removing sulfur oxides and dust, which are the main air pollutant emitters of coal-fired power plants, and conducted four case studies to improve the performance of 1,000 MW power plants currently in operation and carried out construction. Liquid ratio was increased by remodeling the absorption tower of desulfurization facilities, and vaporization reaction was promoted by increasing the flow rate of oxidized air. In addition, the gas heater leakage rate was improved to improve the efficiency of final desulfurization facilities. It is expected that performance improvement work considering harmony with existing facilities will satisfy the regulations(25ppm of sulfur oxides, 5mg/Sm³) that will be applied from 2023, and can be referred to other thermal power plants for review and application.

• Convergence Security Journal
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• 제23권1호
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• pp.147-159
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• 2023

Recently, Chat GPT artificial intelligence (AI) is of keen interest to all governments, companies, and military sectors around the world. In the existing era of literacy AI, it has entered an era in which communication with humans is possible with generative AI that creates words, writings, and pictures. Due to the complexity of the current laws and ordinances issued during the recent national crisis in Korea and the ambiguity of the timing of application of laws and ordinances, the golden time of situational measures was often missed. For these reasons, it was not able to respond properly to every major disaster and military conflict with North Korea. Therefore, the purpose of this study was to revise the National Crisis Management Basic Act, which can act as a national tower in the event of a national crisis, and to promote artificial intelligence governance by linking artificial intelligence technology with the civil, government, military, and police.

• Publications of The Korean Astronomical Society
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• 제39권1호
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• pp.1-12
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• 2024

In this study, we investigated the time signal devices of Deungnu (circa 1270) and Gungnu (1354), the water clocks produced during the Yuan Dynasty (1271-1368). These clocks influenced Heumgyeonggaknu (1438) of the Joseon Dynasty (1392-1910), exemplifying the automatic water clocks of the Yuan Dynasty. Deungnu, Gungnu, and Heumgyeonggaknu can be considered as automatic mechanical clocks capable of performances. The Jega-Yeoksang-Jip (Collection of Calendrical and Astronomical Theories of Various Chinese Masters) contains records of Deungnu extracted from the History of the Yuan Dynasty. We interpreted these records and analyzed reproduction models and technical data previously produced in China. The time signal device of Deungnu featured a four-story structure, with the top floor displaying the four divine constellations, the third floor showcasing models of these divinities, the second floor holding 12-h jacks and a 100-Mark ring, and the first floor with four musicians and a 100-Mark Time-Signal Puppet providing a variety of visual attractions. We developed a 3D model of Deungnu, proposing two possible mechanical devices to ensure that the Time-Signal Puppet simultaneously pointed to the 100-Mark graduations in the east, west, south, and north windows: one model reduced the rotation ratio of the 100-Mark ring to 1/4, whereas the other model maintained the rotation ratio using four separate 100-Mark rings. The power system of Deungnu was influenced by Suunuisangdae (the water-driven astronomical clock tower) of the Northern Song Dynasty (960-1127); this method was also applied to Heumgyeonggaknu in the Joseon Dynasty. In conclusion, these automatic water clocks of East Asia from the 13th to 15th centuries symbolized creativity and excellence, representing scientific devices that were the epitome of clock-making technology in their times.

• The Journal of the Korea Contents Association
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• 제16권7호
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• pp.73-90
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• 2016

The purpose of this study is to contribute to developing psychological support system in disaster response of South Korea by examining that of Japan. Psychosocial support from the Red Cross with the psychiatric support by the DPAT from local government were achieved in the early stage of disaster psychology support system in Japan. In the long term intervention after disaster, psychiatric support from Kokoro-no care center has been established. In other words, not only traditional mental health approach but also disaster psychology support activities including psychosocial support are deployed. National Information Center of Disaster Mental Health, which is control tower of disaster psychology support, understand the disaster in the level of nationwide through collecting and analyzing the data related to disaster, and manage disaster psychological support activities. Disaster psychology support system in Japan modified problems immediately during large scale disaster that they are equipped with state of the current. Implications for disaster psychological support system and crisis counseling program in South Korea are discussed.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제24권4호
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• pp.167-176
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• 2024

The Personal Information Protection Commission was launched in August 2020 as an integrated control tower for personal information protection, but several problems have been pointed out in the personal information protection operation system. First, despite the fact that Korea's personal information protection system has an integrated legal system that regulates both the public and private sectors, it has been pointed out that it is difficult to carry out smooth personal information protection functions due to incomplete integration of protection functions, such as the Financial Services Commission being in charge of personal credit information protection and the Korea Communications Commission being in charge of personal location information protection. Next, despite the increasing number of public sector personal information leakage incidents, there is a lack of personnel with expertise and specialized support organizations to efficiently investigate them, and there is a concern that the lack of an efficient response system to personal information infringement by global IT companies in Korea in the era of digital commerce may weaken the protection of citizens' personal information. In order to solve these problems, I reviewed overseas cases and literature and proposed the following measures. First, it is necessary to centralize the personal information protection supervision function for credit information and location information to the Personal Information Protection Commission. Second, it is necessary to secure expertise by securing specialized personnel and establishing specialized institutions to respond to public sector personal information leakage incidents. Third, it is necessary to revitalize the domestic agency designation system and establish an international cooperation system to protect people's personal information in the digital commerce era. I believe that these measures to develop the personal information protection system will lead to more systematic personal information protection.

• Journal of the Korean Society for Marine Environment & Energy
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• 제16권4호
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• pp.239-247
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• 2013

Recently renewable energy such as offshore wind energy takes a higher interest due to the depletion of fossil fuel and the environmental pollution. This paper deals with multi-body dynamics (MBD) analysis technique for offshore wind turbine system considering aerodynamic loads and Thevenin equation used for determination of electric generator torque. Dynamic responses of 5MW offshore wind turbine system are evaluated via the MBD analysis, and the system is the horizontal axis wind turbine (HAWT) which generates electricity from the three blades horizontally installed at upwind direction. The aerodynamic loads acting on the blades are computed by AeroDyn code, which is capable of accommodating a generalized dynamic wake using blade element momentum (BEM) theory. In order that the characteristics of dynamic loads and torques on the main joint parts of offshore wind turbine system are simulated similarly such an actual system, flexible body modeling including the actual structural properties are applied for both blade and tower in the multi-body dynamics model.

• Journal of Advanced Marine Engineering and Technology
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• 제40권4호
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• pp.282-287
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• 2016

Recently in order to protect the ocean environment and to reduce energy consumption, shipbuilders have been developing highly economized ships. This research analyzed the possibility of adopting the onshore absorption refrigerator to offshore ships having a cooling system with refrigerant by using the waiste heat of the engine jacket cooling water instead of compression refrigerators. The results showed that R236fa could be a suitable medium for absorbing the heat of the absorber and condenser in an absorption refrigerator. The cooling system using R236fa achieved a high COP of 0.798, which is 15% and 5% higher than an air cooling system with a cooling tower and a water cooling system with a heat exchanger, respectively. The cooling system with R236fa achieved high efficiency with a 25% reduction in flow rate of LiBr solution and only 15.7% flow rate of cooling medium as compared to the water cooling system. The heating of sea water by the engine jacket water flowing out from the generator can prevent the crystallization of LiBr solution due to the low temperature of sea water.