• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 센서 박막재료
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• pp.66-70
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• 2001

The partial discharge testing is widely used in diagnostic measuring technology because it gives low stress to power equipment which is undertaken tests. Therefore it is very useful method compare to previous destructive methods and effective diagnosis method in power system that requires on-line/on-site diagnosis. But partial discharges have very complex characteristics of discharge pattern, so it is required continuous research to development of precise analysis method. In recent, the study of partial discharge is carrying out discover of initial defect of power equipment through condition diagnosis and system development of degradation diagnosis using HFPD(High Frequency Partial Discharge) detection. In this study, simulated system is manufactured and HFPD occurred from those simulator is measured with broad-band antenna in real time, the degradation grade of system is analyzed through produced patterns in simulated target according to the AI/statistics processing.

• Transactions on Electrical and Electronic Materials
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• 제12권4호
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• pp.152-155
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• 2011

This paper presents a comparative analysis on step and the touch voltages generated by either a sine and a ring wave voltage generator; this analysis was done as a basic study in order to develop a small and lightweight ground meter. A ring wave generator using pulsed power technology was fabricated; an experimental grounding system specified in Institute of Electrical and Electronics Engineers standards 80 and 81 was installed. The step and the touch voltages, which were measured using comparable a sine and a ring waves in terms of magnitude and frequency, were equal. Using pulsed power technology, the weight of the fabricated ring wave generator could be reduced to one-fifth of that of a sine wave generator. Consequently, if a ground meter adopts the ring wave instead of a sine wave, it will be possible to reduce the weight of a ground meter and improve the efficiency of measurement.

• 한국유체기계학회 논문집
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• 제18권1호
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• pp.51-58
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• 2015

This paper presents a study on Vane Tidal Turbine (VTT) focusing on analysis of two types of blade arrangement originated from the previous studies where the original design was examined and performance-tested for different numbers of blades (six, eight and twelve). Compared to conventional tidal turbines, VTT has several special features and potential advantages which have been being thoroughly developed. The purpose of this study is to analyze VTT's capability of extracting and converting the hydrokinetic energy of tidal currents into electricity at given arrangement of blades (single and double rows, six and twelve blades) using CFD. From the calculation results, the six-blade single row turbine shows the best performance, in which the highest power and torque coefficients reach up to about 34 % and 36 %, respectively, at TSR=0.94. However, despite of lower power coefficient, by adding more blades, the torque's extraction of twelve-blade turbine, especially the double row type, is less fluctuate than that of the six-blade setups.

• Journal of Advanced Marine Engineering and Technology
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• 제36권1호
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• pp.141-148
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• 2012

The power system of leisure ship has a character of stand-alone type, so it continuously checks the usable power. Especially, the leisure ship using renewable energy needs to adjust the power consumption of loads according to the usable power. Also, the important loads of leisure ship are different by operation mode. However, current power management system doesnot consider such character. This paper studied load management system of the SPMS(Smart Power Management System) and composed using the smart plug. The SPMS controls the loads depending on a user's pattern and character through variable priority number control. This control algorithm was verified through simulation of assumed user and situation using LabVIEW.

• Strategy21
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• 통권37호
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• pp.65-103
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• 2015

This study is an attempt to look into the future role of the ROKN and to provide a strategic way forward with a special focus on naval strategic concept and force planning. To accomplish this goal, this research takes four sequential steps for analysis: 1) assessing the role and utility of naval power of ROKN since its foundation back in 1945; 2) forecasting features of various maritime threats to influence the security of Korea in the future directly or indirectly; 3) identifying the roles to be undertaken by future ROKN; and 4) recommending Korean way of naval force planning and the operational concept of naval power. This study seeks to show that ROKN needs comprehensive role to better serve the nation with respect to national security, national prosperity and development, and future battle-space management. To safeguard the national security of Korea, it suggests three roles: 1) national guard for the peaceful unification; 2) protector of the maritime sovereignty; and 3) suppressor to maritime threats. Three more roles are highlighted for national prosperity: 1) escort of the national economy; 2) guardian for national maritime activities; and 3) contributor to the world peace. These roles need to be closely connected with the role for the battle-space management. This paper addresses the need for a dramatic shift of the central operational domain from land to maritime in the future. This will eventually offer future ROKN a leading role for developing strategic concept and force planning rather than merely a supporting one. This study finally suggests 'balanced' strategy both in concept development and force planning. A balanced force planning is a 'must' rather than an 'option' when considering a division of function between Task Fleets and Area Fleets, constructing cutting-edge conventional forces such as Aegis destroyer, CVs, or submarines, and the mix of high-profile platform and low-profile when composing future fleets. A 'balance' is also needed in operational concept. The fleet should be prepared to fulfill its missions based on two different types of force operation i.e., coercive or cooperative application of the utility of naval force. The findings and recommendations of the study are relevant today, and will be increasingly important in the future to achieve various political goals required by enhancing the utility of naval power.

• Strategy21
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• 통권45호
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• pp.33-59
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• 2019

본 논문의 목적은 최근 중국의 해양안보전략의 수단과 실행방법, 그 특징을 구체적으로 분석하는 것이다. 중국은 급격한 경제성장 및 강화된 군사력을 바탕으로 '해양강국 건설'이라는 국가목표를 설정하고 이를 달성하기 위해 노력하고 있다. 특히 해양강국을 뒷받침하기 위해 자국의 해양영토주권 수호, 배타적 해양권익 확보 등을 중점적으로 추진하고 있다. 이러한 목표 아래 추진되고 있는 중국의 해양안보전략은 그 수단과 방법 면에서 과거와는 많은 차이를 보인다. 과거 해양안보전략의 주 구현 수단이 해군이었다면 현재는 해군 뿐 아니라 준군사력이 해경과 예비전력인 해상민병도 적극 참여하고 있다. 또한 과거에는 해양에서 전면적인 무력행동을 통해 전략적 목표를 달성하려 했지만 최근은 직접적 충돌 보다는 살라미 자르기 전략, 회색지대전략 및 양배추 전략 등의 전면적 전쟁까지는 이르지 않는 분쟁 수준의 통제를 통해 자신들의 목적을 달성하려 하고 있다. 이러한 중국의 해양안보전략 추구에 대응하여 한국은 적절한 대응방안을 모색할 필요가 있다. 먼저 서해에서의 해군력 현시를 강화해야 하며, 전면전이 아닌 중강도 분쟁에 대비한 전력을 발전시켜야 한다. 또한 회색지대전략, 양배추 전략 등을 활용한 중국의 공세적 해양활동에 효과적으로 대응하기 위해 '해양전장 선점 전략'개념을 발전시킬 필요가 있다.

• 정보학연구
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• 제12권1호
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• pp.35-56
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• 2009

After Chinese reforms and market opening, China actively started working on ways to attach importance to the ocean and it's maritime strategy has been developed and carried out by external and internal factors. We can take two things as external factors attributed to China's marine strategy. The first one is maritime environment change in the East Asian region and the second one is the strategic importance of Taiwanese Straits and the South China Sea. And we can take about national strategy, security strategy, and change of foreign policy as internal factors. China recognizes the ocean as a major step to achieve a goal of national development. The main goal of China's marine strategy in the 21st century is to secure marine transportation and marine resources and to make peaceful maritime environment in the ocean to keep up with their economic development by opening itself to the world. China has strengthened their defense abilities to act against threat of national security by modernizing sea forces and increased national power by building up the marine power. It is expected that China will continue to seek more aggressive maritime strategy on matters of national security as well as pour heir efforts into making economic development and obtaining energy resources. This will also be one factor making new dynamics between countries in and around the East Asian region.

• Journal of Advanced Marine Engineering and Technology
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• 제28권2호
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• pp.382-392
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• 2004

The usage of constant velocity (CV) joint is effective for motorboats on gliding regime of the motion. During transition on the gliding when angle of the CV differs from null on driving and driven composite shafts there are moments of the second order. Excitation of oscillations of the second order moments occurs when driving shafts transmits a variable torque. which generates through CV joint a lateral moment acting on the bearing. As a result of oscillations from a resonating harmonic of a shafting the harmonic with the greater or periodically varying amplitude for power condition trough transferring to nominal power 144kW. Beating conditions coincide with third mode having frequency 45.486 Hz. In that case there is high increasing of the equivalent stresses. The forming of the stiffness of the composite material is concerned to use most orientation of the layer angle in the range of $\pm$60 degrees relatively of shaft axis. Application of that angles for layer orientation gives possibility to avoid high disturbance of the shafting for motorboat transition regime.

• 신재생에너지
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• 제20권2호
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• pp.44-54
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• 2024

The objective of this study was to contribute to domestic offshore wind farms by reasonably predicting the expected completion time and installed power generation capacity of offshore wind projects in South Korea. Offshore wind power is drastically regarded as a core tool for clean energy transition and industrial decarbonization in the fight against the climate crisis globally. Especially in South Korea offshore wind power is the main tool in partaking in RE100 and K-RE100, and the Korean government aims to install 14.9 GW of offshore wind farms by 2030. However, this seems to have been significantly delayed due to the complex process of obtaining permits for offshore wind power in Korea. Thus, a reasonable prediction of power generation and a timeline for the final construction are imperative. To establish the delay time for permit licenses, classified location factors were included into site analysis. These factors comprised reviews of transmission and military operability, environmental impact assessment, maritime traffic safety examination, wind resource assessment and an analysis of current offshore wind projects. According to the analysis, the majority of offshore wind projects currently being developed in Korea are predicted to be delayed by 3-5 years as they are among the criteria included in key discussion points for obtaining permits. The cumulative installed power capacity and annual power generation after construction are expected to be 37 GW and 97 TWh respectively.

• Strategy21
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• 통권32호
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• pp.160-191
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• 2013

This article is focused how the maritime strategy between continental powered country(the Soviet, the China) and maritime powered country(the U.S.) interact with attack and defense theory. We will know, what is the maritime strategy that the U.S. of military superiority has pursued with the point of view of attack, on the other hand, relatively what is the maritime strategy that the Soviet-Sino of military inferiority has pursued with the point of view of defense. In cold war, the Soviet has counteracted to 'blue belt defense' in active defense as to the U.S. 'sea strike' and in post cold war, the China counteract to 'A2/AD' as to the U.S. 'Air-Sea Battle'. The difference between the Soviet-Sino maritime strategy is that the China has emerged the second an economic power and their leadership has a strong's will to strengthen their navy's power. although the U.S. declare the pivot to Asia, the influence on Asia of the U.S. tend to decrease because of sequest. therefore, the China will seek to the more active defense beyond the first island chain. Meanwhile, the U.S. has reinforced of 'hub and spoke strategy' to solidify the U.S. formal allies to band together regional powers and to overcome the A2/AD challenge, the U.S. has been developed that the Air-Sea Battle concept meshes with Washington's 'rebalancing' policy toward the Asia-Pacific as its vital missions to safeguard core island or semi-island allies-namely, Korea and Japan-and crucial sea lanes of communication in the region are conducted mostly from or over the sea.