• Journal of the Microelectronics and Packaging Society
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• v.25 no.3
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• pp.21-30
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• 2018

Driven by the recent energy saving trend, conventional silicon based power conversion modules are being replaced by modules using silicon carbide. Previous papers have focused mainly on the electrical advantages of silicon carbide semiconductors that can be used to design switching devices with much lower losses than conventional silicon based devices. However, no systematic study of their thermomechanical reliability in power conversion modules using finite element method (FEM) simulation has been presented. In this paper, silicon and silicon carbide based power devices with three-phase switching were designed and compared from the viewpoint of thermomechanical reliability. The switching loss of power conversion module was measured by the switching loss evaluation system and measured switching loss data was used for the thermal FEM simulation. Temperature and stress/strain distributions were analyzed. Finally, a thermal fatigue simulation was conducted to analyze the creep phenomenon of the joining materials. It was shown that at the working frequency of 20 kHz, the maximum temperature and stress of the power conversion module with SiC chips were reduced by 56% and 47%, respectively, compared with Si chips. In addition, the creep equivalent strain of joining material in SiC chip was reduced by 53% after thermal cycle, compared with the joining material in Si chip.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.1
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• pp.32-39
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• 2011

When the laws about the security of ships are revised, or voyage conditions are changed, ship owners have converted rather than built new passenger ships including cruise ships recently. As conversion causes a lot of changes in principal dimension, structural strength, hydrodynamic performance, the number of passengers, and cargo capacity, detailed pre-review is needed. But any studies on conversion have not been carried out yet, this study investigated and analyzed the trend of consulting companies' reports (Delta Marine Report, 2005, 2008). As a result, it was found that lengthening conversion brought about the main changes in principal dimension, and performance. Also it was suggested that there be factors for consideration like hull scantling, hull form, and cutting point to minimize side effects when ship owners build ships having lengthening conversion in mind.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.4
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• pp.170-179
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• 2004

The paper presents technical issues which integrated sensors must address to be implemented in the next generation of power electronics and motor drives. The underlying goal of the sensor integration will be to improve reliability of power conversion systems while making the power converter and motor drive become the primary source of diagnostic signals for the application. The paper focuses on design methodologies that will allow this integration to succeed in meeting the technical demands for both reliability and for application level diagnostics.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.986-989
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• 2004

The concept and results of a simple constant switching frequency delta modulation scheme suitable for DC-AC power conversion in uninterruptable power supply (UPS) applications are presented. Unlike the traditional delta modulation scheme, the scheme has a well defined harmonic spectrum, resulting in a simple filter design and reduced radio interference.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.203-206
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• 1998

Since it has been very difficult to collect Korean rain data for winter season, e.g. from November to March, it would be very useful to design satellite communication links if there is a method to extract annual distribution from rain data collected for a specific month. This paper presents a conversion method to annual rainfall rate distribution from rain data for worst month of a year, and illustrates some analysis of the conversion results.

• Journal of Power Electronics
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• v.3 no.2
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• pp.69-80
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• 2003

Computer aided engineering (CAE) is a systematic approach to develop a better product/application with maximum possible options and minimum transition time. This paper presents a comprehensive feasibility analysis of various CAE techniques for evaluation and optimization of power electronic converters and systems. Different CAE methods for analysis, design, and performance improvement are classified. In addition, their advantages compared to the conventional workbench experimental methods are explained in detail and through examples.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.689-689
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• 2006

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.426-429
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• 1988

A simple design method of a single balanced MMIC mixer is described. It uses small signal S11 and capacitive load for the input matching circuit and the output loading circuit, respectively. It is found that the conversion gain of the FET mixer is independent of FET gate width. The fabricated mixer has 2.5 dB conversion gain at 9 GHz with 50 ohm IF load and 2 dBm local oscillator power.

• Journal of Digital Convergence
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• v.14 no.8
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• pp.441-451
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• 2016

The purpose of this study is to analyze the trend of spatial design education focusing on creativity based on design process. In this research, the theoretical frame of design process focused on creativity was organized and the trend of creativity education study in the spatial design and other design sectors was compared and analyzed. As a result of the research, the creativity education study of spatial design analyzed such a result showed the relatively low frequency, many of studies related to formative expression of idea. On the contrary, the creativity education of other design sectors is related to overall process the most, the major contents were represented as a creativity enhancement eduction through the conversion with other sectors, the utilization of study method and theology and the utilization of IT technology. The result of this study suggests that more various attempts are required for the spatial design education and that the attempts should orient the conversion between science and art, humanity and science and the integrated access of digital and analogue.

• Proceedings of the CALSEC Conference
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• 1998.10a
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• pp.141-148
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• 1998

ㆍ Design Creation is More Efficient ㆍ Large Shared Body of Knowledge Created and Maintained...Reducing Training Time, Re-Training, Costs and Design Efforts. ㆍ Electronic Data Easier to Exchange and Integrate. An Overall Increase in Efficiency, Savings and Competitiveness Will be Achieved(omitted)