• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.385-392
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• 2008

Modern city have had a lot of high-rise building in high standards and multi-level performance. Using of city space reach better stages by using integration. These skyscraper have increased working load on ground. that building is efficiently designed for that soil capacity is well applied. With material side, big size pile, high strength concrete and high strength steel is used for that getting enough lobby space and resisting load increased of high-rise building. limit load test and load transmitted test can make soil capacity optimized. By the way, method of measuring pile capacity is more advanced and bigger. pile type applied by high rise building have underground excavation space, also reflect regional soil property and have some fact reviewed. A lot of high rise building recently is built as land mark in Seoul, Busan and Incheon. about method of measuring capacity of foundation pile, example of construction field is compared and reviewed.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.200-202
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• 2006

In this paper, a novel type of auxiliary active snubbing circuit assisted quasi-resonant soft-switching pulse width modulation inverter is proposed for consumer induction heating equipments. The operation principle of this high frequency inverter is described using switching modes and equivalent circuits. This newly developed series resonant high frequency inverter can regulate its high frequency output AC power under a principle of constant frequency active edge resonant soft-switching commutation by asymmetrical PWM control system. The high frequency power regulation and actual power conversion efficiency characteristics of consumer induction heating (IH) products using the proposed soft-switching pulse width modulation (PWM) series load resonant high frequency inverter evaluated. The practical effectiveness and operating performance of high frequency inverter are discussion on the basis of simulation and experimental results as compared with the conventional soft-switching high frequency inverter.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.754-757
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• 2005

액정 디스플레이 (LCD: Liquid Crystal Display)의 광원은 주로 냉음극 방전램프 (CCFL: Cold Cathode Fluorescent Lamp)가 사용되고 있으며, 19인치급 이하의 LCD 백라이트 인버터의 램프 구동방식은 가장 일반적인 램프 구동방식인 H-L(High-Low) 방식을 채택하여 사용하고 있다. 그러나 21인치 이상의 중 ${\cdot}$ 대형 LCD 백라이트 인버터는 소형 LCD 에 비해 보다 높은 구동 전압 ${\cdot}$ 전류가 필요함에 따라 기존의 H-L(High-Low) 방식이 아닌 H-H(High-High) 방식 사용하고 있다. 본 논문에서는 대형 LCD 백라이트 인버터에 주로 사용되고 있는 H-H(High-High) 방식을 압전 인버터(Piezoelectric Inverter)에 적용하여 H-L(High-Low) 램프구동 방식과 비교 하였으며, H-H(High-High) 램프구동방식을 통한 멀티램프 구동과 효율, 휘도가 우수함을 검증하였다.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1503-1510
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• 2017

In this paper, a thermal analysis of a high speed induction motor with a PWM voltage source was performed by considering harmonic loss components. The electromagnetic analysis of the high speed induction motor was conducted using the time-varying finite element method, and its thermal characteristics were carried out using the lump-circuit method. Harmonic losses from tests in the high frequency region were divided into core loss and conductor loss components using various ratios, in order to determine the loss distributions for the thermal analysis. The results from both the calculations and experiment were validated using a high speed induction motor prototype operating at 20,000rpm.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.38-42
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• 1999

We prepared hish T$_c$ Josephson junctions that have different I$_c\;'s$ and R$_n\;'s$ and studied their microwave properties. We measured the current-voltage characteristics of the junctions under the irradiation of 22 GHz electromagnetic wave at various temperatures. from the Shapiro steps, we calculated the maximum detectable frequency and the microwave received power of the junctions. Increasing critical current values increase both maximum detectable frequency and sensitivity. However, increasing temperature increase sensitivity but decrease maximum detectable frequency.

• Journal of Information Display
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• v.4 no.4
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• pp.25-32
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• 2003

One of the important problems in ac PDP in recent years is the misfiring of ac PDP at high ambient temperatures which consequently degrades the image quality of the ac PDP. This may be due to the change of working gas pressure and/or MgO surface characteristics at high ambient temperatures. This paper deals with the effect of working gas pressure on the misfiring of ac PDP at high ambient temperature. From this study, we found that the main cause of the misfiring at high ambient temperature is the increase in discharge firing voltage induced by increased working gas pressure

• Proceedings of the KIEE Conference
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• summer
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• pp.630-632
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• 2004

본 논문에서는 전력 계통에서 보호기기로 사용되는 차단기의 50/60Hz 공용주파수 정격의 시험방법에 대하여 기술하였다. 그 과정으로 차단기의 개발시험 항목에 대한 시험목적, 전류투입차단시 차단기에 미치는 영향 및 국제적으로 적용되고 있는 관련 적용규격을 고찰하고 50 Hz 및 60 Hz 공용정격으로서 성능을 검증할 수 있는 방안을 제시한다.

• East Asian mathematical journal
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• v.26 no.2
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• pp.267-280
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• 2010

In this paper we study construction methods of $n^{th}$ line in triangle. Russian Mathematician Zetel suggested some construction methods of $n^{th}$ line in triangle 80 years ago. We find Zetel's papers, in detail explain the Zetel's construction methods, and suggest two elementary construction methods. Our results are received in the process of Research and Education program in science high school.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.379-381
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• 2002

Mitsubishi Electric Corporation has marketed a series of multimedia CRTs enabling bright picture windows in a high-resolution date display screen. The key components of the multimedia CRTs named Diamondtran $M^2$ are a high-gm (low drive-voltage) electron gun and an aperture grille mask. A high-gm electron gun has been developed by designing a beam forming region with high-gm configuration combining with a high current-density cathode. The development of next generation high-gm guns are also introduced

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.378-380
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• 2002

There has been lower the tilt margin by the increase of coma aberration due to the reduction of wave-length and the increase of numerical aperture for high density recording. The RF signal degradation is increased as the decrease of tilt margin. To compensate the tilt margin, the optical pick-up actuator for high-speed CD/DVD re-writable system should be able to drive the radial-tilt motion. We announce that the 3-axis drive actuator for high-speed CD/DVD rewritable system. And what was more, the DC/AC sensitivities of this actuator are suitable fur the low-speed playability, the high-speed readability and the high-speed rewritability.