• Economic and Environmental Geology
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• v.32 no.3
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• pp.281-291
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• 1999

This study presents the gravity data with GPS survrying and the geophysical profiles at the Choogaryeong Rift Valley. And in determing geoid by GPS measurement, survey control points (SCP) whoch built by the Republic of Korean Army are used. Seventy nine SCP and the two triangulation stations are reviewd by GPS. Digital terain model is under for terrain analysis. The analyses of the gravity surveying with GPS are as follows. The low values of the negative Bouguer anomalies represent the high elevation terrain. The Bouguer anomalies show the decrrasing trend toward the eastern part of the study area. Characteristics of free-air anomalies are related with terrain elevation. The regional gravity anomalies decreas toward the eastern part of the study area. The trends of variations are associated with the thermotectonic and geologic structure beneath the Choogaryeong Rift Valley. The most parts of the study area represent negative residual gravity anomalies due to the low dencity of sedimentary cover in the Rift Valley. There are three valleys and four mountains in the direction of NE-SW or NNE-SSW which are structured by the geological features.

• Journal of Environmental Science International
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• v.11 no.9
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• pp.857-863
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• 2002

The meteorological elements were measured to investigate cause of summertime ice formation at Unchiri, Gangwon Province. The cause of freezing at valley was conformed as adiabatic expansion theory, latent heat of evaporation, natural convective theory, cold air remain theory, and convective freezing theory according to former study. However nither theory produced a satisfactory explanation. This studying area is not valley but ridge, and underground water surface exists at below than freezing height. wintertime temperature drop and summertime cold air spouting were explain as natural convective theory, generation of water drop on the rock was explained as cooling theory by air expansion, and ice formation on the rock was explained as adiabatic expansion theory. In conclusion, formation of ice valley at Unchiri was formed by natural convective theory, adiabatic expansion theory, and latent heat of evaporation successively.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1219-1226
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• 2005

In this study, crest settlement characteristics of CFRD (Concrete Faced Rockfill Dam) and ECRD (Earth Cored Rockfill Dam) were analysed through the instrumentation data from representative 7 large dams in Korea. Also, We have studied the effect of valley shape and uniaxial compressive strength of intact rock to better understand the impact of the parent rock strength and the valley shape on the long term crest settlement of CFRDs. From the results, we found that the valley shape and strength of intact rock on crest settlement of dams are an important parameters. As a result, we obtained that the maximum crest settlement of CFRD is larger than that of ECRD and long term crest settlement rate per dam height of rockfill dams is less than 0.60% during service period.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2798-2800
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• 1999

A new circuit, modified valley fill (MVF) combined with resonant inductor of the self-excited resonant inverter and charge pump capacitors(CPCs), is presented to achieve high PF electronic ballast providing sufficient preheat current to lamp filaments for soft start maintaining low DC bus voltage. The MVF can adjust the valley voltage higher than half the peak line voltage. The CPCs draw the current from the input line to make up the current waveform during the valley interval. The measured PF and THD are 0.99 and 12%, respectively. The lamp current CF is also acceptable in the proposed circuit. The proposed circuit is suitable for implementing cost-effective electronic ballast.

• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.134-138
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• 1992

The GaAs/AlAs double barrier structures was grown by MBE(Mo1ecular Beam Epitaxy). Mesa diode was fabricated and I-V characteristics of the diode were measured by semiconductor parameter analyser at room temperature. TEM pictures show the double barrier structure with abrupt interface. PVCR(Peak to Valley Current Ratio) proves to be independent of barrier thickness. These results show that increase in barrier thickness leads to larger valley current by non-resonant tunneling.

• Environmental and Resource Economics Review
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• v.11 no.1
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• pp.57-79
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• 2002

동 연구는 미국 캘리포니아주 San Joaquin Valley의 고정오염원들로부터 발생되는 ROG(Reactive Organic Gases) 배출량을 저감하기 위하여 명령통제방식(CAC)과 경제적 유인제도를 적용할 경우의 비용효과성을 비교 분석하였다. 경제적 유인제도로서는 UMPS(uniform marketable permit system)와 LMPS(localized marketable permit system) 배출권거래제도를 적용하였다. 분석결과 배출권거래제도(UMPS, LMPS)를 이용한 ROG 배출량 저감이 명령통제방식보다 비용이 적게 드는 것으로 나타났다. 한편, one-to-one permits trading이 허용되는 UMPS의 경우에는 일부 특정 지역에 대한 환경질이 악화되는 결과를 초래하는 경우가 발생하여, 궁극적으로 San Joaquin Valley의 ROG 배출량 저감을 위해서는 UMPS 방식의 배출권거래제도 도입이 보다 바람직한 것으로 나타났다.

• Journal of Information Technology Applications and Management
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• v.12 no.2
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• pp.163-184
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• 2005

The purpose of this research is to examine the major determinants affecting the usage and performance of information technologies in Daedeok Valley and Zhongguancun venture firms. The development of the research model is based on the theoretical linkages of IDT (Innovation Diffusion Theory) and TAM(Technology Acceptance Model). Seven hypotheses are derived and tested using regression analysis. The results from regression analysis suggest that the usage of Information technologies is affected by innovation characteristics (perceived usefulness) as well as organizational characteristics (top management support, employee capability on information technology acceptance) in Daedeok Valley venture firms. But, The results from regression analysis suggest that the usage of Information technologies is affected by innovation characteristics (perceived usefulness), organizational characteristics (top management support, employee capability on information technology acceptance), and external pressure (environmental uncertainty, intensity of competition) in Zhongguancun venture firms.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.339-340
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• 2014

본 논문에서는 아답터의 크기를 소형화하기 위한 Active Valley Filler 플라이백 컨버터를 제안한다. 기존의 아답터에서 입력 전해 캐패시터는 전파 정류된 AC 전압($90{\sim}264V_{RMS}$)을 평활 시키고, 안정적으로 출력단에 에너지를 공급하기 위해 입력 에너지를 저장하는 수단으로 사용된다. 입력 전해 캐패시터는 마진이 고려되어야 하기 때문에 설계를 통해 구한 용량 및 내압보다 더 큰 값의 캐패시터가 사용되고, 이것은 아답터의 크기 증가로 이어진다. 반면, 제안 방식은 플라이백 컨버터의 입력단에 Active Valley Filler 회로를 적용하여 기존에 사용되었던 큰 크기의 입력 전해 캐패시터보다 작은 크기의 캐패시터를 사용할 수 있으므로 아답터의 소형화가 가능하다. 제안 방식의 타당성을 검증하기 위해 휴대폰 아답터용 10W급 플라이백 컨버터의 시작품을 제작하여 실험하고 그 결과를 제시한다.

• 정보화사회
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• s.167
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• pp.35-39
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• 2004

10년 혹은 20년이 흐른 뒤에 지금의 조그만 연구실이 커다란 기업의 모태가 되어 관광객들의 발길을 이끄는 또 하나의 'Birthplace of Silicon Valley'가 될 수 있도록 땀을 흘리며 꿈을 캐고 있다.

• Magazine of the Korea Concrete Institute
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• v.18 no.6 s.95
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• pp.77-80
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• 2006